FLOW AND HEAT TRANSFER SIMULATION IN MINI CHANNEL

Transcription

1 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 Reeach Pape ISSN ol. 3, No. 3, Jul IJMERR. All Right Reeved FLOW AND HEA RANSFER SIMULAION IN MINI CHANNEL winkal M Bhava * and Manih Maiuia *Coeponding Autho: winkal M Bhava, twinkal707@gmail.com hi pape peent the a numeical imulation o a ont ide o mini channel (o = 0 uace) to invetigate the tempeatue ditibution obtained b olid domain uing bounda condition. Hee uniom heat lu i applied to the bottom ide o the mini channel top uace i aumed to be adiabatic and emaining two uace ae elected to be mmetic. he vaiation o maimum tempeatue o the peiphe o the mini channel with the dieent value o the lu i illutated in thi tud. Hee themal chaacteitic o the mini channel i epeented b maimum tempeatue obtained b the peiphe o the mini channel. In ode to obtain the behaviou o themal conductivit o the mateial in heat tane chaacteitic o the mini channel thee dieent olid mateial i ued one i coppe which ha highet themal conductivit econd one i tainle teel which i lowe themal conductive mateial and thid one i ilicon whoe themal conductivit ange between the themal conductivit o the othe two olid mateial coppe and tainle teel. Fo the cooling pupoe o the mini channel thee dieent cooling luid ae taken into anali wate, engine oil and mecu. And alo compaing the eult o the bet luid and olid to that o the eult obtained b eeache. Kewod: lamina low, Mini channel, Fluent, Mecu, Wate, Engine oil INRODUCION Mini Channel Heat Echange Claiication o heat echange ae baed on the woking pinciple, geomet o contuction, heat tane mechanim, luid low aangement, and tane pocee. he can alo be claiied baed on ie and uace aea to volume atio. Baed on channel dimenion, epeciall the chaacteitic length o hdaulic diamete, two main claiication cheme ae available in open the liteatue which i hown in table below. Channel ae o dieent co ection ma be it cicula, tiangula, ectangula, tapeoidal, etc. Channel ued o the cuent Depatment o Mechanical Engineeing, Chhotubhai Gopalbhai Patel Intitute o echnolog, Badoli. 73

2 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 tud i the cicula hape mini channel. Cicula channel ae mot likel a hown in Figue. he MICHX ued in the cuent tud i o ectangula hape and hole ae placed in thi ectangula pace o dieent mateial and mini channel ae placed inide the hole o thi ectangula block. hee i no gap in between adjacent channel o luid inteaction. Flat heat tane uace at the top and the bottom ace o each hole oe the luid low an ecellent contact with the heating uace, which lead to elevated heat tane ove the conventional heat echange o iolated tube ow. Flow, in a co-low oientation, ove tube in inline o taggeed aangement, which Figue : Cicula Shape Mini Channel Flow Paage Figue : Cicula Channel Inide Solid Domain i widel ued in man conventional heat echange application om a wake egion at the ea o each tube when luid i lowing in the tube. Figue and illutate the dieence between tube and monolithic channel tuctue inide heat echange coe. Wh to Chooe Smalle Flow Paage? Fluid low inide channel i at the heat o man natual tem. Heat and ma tane i accomplihed aco the channel wall in biological tem a well a in man manmade tem. In geneal, in mini channel tanpotation o heat occu though the olid egion and luid i paing though the luid egion mean though hole o the block. A ome uace o the lab i heated o much o that the need o cooling thi plate o lab i necea o o that thi mini channel ae ued block i placed on that heated uace and cold luid i paing though thi hole a the luid i paing though thi hole hot uace echange heat om hot uace to the cold luid o the luid get heated and then thi luid i emoved and new luid i ineted again and again. A channel eve to accomplih two objective:. Bing a luid into intimate contact with the channel wall; and. Bing eh luid to the wall and emove luid awa om the wall a the tanpot poce i accomplihed. Claiication o Channel A claiication o the channel i decibed in given table: 74

3 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 able : Channel Claiication Accoding to Mehendale Micochannel Meo-channel Compact paage Conventional -00 m 00 m- mm -6 mm paage > 6 mm able : Channel Claiication Accoding to Kandlinka Conventional Paage Minichannel Micochannel anitional Micochannel anitional Nanochannel Nanochannel > 3 mm 3 mm > D > 00 m 00 m > D > 0 m 0 m > D > m m > D > 0. m 0. m > D Special chaacteitic o the mini channel ae a dicued below: High uace aea pe unit volume and high heat tane coeicient. he atio o aea co- ection o the olid ubtate to that o the luid domain i quite mall. And a a eult o high heat tane coeicient with high conductive mateial, the conduction eitance o the ubtate i compaable to the convective eitance. Conideing a ingle cell om man paallel cell oming the minichannel heat ink, the heat i upplied to one ide o the ubtate (at the bottom ide) while the othe thee ide ae conideed a adiabatic uace (auming the channel i cut om two ided while the topide i aumed to have a negligible heat loe). he eult o thi aangement dictate the mini/mico channel to have vaiable heat lu aound the channel peimete. All the above mentioned concen impoe that the heat tane condition which the luid actuall epeience at the olid-luid inteace igniicantl deviate om the conventional uniom heat lu o uniom wall tempeatue heat tane poblem heat tane poblem. Hee in thi tud addeing the eect o heat lu magnitude which i applied on one o the uace o the mini channel, on the heat tane chaacteitic. and o thi epeentation dicuion eect o heat lu value ae compaed with maimum peipheal tempeatue. Hee anali i peomed with the help o thee olid ubtate mateial coppe, ilicon and tainle till. he anali i peomed with thee dieent cooling liquid mecu, wate and engine oil. MAHEMAICAL MODELLING Fo invetigation about the heat tane in mini channel heat ink, the geometical coniguation o the mini channel heat ink i a hown in Figue 3. It i a plate o length L, width W and height H in which numbe o cell ae thee om which luid i lowing and all the cell ae o ame diamete and ditance between two cell i alo ame o all. Figue 3: Geometical Coniguation o the wo Dieent Heat Sink 75

4 76 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 he aumption which have been taken into account ae a ollow:. he luid i newtonian and incompeible with contant phical popetie in tead tate heat tane poblem.. Negligible vicou heat diipation. 3. he low i lamina. 4. Hdodnamic and themal developing low. 5. Bod oce i neglected and no etenal oce i applied. 6. he adiation heat tane i neglected. 7. hemal conductivit o the olid ubtate i contant. 8. No heat geneation. Hee thi poblem o heat tane in mini channel, conjugate heat tane poblem i coniting o the lowing luid and the channel wall i govened b the epective eneg equation in 3D om. Hee, we ae electing one cell o the calculation o tempeatue ditibution in olid egion a how in Figue 4. hi i attibuted to the mmetical deign o the man cell oming the mini channel heat ink. Hee, Heat i upplied to the bottom ide o the ubtate, the top ide o the ubtate i aumed to be adiabatic (negligible heat lo) and the othe two ide ae conideed a mmet bounda condition. he govening equation o the conevation o ma, momentum and eneg in the olid and liquid egion in cicula mini channel ae a ollow: Govening Equation o Fluid Domain 0...() P v...() P v...(3) P v...(4)...(5) Solid Domain Now o olid domain, auming tead tate condition and contant popetie o the wall, the eneg equation o thi egion i a ollow: 0...(6) Figue 4: Geometical Coniguation o Domain o the Unit Cell

5 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 Since it i a mini channel imulation poblem we have to ue clindical coodinate tem to imulate the model convection within the cicula channel while the cateian coodinate tem i ued to imulate the conduction within the olid ubtate domain. Bounda Condition At Inlet Section At the inlet ection o the luid domain, elocit and tempeatue ae conideed a uniom, Fo the olid domain velocit i eo, and Wall i adiabatic. At d 0, 0, 0, 0, in, in d At 0,, 0 W, 0 H, At Outlet Section 0, 0 Flow i aumed to be a ull developed at the channel outlet and the outlet boundaie o the olid domain ae ame a that o the inlet ection: d At L, 0, 0, 0 d At L,, 0 W, 0 H, 0, 0 At Solid-Fluid Inteace No lip condition i aumed at the wall inteace between the olid and luid domain: d At 0 L,, 0, in, K At Solid Wall K Adiabatic bounda condition ae applied to all the boundaie o the olid egion ecept the heat ink bottom wall, whee a contant heat lu i aumed: At 0, 0 H, 0 L, 0, 0 At W, 0 H, 0 L, At At 0, 0 0 W, 0, 0 L K K 0 W, H, 0 L q, 0 0, 0 RESULS AND DISCUSION he numeical anali and imulation uing ANSYS otwae i dicued in peviou chapte. Now hee dicuion i taken out o the themal chaacteitic o the mini channel in tem o tempeatue ditibution. Hee dieent luid and dieent olid mateial ae taken one b one to each othe o the imulation. Wate a cooling liquid and ilicon a a ubtate mateial ae elected a the bae opeating condition o mini channel heat ink with the vaiation o heat lu. wo luid election i taken out with the help o themal popet o the luid. Hee mecu i elected due to it high themal popet with epect to 77

6 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 wate and othe luid engine oil act a coolant which ha pooe themal popetie a compaed to wate. And in olid mateial election o mateial i done with epect to themal conductivit. Coppe ha highe themal conductivit with epect to ilicon and teel ha lowe themal conductivit a compaed to ilicon. So behaviou o themal popet (tempeatue ditibution) i dicued in thi ection b changing lu value. Suace tempeatue i calculated om the outlet tempeatue o the luid domain. At highe heat lu value, it i inteeting to note that uace tempeatue o peiphe o the mini channel o coolant engine oil i highe a compaed to othe liquid coolant wate and mecu which we have ued. Figue 5 how the uace tempeatue o mini channel peiphe o coppe a ubtate mateial ued o olid domain, with change in value o heat lu. It i een om the igue that engine oil ha highet value o peiphe tempeatue a epect to othe luid wate and mecu. When luid i wate o mecu Figue 5: Peipheal empeatue Ditibution o Coppe a Subtate Mateial peipheal tempeatue o mini channel i almot ame o both luid when olid mateial i coppe. Figue 6 how the uace tempeatue o mini channel peiphe o tainle teel a ubtate mateial ued o olid domain, with change in value o heat lu. It i een om the igue that engine oil ha highet value o peiphe tempeatue a epect to othe luid wate and mecu. When luid i wate o mecu peipheal Figue 6: Peipheal empeatue Ditibution o Steel a Subtate Mateial Figue 7: Peipheal empeatue Ditibution o Silicon a Subtate Mateial 78

7 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 tempeatue o mini channel i almot ame o both luid when olid mateial i tainle teel. Figue 7 how the uace tempeatue o mini channel peiphe o ilicon a ubtate mateial ued o olid domain, with change in value o heat lu. It i een om the igue that engine oil ha highet value o peiphe tempeatue a epect to othe luid wate and mecu. When luid i wate o mecu peipheal tempeatue o mini channel i almot ame o both luid when olid mateial i ilicon. Figue 8 how the uace tempeatue o mini channel peiphe o wate ued a luid o luid domain, with change in value o heat lu. It i een om the igue that tainle teel ha highet value o peiphe tempeatue a epect to othe olid mateial coppe and ilicon. When olid ubtate mateial i coppe o ilicon peipheal tempeatue o mini channel i almot ame o both olid when luid ued i wate. Figue 9 how the uace tempeatue o mini channel peiphe o mecu ued a luid o luid domain, with change in value o heat lu. It i een om the igue that tainle Figue 9: Peipheal empeatue Ditibution o Mecu a Coolant Medium Figue 0: Peipheal empeatue Ditibution o Engine Oil a Coolant Medium Figue 8: Peipheal empeatue Ditibution o Wate a Coolant Medium teel ha highet value o peiphe tempeatue a epect to othe olid mateial coppe and ilicon. When olid ubtate mateial i coppe o ilicon peipheal tempeatue o mini channel i almot ame o both olid when luid ued i mecu. Figue 0 how the uace tempeatue o mini channel peiphe o engine oil ued a luid o luid domain, with change in value o heat lu. It i een om 79

8 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 the igue that tainle teel ha highet value o peiphe tempeatue a epect to othe olid mateial coppe and ilicon. When olid ubtate mateial i coppe o ilicon peipheal tempeatue o mini channel i almot ame o both olid when luid ued i engine oil. A hown in the gaph wheneve high themal conductive mateial i ued o olid domain (tainle teel) the peipheal tempeatue dieence i highe a compaed to the lowe themal conductive mateial. Coppe a ubtate mateial come in the cente o the othe two olid ubtate mateial when uing all luid which i dicued ealie one b one a hown in the Figue 8-0. And the eult o the coppe mateial obtained b imulation i neal ame a that o ilicon till the eult o the ilicon i o good a compaed to othe olid mateial. A the luid i elected one b one o all olid ubtate mateial om the gaph o dieent value o heat lu againt the maimum peipheal tempeatue o the mini channel, the eult o the mecu a luid i elected a bet ince it give highet heat Figue : Peipheal empeatue Ditibution o Silicon and Mecu Figue : Aveage Bottom Suace emp. o Silicon and Mecu a Solid and Fluid Mateial tane coeicient value a compaed to othe luid. And alo tempeatue ditibution on the peiphe o the mini channel i alo lowet a hown in gaph o mecu a luid. So i the value o the maimum peipheal tempeatue o the mini channel and heat tane coeicient i lowe and highe epectivel. Figue how the peipheal tempeatue ditibution o coppe a olid ubtate mateial and mecu a luid ince it give bet eult o cooling pupoe. Figue how the vaiation o aveage bottom uace tempeatue o the mini channel to that o the obtained b eeache M. Khami Manou. hi Figue how that a the aea o the olid ubtate i inceae the aveage bottom uace o the mini channel i alo inceae. a hown in Figue thee i about 68.6 K tempeatue dieence obtained when aea o the olid domain i inceae om mm to mm. Since the aea ued b eeache M. Khami Manou i mall a compaed to the domain ued in thi tud, aveage o tempeatue o bottom uace i obtained about K and aveage o the bottom 80

9 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 uace tempeatue o the domain ued o the tud i K. So a the aea o the olid domain inceae heat tane aea alo inceae and theeoe highe tempeatue obtained in thi tud. So, Wheneve channel ued o cooling pupoe elect lowet co ection a poible o the olid domain o that aveage uace tempeatue o the bottom uace i low and it cool the domain. CONCLUSION Fom the above tud ollowing concluion ma occu: he behaviou o the peiphe o the mini channel i ve dieent when domain i ubjected to the highe heat lu value o when it i ubjected to lowe heat lu value. empeatue dieence o the peiphe o the mini channel i highe when the olid domain i o the highe themal conductive mateial. At maimum value o the heat lu (30 KW/ m²) teel with engine oil ha highet peipheal tempeatue and ilicon and mecu ha lowet peipheal tempeatue. With the inceae in the aea o the olid domain, aveage bottom uace tempeatue o the mini channel i alo inceae. REFERENCES. Al Omai S-A B (0), Enhancement o Heat ane om Hot Wate b Co-Flowing it with Mecu in a Mini-Channel, Intenational Communication in Heat and Ma ane, ol. 38, pp Amado M Guman, Maimiliano P Beia, Ande J Dia, Paul F Fiche and Juan C Ramo (03), Flow and Heat ane Chaacteitic in Mico and Mini Communicating Peue Diven Channel Flow b Numeical Simulation, Intenational Jounal o Heat and Ma ane, ol. 58, pp Hetoni G, Moak A, Pogebnak E and Yain L P (005), Heat ane in Mico- Channel: Compaion o Epeiment with heo and Numeical Reult, Intenational Jounal o Heat and Ma ane, ol. 48, pp Khami Manou M (03), Numeical Anali o Conjugate Heat ane o Cicula Liquid Mini Channel, JP Jounal o Heat and Ma ane, ol. 7, pp Motaa Kehava Moaveji, Rea Mohammadi Adehali and Ali Ijam C F D (03), Invetigation o Nanoluid Eect (Cooling Peomance and Peue Dop) in Mini-Channel Heat Sink, Intenational Communication in Heat and Ma ane, ol. 40, pp Pei-Xue Jiang, Yi-Jun Xu, Jing Lv, Run- Fu Shi, He S and Jackon J D (004), Epeimental Invetigation o Convection Heat ane o CO at Supe-Citical Peue in etical Mini-ube and in Poou Media, Applied hemal Engineeing, ol. 4, pp Pamod Kuma and Nagaj M R (03), CFD Anali o Fluid Flow and Heat ane in wo Phae Flow Micochannel, Intenational Jounal o 8

10 Int. J. Mech. Eng. & Rob. Re. 04 winkal M Bhava and Manih Maiuia, 04 Engineeing Reeach & echnolog (IJER), ol., No Satih G Kandlika, Siniva Gaimella, D Li S Colin and M King (006), Heat ane and Fluid Flow in Mini Channel and Mico Channel, ISBN: Zhaning Zheng, David F Fletche and Bian S Hane (03), Lamina Heat ane Simulation o Peiodic Zigag Semicicula Channel: Chaotic Advection and Geometic Eect, Intenational Jounal o Heat and Ma ane, ol. 6, pp