International Journal of Advanced Research in ISSN : 2454 ...ijarmet.com/wp-content/themes/felicity/issues/Vol5issue2/pshri.pdfratio. MWNTs are a great choice of Nano scale additives

International Journal of Advanced Research in Mechanical Engineering & Technology (IJARMET)

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Vol. 5, Issue 2 (April - June 2019) ISSN : 2454-4736 (Online) ISSN : 2454-8723 (Print)

www.ijarmet.com © All Rights Reserved, IJARMET 2015

Heat Transfer Analysis in Serpentine Shaped Micro Tube by using Carbon Nano Fluid

IE.Manikandan, IIP. Shribalaji, IIIA. Jeevan, IVDr.K.VelmuruganI,II,III,IVSri Manakula Vinayagar Engineering College, Pondicherry-605 107

I. IntroductionRecently thermal science has been developed tremendously.Many researches are made to increase the heat transfer rate. The recent development in the heat transfer improvement is the addition of solid materials into the liquid medium. In these suspended liquids the flow media itself is a controlling factor of heat transfer performance, the solid particles suspended in the base fluids change the transport properties, flow and heat transfer features of the liquid. The term ‘‘Nano fluid’’ is applied to a suspension of solid, Nano-sized particles in conventional fluids the most prominent features of such fluids include enhanced heat characteristics, such as convective heat transfers coefficient and thermal conductivity in comparison to the base fluid without considerable alterations in physical and chemical properties. The improved heat transfer in a system has the benefit of decreased energy expenditure, decreased raw materials input, reduced size of equipment, and consequently, reduced expenses and increased system.

II. Why Nano Particles Used?The technological problems in micro tube when using micro or millimeter sized particles is quickly settling down of the solid particles, clogging in the path way increasing pressure drop considerably and furthermore, the abrasive actions of the particles cause erosion of components and pipe lines. This problem has overcome by the Nano sized particles and its characteristics.

III. Preparation of Nano Fluid

1. Nano particleThe structure of Multi Walled Carbon Nanotubes is unique, they come in a complex array of forms, and there are a variety of sequential arrangements. The simplest sequence is when concentric layers are identical but different in diameter.

Moreover, mixed variants are possible, consisting of two or more types of concentric Carbon Nanotubes (CNTs) arranged in different proportion. These can have either regular layering or random layering. The structure of the carbon nanotubes influences electrical and thermal conductivity, density, and lattice structure. Both type and diameter are important. The wider the diameter of the carbon nanotube, it behaves like graphite. The narrower the diameter of

the Carbon Nanotubes, its intrinsic properties depends upon its specific type. Multi Walled Carbon Nanotubes properties come from their all carbon structure, extremely small geometries and high aspect ratio. MWNTs are a great choice of Nano scale additives and can improve mechanical properties as well as electrical and thermal conductivity in the products you add them into. Since Multi Walled Carbon nanotubes are cheap and easily available, we selected that use as nanoparticle to mix with water to prepare Nano fluid to conduct experiment on it.

2. Base fluidDistilled Water is used as a base fluid.

3. Particle sizeNano particles used in Nano fluid preparation usually have diameters below 100 nm. When particles are not spherical but rod or tube-shaped, the diameter is still below 100 nm, but the length of the particles may be in the order of micrometers. It should also be noted that due to the clustering phenomenon, particles may form clusters with size of micros.

4. Properties of MWCNTS Thermal conductivity –When it is single it has 2586 W/mK, • if it is in bundle it has 150 W/mK. Specific heat capacity 700 J/Kg K.• Density 1900 Kg/m3.•

5. Specification of MWCNTs Production method – Chemical Vapour Deposition • Diameter – Outer diameter = 20nm • Length - 10μm • Nanotubes purity – 98% • Metal particles – 1% • Amorphous carbon – 1% • Specific surface area – 330m2/g •

6. Particle shapeSpherical particles are mostly used in Nano fluids. nanoparticles are also used. On the other hand, the However, rod-shaped, tube-shaped and disk-shaped clusters formed by nanoparticles may have fractal-like shapes.

AbstractHeat transfer is one of the most important criteria in obtaining better efficiency in any mechanical system. Hence an experimental setup was made to enhance the heat transfer rate and to study the different heat transfer rates obtained in a serpentine micro tube of 7.93mm diameter and 960mm length with a circular copper plate of 220 mm diameter. The concentration of the carbon nanotube in the distilled water and the flow rate of the fluid are varied for obtaining different heat transfer rates. For different Reynolds number of flow rates, and respected heat transfer are noted. It has been observed that the heat transfer rates are gradually increased in usage of Nano particles over the conventionally used micro particles.

KeywordsCarbon Nanotube, Distilled Water, Serpentine Micro Tube, Reynolds Number, Heat Transfer.


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Vol. 5, Issue 2 (April - June 2019) ISSN : 2454-4736 (Online)

ISSN : 2454-8723 (Print)

www.ijarmet.com© 2015, IJARMET All Rights Reserved

7. Production of Nano particleProduction of nanoparticles can be divided into two main categories, namely, physical synthesis and chemical synthesis.

Physical Synthesis: Mechanical grinding, inert-gas-• condensation technique. Chemical Synthesis: Chemical precipitation, chemical • vapour deposition, micro-emulsions, spray pyrolysis, thermal spraying.

8. Production of nano fluidThere are two methods to prepare Nano fluid, namely two step and one step technique. In two step technique first Nano particles in prepared and then dispersed in base fluid. It plays an important role when mass production of Nano fluids is considered and more efficient than conventional method of inert gas condensation of Nano fluid preparation.The main disadvantage of two step technique is that there is a chance of cluster formation of Nano particles while dispersing in base fluid if it is not mixed properly. Thus one step process is developed in which preparation and dispersion of Nano particles takes place in a single step.direct evaporation one-step method, the Nano fluid is produced by the solidification of the nanoparticles, which are initially gas phase, inside the base fluid. There are some variations of this technique.Nano fluids produced with one-step techniques are better than those produced with two-step technique. The main drawback of is that they are not proper for mass production, thus it is not used widely.

IV. Nanofluid Preparation And StabilizationThe process of preparation of Nano fluid and stabilization is an important activity because nanoparticle needs proper preparation and stabilization. Poorly prepared Nano fluids results in biphasic heat transfer. Particle instability results in particle fouling in reservoir, pipes, pumps and other equipment of thermal cycle, as well as reduced pressure. The fluid was prepared without surfactants with magnetic stirring for 1 hour and subsequent ultrasonic irradiation for 2 hour.

Table 1 : Thermo physical properties of nanoparticles, base fluid and Nano fluid

S. No

Properties Nanoparticle(Al2O3)

Base fluid

Nano fluid(0.3%)

1 Density (ρ)Kg/m3

3970 998.2 1005.919

2 Cp (J/Kg k) 765 4182 3156.9

3 K (W/m k) 36 0.613 1.3466

4 Viscosity (μ)N/m2

- 0.00089 0.0015575

Fig. 1: Experimental layout

V. ConstructionFor making the experimental setup of heat transfer on serpentine micro tube we used different kind of mechanical and electrical components to find out the heat transfer rate of the micro tube. The components are listed below

Copper tube • Rotameter • Heater • Pressure gauge • Water cooled heat exchanger • Digital thermometer • Thermocouple • Submersible Pump • Voltmeter and ammeter.•

Fig. 2: Experimental setup

1. Serpentine micro tubeThe serpentine micro tube was made by copper tube of 7.93 mm diameter and a length of 96 cm with a circular copperPlate of 22 cm of diameter. The copper plate and copper tube are


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fixed by gas welding. Serpentine microtube is used to

Fig. 3: Serpentine microtube

flow the Aluminum oxide Nano fluid in to the heat sink to transfer the heat from the micro tube to Nano fluid. In Serpentine micro tube the heat transfer takes place in quick manner and also the transfer of heat is uniform all around the copper plate.

2. Rotameter A Rotameter is a device that measures the volumetric flow rate of fluid in a closed tube. It belongs to a class of meters called variable area meters, which measure flow rate by allowing the cross-sectional area the fluid travels through to vary, causing a measurable effect. This Rota meter range will be (0.1-0.5 LPM).

3. HeaterA circular heater is used to heat circular heat sink. When the heat sink will reach up to the defined temperature it will cut off automatically to maintain the temperature. A thermostat will provide in the heater to cut off the heater. When compared to other types of heater a circular heater will provide sufficient heat at less timing. The primary objective is to supply heat to micro tube, it consumes 1500 W.

4. Pressure gaugePressure measurement is the analysis of an applied force by a fluid on a surface. Pressure is typically measured in units of force per unit of surface area. Instruments used to measure and display pressure in an integral unit are called pressure gauges or vacuum gauges. The pressure gauge range will be 2.1 kg/cm2.

5. Condenser In systems involving heat transfer, a condenser is a device or unit used to condense a substance from its gaseous to its liquid state, by cooling it. In so doing, the latent heat is given up by the substance and transferred to the surrounding environment. Condensers can be made according to numerous designs, and come in many sizes ranging from rather small (hand-held) to very large (industrial-scale units used in plant processes). Condensers are used in air conditioning industrial chemical processes such as distillation, steam power plants and other heat-exchange systems. Use of cooling water or surrounding air as the coolant is common in many condensers.

6. Digital thermometerThermometers are used to see if you have a fever or tell you

how cold it is outside. Made up of thermo (heat) and meter (measuring device), the meaning of the word thermometer is pretty straightforward. Thermometers measure temperatures in degrees, according to either the Celsius or Fahrenheit system. We are using 6-point selector thermometer. Maximum range will be 0-400 0C.

7. ThermocoupleA Thermocouple is a sensor used to measure temperature. Thermocouples consist of two wire legs made from different metals. The wires legs are welded together at one end, creating a junction. This junction is where the temperature is measured. When the junction experiences a change in temperature, a voltage is created. Fe material is used for positive terminal and Cu-Ni material used for negative terminal.

Type j temperature range Thermocouple grade wire, -346 to 1,400F (-210 to 760C) • Extension wire, 32 to 392F (0 to 200C) •

8. Submersible pumpSubmersible pump is used to move water lower point to higher point with a required discharge and pressure head Pressure head 2.8 m.

VI. WorkingFirst the prepared Nano fluid mixture of 0.1 concentrations is poured into the vessel. Using submersible pump it is made to flow through the copper tubes. Using flow meter the flow rate is varied from 0.1 LPM up to 0.5 LPM. Thus for each concentration of Nano fluid by varying flow rate five sets of readings are taken. Parameters such as inlet temperature, outlet temperature, wall temperature, inlet pressure and outlet pressure are noted down.Similar process is carried out with 0.2 and 0.3 concentration of Nano fluid and the readings are noted.Constant voltage of 230v and current of 9.6amps is maintained throughout the process.

Table 2 : Data’s obtained from the experimentS.no Conc

(%)FlowLPM

TIN TOUT TWALL PIN POUT

1. 0.1 0.1 34 59 85 0.17 0.152. 0.1 0.2 34 57 84 0.14 0.103. 0.1 0.3 35 56 82 0.20 0.154. 0.1 0.4 36 54 81 0.24 0.155. 0.1 0.5 37 53 80 0.29 0.126. 0.2 0.1 35 63 86 0.17 0.207. 0.2 0.2 36 61 84 0.21 0.168. 0.2 0.3 36 59 83 0.24 0.179. 0.2 0.4 37 58 81 0.29 0.1910. 0.2 0.5 38 56 80 0.30 0.1811. 0.3 0.1 35 67 87 0.16 0.1412. 0.3 0.2 36 65 85 0.14 0.1013. 0.3 0.3 36 62 84 0.20 0.1414. 0.3 0.4 37 60 83 0.26 0.1715. 0.3 0.5 38 58 80 0.30 0.18


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Vol. 5, Issue 2 (April - June 2019) ISSN : 2454-4736 (Online)

ISSN : 2454-8723 (Print)

www.ijarmet.com© 2015, IJARMET All Rights Reserved

Table 3 : Experimental heat transfer data for carbon nanotubes/distilled water

Sl. no.

Concentration %

Flow rate

Nusselt number

Heat transfer

Heat flux

1. 0.1 0.1 0.831 132.45 3.4952. 0.1 0.2 1.5 220.43 5.8163. 0.1 0.3 1.9 297.07 7.8384. 0.1 0.4 2.18 335.66 8.8575. 0.1 0.5 2.3 346.5 9.1426. 0.2 0.1 0.705 137.28 3.6227. 0.2 0.2 1.168 230.53 6.0838. 0.2 0.3 1.52 308.19 8.1329. 0.2 0.4 1.76 357.17 9.44310. 0.2 0.5 1.9 146.2 9.88911. 0.3 0.1 0.59 249.55 3.85812. 0.3 0.2 0.99 318.48 6.58413. 0.3 0.3 1.25 373.48 8.40314. 0.3 0.4 1.47 373.45 9.85315. 0.3 0.5 1.61 396.46 10.416

Fig. 4 : Graph between Nusselts and Reynolds number

Fig. 5 : Graph between heat transfer and Reynolds number

Fig. 6 : Graph between heat flux and Reynolds number

VII. ResultIn this we compare our Heat transfer rate with Reynolds Number with two Nano fluids on the above graph. The Nano fluid of aluminium oxide and carbon nanotube gives the different result in the heat transfer. When we compare our Heat transfer of aluminium oxide Nano fluid with the carbon nanotube Nano fluid, aluminium oxide Nano fluid gives better heat transfer rate than the carbon nanotube Nano fluid. With this we conclude that the heat transfer is better in aluminium oxide Nano fluid. We expert aluminium oxide Nano fluid is sufficient for industrial application or else where the heat transfer will take place in high rate. When we increasing the flow rate of the Nano fluid and the volumetric concentration it will give better results.


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Fig. 7 : Resultant Graph between Reynolds no. and heat transfer.

VIII. ConclusionNano fluids are important because they can be used in numerous applications involving heat transfer and other applications such as in detergency. Colloids which are also Nano fluids have been used in the biomedical field for a long time, and their use will continue to grow. Nano fluids have also been demonstrated for use as smart fluids. Problems of nanoparticle agglomeration, settling, and erosion potential all need to be examined in detail in the applications. Nano fluids employed in experimental research have to be well characterized with respect to particle size, size distribution, shape and clustering so as to render the results most widely applicable. Once the science and engineering of Nano fluids are fully understood and their full potential researched, they can be reproduced on a large scale and used in many applications. Colloids which are also Nano fluids will see an increase in use in biomedical engineering and the biosciences. Further research still has to be done on the synthesis and rendering the environment cleaner and healthier. Applications of Nano fluids so that they may be applied as predicted. Nevertheless, there have been many discoveries and improvements identified about the characteristics of Nano fluids in the surveyed applications and we are a step closer to developing systems that are more efficient and smaller, thus rendering the environment cleaner and healthier.

IX. AcknowlegementWe thank our honourable principle and head of the department for being supportive in many situations and their guidance helped us to finish the project as early as possible.

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International Journal of Advanced Research in ISSN : 2454 ...ijarmet.com/wp-content/themes/felicity/issues/Vol5issue2/pshri.pdfratio. MWNTs are a great choice of Nano scale additives