Shrabanti RoyDepartment of Mechanical Engineering,

Mississippi State University,

Starkville, MS 39762

Saeid ZareDepartment of Mechanical Engineering,

Mississippi State University,

Starkville, MS 39762

Omid AskariDepartment of Mechanical Engineering,

Mississippi State University,

Starkville, MS 39762

Understanding the Effectof Oxygenated Additiveson Combustion Characteristicsof GasolineLaminar burning speed and ignition delay time behavior of iso-octane at the presence oftwo different biofuels, ethanol and 2,5 dimethyl furan (DMF), was studied in this work.Biofuels are considered as a better alternative source of fossil fuels. There is a potential-ity that combustion characteristics of iso-octane can be improved using biofuels as anoxygenated additive. In this study, three different blending ratios of 5%, 25%, and 50%of ethanol/iso-octane and DMF/iso-octane were investigated. For laminar burning speedcalculation, equivalence ratio of 0.6–1.4 was considered. Ignition delay time was meas-ured under temperature ranges from 650 K to 1100 K. Two different mechanisms wereconsidered in numerical calculation. These mechanisms were validated by comparing theresults of pure fuels with wide range of experimental and numerical data. The character-istic change of iso-octane with the presence of additives was observed by comparing theresults with pure fuel. Significant change was observed on behavior of iso-octane at 50%blending ratio. A comparison was also done on the effect of two different additives. It hasfound that addition of DMF brings significant changes on iso-octane characteristics com-paring to ethanol. [DOI: 10.1115/1.4041316]

Keywords: biofuel, oxygenated additive, ignition delay time, laminar burning speed, fuelblends, chemical mechanism

Introduction

Transportation is one of the major sources of global energy con-sumption and one of the main contributors to the pollutant andgreenhouse gas (GHG) emissions. To maximize fuel efficiencywhile dramatically reducing transportation related petroleum con-sumption and GHG emissions, comprehensive fuel and engineresearch and development are required. It is commonly acceptedthat clean combustion can be fulfilled only if engine developmentis coupled with development of improved or reformulated fuels.This can be achieved by blending conventional petroleum-basedfuels with sustainable oxygenated additives. Oxygenated additivescan be used in order to reduce HC and CO emissions, increase theoctane number in gasoline-like fuels, lower GHG emissionsthrough the carbon fixation, and significantly reduce the particu-late levels in diesel engines. In order to improve and optimizeexisting combustion engines for oxygenated biofuel blends, it isessential to deeply understand their fundamental combustion char-acteristics and kinetic pathways.

Laminar burning speed is a physiochemical property of theair–fuel mixture and a very important and widely used parameterin combustion. It has also an important role in developing and val-idating chemical mechanisms. That is why laminar burning speedis an important target in the combustion researches. Anotherwidely used and important property in the combustion is ignitiondelay time. It has both physical and chemical effects on the com-bustion of diesel and gasoline engines. This parameter is also usedto control the NOx emissions. Due to its chemical effect, it hasalso significance in mechanism development. Therefore, todevelop a new mechanism and to study the combustion, these twoparameters are widely used in various researches [1–18].

Gasoline is one of the most widely used fossil fuels. Variousexperimental and numerical works have been conducted toimprove the combustion properties of gasoline [1,19–31]. Gaso-line is a combination of iso-octane, n-heptane, and toluene. There-fore, to build a kinetic mechanism of gasoline for numericalpurposes, combination of all these surrogate fuels is used. A gaso-line surrogate model was developed by Curran et al. [19] by add-ing iso-octane oxidation over wide range of temperature andpressure. The model was validated by the shock tube experiment.Rapid compression machine and shock tube analysis were alsoused by Curran et al. [19] to add n-heptane in the mechanism byincorporating both high and low pressure cases. Other researchersused his mechanism in their works to do numerical calculation[28,30]. To decrease the computational time, gasoline surrogatereduced mechanism has been developed by other researchers[29,30]. A new optimized mechanism is developed by Cai andPitsch [31] to address the real fuel hydrocarbon and its surrogatemixture. They included all the primary reference fuels along withn-heptane and iso-octane. The compact mechanism was comparedand found to be in good agreement with other models and experi-mental results. This work also included the calculation of ethanolby adding its mechanism.

With the increase in population and growth of economy, thesources of gasoline are getting limited. Moreover, combustion ofgasoline is harmful for environment. Therefore, oxygenated drop-in fuels are being considered as alternative source. Alcohol hasalways been considered as a good source of oxygenated additivein spark ignition engines. Its oxygenated nature and high octanenumber made it popular. Large numbers of research works wereconducted on performance analysis of ethanol [12,32–39]. Thoughalcoholic fuels like ethanol is better alternative, till now it was notused in the engines, as a pure fuel, due to less availability. More-over, the cost of ethanol is high to effort. Therefore, variousresearches were conducted on the effect of the mixture of ethanoland gasoline. Researchers found advantages of ethanol whileusing its mixture with gasoline [13,15,17,40–53]. Palmer [47] in

Contributed by the Advanced Energy Systems Division of ASME for publicationin the JOURNAL OF ENERGY RESOURCES TECHNOLOGY. Manuscript received August 10,2018; final manuscript received August 22, 2018; published online September 26,2018. Editor: Hameed Metghalchi.

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his research used variable blend ratio of ethanol and gasoline totest on engines. Marinov [17] came up with a high temperaturedetailed mechanism to simulate for pure ethanol and compared hisresults with experimental work to validate it. There are worksavailable using the blending of gasoline and ethanol [45,48–51] inimproving emission. Dirrenberger et al. [23] in their researchshowed the effect of adding ethanol with gasoline on laminarburning speed. They generated a new mechanism adding n-heptane, iso-octane, and toluene for the numerical simulation.Both numerical and experimental results were compared with andwithout addition of ethanol. They found a good agreementbetween their experimental and numerical results. The work con-cluded with the observation that up to 15% addition of ethanolwith gasoline brings negligible effect on laminar burning speed.Various ethanol and iso-octane blending effects were studiedexperimentally by Rau et al. [13,23]. They also observed that lam-inar burning speed remains unchanged up to certain percentage ofethanol. They predicted that higher value of ethanol addition maybring similar laminar burning speed as pure ethanol.

Besides ethanol, there are other sources of oxygenated addi-tives. From recent studies, a new form of biofuels under furangroup becomes popular. These biofuels are extracted mostly fromthe cellulose biomass [2,54–62]. Researcher Lifshitz [54,55,63]with his coworker did several studies on furan biofuel. Theyworked on the thermal effect of furan, methyl furan (MF), and 2,5dimethyl furans (DMF). Till now, most available fuels from furangroup are these three. There are published works on measurementof laminar burning speed for MF and DMF [16,58,60,62,64].Chemical mechanisms were also developed for these biofuels.Researcher Sirjean et al. [64] developed mechanism for DMF cal-culation. He used shock tube analysis to validate his work. As asource of oxygenated fuel, DMF is also able to bring change onlaminar burning speed while added with other fuels like gasoline.These changes vary from lean to the rich mixture conditions. Wuet al. [16] used octane-furan blend to test laminar burning speedand concluded that, even adding small fraction of DMF with iso-octane, increased the laminar burning speed at fuel rich condition.Same researcher further updated his work by comparing laminarburning speed of DMF, gasoline and a new fuel, which is the mix-ture of both [16]. A detailed mechanism for MF was developed bySomers et al. [58]. He also later came up with detailed mechanismof DMF [2]. These mechanisms were used by several researchersrecently to do the numerical simulation of DMF. Liu and co-workers [56,57,59], in their research on biofuels, described thecombustion chemistry of available furan group fuels. They cameup with a single mechanism, which was able to perform simula-tion for furan itself, MF and DMF. Their work modified the mech-anism developed by Tian et al. [65]. The mechanism is tested andvalidated with some experimental work, which showed an encour-aging result. In the further study, they have done more experimen-tal work on MF and DMF. Recently, a detailed experimental andcomparative study was done on this three furan groups by Tranet al. [66]. They worked with low to moderate temperature ranges.The mechanism was developed with the help of experimentalwork and it suggested using more experimental work to modifythe mechanism. There are few works available on blending of gas-oline and different biofuels of furan [11,14,16,39,67–73]. Differ-ences in emission were observed while comparing MF and DMFwith other fuels like gasoline on direct injection spark ignitionengine [39]. Researchers also tried to improve the engine emissionquality by using gasoline/DMF blend [67,70–73]. Wei et al. [70]at their research used blending of MF-gasoline and compared theresult of emission with some other blends of gasoline. Theirresults showed that MF-gasoline blend lowers the emission ofunburned hydrocarbons and carbon monoxide. However, itincreases the NOx emission. Similarly, MF blending with gasolinehas tested on spray system [72]. DMF and gasoline blend was alsoobserved by several researchers [67,73]. Adding DMF with gaso-line can increase laminar burning speed as shown by researchersWu et al. [16]. In their work, he studied the laminar burning speed

of 80/20 iso-octane and DMF blend. He also studied the Marks-tein length in his work. The results showed that at equivalenceratio more than 1.2, the laminar burning speed of blending fuel ishigher than laminar burning speed of iso-octane. Eldeeb andAkih-Kumgeh [11], in their research, compared the ignition delaybehavior of DMF and 2-ethyle furan. They also investigated theeffect of 50–50 blend of DMF and iso-octane blend on ignitiondelay time and found that the ignition delay time of the blendingfuel remains in between the result of DMF and iso-octane. Theirproposed mechanism is the combination of Somers et al.’s [2]DMF mechanism and Mehl et al.’s [1] gasoline mechanism, whichis also used in the present research work.

Though till now several works are found on ethanol/iso-octaneblend, very few works exist in literature on blending of DMF/iso-octane. Moreover, the comparisons between these two additives arenot available. Therefore, the goal of the current work is to calculatethe effect of various blending composition of both ethanol/iso-octane and DMF/iso-octane. The calculation is focused on two veryimportant combustion characteristics, laminar burning speed andignition delay time. Three different blending ratios for each case areconsidered with wide range of equivalence ratio and temperature.

Kinetic Analysis

Kinetic analysis has been performed using CANTERA1 software

package. CANTERA uses one-dimensional freely propagating flameto calculate laminar burning speed of premixed combustion. Mix-ture average diffusion model has been considered on the calcula-tion. Laminar burning speed is calculated under wide range ofequivalence ratios ranging from 0.6 to 1.4. Furthermore, an adapt-ive grid refinement with an average of 1000 points is used overthe domain. Ignition delay time is calculated using zero dimen-sional kinetics of a constant volume reactor.

The mechanism of liming Cai and Pitsch [31] is used for calcu-lating pure iso-octane, pure ethanol, and ethanol/iso-octane blend.This mechanism is a combination of C1–C4 hydrocarbons, addedwith n-heptane, toluene, and ethanol model. It is composed of 339species and 2761 reactions. The mechanism is optimized and vali-dated against different experimental results of laminar burningspeed and ignition delay time. To calculate the DMF and DMF/iso-octane blend, mechanism proposed by Eldeeb and Akih-Kumgeh [11] has been considered. The mechanism consists of686 species and 3691 reactions. This mechanism is the combina-tion of iso-octane mechanism by Mehl et al. [1] and detailed DMFmechanism by Somers et al. [2]. The mechanism is validated withthe experimental result of ignition delay time.

Results and Discussion

Laminar burning speed for pure ethanol and iso-octane is calcu-lated at temperature 358 K. Equivalence ratio varies from 0.6 to1.4. A different temperature of 393 K is used for DMF due toavailability of experimental data in literature. All simulation oflaminar burning speed was done at 1 atm pressure. For ignitiondelay time, different equivalence ratios and pressures are consid-ered for each fuel based on available experimental data. For theblending effect, 5%, 25%, and 50% blends of ethanol/iso-octaneand DMF/iso-octane are considered. A pressure of 40 atm andequivalence ratio of one is used in calculating ignition delay timeof blending mixtures. First, the selected mechanisms are validatedagainst available data in literature. Second, the chemical mecha-nisms are used to obtain combustion characteristics of ethanol/iso-octane and DMF/iso-octane blends. Finally, the obtained resultsare compared and the effect of each drop-in fuels is discussed.

Kinetic Mechanisms Validation

Iso-Octane. The actual fuel of gasoline is a complex composi-tion. To meet the behavior of actual gasoline in a simpler way,

1https://cantera.github.io/docs/sphinx/html/about.html?highlight=cite

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several pure hydrocarbons are combined, which results in a surro-gate component. That is why gasoline surrogate is the mixture ofseveral pure hydrocarbons. One of the main components in thegasoline surrogate is the iso-octane. Therefore, in this numericalsimulation, iso-octane is considered in calculating laminar burn-ing speed and ignition delay time. Laminar burning speeds of iso-octane are shown in Fig. 1. The result of current simulation is alsocompared with available experimental data. As shown in Fig. 1,laminar burning speed of current simulation agrees well withexperimental data at temperature of 358 K and pressure 1 atm.

Ignition delay time is also calculated at different temperaturefor iso-octane/air mixture. Figure 2 shows the calculated ignitiondelay time of iso-octane at varying temperature. It also shows thecomparison of calculated results with available experimental data.The calculated results of ignition delay time at Fig. 2 agree wellwith the available data in literature. For computing both laminarburning speed and ignition delay time, 21% oxygen and 79%nitrogen composition of air are used.

Ethanol. Laminar burning speed and ignition delay time ofethanol/air mixture were evaluated through numerical calculation.Figure 3 is showing the laminar flame speed comparison of calcu-lated and experimental results. An equivalence ratio range of0.6–1.4 is considered for calculating laminar burning speed at 358K temperature and 1 atm pressure. A good agreement of the resultis found while comparing with experimental and numerical dataof other researchers. This agreement is better at higher equiva-lence ratios.

Figure 4 shows the comparison of calculated ignition delaytime for ethanol/O2/Ar mixture with experimental results. Similarto the laminar burning speed, a good agreement is observed forignition delay time calculation except in high temperature region.With the increase of temperature, ignition delay time of the exper-imental and numerical result of the reference is higher than thecurrent mechanism used. These discrepancies of the result areaddressed in the later section. In calculating laminar burningspeed, the composition of air is 21% oxygen and 79% nitrogen.The ignition delay time is calculated under the condition of 1.25%ethanol, 3.75% oxygen, and 95% argon to match the condition ofDunphy and Simmie [32,33] shock tube calculation. The pressureand equivalence ratio used in this calculation are 3.5 atm and one,respectively.

2,5 Dimethyl Furan. Calculated laminar burning speed andignition delay time of DMF for current work are shown in Figs. 5and 6. Results are compared with experimental data and numericalcalculation of other researchers. In Fig. 5, it is found that the cal-culated results of DMF vary from the experimental results at lean

Fig. 1 Comparison of laminar burning speed of iso-octane/airat 358 K temperature and 1 atm pressure (bullets representexperimental data [14–16,22,23,27]; dash line, numerical simu-lation [23]; and solid line for this work)

Fig. 2 Comparison of ignition delay time of iso-octane/air mix-ture at pressure of 40 atm and equivalence ratio of 1 (bulletsrepresent experimental data [20,21,26]; dash line, numericalsimulation [31]; and solid line for this work)

Fig. 3 Comparison of laminar burning speed of ethanol/airmixture at 358 K temperature and 1 atm pressure (bullets repre-sent experimental data [23,27,35,37,46]; dash line, numericalsimulation [23]; and solid line for this work)

Fig. 4 Comparison of ignition delay time of ethanol/O2/Armixture at pressure of 3.5 atm and equivalence ratio of 1 (bulletrepresents experimental data [32,33]; dash line, numerical sim-ulation [17]; and solid line for this work)

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condition. However, it matches well with the numerical result ofSomers et al. [2,74]. The sensitivity analysis of this mechanism isdescribed in later section. The comparison of ignition delay timeat Fig. 6 shows a good agreement with experimental result excepta little variation at high temperature region. Pressure and tempera-ture of 1 atm and 393 K and equivalence ratio from 0.8 to 1.4 areused for calculating the laminar burning speed. Equivalence ratioof one and pressure of 80 atm are considered in calculating theignition delay times. In calculating laminar burning speed, thecomposition of air is 21% oxygen and 79% nitrogen. For ignitiondelay time, the composition of air is 20.5% O2 and 79.5% N2. Theresults of laminar burning speed of current simulation followedthe similar pattern with available data from the literature.

Sensitivity Analysis. Sensitivity analysis for laminar burningspeed is performed using CANTERA software. CANTERA uses the fol-lowing normalized equitation:

si ¼ki

Su

dSu

dki(1)

where si is the normalized sensitivities, Su is the laminar burningspeed, and ki is the reaction rate constant. Result of sensitivityanalysis on DMF based on laminar burning speed is shown in theFig. 7. The analysis is performed on different equivalence ratiosfrom 0.8 to 1.2. Temperatures of 393 K and 1 atm pressure areconsidered in this calculation. From sensitivity analysis of differ-ent equivalence ratios, it is obvious that mostly small hydrocarbonspecies and reactions of hydrogen abstraction are affecting thelaminar flame speed. The forward reaction HþO2 () OþOHis the most sensitive reaction in every equivalence ratio. The nexttwo sensitive reactions are COþOH () CO2þH andHCOþM () COþHþM. On the other hand, reactionsHþO2(þM) () HO2(þM) and HþOHþM () H2OþMput adverse effect on laminar burning speed. Apart from most sen-sitive small hydrocarbon reactions, the next most sensitive reac-tions are hydrogen abstraction reactions from alkyl group throughO2 or OH radicals. This H abstraction from alkyl group leads tochain branching reactions which influence the higher burningspeed. These reactions are C2H3þO2 () CH2CHOþH andC2H2þO () HþHCCO. At higher equivalence ratios, Habstraction by OH radical (CH3þOH () CH2OHþH) is moresignificant than in lower equivalence ratios. DMF reaction withhydrogen generates MF along with CH3 radical. At higher equiva-lence ratios, the hydrogen reactions with alkyl group are foundhighly sensitive. This effect is less in lower equivalence cases. Itis found that the chain branching reactions in the presence of alkyl

group for higher equivalence ratios are more sensitive than atlower equivalence ratios, which could be the reason for the differ-ence in laminar flame speed at lean condition as shown in Fig. 5.

The sensitivities of ignition delay time are calculated based onlocal sensitivity of temperature [75]. The following normalizedequation in CANTERA is used for the sensitivity calculation:

sk ¼pi

yk

dyk

dpi(2)

where yk is the state variable like temperature and pi is the reac-tion rate. Mechanism of liming Cai and Pitsch [31] is used in cal-culation. Sensitivity analysis of temperature in current mechanismis shown in Fig. 8. The analysis has done on different temperatureof 1300 K, 1400 K, and 1500 K, pressure of 3.3 atm and equiva-lence ratio of one. Same conditions are used to do sensitivity

Fig. 5 Comparison of laminar burning speed of DMF/O2/N2 at393 K temperature and 1 atm pressure (bullets represent experi-mental data [16,68]; dash line, numerical simulation [2]; andsolid line for this work)

Fig. 6 Comparison of ignition delay time of DMF/O2/N2 at pres-sure of 80 atm and equivalence ratio of 1 (bullets representexperimental data [16]; dash line, numerical simulation [16];and solid line for this work)

Fig. 7 Sensitivity analysis on laminar burning speed of DMF/air at different equivalence ratios, 1 atm pressure and 393 Ktemperature

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analysis on Marinov mechanism [17], which is for pure ethanol asshown in Fig. 9. At 1500 K temperature the most sensitive reac-tions for the current mechanism is the small hydrogen branchingreaction HþO2 () OþOH which generates OH radicals.Same reaction is found sensitive at Marinov mechanism. Othersensitive reactions in the current mechanism are C2H5OH (þM)() CH2OHþCH3 (þM) and CH3þOH () H2Oþ SXCH2.Reaction HCOþM () COþHþM is more sensitive thanhydrocarbon chain branching reaction CH3þHO2 ()CH3OþOH in Marinov mechanism. On the other hand, H atomconsuming reaction HþHO2 () H2þO2 has an adverse effecton the burning speed in Marinov mechanism. In current model,OH atom consuming reaction HO2þOH () H2OþO2 is mostsensitive as termination reaction.

Almost similar sensitive reactions are found at 1400 K tempera-ture for both mechanisms. The most sensitive reaction for currentmechanism at this temperature is C2H5OH (þM)()C2H5þOH(þM). At 1300 K temperature, most sensitive reactionin the current model is the chain branching initiative reaction ofethanol (C2H5OH (þM) () CH2OHþCH3(þM) andCH3þHO2 () CH3OþOH). The sensitivities of these reac-tions are comparatively less in the Marinov mechanism at thesame temperature. This difference has an effect on lowering theignition delay time of current mechanism at higher temperature.The other sensitive reactions at this temperature as shown in Fig.8 are C2H4þOH () C2H3þH2O; HþO2 () OþOH andCH3þOH () H2Oþ SXCH2. One of the important reactionsfor ethanol mechanisms explained by Dunphy and Simmie[32,33] is C2H5OH (þM) () CH2OHþCH3 (þM), which ispresent in the both mechanisms. The CH3þHO2 ()CH3OþOH reaction is considered as the primary supply reactionof OH radicals. This reaction leads to an important alternativepath of reaction CH3þHO2 () CH4þO2, which is a termina-tion reaction. This termination reaction is highly sensitive in thecurrent mechanism than Marinov. This may also cause the lowerignition delay time at high temperature for the current model. OHradical is important for the oxidation of ethanol. The reaction

HþHO2 () H2þO2 has a primary role in reducing OH radi-cal, which is most sensitive termination reaction in Marinovmechanism [17]. In current mechanism, the OH radical reductionis occurred by HO2þOH () H2OþO2 reaction. The termina-tion reactions in most cases for current mechanism show highersensitivity. This could be a reason for lowering ignition delaytime of current model comparing to Marinov mechanism.

Effect of Ethanol Addition. Ethanol is used as an additivewith iso-octane to find its effect on laminar burning speed andignition delay time. Three different compositions of ethanol/iso-octane blends (5/95, 25/75, and 50/50) are used for the calcula-tion. Laminar burning speed of these mixtures is calculated at 358

Fig. 8 Sensitivity analysis on temperature of ethanol with cur-rent mechanism [31] under experimental condition of 1.25%C2H5OH, 3.75% N2, and 95% Ar at different temperatures, 3.4 barpressure and stoichiometric condition

Fig. 9 Sensitivity analysis on ignition delay time of ethanolwith Marinov mechanism [17] under experimental condition of1.25% C2H5OH, 3.75% N2, and 95% Ar at different temperatures,3.4 bar pressure and stoichiometric condition

Fig. 10 Comparison of laminar burning speed of ethanol/iso-octane/air mixture at different ethanol parentages along withpure ethanol and pure iso-octane at pressure of 1 atm and tem-perature of 358 K for different equivalence ratios

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K temperature and 1 atm pressure with varying equivalence ratiosof 0.6–1.4. Figure 10 shows the numerical calculation and com-parison of laminar burning speed for different composition ofethanol/iso-octane. It also shows the laminar burning speed ofpure ethanol and pure iso-octane. At the same conditions, ethanolhas much higher burning speed comparing with iso-octane. Thedifference of laminar burning speed between ethanol and iso-octane is higher at rich condition than the lean condition. It is

found that the trend of laminar burning speed of all blending fuelsis similar to the result of pure iso-octane. Addition of ethanol in avery small amount (5%) does not affect much on laminar burningspeed of iso-octane. Laminar burning speed changes slightly byaddition of 25% ethanol. Addition of 50% ethanol shows a signifi-cant increase of laminar burning speed comparing with iso-octane. This increase is found in all equivalence ratios. However,similar to pure ethanol the difference of burning speed is higher athigher equivalence ratios. Therefore, it indicates that effect ofethanol becomes prominent on iso-octane when 50% or morecomposition is added.

Ignition delay time of three blending fuels is calculated at40 atm pressure and equivalence ratio of 1. Figure 11 shows thecomparison of ignition delay time for three different ethanol/iso-octane mixtures. It also shows the comparison of ignition delaytime of pure ethanol and pure iso-octane. Nitrogen/oxygen ratiofor this calculation is 79/21. The temperature varies from 650 to1100 K. Ethanol has very high ignition delay time than iso-octanespecifically at lower temperatures. Similar to laminar burningspeed, 5% addition of ethanol has negligible effect on ignitiondelay time of iso-octane. At 25% ethanol/iso-octane composition,there is a slight increase in ignition delay time at low tempera-tures. The significant increase of ignition delay time has observedfor the 50/50 blending ratio of ethanol and iso-octane.

Figure 12(a) shows laminar burning speed of ethanol/iso-octaneblend at different ethanol percentages. It is found that, for allblending cases, laminar burning speed is high at equivalenceratios of 1 and 1.2. Lower value of laminar burning speed isobserved at equivalence ratio of 0.6. A percentage change is cal-culated for laminar burning speed and ignition delay time. Thischange is calculated as the ratio of difference between blended

Fig. 11 Comparison of ignition delay time of ethanol/iso-octane/air mixture at different ethanol parentages along withpure ethanol and pure iso-octane at pressure of 40 atm andequivalence ratio of 1

Fig. 12 (a) Laminar burning speed at different equivalenceratios and (b) change of laminar burning speed at different etha-nol percentages

Fig. 13 (a) Ignition delay time at different temperatures and (b)change of ignition delay time at different ethanol percentages

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fuel and pure iso-octane by the absolute difference between pureethanol and pure iso-octane

% change ¼ SLðiso� octaneÞ � SLðblended fuelÞSLðiso� octaneÞ � SLðethanolÞ��

��

(3)

Figure 12(b) shows the percentage change of laminar burningspeed for ethanol and iso-octane blend at different equivalenceratios. The percentage change of burning speed due to addition ofethanol is higher at equivalence ratios of 1.0–1.2. The highestchange of burning speed of mixture is with 50% addition of etha-nol. The percentage change is very negligible for 5% addition ofethanol.

In Fig. 13(a), the effect of ignition delay time is shown at dif-ferent percentage of ethanol. It is found that ignition delay time ofblended fuel increases with increasing the ethanol concentration.This figure also shows that ignition delay time has an inverse rela-tion with temperature. The lowest ignition delay time occurs atthe high temperature of 1100 K. Ignition delay time is higher atlow temperature of 650 K. In Fig. 13(b), the percentage change ofignition delay time for the blended fuel is shown at different tem-perature conditions. At high temperatures, the percentage changeof ignition delay time is negative, because ignition delay timedecreases with ethanol addition. The percentage change of igni-tion delay time at 650 K is not significant as shown in Fig. 13(b).

This is because at 650 K temperature ignition delay time of 50/50composition is not high enough comparing to the value of pureethanol.

Effect of Dimethyl Furan Addition. Laminar burning speedand ignition delay time of DMF/iso-octane blended fuel are shownin Figs. 14 and 15. The simulation is carried out at 5%, 25%, and50% DMF/iso-octane mixture compositions. Laminar burningspeed calculation is done at 358 K temperature and 1 atm pressure.The range of equivalence ratio is from 0.6 to 1.4. The comparisonof laminar burning speed for pure iso-octane and pure DMF isshown in Fig. 14. Similar to ethanol, DMF has high burning speedcomparing to iso-octane. Results showed that laminar burningspeed of iso-octane increases with addition of 5% DMF. Thisincrease in burning speed varies between rich and lean conditions.Similarly, addition of 25% DMF increases laminar burning speedof iso-octane. 50/50 composition of DMF/iso-octane increases theoverall burning speed. The change between 5% and 25% DMF/iso-octane composition is negligible at fuel lean condition but sig-nificant at fuel-rich condition. For 50% DMF addition, the laminarburning speed changes significantly at overall equivalence ratio.

Ignition delay time measurement of DMF/iso-octane is carriedout at 40 atm pressure, equivalence ratio of 1 and fixed nitrogenoxygen ratio of 79/21. Temperature varies from 650 to 1100 K.Figure 15 shows the ignition delay time for DMF/iso-octane mix-tures. It also compares the result of pure DMF and pure iso-octaneignition delay times. DMF has the longest ignition delay timecompared to iso-octane at low temperature. The result of allblending fuels falls between these two pure fuels. With 5% addi-tion of DMF, ignition delay time of iso-octane changes mostly at

Fig. 14 Comparison of laminar burning speed of DMF/iso-octane/air mixture at different DMF parentages along with pureDMF and pure iso-octane at pressure of 1 atm and temperatureof 358 K for different equivalence ratios

Fig. 15 Comparison of ignition delay time of DMF/iso-octane/air mixture at different DMF parentages along with pure DMFand pure iso-octane at pressure of 40 atm and equivalence ratioof 1

Fig. 16 (a) Laminar burning speed at different equivalenceratios and (b) change of laminar burning speed at different DMFpercentages

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lower temperatures. However, at higher temperature, the changeis negligible. With 25% and 50% addition of DMF, the change ofignition delay is significant in both higher and lower temperatureregions. At 50/50 blending ratio, the ignition delay time of iso-octane becomes almost close to DMF results. The relative studyin between three blending ratios showed a gradual increase ofignition delay time at low temperature cases. At higher tempera-ture, this behavior is opposite.

Figure 16(a) shows the laminar burning speed of the DMF/iso-octane mixture at different equivalence ratios. The highest valueof laminar burning speed is found at equivalence ratio 1.0. For allequivalence ratios, 50/50 composition of DMF/iso-octane hashigher value of burning speed. A percentage change in laminarburning speed and ignition delay time is calculated using Eq. (3)for DMF addition. Figure 16(b) shows the percentage change oflaminar burning speed at different equivalence ratios. While com-paring different percentage of DMF addition, the highest percent-age change is found at equivalence of 0.8. However, the changebetween 5% and 25% is high at equivalence ratios 1.2 and 1.4,which defines addition of DMF has a significant effect at fuel-richconditions.

The change of ignition delay at varying percentage of DMFaddition is shown in Fig. 17(a). From this figure, it is found thathighest value of ignition delay time of DMF/iso-octane blend is atlower temperature of 650 K. Value of ignition delay graduallydecreases with the increase of temperature. The lowest value is at1100 K temperature, which indicates that at lower temperature,DMF has higher reactivity. Using Eq. (3), the percentage changeof ignition delay time is calculated with respect to temperatureand shown in Fig. 17(b). It is found that the highest percentagechange of ignition delay occurs at 800 K temperature. As found inFig. 17(b), the change of ignition delay is negative at higher tem-peratures and positive at lower temperatures. DMF was found tobe more active at low temperature cases.

Fig. 17 (a) Ignition delay time at different temperatures and (b)change of Ignition delay time at different DMF percentages

Fig. 18 Comparison of laminar burning speed of 5%, 25%, and50% of ethanol and DMF blend with iso-octane at differentequivalence ratios

Fig. 19 Comparison of ignition delay time of 5%, 25%, and50% ethanol and DMF blend with iso-octane at differenttemperatures

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Ethanol and Dimethyl Furan Comparison. The effect ofethanol and DMF additive on iso-octane is measured under sameblending composition and properties. Addition of both fuelsshows changes on laminar burning speed and ignition delay timeof iso-octane. The prominent change for both fuel blends is foundat 50% composition. A comparison on laminar burning speed andignition delay time of blended fuel of ethanol/iso-octane andDMF/iso-octane with pure iso-octane is shown in Figs. 18 and 19.From Fig. 18, it is clear that for all blending cases, addition ofDMF gives higher burning speed than addition of ethanol. Even at5% blending ratio, where the changes on laminar burning speed ofiso-octane due to ethanol addition are negligible, DMF shows bet-ter increase. For 25% and 50% mixture composition, presence ofDMF shows higher burning speed than ethanol.

Similarly, Fig. 19 shows the comparison of ignition delay timeof different fuel additives with iso-octane. Almost no change isobserved in ignition delay time of iso-octane with addition of 5%ethanol. At the same percentage, addition of DMF shows a signifi-cant difference in ignition delay time. The highest increase ofignition delay due to DMF or ethanol is observed at 650 K tem-perature. For ethanol additive, this change is only significant for50% composition. Except high temperature of 1000 K and 1100K, DMF shows significant changes on ignition delay time at allpercentage addition. At higher temperatures, both additives showless effectiveness on ignition delay.

Conclusion

Two important combustion characteristics, laminar burningspeed and ignition delay time, were calculated numerically in thiswork on three different blending ratios of ethanol/iso-octane andDMF/iso-octane. To validate the mechanism and simulation, adetailed comparison of laminar burning speed and ignition delaytime with available data in literature is done on each pure fuel.Different percentage of 5%, 25%, and 50% ethanol and DMFwere added with iso-octane separately to find the effect of drop-infuels. Laminar burning speed for each case was calculated at0.6–1.4 equivalence ratios and 358 K temperature. Ignition delaytime was calculated at temperature from 650–1100 K. The resultswere compared with pure iso-octane, pure ethanol, and pureDMF. For each case, it is obvious that blended fuel results fall inbetween two pure fuels.

In case of laminar burning speed, ethanol has very little effectat 5% and 25% addition, comparing to 50%. DMF shows signifi-cant effect on laminar burning speed but it is more prominent atfuel-rich conditions. For ignition delay time, addition of ethanol isnot significant at high temperature. At low temperature, 50% addi-tion of ethanol increases the ignition delay time. The effect ofDMF addition on ignition delay is significant in all temperatures.However, this change is positive at lower temperatures and nega-tive at higher temperatures. Comparing both ethanol and DMFblend with iso-octane, it is clear that addition of DMF changes thecharacteristics of iso-octane more significantly than ethanol. Inboth fuels, 5% addition is not that significant compared to 50%addition. However, the change for the same percentage of DMF ismore prominent than ethanol. It is also found that DMF additionfor fuel-rich condition and low temperature conditions are signifi-cant. Based on these observations, DMF seems to be a betterdrop-in fuel than ethanol. However, further study is required onvarying range of parameters to get a conclusion on theobservation.

References[1] Mehl, M., Pitz, W. J., Westbrook, C. K., and Curran, H. J., 2011, “Kinetic Mod-

eling of Gasoline Surrogate Components and Mixtures Under Engine Con-ditions,” Proc. Combust. Inst., 33(1), pp. 193–200.

[2] Somers, K. P., Simmie, J. M., Gillespie, F., Conroy, C., Black, G., Metcalfe, W.K., Battin-Leclerc, F., Dirrenberger, P., Herbinet, O., Glaude, P. A., Dagaut, P.,Togb�e, C., Yasunaga, K., Fernandes, R. X., Lee, C., Tripathi, R., and Curran,H. J., 2013, “A Comprehensive Experimental and Detailed Chemical Kinetic

Modelling Study of 2,5-Dimethylfuran Pyrolysis and Oxidation,” Combust.Flame, 160(11), pp. 2291–2318.

[3] Yu, G., Askari, O., Hadi, F., Wang, Z., Metghalchi, H., Kannaiyan, K., andSadr, R., 2017, “Theoretical Prediction of Laminar Burning Speed and IgnitionDelay Time of Gas-to-Liquid Fuel,” ASME J. Energy Resour. Technol., 139(2),p. 022202.

[4] Askari, O., Elia, M., Ferrari, M., and Metghalchi, H., 2017, “Cell FormationEffects on the Burning Speeds and Flame Front Area of Synthetic Gas at HighPressures and Temperatures,” Appl. Energy, 189, pp. 568–577.

[5] Askari, O., Wang, Z., Vien, K., Sirio, M., and Metghalchi, H., 2017, “On theFlame Stability and Laminar Burning Speeds of Syngas/O2/He PremixedFlame,” Fuel, 190, pp. 90–103.

[6] Askari, O., Elia, M., Ferrari, M., and Metghalchi, H., 2017, “Auto-IgnitionCharacteristics Study of Gas-to-Liquid Fuel at High Pressures and Low Tem-peratures,” ASME J. Energy Resour. Technol., 139(1), p. 012204.

[7] Askari, O., Vien, K., Wang, Z., Sirio, M., and Metghalchi, H., 2016, “ExhaustGas Recirculation Effects on Flame Structure and Laminar Burning Speeds ofH2/CO/Air Flames at High Pressures and Temperatures,” Appl. Energy, 179,pp. 451–462.

[8] Askari, O., Moghaddas, A., Alholm, A., Vien, K., Alhazmi, B., and Metghalchi,H., 2016, “Laminar Burning Speed Measurement and Flame Instability Studyof H2/CO/Air Mixtures at High Temperatures and Pressures Using a NovelMulti-Shell Model,” Combust. Flame, 168, pp. 20–31.

[9] Rokni, E., Moghaddas, A., Askari, O., and Metghalchi, H., 2014, “Measurementof Laminar Burning Speeds and Investigation of Flame Stability ofAcetylene (C2H2)/Air Mixtures,” ASME J. Energy Resour. Technol., 137(1),p. 012204.

[10] Katre, V., and Bhele, S. K., 2013, “A Review of Laminar Burning Velocity ofGases and Liquid Fuels,” Int. J. Comput. Eng. Res., 3(7), pp. 33–38.

[11] Eldeeb, M. A., and Akih-Kumgeh, B., 2015, “Investigation of 2,5-DimethylFuran and Iso-Octane Ignition,” Combust. Flame, 162(6), pp. 2454–2465.

[12] Vancoillie, J., Demuynck, J., Galle, J., Verhelst, S., and Van Oijen, J. A., 2012,“A Laminar Burning Velocity and Flame Thickness Correlation for Ethanol-AirMixtures Valid at Spark-Ignition Engine Conditions,” Fuel, 102, pp. 460–469.

[13] Rau, F., Hartl, S., Voss, S., Still, M., Hasse, C., and Trimis, D., 2015, “LaminarBurning Velocity Measurements Using the Heat Flux Method and NumericalPredictions of Iso-Octane/Ethanol Blends for Different Preheat Temperatures,”Fuel, 140, pp. 10–16.

[14] Ma, X., Jiang, C., Xu, H., Ding, H., and Shuai, S., 2014, “Laminar BurningCharacteristics of 2-Methylfuran and Isooctane Blend Fuels,” Fuel, 116,pp. 281–291.

[15] Van Lipzig, J. P. J., Nilsson, E. J. K., De Goey, L. P. H., and Konnov, A. A.,2011, “Laminar Burning Velocities of n-Heptane, Iso-Octane, Ethanol andTheir Binary and Tertiary Mixtures,” Fuel, 90(8), pp. 2773–2781.

[16] Wu, X., Li, Q., Fu, J., Tang, C., Huang, Z., Daniel, R., Tian, G., and Xu, H.,2012, “Laminar Burning Characteristics of 2,5-Dimethylfuran and Iso-OctaneBlend at Elevated Temperatures and Pressures,” Fuel, 95, pp. 234–240.

[17] Marinov, N. M., 1999, “A Detailed Chemical Kinetic Model for High Tempera-ture Ethanol Oxidation,” J. Chem. Kinet., 31(3), pp. 183–220.

[18] Yu, G., Askari, O., and Metghalchi, H., 2018, “Theoretical Prediction of theEffect of Blending JP-8 With Syngas on the Ignition Delay Time and LaminarBurning Speed,” ASME J. Energy Resour. Technol., 140(1), p. 012204.

[19] Curran, H. J., Gaffuri, P., Pitz, W. J., and Westbrook, C. K., 2004, “A Compre-hensive Modeling Study of Hydrogen Oxidation,” Int. J. Chem. Kinet., 36(11),pp. 603–622.

[20] Fieweger, K., Blumenthal, R., and Adomeit, G., 1997, “Self-Ignition of SIEngine Model Fuels: A Shock Tube Investigation at High Pressure,” Combust.Flame, 109(4), pp. 599–619.

[21] Gauthier, B. M., Davidson, D. F., and Hanson, R. K., 2004, “Shock Tube Deter-mination of Ignition Delay Times in Full-Blend and Surrogate Fuel Mixtures,”Combust. Flame, 139(4), pp. 300–311.

[22] Kumar, K., Freeh, J. E., Sung, C. J., and Huang, Y., 2007, “Laminar FlameSpeeds of Preheated iso-Octane/O2/N2 and n-Heptane/O2/N2 Mixtures,” J.Propul. Power, 23(2), pp. 428–436.

[23] Dirrenberger, P., Glaude, P. A., Bounaceur, R., Le Gall, H., Da Cruz, A. P.,Konnov, A. A., and Battin-Leclerc, F., 2014, “Laminar Burning Velocity ofGasolines With Addition of Ethanol,” Fuel, 115, pp. 162–169.

[24] Andrae, J. C. G., Bj€ornbom, P., Cracknell, R. F., and Kalghatgi, G. T., 2007,“Autoignition of Toluene Reference Fuels at High Pressures Modeled WithDetailed Chemical Kinetics,” Combust. Flame, 149(1–2), pp. 2–24.

[25] Kukkadapu, G., Kumar, K., Sung, C. J., Mehl, M., and Pitz, W. J., 2013,“Autoignition of Gasoline and Its Surrogates in a Rapid CompressionMachine,” Proc. Combust. Inst., 34(1), pp. 345–352.

[26] Kukkadapu, G., Kumar, K., Sung, C. J., Mehl, M., and Pitz, W. J., 2012,“Experimental and Surrogate Modeling Study of Gasoline Ignition in a RapidCompression Machine,” Combust. Flame, 159(10), pp. 3066–3078.

[27] Bradley, D., Hicks, R. A., Lawes, M., Sheppard, C. G. W., and Woolley, R.,1998, “The Measurement of Laminar Burning Velocities and Markstein Num-bers for Iso-Octane-Air and Iso-Octane-n-Heptane-Air Mixtures at ElevatedTemperatures and Pressures in an Explosion Bomb,” Combust. Flame,115(1–2), pp. 126–144.

[28] Huang, Y., Sung, C. J., and Eng, J. A., 2004, “Laminar Flame Speeds of Pri-mary Reference Fuels and Reformer Gas Mixtures,” Combust. Flame, 139(3),pp. 239–251.

[29] Seiser, R., Pitsch, H., Seshadri, K., Pitz, W. J., and Curran, H. J., 2000,“Extinction and Autoignition of n-Heptane in Counterflow Configuration,”Proc. Combust. Inst., 28(2), pp. 2029–2037.

Journal of Energy Resources Technology FEBRUARY 2019, Vol. 141 / 022205-9

Downloaded From: https://energyresources.asmedigitalcollection.asme.org on 12/09/2018 Terms of Use: http://www.asme.org/about-asme/terms-of-use

[30] Jerzembeck, S., Peters, N., Pepiot-Desjardins, P., and Pitsch, H., 2009,“Laminar Burning Velocities at High Pressure for Primary Reference Fuels andGasoline: Experimental and Numerical Investigation,” Combust. Flame,156(2), pp. 292–301.

[31] Cai, L., and Pitsch, H., 2015, “Optimized Chemical Mechanism for Combustionof Gasoline Surrogate Fuels,” Combust. Flame, 162(5), pp. 1623–1637.

[32] Dunphy, M. P., and Simmie, J. M., 1991, “High Temperature Oxidation ofEthanol—Part 1: Ignition Delays in Shock Waves,” Chem. Soc. Faraday Trans.,87(11), pp. 1691–1695.

[33] Dunphy, M. P., and Simmie, J. M., 1991, “High Temperature Oxidation ofEthanol—Part 2: Kinetic Modelling,” Chem. Soc. Faraday Trans., 87(11),pp. 2549–2559.

[34] Vancoillie, J., Christensen, M., Nilsson, E. J. K., Verhelst, S., and Konnov, A.A., 2012, “Temperature Dependence of the Laminar Burning Velocity of Meth-anol Flames,” Energy Fuels, 26(3), pp. 1557–1564.

[35] Liao, S. Y., Jiang, D. M., Huang, Z. H., Zeng, K., and Cheng, Q., 2007,“Determination of the Laminar Burning Velocities for Mixtures of Ethanoland Air at Elevated Temperatures,” Appl. Therm. Eng., 27(2–3), pp.374–380.

[36] Bradley, D., Lawes, M., and Mansour, M. S., 2009, “Explosion Bomb Measure-ments of Ethanol-Air Laminar Gaseous Flame Characteristics at Pressures Upto 1.4 MPa,” Combust. Flame, 156(7), pp. 1462–1470.

[37] Eisazadeh-Far, K., Moghaddas, A., Al-Mulki, J., and Metghalchi, H., 2011,“Laminar Burning Speeds of Ethanol/Air/Diluent Mixtures,” Proc. Combust.Inst., 33(1), pp. 1021–1027.

[38] Egolfopoulos, F. N., Du, D. X., and Law, C. K., 1992, “A Study on EthanolOxidation Kinetics in Laminar Premixed Flames, Flow Reactors, and ShockTubes,” Symp. Combust., 24(1), pp. 833–841.

[39] Wang, C., Xu, H., Daniel, R., Ghafourian, A., Herreros, J. M., Shuai, S., andMa, X., 2013, “Combustion Characteristics and Emissions of 2-MethylfuranCompared to 2,5-Dimethylfuran, Gasoline and Ethanol in a DISI Engine,” Fuel,103, pp. 200–211.

[40] Y€uksel, F., and Y€uksel, B., 2004, “The Use of Ethanol-Gasoline Blend as aFuel in an SI Engine,” Renew. Energy, 29(7), pp. 1181–1191.

[41] Abdel-Rahman, A. A., and Osman, M. M., 1997, “Experimental Investiga-tion on Varying the Compression Ratio of SI Engine Working UnderDifferent Ethanol—Gasoline Fuel Blends,” Int. J. Energy Res., 21(1), pp.31–40.

[42] Metghalchi, M., and Keck, J. C., 1982, “Burning Velocities of Mixtures of AirWith Methanol, Isooctane, and Indolene at High Pressure and Temperature,”Combust. Flame, 48, pp. 191–210.

[43] Varea, E., Modica, V., Renou, B., and Boukhalfa, A. M., 2013, “PressureEffects on Laminar Burning Velocities and Markstein Lengths for Isooctane-Ethanol-Air Mixtures,” Proc. Combust. Inst., 34(1), pp. 735–744.

[44] Ra, Y., and Reitz, R. D., 2008, “A Reduced Chemical Kinetic Model for ICEngine Combustion Simulations With Primary Reference Fuels,” Combust.Flame, 155(4), pp. 713–738.

[45] Masum, B. M., Masjuki, H. H., Kalam, M. A., Rizwanul Fattah, I. M. M.,Palash, S., and Abedin, M. J., 2013, “Effect of Ethanol-Gasoline Blend onNOx Emission in SI Engine,” Renewable Sustainable Energy Rev., 24,pp. 209–222.

[46] Gulder, O., 1984, “A Burning Velocity of Ethanol-Isooctane Blends,” CombustFlame, 56(3), pp. 261–268.

[47] Palmer, F. H., 1986, “Vehicle Performance of Gasoline Containing Oxygen-ates,” International Conference on Petroleum Based Fuels and AutomotiveApplications, London, UK, pp. 33–35.

[48] Hsieh, W. D., Chen, R. H., Wu, T. L., and Lin, T. H., 2002, “Engine Perform-ance and Pollutant Emission of an SI Engine Using Ethanol-Gasoline BlendedFuels,” Atmos. Environ., 36(3), pp. 403–410.

[49] Song, C. L., Zhou, Y. C., Huang, R. J., Wang, Y. Q., Huang, Q. F., and L€uG,E., 2007, “Influence of Ethanol-Diesel Blended Fuels on Diesel Exhaust Emis-sions and Mutagenic and Genotoxic Activities of Particulate Extracts,” J. Haz-ard. Mater., 149(2), pp. 355–363.

[50] Najafi, G., Ghobadian, B., Tavakoli, T., Buttsworth, D. R., Yusaf, T. F., andFaizollahnejad, M., 2009, “Performance and Exhaust Emissions of a GasolineEngine With Ethanol Blended Gasoline Fuels Using Artificial NeuralNetwork,” Appl. Energy, 86(5), pp. 630–639.

[51] Galbiati, M. A., Cavigiolo, A., Effuggi, A., and Gelosa, D. R., 2004, “MildCombustion for Fuel-Nox Reduction,” Combust. Sci. Technol., 176(7), pp.1035–1054.

[52] Cancino, L. R., Fikri, M., Oliveira, A. A. M., and Schulz, C., 2011, “IgnitionDelay Times of Ethanol-Containing Multi-Component Gasoline Surrogates:Shock-Tube Experiments and Detailed Modeling,” Fuel, 90(3), pp. 1238–1244.

[53] Jing Zhong, B. D. Z., 2012, “Chemical Kinetic Mechanism of a Three-Component Fuel Composed of Iso-Octane/n-Heptane/Ethanol,” Combust. Sci.Technol., 185(4), pp. 627–644.

[54] Lifshitz, A., Tamburu, C., and Shashua, R., 1997, “Decomposition of 2-Methylfuran. Experimental and Modeling Study,” J. Phys. Chem. A, 101(6),pp. 1018–1029.

[55] Lifshitz, A., Tamburu, C., and Shashua, R., 1998, “Thermal Decomposition of2,5-Dimethylfuran: Experimental Results and Computer Modeling,” J. Phys.Chem, 102(52), pp. 10655–10670.

[56] Tran, L. S., Togb�e, C., Liu, D., Felsmann, D., Oßwald, P., Glaude, P. A., Four-net, R., Sirjean, B., Battin-Leclerc, F., and Kohse-H€oinghaus, K., 2014,“Combustion Chemistry and Flame Structure of Furan Group Biofuels UsingMolecular-Beam Mass Spectrometry and Gas Chromatography—Part II: 2-Methylfuran,” Combust. Flame, 161(3), pp. 766–779.

[57] Liu, D., Togb�e, C., Tran, L.-S, Felsmann, D., Oßwalda, P., Naua, P.,Koppmanna, J., Lackner, A., Glaude, P.-A., Sirjean, B., Fournet, R., Battin-Leclerc, F., and Kohse-H€oinghaus, K., 2014, “Combustion Chemistry and FlameStructure of Furan Group Biofuels Using Molecular-Beam Mass Spectrometryand Gas Chromatography—Part I: Furan,” Combust. Flame, 161(3), pp.748–765.

[58] Somers, K. P., Simmie, J. M., Gillespie, F., Burke, U., Connolly, J., Metcalfe,W. K., Battin-Leclerc, F., Dirrenberger, P., Herbinet, O., Glaude, P. A., andCurran, H. J., 2013, “A High Temperature and Atmospheric Pressure Experi-mental and Detailed Chemical Kinetic Modelling Study of 2-Methyl FuranOxidation,” Proc. Combust. Inst., 34(1), pp. 225–232.

[59] Togb�e, C., Tran, L.-S., Liu, D., Felsmann, D., Oßwalda, P., Glaude, P.-A., Sir-jean, B., Fournet, R., Battin-Leclerc, F., and Kohse-H€oinghaus, K., 2014,“Combustion Chemistry and Flame Structure of Furan Group Biofuels UsingMolecular-Beam Mass Spectrometry and Gas Chromatography—Part III: 2,5-Dimethylfuran,” Combust. Flame, 161(3), pp. 780–797.

[60] Wu, X., Huang, Z., Jin, C., Wang, X., Zheng, B., Zhang, Y., and Wei, L., 2009,“Measurements of Laminar Burning Velocities and Markstein Lengths of 2, 5Dimethylfuran-air-Diluent Premixed Flames,” Energy Fuels, 23(9),pp. 4355–4362.

[61] Xu, N., Wu, Y., Tang, C., Zhang, P., He, X., Wang, Z., and Huang, Z., 2016,“Experimental Study of 2,5-Dimethylfuran and 2-Methylfuran in a Rapid Com-pression Machine: Comparison of the Ignition Delay Times and Reactivity atLow to Intermediate Temperature,” Combust. Flame, 168, pp. 216–227.

[62] Wu, X., Huang, Z., Wang, X., Jin, C., Tang, C., Wei, L., and Law, C. K., 2011,“Laminar Burning Velocities and Flame Instabilities of 2,5-Dimethylfuran-AirMixtures at Elevated Pressures,” Combust. Flame, 158(3), pp. 539–546.

[63] Lifshitz, A., Bidani, M., and Bidani, S., 1986, “Thermal Reactions of CyclicEthers at High Temperatures—Part 3: Pyrolysis of Furan Behind ReflectedShocks,” J. Phys. Chem., 90(21), pp. 5373–5377.

[64] Sirjean, B., Fournet, R., Glaude, P.-A., Battin-Leclerc, F., Wang, W., andOehlschlaeger, M. A., 2013, “Shock Tube and Chemical Kinetic ModelingStudy of the Oxidation of 2,5-Dimethylfuran,” J. Phys. Chem. A, 117(7), pp.1371–1392.

[65] Tian, Z., Yuan, T., Fournet, R., Glaude, P. A., Sirjean, B., Battin-Leclerc, F.,Zhang, K., and Qi, F., 2011, “An Experimental and Kinetic Investigation of Pre-mixed Furan/Oxygen/Argon Flames,” Combust. Flame, 158(4), pp. 756–773.

[66] Tran, L. S., Wang, Z., Carstensen, H. H., Hemken, C., Battin-Leclerc, F., andKohse-H€oinghaus, K., 2017, “Comparative Experimental and Modeling Studyof the Low- to Moderate-Temperature Oxidation Chemistry of 2,5-Dimethyl-furan, 2-Methylfuran, and Furan,” Combust. Flame, 181, pp. 251–269.

[67] Xiao, M., Changzhao, J., and Hongming, X., and Richardson, S., 2012, “In-Cylinder Optical Study on Combustion of DMF and DMF Fuel Blends,” SAETechnical Paper No. 2012-01-1235.

[68] Tian, G., Daniel, R., Li, H., Xu, H., Shuai, S., and Richards, P., 2010, “LaminarBurning Velocities of 2,5-Dimethylfuran Compared With Ethanol and Gaso-line,” Energy Fuels, 24(7), pp. 3898–3905.

[69] Pan, M., Shu, G., Pan, J., Wei, H., Feng, D., Guo, Y., and Liang, Y.,2014, “Performance Comparison of 2-Methylfuran and Gasoline on aSpark-Ignition Engine With Cooled Exhaust Gas Recirculation,” Fuel, 132,pp. 36–43.

[70] Wei, H., Feng, D., Shu, G., Pan, M., Guo, Y., Gao, D., and Li, W., 2014,“Experimental Investigation on the Combustion and Emissions Characteristicsof 2-Methylfuran Gasoline Blend Fuel in Spark-Ignition Engine,” Appl.Energy, 132, pp. 317–324.

[71] Rothamer, D. A., and Jennings, J. H., 2012, “Study of the Knocking Propensityof 2,5-Dimethylfuran-Gasoline and Ethanol-Gasoline Blends,” Fuel, 98,pp. 203–212.

[72] Wei, H., Gao, D., Zhou, L., Feng, D., Chen, C., and Pei, Z., 2016,“Experimental Analysis on Spray Development of 2-Methylfuran-GasolineBlends Using Multi-Hole dI Injector,” Fuel, 164, pp. 245–253.

[73] Wu, X., Daniel, R., Tian, G., Xu, H., Huang, Z., and Richardson, D., 2011,“Dual-Injection: The Flexible, bi-Fuel Concept for Spark-Ignition EnginesFuelled With Various Gasoline and Biofuel Blends,” Appl. Energy, 88(7),pp. 2305–2314.

[74] Lee, C., Vranckx, S., Heufer, K. A., Khomik, S. V., Uygun, Y., Olivier, H., andFernandez, R. X., 2012, “On the Chemical Kinetics of Ethanol Oxidation:Shock Tube, Rapid Compression Machine and Detailed Modeling Study,” Z.F€ur Phys. Chem., 226(1), pp. 1–28.

[75] Ji, W., Ren, Z., and Law, C. K., 2018, “Evolution of Sensitivity Directions Dur-ing Autoignition,” Proc. Combust. Inst. (in press).

022205-10 / Vol. 141, FEBRUARY 2019 Transactions of the ASME

Downloaded From: https://energyresources.asmedigitalcollection.asme.org on 12/09/2018 Terms of Use: http://www.asme.org/about-asme/terms-of-use