扭转流换热器结构参数对流场和温度场的影响
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摘要
建立扭转流换热器和弓形折流板换热器两种周期性全截面模型,采用计算流体力学方法对两种换热器的传热系数、阻力、综合性能进行了数值研究。分析了扭转流换热器管束支撑物类梯形导流板结构参数对换热器传热和流阻性能的影响。结果表明:导流板倾角和相邻两组导流板间距对扭转流换热器传热性能的影响显著,导流板宽度的影响次之,每组导流板的数量的影响较小。扭转流换热器优化结构,压降较弓形折流板换热器降低42.5%~46.9%,综合性能提高7.2%~14.1%。研究结果为管壳式换热器结构优化和强化传热提供了新方案。
Periodic whole cross-section computation models of twisty flow heat exchanger and segmental baffle heat exchanger are established respectively. The heat transfer coefficient, flow resistance and thermal performance are studied with CFD simulation. The influence of inclination angle of trapezoidal baffles, baffles width, baffles pitch and number of baffles on the heat transfer performance in the twisty flow heat exchanger was studied. The results showed that the inclination angle of trapezoidal baffles and baffles pitch have a significant effect on heat transfer performance, the effect of baffles width is secondary, and the number of baffles have no significant effect. When the thermal performance factor TEF of twisty flow heat exchanger reaches the best, compared to segmental baffle heat exchanger, the pressure drop decrease by 42.5% to 46.9%, the TEF is improved by 7.2% to 14.1%. The results of this paper provide a new scheme of the shell and tube heat exchanger for structure optimization and heat transfer enhancement.
Periodic whole cross-section computation models of twisty flow heat exchanger and segmental baffle heat exchanger are established respectively. The heat transfer coefficient, flow resistance and thermal performance are studied with CFD simulation. The influence of inclination angle of trapezoidal baffles, baffles width, baffles pitch and number of baffles on the heat transfer performance in the twisty flow heat exchanger was studied. The results showed that the inclination angle of trapezoidal baffles and baffles pitch have a significant effect on heat transfer performance, the effect of baffles width is secondary, and the number of baffles have no significant effect. When the thermal performance factor TEF of twisty flow heat exchanger reaches the best, compared to segmental baffle heat exchanger, the pressure drop decrease by 42.5% to 46.9%, the TEF is improved by 7.2% to 14.1%. The results of this paper provide a new scheme of the shell and tube heat exchanger for structure optimization and heat transfer enhancement.
引文
[1]董其伍,张垚.换热器[M].北京:化学工业出版社,2009.DONG Q W,ZHANG Y.Heat Exchanger[M].Beijing:Chemical Industry Press,2009.
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[3]杜婷婷,车凯,王丹华,等.变螺距搭接螺旋折流板换热器综合性能[J].化工学报,2015,66(S2):143-152.DU T T,CHE K,WANG D H,et al.Comprehensive performance of variable-pitch overlapped helical baffled heat exchangers[J].CIESC Journal,2015,66(S2):143-152.
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[9]王斯民,王萌萌,顾昕,等.基于火积理论的螺旋折流板换热器结构优化[J].高校化学工程学报,2016,30(3):532-539.WANG S M,WANG M M,GU X,et al.Structure optimization of helical baffle heat exchangers using entransy theory[J].J.Chem.Eng.Chinese Univ.,2016,30(3):532-539.
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[12]LUTCHA J,NEMCANSKY J.Performance improvement of tubular heat exchangers by helical baffles[J].Chemical Engineering Research&Design,1990,68(3):263-270.
[13]ZHANG J F,HE Y L,TAO W Q.3D numerical simulation on shelland-tube heat exchangers with middle-overlapped helical baffles and continuous baffles(Ⅰ):Numerical model and results of whole heat exchanger with middle-overlapped helical baffles[J].International Journal of Heat and Mass Transfer,2009,52(23/24):5371-5380.
[14]ZHANG J F,HE Y L,TAO W Q.3D numerical simulation on shelland-tube heat exchangers with middle-overlapped helical baffles and continuous baffles(Ⅱ):Simulation results of periodic model comparison between continuous and noncontinuous helical baffles[J].International Journal of Heat and Mass Transfer,2009,52(23/24):5381-5389.
[15]WANG Q W,CHEN G D,CHEN Q Y,et al.Review of improvements on shell-and-tube heat exchangers with helical baffles[J].Heat Transfer Engineering,2010,31(10):836-853.
[16]YOU Y H,FAN A W,LAI X J,et al.Experimental and numerical investigations of shell-side thermo-hydraulic performances for shelland-tube heat exchanger with trefoil-hole baffles[J].Applied Thermal Engineering,2013,50(1):950-956.
[17]MAAKOUL A E,LAKNIZI A,SAADEDDLINE S,et al.Numerical comparison of shell-side performance for shell and tube heat exchangers with trefoil-hole,helical and segmental baffles[J].Applied Thermal Engineering,2016,109:175-185.
[18]王英双,张晓屿,刘志春,等.花格板换热器的流动与传热[J].化工学报,2012,63(S1):99-106.WANG Y S,ZHANG X Y,LIU Z C,et al.Fluid flow and heat transfer study for flower baffle heat exchanger[J].CIESC Journal,2012,63(S1):99-106.
[19]WEN J,YANG H Z,WANG S M,et al.Numerical investigation on baffle configuration improvement of the heat exchanger with helical baffles[J].Energy Conversion and Management,2015,86:438-448.
[20]古新,董其伍,刘敏珊.帘式折流片换热器强化传热数值研究[J].高校化学工程学报,2010,24(2):340-345.GU X,DONG Q W,LIU M S.Numerical research on heat transfer enhancement of shutter baffle heat exchanger[J].Journal of Chemical Engineering of Chinese Universities,2010,24(2):340-345.
[21]GU X,LIU B,WANG Y Q,et al.Heat transfer and flow resistance performance of shutter baffle heat exchanger with triangle tube layout in shell side[J].Advances in Mechanical Engineering,2016,8(3):1-8.
[22]ROBERT W S,THOMAS G L.Process Heat Transfer[M].2nd ed.USA:Academic Press,2014:199-222.
[23]古新,秦晓柯,王永庆,等.倾斜折流栅式换热器壳程流体流动与传热特性[J].化工进展,2017,36(10):3584-3589.GU X,QIN X K,WANG Y Q,et al.Research on fluid flow and heat transfer characteristics in shell side of inclined shutter baffle heat exchanger[J].Chemical Industry and Engineering Progress,2017,36(10):3584-3589.
[24]PROMVONGE P,KOOLNAPADOL N,PIMSARN M,et al.Thermal performance enhancement in a heat exchanger tube fitted with inclined vortex rings[J].Applied Thermal Engineering,2014,62(1):285-292.
[25]WEN J,YANG H Z,WANG S M,et al.Experimental investigation on performance comparison for shell-and-tube heat exchangers with different baffles[J].International Journal of Heat and Mass Transfer,2015,84:990-997.
[26]SAHA A K,MALIK T.Mixed convective flow and heat transfer through a horizontal channel with surface mounted obstacles[J].Enhanced Heat Transfer,2012,19(4):331-329.
[2]HAJABDOLLAHI H,NADERI M,ADIMI S.A comparative study on the shell and tube and gasket-plate heat exchangers:the economic viewpoint[J].Applied Thermal Engineering,2016,92:271-282.
[3]杜婷婷,车凯,王丹华,等.变螺距搭接螺旋折流板换热器综合性能[J].化工学报,2015,66(S2):143-152.DU T T,CHE K,WANG D H,et al.Comprehensive performance of variable-pitch overlapped helical baffled heat exchangers[J].CIESC Journal,2015,66(S2):143-152.
[4]LIU W,LIU Z C,WANG Y S,et al.Flow mechanism and heat transfer enhancement in longitudinal-flow tube bundle of shell-and-tube heat exchanger[J].Science in China,2009,52(10):2952-2959.
[5]段振亚,沈锋,张俊梅,等.三螺旋折流板换热器多流路通道流动与传热数值模拟[J].化工学报,2016,67(S1):232-238.DUAN Z Y,SHEN F,ZHANG J M,et al.Numerical simulation of multi-flow and heat transfer characteristics in heat exchangers with triple-helical baffles.[J].CIESC Journal,2016,67(S1):232-238.
[6]MAAKOUL A E,LAKNIZI A,SAADEDDLINE S,et al.Numerical design and investigation of heat transfer enhancement and performance for an annulus with continuous helical baffles in a double-pipe heat exchanger[J].Energy Conversion&Management,2017,133:76-86.
[7]WANG Q,CHEN G,CHEN Q,et al.Review of improvements on shell and tube heat exchangers with helical baffles[J].Heat Transfer Engineering,2010,31(2010):836-853.
[8]董聪,陈亚平,吴嘉峰,等.三分螺旋折流板换热器水-水传热壳侧综合性能[J].化工学报,2012,63(3):721-727.DONG C,CHEN Y P,WU J F,et al.Water to water heat transfer on shell-side of trisection helical baffle heat exchangers.[J].CIESC Journal,2012,63(3):721-727.
[9]王斯民,王萌萌,顾昕,等.基于火积理论的螺旋折流板换热器结构优化[J].高校化学工程学报,2016,30(3):532-539.WANG S M,WANG M M,GU X,et al.Structure optimization of helical baffle heat exchangers using entransy theory[J].J.Chem.Eng.Chinese Univ.,2016,30(3):532-539.
[10]张剑飞,陶文铨,何雅玲.螺旋折流板换热器热力设计方法及其实验校核[J].中国电机工程学报,2013,33(26):75-80.ZHANG J F,TAO W Q,HE Y L.A calculation method for helical baffled heat exchanger design and experimental validation[J].Proceedings of the CSEE,2013,33(26):75-80.
[11]马雷,王英双,刘志春.变截面折流杆换热器的数值模拟[J].工程热物理学报,2012,33(1):113-117.MA L,WANG Y S,LIU Z C.Analysis of flow and heat transfer in rod baffle heat exchangers with rods of variable sections[J].Journal of Engineering Thermophysics,2012,33(1):113-117.
[12]LUTCHA J,NEMCANSKY J.Performance improvement of tubular heat exchangers by helical baffles[J].Chemical Engineering Research&Design,1990,68(3):263-270.
[13]ZHANG J F,HE Y L,TAO W Q.3D numerical simulation on shelland-tube heat exchangers with middle-overlapped helical baffles and continuous baffles(Ⅰ):Numerical model and results of whole heat exchanger with middle-overlapped helical baffles[J].International Journal of Heat and Mass Transfer,2009,52(23/24):5371-5380.
[14]ZHANG J F,HE Y L,TAO W Q.3D numerical simulation on shelland-tube heat exchangers with middle-overlapped helical baffles and continuous baffles(Ⅱ):Simulation results of periodic model comparison between continuous and noncontinuous helical baffles[J].International Journal of Heat and Mass Transfer,2009,52(23/24):5381-5389.
[15]WANG Q W,CHEN G D,CHEN Q Y,et al.Review of improvements on shell-and-tube heat exchangers with helical baffles[J].Heat Transfer Engineering,2010,31(10):836-853.
[16]YOU Y H,FAN A W,LAI X J,et al.Experimental and numerical investigations of shell-side thermo-hydraulic performances for shelland-tube heat exchanger with trefoil-hole baffles[J].Applied Thermal Engineering,2013,50(1):950-956.
[17]MAAKOUL A E,LAKNIZI A,SAADEDDLINE S,et al.Numerical comparison of shell-side performance for shell and tube heat exchangers with trefoil-hole,helical and segmental baffles[J].Applied Thermal Engineering,2016,109:175-185.
[18]王英双,张晓屿,刘志春,等.花格板换热器的流动与传热[J].化工学报,2012,63(S1):99-106.WANG Y S,ZHANG X Y,LIU Z C,et al.Fluid flow and heat transfer study for flower baffle heat exchanger[J].CIESC Journal,2012,63(S1):99-106.
[19]WEN J,YANG H Z,WANG S M,et al.Numerical investigation on baffle configuration improvement of the heat exchanger with helical baffles[J].Energy Conversion and Management,2015,86:438-448.
[20]古新,董其伍,刘敏珊.帘式折流片换热器强化传热数值研究[J].高校化学工程学报,2010,24(2):340-345.GU X,DONG Q W,LIU M S.Numerical research on heat transfer enhancement of shutter baffle heat exchanger[J].Journal of Chemical Engineering of Chinese Universities,2010,24(2):340-345.
[21]GU X,LIU B,WANG Y Q,et al.Heat transfer and flow resistance performance of shutter baffle heat exchanger with triangle tube layout in shell side[J].Advances in Mechanical Engineering,2016,8(3):1-8.
[22]ROBERT W S,THOMAS G L.Process Heat Transfer[M].2nd ed.USA:Academic Press,2014:199-222.
[23]古新,秦晓柯,王永庆,等.倾斜折流栅式换热器壳程流体流动与传热特性[J].化工进展,2017,36(10):3584-3589.GU X,QIN X K,WANG Y Q,et al.Research on fluid flow and heat transfer characteristics in shell side of inclined shutter baffle heat exchanger[J].Chemical Industry and Engineering Progress,2017,36(10):3584-3589.
[24]PROMVONGE P,KOOLNAPADOL N,PIMSARN M,et al.Thermal performance enhancement in a heat exchanger tube fitted with inclined vortex rings[J].Applied Thermal Engineering,2014,62(1):285-292.
[25]WEN J,YANG H Z,WANG S M,et al.Experimental investigation on performance comparison for shell-and-tube heat exchangers with different baffles[J].International Journal of Heat and Mass Transfer,2015,84:990-997.
[26]SAHA A K,MALIK T.Mixed convective flow and heat transfer through a horizontal channel with surface mounted obstacles[J].Enhanced Heat Transfer,2012,19(4):331-329.