MHD assignment

8/8/2019 MHD assignment

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4/26/2010

Assignment 1 | Dariusz Zielinski

SHEFFIELDHALLAMUNIVERSITY

MHD (MAGNETO-HYDRO-DYNAMIC) ENERGY GENERATOR


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ContentsIntrodu ction ................................ ................................ ................................ ................................ ...... 3

MHD Principles ................................ ................................ ................................ ................................ .. 4 MHD Syste s ................................ ................................ ................................ ................................ .... 5

Fluid and T he rmo D ynami cs in MHD generator ................................ ................................ ................ 10

MHD generator p erforman ce................................ ................................ ................................ ........... 18

Environm ental MHD impa ct ................................ ................................ ................................ ............. 21

Hybrid MHD pow er generator s ................................ ................................ ................................ ........ 22

MHD Optimization ................................ ................................ ................................ ........................... 24

Conclusion ................................ ................................ ................................ ................................ ....... 25

Table of Figur es ................................ ................................ ................................ ............................... 26

Bibliograp hy ................................ ................................ ................................ ................................ .... 27


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Mech ani cal Engin ee ring IP4 Dariu sz Zielins i 16-6079 P a g e | 3

I ntroductionSince generation of electric energy be gan t he main ta s in human liv es, we perman entl y tr y toincrease the efficiency of u se of fu els, as well as redu ce the pollution to t he atmo sphe re. As the traditional m ethod s ar e onl y up to 40% efficient , what pra ctically mean t hat wa ste of he at i s unu sedin pro cess and emitt ed to t he atmo sphe re, and t he developm ent s of traditional in stallation s ar e

res tricted by man y physical fa ctor s.

As MHD impli es, magn eto -hydro -dynami c (MHD) is con cerned wit h the flow of condu cting fluid inpr ese nce of magn etic and elec tric fie ld. This fluid ma y be gas at elevat ed t emp eratur e or liquid m etallike sodium or pota ssium. A MHD g enerator i s a d evice for conv erting he at energy of fu el directly into electric energ y without a conv entional compl ex elec tric generator. T he MHD prin ciples hadbee n fir st pu blishe d by Michael Farada y in 189 3, but du e to un success ful experim ent on riv erTham es the idea had bee n a bandon ed for n ext 4 decad es, untilt he att empt of d evelop of MHDgenerator around 1936 by Wes ting Hou se rese ar ch laborator y in USA.


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Mech ani cal Engin ee ring IP4 Dariu sz Zielinski 16-6079 P a g e | 4

MHD Principles

(1)The prin ciple of MHD g enerator adopt s the sam e prin ciples as the traditional g enerator s. The elec tric energy is produ ced du e to t he mov ement of condu ctor a cro ss the magn etic field andFarada y s electromotiv e for ce indu ces elec tric curr ent. In MHD pro cess the traditional solidcondu ctor i s repla ced by gaseou s condu ctor such as ioni sed ga s, or liquid ioniz ed m etal , which is pa sse d t hroug h magn etic field p erpendi cular to high velocity vec tor of t he fluid.

Figure 1 MHD Principles (2)

The pro cess ma y be desc ribe d by Farada y sLaw of Indu ction:

Whe re E is electromotiv e force, which is proportional to electric pot ential diff erence U (volt) andmagn etic density B (Tes la). Since the condu ctor i s not a solid element but fluid t he Lorentz for ce appli es to MHD g enerator to gov ern t he prin ciples of curr ent g eneration in MHD pro cess . Due tomagn etic fie ld dir ection t he po sitive and n egativ e parti cles ar e acce lerat ed toward s elec trod es

he nce the Lorentz Law appl y.

Whe re F is force (Newton) and J i s curr ent d ensity. Hence the po sitive ion s will be attra cted by negativ e elec trod e and n egativ e ion s by po sitive electrod e.


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Figure 2 Physics of MHD (3)

Impl ementing bot h equation s for Farada y sand Lor entz Law s the general express ion for curr entpow er bec om e

and t he lost ent halp y Thus gas energy directly conv ert ed into elec trical energy. This is the prin ciple of MHD g enerator. AMHD conv ersion i s known a s direct energy conv ersion bec au se it produ ced electricity directly fromhe at sour ce without t he necess ity of t he additional stag e of steam g eneration a s in a steam pow erplant.

One of t he MHD pow er generation advantag e is that t he pro cess do es n t r equir e high spee d rotatingpart s he nce advan ce d mat erials ma y be used, which ma y op erat e in highe r t emp eratur es . Usedmat erials includ e high temp eratur e ce rami cs, which allow to flow of high ioniz ed pla sma , which is hott er t hat elec tric ar c. Also bec au se the re is no r equir ement for moving element s, and t he high curr ent d ensity the size of MHD g enerator ma y be redu ced w hat allow u sing it in man y close spa ce appli cation s such as spa ce sh ips or submarin es . The submarin es appli cation al so be nefit from qui etop eration.

MHD SystemsThe MHD energy generator s primaril y ma y be divided into two t ypes depending on op erationprin ciples, op en or close cycle systems.

(1)An elementar y op en cycle MHD system, con sist of op en flow chann el surround ed by a magn e t. Afuel is use d to produ ce hot ga s, which is the n see ded wit h an ioniz ed alkali m etal ( caes ium orpota ssium) to in crease the elec trical condu ctiviti es of ga s. The gas expand s throug h the generatorsurround ed by high pow er magn et. During t he flow of ga s the po sitive and n egativ e ion s mov e tothe electrod es and con stitut e an elec tric curr ent. T he rejec ted ga s pa sses throug h an air he at er for


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pr ehe ating t he inlet air. T he see d mat erial is recovered for r euse, the nitrog en and sulp hur, which ar e the side eff ec ts, ar e remov ed for pollution controll ed and t hen ga sses ar e disch arg ed to t he atmo sphe re.

The above cycle is not suita ble for comm ercial u se . The exh au st ga ses of MHD unit ar e still ata suffi cientl y hot t emp eratur e it is po ssible to u se for additional pow er generation in a steam tur bine alt ernator unit. T his is increase the efficiency of pro cess . Such cycle is known a s hyb rid MHD-steamplant cycle.

Figure 3 Sc hematic MHD open cycle hybrid generator (1)

Figur e 3 sh ow s hyb rid MHD steam cycle, coal i s pro cesse d and burnt in t he com bustor athigh temp eratur e (2750 to 3 000 K) and pr ess ure (7 to 15 at atmo sphe re), with prehe at ed air toform t he pla sma. T he pla sma i s the n see ded wit h small fra ction ( 1%) of an alkali m etal (pota ssium)introdu ced u sually as a car bonat e powd er or solution.

(1)Second t ype of MHD g enerator i s close cycle. The inert ga s MHD system wa s con ceived 196 5.Since the main di sadvantag e of t he op en cycle system is very high temp eratur e requir ement and avery che mically active flow could be remov ed, by close d cycle MHD system. As the nam e sugges ts the working fluid , is circulat ed in a closed loop. T he working fluid i s he lium or argon wit h caes iumsee ding. T he compl ete system has three distin ct but int erlocking loop s. First is the external he atingloop , coal i s gasified and t he gas has a high he at valu e of a bout 5.35 MJ/kg and t emp eratur e of about 53 0C, the n it i s burnt in a com bustor to produ ce he at. In t he he at exch ang er HX, this he at i s

tran sf erred to t he working fluid for MHD cycle. The com bustion produ cts aft er pa ssing t hroug h anot he r he at exch ang er, to pr ehe at com bustion air (to r ecover a part of t he he at of com bustionprodu ct) and purifi ers (To r emov e harmful emission s) and di sch arg ed to atmo sphe re.

Second loop i s the MHD loop. T he hot ga s is see ded wit h caes ium and send to MHDgenerator. T he DC pow er output of MHD g enerator i s conv ert ed to AC by the invert er and i s the nf ee d into t he grid.


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The third loop in fig 4 is the steam loop for furt he r rec over the he at of t he working fluid andconv ert t his he at into elec trical energy, by produ cing steam in anot he r he at exch ang er, which is use by tur bine, which generat e elec tric output and pow er to driv e compr ess or.

Figure 4 Close loop MHD generator (1)

As the desc ribe d a bove ar e the MHD systems, the re ar e also t hree diff erent MHD g enerator. T he basic generator i s Farada y sgenerator sh ow in figur e 5.

Figure 5 Faraday generator (2)

Farada y generator con sist a w edge-sh ap ed pip e or tu be mad e of non -condu ctive mat erial such as cerami c. Whe n an elec trically condu ctive fluid flow s throug h the tu be, in t he prese nce of asignificant p erp endi cular magn etic field, a charg e is indu ced. This charg e is drawn off a s electricalenergy by pla cing t he electrod es on t he sides at 90o angl es to t he magn etic field. The amount of produ ced pow er is proportional to t he cro ss sec tion ar ea of t he tu be and t he spee d of t he condu ctive flow. T he main pra ctical pro blem of a Farada y generator i s that diff erent voltag es andcurr ent s have to be con solidat ed to inv entor to produ ce AC output voltag e. The mo st pow erfulwa ste is from t he Hall Eff ect curr ent.


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(4)The Hall Eff ect in pla sma can tak e an y valu e. The Hall param eter in a pla sma i s the ratiobe tw ee n t he electron g yro fr equ ency e and t he electron -he avy parti cles collision fr equ ency :

whe re

e is the electron charg e (1.6 10 -19 coulom b)B is the magn etic field (in t es las)me is the elec tron ma ss (0.9 10-30 kg)

As seen from expression above the Hall parameter value increases with the magnetic fieldstrength.

Phys ically, whe n t he Hall param eter is low, the tra jec tori es of electron s be tw ee n two encount ers with he avy parti cles ar e almo st lin ear. But if t he Hall param eter is high, the electron mov ement s ar e highly curved. The curr ent d ensity vector i s no mor e collinear wit h the electric field vec tor. T he twovec tor s mak e the Hall angl e which also gives the Hall param eter:

Anot he r t ype of MHD generator i s Hall type generator. T he Hall generator po sses arra ys of short , verti cal electrod es on t he sides of t he du ct, and t he load i s conn ected to fir st and la st electrod es inthe du ct, each ot he r electrod e is sh ort ed to an electrod e on t he oppo site side of t he du ct. These sh ort s of t he Farada y curr ent indu ce a pow erful magn etic fie ld wit hin the fluid , but in a chord of acircle at rig ht angl es to t he Farada y curr ent. T his sec ondar y, indu ced field mak es curr ent flow in arain bow sh ap e be tw ee n t he first and la st electrod es . Losses ar e less than a Farada y generator , andvoltag es ar e highe r.

Figure 6 Hall generator (2)

Third t ype of MHD generator i s Disc generator. T he disc generator has fluid flow from centr e of adisc, to a du ct wrapp ed around t he edge. The magn e tic excitation fi eld is perform ed by a pair of circular coils above and be low t he disc. The Farada y curr ent s flow tang entiall y and t he Hall eff ectcurr ent s flow be tw ee n radiall y be tw ee n inert and out e r electrod es . Becau se hall curr ent int era cting


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with magn etic field t he flow bec am e spiral and t he Hall curr ent i s equal to centrifugal for ce. Anot he rsignificant advantag e of t his des ign is that t he magn et is mor e efficient.

Figure 7 Disc generator (2)

Anot he r t ype is Diagonal MHD g enerator. It i s build similarl y to t he Farada y the common diff erence is that t he electrod es ar e not load ed se parat ely, but conn ec ted in a slant ed wa y and t he load i s conn ec ted to fir st and t he last electrod e. Since the re is Farada y curr ent in t he pla sma t he elec trod es ar e conn ected at optimum angl e. This type of generator s is not suff ered from Hall curr ent.

Figure 8 Diagonal generator (2)


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F luid and Thermo D ynamics in MHD generator

Figure 9 Transient flow physical model with coordinate system ( 5 )

(5)Whe n con sidering tran sient , hydromagn e tic, viscou s, incompr ess ible Newtonian flow in parall elchann el as show in figur e 9, with con stant pr ess ur e and uniform magn e tic field. All the physicalquantiti es with exce ption of pr ess ur e ar e fun ction s of ind epend ent varia bles . Also a ssumption s are con sidered a s follow:

Whe re , , , ar e repr ese nting v ec tor s respec tively, velocity, magn etic field, electric field andcurr ent d ensity. The con se rvation s equation s for t he flow i. e . mom entum con se rvation andmagn etic indu ction con se rvation ar e represe nt ed a s follow:

Wh ere and are t h e velocity components in t h e x- and y-directions, is time, is t h e fluid density,is pressure, is kinematic viscosity, is fluid electrical conductivity, is t h e applied magnetic

field, is t h e dielectric constant, is inclination of t h e applied magnetic field, to t h e positive z-axis(i.e. axis of rotation) and and are magnetic induction components in t h e x- and y-directions.

(5)


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For mat he mati cal and anal ytical scale less solution propo ses dim ension l ess param eters ar e introdu ced.

Whe re

is dim ensionl ess z coordinat e

ar e dim ensionless velocities in x and y direction

ar e dim ensionless magn etic indu ction compon ent s in x and y direction

is dim ensionless time

is dim ensionless angular fr equ encies is dim ensionless longitudinal pr ess ure gradi ent

is dimensionless inverse off Ekman num be r

is Hartmann hydromagn etic param eter

is magn etic Prandtl num be r

is dielectric str engt h relat ed to Ma xwell displa cement curr ent eff ect

is magn etic perm eability

Impl ementing con se rvation s equation s with dim ensionl ess param eters the flow i s represe nt ed by expr ess ion s as follow

The ta bles be llow show num erical simulation s using a bove equation s with varying diff erentelement s driving flow.


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Figure 10 Spatial induced magnetic field distribution for M2 = 10, = 0.2, T = /4, = /4 with K2 = 5 (5 )

Figure 11 Spatial induced magnetic field distribution for K2 = 5 , = 0.2, T = /4, = /4 with M 2 = 5 (5 )

Figure 12 Spatial induced magnetic field distribution for M2 = 10, K2 = 5 , T = /4, = /4 with = 0. 6 (5 )

And grap hically represe nt ed calculation s show in figur es 13, 14, 15 indi cat e that t he magn etic indu ction compon ent s in x and y direc tion varni sh at t he ce ntr e of chann el he nce the magn etic flux indu ction do esn t tak e pla ce in t he chann el centr e


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Figure 13 Graphical interpretation for M2 = 10, = 0.2, T = /4, = /4 with K2 = 5, 7 and 9 (5 )

Figure 14 Graphical interpretation for K2 = 5 , = 0.2, T = /4, = /4 for M 2 = 6, 8 and 10 (5 )


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Figure 1 5 Graphical interpretation for M2 = 10, K2 = 5 , T = /4, = /4 for = 0.2, 0.4 and 0.6 (5 )

(6)Whe n con sidering stead y, dissipativ e laminar two -dimensional N ewtonian flow , he at and ma ss tran sf er ov er a flat surfa ce which temp eratur e is , surfa ce con centration ,whe re bot h ar e con stant. T he rmal condu ctivity , which ar e desc ribe d by linear t emp eratur e law

whe re is the rmal condu ctivity

is the rmop hysical con stant w hich value is


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Whe re

and ar e x and y-direction v elocities

is the kinemati c fluid vi scosity

is e lectrical condu ctivit y

is fluid t emp eratur e

is species con centration (of parti cles )

and ar e the free str eam v elocity and t emp eratur e

is density

is specific he at capa city of t he fluid at con stant pr ess ure

is the Fickian ma ss diffu sion coefficient

is the rmop hor e tic velocity

is the magn etic field str engt h

is he at sour ce/ sink param eter

is dynami c viscosity of t he fluid

is the the rmal condu ctivit y of t he fluid

Figure 1 6 Physical model and coordinate system ( 7 )


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Whe n t he rmop hor e tic diffu sivity and t he rmop hor etic condu ctivit y adopt ed, and comput ed fordim ensionless valu es Lingen Che n (7) obtain ed following dat e sh own on grap hs be llow.

In figur e 17 ma y be obse rved in crease in dim ensionless velocities of fluid w he n Hartman num be rincreases . The reason of t his increase of velocity is bec au se magn etic str eam i s moving wit h the free str eam. W he n approa ches valu e of 0.35 ind epend entl y on Ha v elocity is close to unit y. Similarit y ma y be obse rved on grap h in figur e 19 represe nting non dim ensional con centration v ersus Hartmannum be r, in this case the con centration in crease with increase of Hartmann num be r and a chievingunit y at . But in figur e 18 the drop of dim ensionless temp eratur e with increase of Hartman num be r ma y be see n. Also all curves dec ay from ma ximum t emp eratur e at t he chann elwall to z ero in t he str eam. T he reason for t his beh aviour i s bec au se Joule he ating i s generat ed du e tores istan ce of t he fluid to t he flow of curr ent. Similar beh aviour of t he non dim ensional t emp eratur e and con centration i s obse rved in figur es 20 and 21 with diff erent valu es of Eckert num be rs, temp eratur e decrease whe n Eckert num be r rise and con centration in crease with highe r Eckertnum be rs.

Figure 1 7 Dimensionless velocity (df/dg) versus g for Ha = 0, 1, 2, 5 , 10 with Ec = 0.1, D = 0.1, Pr = 0. 7 , Sc = 0. 6 , b = 0. 5 ,f0 = 0.1, s = 0. 5 . ( 6 )

Figure 1 8 Dimensionless temperature (h) versus for Ha = 0, 1, 2, 5 , 10 with Ec = 0.1, D = 0.1, Pr = 0. 7 , Sc = 0. 6 , b = 0. 5 , f0= 0.1, s = 0. 5 . ( 7 )


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Figure 1 9 Dimensionless concentration (U) versus g for Ha = 0, 1, 2, 5 , 10 with Ec = 0.1, D = 0.1, Pr = 0. 7 , Sc = 0. 6 , b = 0. 5 ,f0 = 0.1, s = 0. 5 . ( 6 )

Figure 20 Dimensionless temperature (h) versus g for Ec = 0, 0.1, 0.2, 0.3, with Ha = 1, D = 0.1, Pr = 0. 7 , Sc = 0. 6 , b = 0. 5 , f0

= 0.1, s = 0. 5 (6 )

Figure 21 Dimensionless concentration (U) versus g for D = 0. 7 , 0.2, 0, 0.2, 0. 7 with Ha = 1, Ec = 0.1, Pr = 0. 7 , Sc = 0. 6 , b =0. 5 , f0 = 0.1, s = 0. 5 (6 )


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MHD generator performanceTo anal yze efficiency of MHD g enerator a spec t of he at exch ang er and compr ess or have to be con sidered. Becau se the cycle sh ow in figur e 22 is similar to t he cycle of ga s tur bine used wid ely intraditional pow er plant , the anal ysis ma y be base d on t hese prin ciples .

Figure 22 Power cycle for MHD generator ( 7 )

Follow Ling en Che n (7) in ord er to inv es tigat e pow er efficiency two cases are con sidered forsolution , which ar e the con stant ga s velocity and con stant Ma ch num be r. To see variou s aspect of con stant ga s case the param etric calculation s out com es for t he con stant ga s velocity case ar e sh ownbe low in r espect to compr ess or pr ess ur e ratio. Figur e 23 sh ow s the eff ec t of t he eff ec tivenesses

of t he hot and cold side he at exch ang ers on with and . Figur e 24 sh ow s the eff ec t of t he compr ess or efficiency on with and , and Figur e 25 sh ow s the eff ec t of t he MHD generator efficiency on with and

Figure 23 Effect of heat exchanger effectiveness on the performance (constant gas velocity). ( 7 )


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Figure 24 Effect of compressor efficiency on the performance (constant gas velocity). ( 7 )

Figure 2 5 Effect of generator efficiency on the performance (constant gas velocity). ( 7 )

Second simulation had bee n und ertak en by Lingen Che n (7) to inv es tigat e efficiency in case of con stant Ma ch num be r. The grap hical result s ar e sh own be low. T he param eters used in calculationar e as follow:

Figur e 26 sh ow eff ec t of Ma ch num be r on with , and Figur e 27 sh ow eff ec t of t he eff ec tivenesses of t he hot and cold side he at exch ang ers on

with , and Figur e 28 sh ow s the eff ect of t he compr ess or efficiency on wit h , and .


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Figure 2 6 Effect of Mach number on the performance (constant Mach number). ( 7 )

Figure 2 7 Effect of heat exchanger effectiveness on the performance (constant Mach number). ( 7 )


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Figure 2 8 Effect of compressor efficiency on the performance (constant Mach number). ( 7 )

If compar e the diagram s above the press ur e ratio ma y be delivered for optimum efficiency of t he MHD generator. T he efficiency the n should be compromi sed wit h optimum pow er output w hich is explain ed in d etail s in Lingen Che n (7) work.

E nvironmental MHD impact

Since the main con cern a bout impa ct of energy generation on environm ent i s the emission of CO2 inatmo sphe re which raise the global t emp eratur e, the stud y have bee n p erform ed to r edu ce this emission. In MHD g eneration t he re is requir ement of high temp eratur e to o btain optimum

performan ce of t he generator. To a chieve the requir ed t emp eratur e according to M. I sh ikawa ( 8)propo sed to u se oxygen in stead of air. U sage of o xygen in com bustion not onl y increases the temp eratur e but al so increase the purit y of t he exh au st ga sses emitt ed by the pro cess . Wit h this system t he CO2 ma y be recovered a s a liquid. M. I sh ikawa ( 8) stud y sh ow t hat t he re is not high requir ement r equir ed to liquid t he gas which ma y be utilised in d ee p sea wat er. His furt he r stud y sh ow t hat by utili sing part of t he produ ced energy for 95% oxygen and r ecovery of 90% CO2 efficiency of cycle is 42 .9%, which is highe r t hat efficiency of t he traditional pow er plant w hich cannot be highe r t hat 3 8-40% . The arrang ement of propo sed by M. Ish ikawa ( 8) plant i s sh ow infigur e 29 .


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Figure 2 9 Power balance of coal-fired MHD-steam combined system with CO2 recovery (thermal input of about 1000MW and magnetic flux density of 8 T). (8 )

Performan ce param eters for 1000 MW pow er input a ccording to M. I shikawa ( 8) are as follow:

P ower output of MHD generator supplied to t h e a.e. grid: 217.9 M W

P ower output of sync h ronous generator supplied to t h e a.c. grid: 316.8 M W

P ower required for oxygen production: 50.0 M W

P ower required for CO2 liquefaction (90% recovery): 64.0 M W

P ower output of total system supplied to t h e a.c. grid: 420.7 M W

Cycle efficiency (including t h e power for CO2 liquefaction): 42.9% (HHV).

H ybrid MHD power generatorsSince to g enerat e pow er u sing MHD t ech nolog y the re is requir ement for he at , following O s Beg(3)man y diff erent sour ces ma y be used. Os Beg (3) propo sed solar pow er whe re sun energy is con centrat ed and g enerat e he at , which is used in t he plant to produ ce pla sma ga s. Plasma ga s is

in jec ted into MHD chann el to produ ce elec tric energy. Figur e 30 show solar pow ered generator wit h regenerativ e he at exch ang er in close loop arrang ement. T he main propo se of use of t his type generator i s in Spa ce.


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Figure 30 Solar MHD generator (3)

Anot he r solution to MHD hyb rid generator , mention ed by Os Beg (3) i s MHD generator wit h nu clearreactor working in close loop system. Figur e31 sh ow t hat t he he ating d evice is not lik e previou s exampl e solar it i s nu clear r eactor w hich is recogniz ed a s long la sting maint enan ce free device he nce ma y be used on Spa ce on crewless spa cesh ips. Anot he r propo ses for t his type of generator ma y be submarin e use . It is suita ble for submarin es thank s to t he qui et work.

Figure 31 Nuclear MHD power generator (3)

In rece nt year s developm ent had bee n p erform ed on seawat er MHD generator w hich uses elec tromotiv e for ce to g enerat e energ y in he lical MHD chann el. Figur e 32 sh ow he lical MHDgenerator and fluid flow simulation. Stud y perform ed by Minoru Tak eda ( 9) that protot ype of a s small a s 260 mm long and 100 mm diam eter chann el can produ ce 0.05W at t he averag e flowvelocities of 5. 6m/ s. The he lical MHD generator i s show in figur e 32.


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Figure 32 Helical - Type seawater MHD generator ( 9 )

MHD OptimizationMo st of t he rece nt studi es for optimization of MHD g enerator s ar e perform ed num erically, but t his is not di screditing o btain ed valu es bec au se the num erical solution s are perform ed on nondim ensional data he nce the result s ma y be scaled wit hout di screpan cies . One of t he num erical case studi es is (7) Heat transfer effect on t h e performance of MHD power plant by Lingen C h en. The stud y sh ow s aspect of con stant ga s velocity and con stant Ma ch num be r on p erforman ce .Alsoexperimental anal yzes are und ertak en on e of w hich is coal fir ed MHD Farada y chann el at IEE inChina ( 10). The experim ents sh ow fi elds whe re performan ce ma y be increase d. First ar e the linkag es in x and y direction and al so t he eff ec tive electrical condu ctivity which ma y be obtain ed by compl e te

com bustion of coal or be tt er mixing of see ds.


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ConclusionThe MHD generation of energy is still und er d evelopm ent but it s advantag es attra ct indu stries andthe po ssibility of improv ement of efficiency of standard pow er plant s. The system ma y be emplo yedin existing plant s as well ma y be op erat ed alon e. The emplo yment in existing plant s ma y bringsignificant r edu ction of CO 2 emission a s sh own by utili sing it in liquid form , or even if from t he sam e

he at input t he plant will produ ce mor e energy its mean t he re will be redu ction of CO 2 for KWoutput.

MHD generator s ma y op erat e with diff erent sour ces of he at , and t he small dim ension s of systemma y be emplo yed spa ce appli cation s and naval appli cation s.


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Table of F iguresFigur e 1 MHD Principles (2)................................ ................................ ................................ ................ 4 Figur e 2 Phys ics of MHD (3) ................................ ................................ ................................ ............... 5Figur e 3 Sche mati c MHD op en cycle hyb rid g enerator ( 1) ................................ ................................ .. 6 Figur e 4 Close loop MHD g enerator ( 1) ................................ ................................ .............................. 7

Figur e 5 Farada y generator ( 2) ................................ ................................ ................................ ........... 7 Figur e 6 Hall generator ( 2) ................................ ................................ ................................ ................. 8 Figur e 7 Disc generator ( 2) ................................ ................................ ................................ ................. 9 Figur e 8 Diagonal g enerator ( 2)................................ ................................ ................................ .......... 9 Figur e 9 Tran sient flow p hys ical mod el with coordinat e system (5) ................................ .................. 10 Figur e 10 Spatial indu ced magn e tic fie ld di stribution for M 2 = 10, = 0.2, T = / 4, = / 4 with K2 =5 (5) ................................ ................................ ................................ ................................ ................. 12 Figur e 11 Spatial indu ced magn e tic fie ld di stribution for K 2 = 5, = 0.2, T = / 4, = / 4 with M2 =5 (5) ................................ ................................ ................................ ................................ ................. 12 Figur e 12 Spatial indu ced magn e tic fie ld di stribution for M 2 = 10, K2 = 5, T = / 4, = / 4 with =0.6 (5) ................................ ................................ ................................ ................................ .............. 12 Figur e 13 Grap hical int erpr e tation for M 2 = 10, = 0.2, T = / 4, = / 4 with K 2 = 5, 7 and 9 (5) .. 13Figur e 14 Grap hical int erpr etation for K 2 = 5, = 0.2, T = / 4, = / 4 for M2 = 6, 8 and 10 (5) .... 13Figur e 15 Grap hical int erpr e tation for M 2 = 10, K2 = 5, T = / 4, = / 4 for = 0.2, 0.4 and 0.6 (5)................................ ................................ ................................ ................................ ........................ 14 Figur e 16 Phys ical mod el and coordinat e system (7) ................................ ................................ ........ 15Figur e 17 Dimensionless velocity (df/dg) v ersus g for Ha = 0, 1, 2, 5, 10 with Ec = 0.1, D = 0.1, Pr = 0.7, Sc = 0.6, b = 0.5, f 0 = 0.1, s = 0.5. ( 6) ................................ ................................ .............................. 16 Figur e 18 Dimensionless temp eratur e (h) versus for Ha = 0, 1, 2, 5, 10 with Ec = 0.1, D = 0.1, Pr =0.7, Sc = 0.6, b = 0.5, f 0 = 0.1, s = 0.5. ( 7) ................................ ................................ .......................... 16 Figur e 19 Dimensionless con centration (U) v ersus g for Ha = 0, 1, 2, 5, 10 with Ec = 0.1, D = 0.1, Pr =

0.7, Sc = 0.6, b = 0.5, f 0 = 0.1, s = 0.5. ( 6) ................................ ................................ .......................... 17 Figur e 20 Dimensionless temp eratur e (h) versus g for Ec = 0, 0.1, 0.2, 0.3, with Ha = 1, D = 0.1, Pr =0.7, Sc = 0.6, b = 0.5, f 0 = 0.1, s = 0.5 (6) ................................ ................................ ........................... 17 Figur e 21 Dimensionless con centration (U) v ersus g for D = 0.7, 0.2, 0, 0.2, 0.7 with Ha = 1, Ec = 0.1, Pr = 0.7, Sc = 0.6, b = 0.5, f 0 = 0.1, s = 0.5 (6) ................................ ................................ .................... 17 Figur e 22 Pow er cycle for MHD g enerator ( 7) ................................ ................................ .................. 18 Figur e 23 Eff ec t of he at exch ang er eff ec tiveness on t he performan ce (con stant ga s velocity). (7).... 18 Figur e 24 Eff ec t of compr ess or efficiency on t he performan ce (con stant ga s velocity). (7) ............... 19 Figur e 25 Eff ec t of g enerator efficiency on t he performan ce (con stant ga s velocity). (7) .................. 19 Figur e 26 Eff ec t of Ma ch num be r on t he performan ce (con stant Ma ch num be r). (7)....................... 20 Figur e 27 Eff ec t of he at exch ang er eff ec tiveness on t he performan ce (con stant Ma ch num be r). (7)20 Figur e 28 Eff ec t of compr ess or efficiency on t he performan ce (con stant Ma ch num be r). (7) ........... 21 Figur e 29 Pow er balan ce of coal-fired MHD-steam com bined system wit h CO2 recovery (the rmalinput of a bout 1000 MW and magn etic flux density of 8 T). (8) ................................ ........................ 22 Figur e 30 Solar MHD g enerator (3) ................................ ................................ ................................ .. 23Figur e 31 Nuclear MHD pow er generator (3) ................................ ................................ ................... 23Figur e 32 Helical - Type seawat er MHD generator ( 9) ................................ ................................ ...... 24


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B ibliography1. MHD P ower Generation. Khamgaon : Govt. Polytech nic.

2. MHD Generator s. Encyclopedia Britannica. [Onlin e] [Cited: 16 04 2010 .] http://www. britanni ca. com/EB chec ked/topi c-art/35 7424 / 929 59/MHD-generator -configuration s-Segm ent ed-Farada y-generator.

3. B g, Dr Os. INDUSTRIAL ENERGY MANAGEMENT: MHD ENERGYSYSTEMS. Lecture P resentation.She ffield : s.n. , 2010 .

4. Electrot he rmal in sta bility. W kipidia Encyclopedia. [Onlin e] [Cited: 14 4 2010 .] http:// en.wikip edia.org/wiki/El ectrot he rmal_in sta bility.

5. Transient h ydomagnetic flow in rotating c h annel permeated by an inclined magnetic field wit h induction and Maxwell displacement current effect. S. K. Ghosh, O. A. Beg, J. Zueco, V. R. Prased. Base l : Z. Angew. Mat h. Phys, 2009 .

6. T h ermop h oretic h ydromagnetic dissipative h eat and mass transfer wit h lateral. Joaqun Zueco a,O. Anwar B g, H.S. Takhar, V.R. Prasad. 29, s.l. : Appli ed The rmal Engin ee ring , 2009 .

7. Heat Transfer effect on t h e performance of MHD power plant. Lingen Chen, jianzheng Gong,Fengrui Sun, Chih Wu. s.l. : Energy Conversion & manag ement , 2002, Vol. 43.

8. MHD P OW ER SYSTEMS FOR REDUCTION OF CO2 EMISSION.M. ISHIKAWA, MEYER STEINBERG. s.l. : Energy Conversion & manag ement , 1998, Vol. 3 9.

9. Fundamental Studies of Helical - Type Seawater MHD Generation System. Minoru Takeda, YasuakiOkuji, Teruhico Akazawa, Xiaojun Liu, Tsukasa Kiyoshi. s.l. : Tran saction s OnAppliedn Sup ercondu ctivit y, 200 5, Vol. 15 No 2.

10 . P ERFORMANCE ANALYSIS OF COAL-FIRED MHD.M. ISHIKAWA, T. IWASHITA, J. TONG+. s.l. :Energ y Conversion & manag ement , 199 5, Vol. 3 8.

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