利用多孔肋片和纳米颗粒加入基液强化环形通道中强制对流的数值分析（英文）
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摘要
电子设备的小型化迫使研究人员设计出更有效的方法来释放设备中产生的热量。在此研究中,通过在基液中插入多孔介质和加入纳米颗粒两种方法,以改善在两个壁面上加热的环行通道的传热性能。为了研究多孔介质嵌入,分别在内外壁上使用多孔肋片。结果表明,当多孔肋片置于外壁时,尽管传热增强,但压降量相当大,以至于所有研究的多孔肋片高度与多孔介质渗透性的性能参数(P_N),即传热增量与压降增量之比均小于1。当多孔肋片置于内壁时,P_N取决于Darcy数(Da)。例如,对于Da=0.1和Da=0.0001的肋片,最大性能数P_N=4出现在多孔肋片高度与水力直径比为H/D_h=1和H/D_h=0.25。在这些情况下,传热增强了两个数量级。结果表明,在上述两种情况下,在基液中加入5%的纳米颗粒可使Nusselt数和P_N提高10%～40%。
Miniaturization of electronic equipment has forced researchers to devise more effective methods for dissipating the generated heat in these devices. In this study, two methods, including porous media inserting and adding nanoparticles to the base fluid, are used to improve heat transfer in an annulus heated on both walls. To study porous media insert, porous ribs are used on the outer and inner walls independently. The results show that when porous ribs are placed on the outer wall, although the heat transfer enhances, the pressure drop increment is so considerable that performance number(the ratio of heat transfer enhancement pressure increment, P_N) is less than unity for all porous rib heights and porous media permeabilities that are studied. On the other hand, the P_N of cases where porous ribs were placed on the inner wall depends on the Darcy number(Da). For example, for ribs with Da=0.1 and Da=0.0001, the maximum performance number, P_N=4, occurs at the porous ribs height to hydraulic diameter ratios H/D_h=1 and H/D_h=0.25. Under these conditions, heat transfer is enhanced by two orders of magnitude. It is found that adding 5%nanoparticles to the base fluid in the two aforementioned cases improves the Nusselt number and P_N by 10%–40%.
Miniaturization of electronic equipment has forced researchers to devise more effective methods for dissipating the generated heat in these devices. In this study, two methods, including porous media inserting and adding nanoparticles to the base fluid, are used to improve heat transfer in an annulus heated on both walls. To study porous media insert, porous ribs are used on the outer and inner walls independently. The results show that when porous ribs are placed on the outer wall, although the heat transfer enhances, the pressure drop increment is so considerable that performance number(the ratio of heat transfer enhancement pressure increment, P_N) is less than unity for all porous rib heights and porous media permeabilities that are studied. On the other hand, the P_N of cases where porous ribs were placed on the inner wall depends on the Darcy number(Da). For example, for ribs with Da=0.1 and Da=0.0001, the maximum performance number, P_N=4, occurs at the porous ribs height to hydraulic diameter ratios H/D_h=1 and H/D_h=0.25. Under these conditions, heat transfer is enhanced by two orders of magnitude. It is found that adding 5%nanoparticles to the base fluid in the two aforementioned cases improves the Nusselt number and P_N by 10%–40%.
引文
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[21]LOU W,ZHU M.Numerical simulation of gas and liquid two-phase flow in gas-stirred systems based on Euler-Euler approach[J].Metallurgical and Materials Transactions B,2013,44(5):1251-1263.
[22]BAHIRAEI M,HANGI M,RAHBARI A.A two-phase simulation of convective heat transfer characteristics of water-Fe3O4 ferrofluid in a square channel under the effect of permanent magnet[J].Applied Thermal Engineering,2019,147:991-997.
[23]KHOSRAVI-BIZHAEM H,ABBASSI A.Effects of curvature ratio on forced convection and entropy generation of nanofluid in helical coil using two-phase approach[J].Advanced Powder Technology,2018,29(4):890-903.
[24]NAJAFI KHABOSHAN H,NAZIF H R.Heat transfer enhancement and entropy generation analysis of Al2O3-water nanofluid in an alternating oval cross-section tube using two-phase mixture model under turbulent flow[J].Heat Mass Transfer,2018,54(10):3171-3183.
[25]KRISTIAWAN B,SANTOSO B,WIJAYANTA A T,AZIZ M,MIYAZAKI T.Heat transfer enhancement of Ti O2/water nanofluid at laminar and turbulent flows:A numerical approach for evaluating the effect of nanoparticle loadings[J].Energies,2018,11(6):1-15.
[26]WEN D,DING Y.Experimental investigation into convective heat transfer of nanofluids at the entrance region under laminar flow conditions[J].International Journal of Heat and Mass Transfer,2004,47(24):5181-5188.
[27]G?KTEPE S,ATALIK K,ERTüRK H.Comparison of single and two-phase models for nanofluid convection at the entrance of a uniformly heated tube[J].International Journal of Thermal Sciences,2014,80:83-92.
[28]MAHDAVI M,SAFFAR-AVVAL M,TIARI S,MANSOORIZ.Entropy generation and heat transfer numerical analysis in pipes partially filled with porous medium[J].International Journal of Heat and Mass Transfer,2014,79:496-506.
[29]PAVEL B I,MOHAMAD A A.An experimental and numerical study on heat transfer enhancement for gas heat exchangers fitted with porous media[J].International Journal of Heat and Mass Transfer,2004,47(23):4939-4952.
[30]MAEREFAT M,MAHMOUDI S Y,MAZAHERI K.Numerical simulation of forced convection enhancement in a pipe by porous inserts[J].Heat Transfer Engineering,2011,32(1):45-56.
[2]MAHMOODI M,KANDELOUSI S.Kerosene-alumina nanofluid flow and heat transfer for cooling application[J].Journal of Central South University,2016,23(4):983-990.
[3]ZAIB A,BHATTACHARYYA K,SHAFIE S.Unsteady boundary layer flow and heat transfer over an exponentially shrinking sheet with suction in a copper-water nanofluid[J].Journal of Central South University,2015,22(12):4856-4863.
[4]HUSSAIN T,SHEHZAD S A,ALSAEDI A,HAYAT T,RAMZAN M.Flow of Casson nanofluid with viscous dissipation and convective conditions:A mathematical model[J].Journal of Central South University,2015,22(3):1132-1140.
[5]SARI M R,KEZZAR M,ADJABI R.Heat transfer of copper/water nanofluid flow through converging-diverging channel[J].Journal of Central South University,2016,23(2):484-496.
[6]SHEIKHOLESLAMI M.CuO-water nanofluid flow due to magnetic field inside a porous media considering Brownian motion[J].Journal of Molecular Liquids,2018,249:921-929.
[7]SHEIKHOLESLAMI M.Influence of magnetic field on Al2O3-H2O nanofluid forced convection heat transfer in a porous lid driven cavity with hot sphere obstacle by means of LBM[J].Journal of Molecular Liquids,2018,263:472-488.
[8]SHEIKHOLESLAMI M,HAQ R,SHAFEE A,LI Z.Heat transfer behavior of nanoparticle enhanced PCMsolidification through an enclosure with V shaped fins[J].International Journal of Heat and Mass Transfer,2019,130:1322-1342.
[9]BARAGH S,SHOKOUHMAND H,AJAROSTAGHI S S M,NIKIAN M.An experimental investigation on forced convection heat transfer of single-phase flow in a channel with different arrangements of porous media[J].International Journal of Thermal Sciences,2018,134:370-379.
[10]HASSAN M,MARIN M,ALSHARIF A,ELLAHI R.Convective heat transfer flow of nanofluid in a porous medium over wavy surface[J].Physics Letters A,2018,382(38):2749-2753.
[11]RAIZAH Z A S,ALY A M,AHMED S E.Natural convection flow of a power-law non-Newtonian nanofluid in inclined open shallow cavities filled with porous media[J].International Journal of Mechanical Sciences,2018,140:376-393.
[12]SIAVASHI M,TALESH BAHRAMI H R,SAFFARI H.Numerical investigation of flow characteristics,heat transfer and entropy generation of nanofluid flow inside an annular pipe partially or completely filled with porous media using two-phase mixture model[J].Energy,2015,93(2):2451-2466.
[13]MAHIAN O,KOLSI L,AMANI M,ESTELLéP,AHMADIG,KLEINSTREUER C,MARSHALL J S,TAYLOR R A,ABU-NADA E,RASHIDI S,NIAZMAND H,WONGWISES S,HAYAT T,KASAEIAN A,POP I.Recent advances in modeling and simulation of nanofluid flows-part II:Applications[J].Physics Reports,2019,791:1-59.DOI:doi.org/10.1016/j.physrep.2018.11.003.
[14]MAHIAN O,KOLSI L,AMANI M,ESTELLéP,AHMADIG,KLEINSTREUER C,MARSHALL J S,SIAVASHI M,TAYLOR R A,NIAZMAND H,WONGWISES S,HAYAT T,KOLANJIYIL A,KASAEIAN A,POP I.Recent advances in modeling and simulation of nanofluid flows-part I:Fundamental and theory[J].Physics Reports,2019,790:1-48.
[15]JAVED M,FAROOQ M,AHMAD S,ANJUM A.Melting heat transfer with radiative effects and homogeneousheterogeneous reaction in thermally stratified stagnation flow embedded in porous medium[J].Journal of Central South University,2018,25(11):2701-2711.
[16]VALIPOUR P,GHASEMI S E,VATANI M.Theoretical investigation of micropolar fluid flow between two porous disks[J].Journal of Central South University,2015,22(7):2825-2832.
[17]SIAVASHI M,BAHRAMI H R T,AMINIAN E.Optimization of heat transfer enhancement and pumping power of a heat exchanger tube using nanofluid with gradient and multi-layered porous foams[J].Applied Thermal Engineering,2018,138:465-474.
[18]SIAVASHI M,BAHRAMI H R T,SAFFARI H.Numerical investigation of porous rib arrangement on heat transfer and entropy generation of nanofluid flow in an annulus using a two-phase mixture model[J].Numerical Heat Transfer,Part A:Applications,2017,71(12):1251-1273.
[19]PAKRAVAN H A,YAGHOUBI M.Analysis of nanoparticles migration on natural convective heat transfer of nanofluids[J].International Journal of Thermal Sciences,2013,68:79-93.
[20]SOKOLICHIN A,EIGENBERGER G,LAPIN A,LüBERTA.Dynamic numerical simulation of gas-liquid two-phase flows Euler/Euler versus Euler/Lagrange[J].Chemical Engineering Science,1997,52(4):611-626.
[21]LOU W,ZHU M.Numerical simulation of gas and liquid two-phase flow in gas-stirred systems based on Euler-Euler approach[J].Metallurgical and Materials Transactions B,2013,44(5):1251-1263.
[22]BAHIRAEI M,HANGI M,RAHBARI A.A two-phase simulation of convective heat transfer characteristics of water-Fe3O4 ferrofluid in a square channel under the effect of permanent magnet[J].Applied Thermal Engineering,2019,147:991-997.
[23]KHOSRAVI-BIZHAEM H,ABBASSI A.Effects of curvature ratio on forced convection and entropy generation of nanofluid in helical coil using two-phase approach[J].Advanced Powder Technology,2018,29(4):890-903.
[24]NAJAFI KHABOSHAN H,NAZIF H R.Heat transfer enhancement and entropy generation analysis of Al2O3-water nanofluid in an alternating oval cross-section tube using two-phase mixture model under turbulent flow[J].Heat Mass Transfer,2018,54(10):3171-3183.
[25]KRISTIAWAN B,SANTOSO B,WIJAYANTA A T,AZIZ M,MIYAZAKI T.Heat transfer enhancement of Ti O2/water nanofluid at laminar and turbulent flows:A numerical approach for evaluating the effect of nanoparticle loadings[J].Energies,2018,11(6):1-15.
[26]WEN D,DING Y.Experimental investigation into convective heat transfer of nanofluids at the entrance region under laminar flow conditions[J].International Journal of Heat and Mass Transfer,2004,47(24):5181-5188.
[27]G?KTEPE S,ATALIK K,ERTüRK H.Comparison of single and two-phase models for nanofluid convection at the entrance of a uniformly heated tube[J].International Journal of Thermal Sciences,2014,80:83-92.
[28]MAHDAVI M,SAFFAR-AVVAL M,TIARI S,MANSOORIZ.Entropy generation and heat transfer numerical analysis in pipes partially filled with porous medium[J].International Journal of Heat and Mass Transfer,2014,79:496-506.
[29]PAVEL B I,MOHAMAD A A.An experimental and numerical study on heat transfer enhancement for gas heat exchangers fitted with porous media[J].International Journal of Heat and Mass Transfer,2004,47(23):4939-4952.
[30]MAEREFAT M,MAHMOUDI S Y,MAZAHERI K.Numerical simulation of forced convection enhancement in a pipe by porous inserts[J].Heat Transfer Engineering,2011,32(1):45-56.