内螺旋连续式铜换热器换热分析与数值模拟
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摘要
为了提高低流量情况下换热器的换热效率,基于有限元模拟技术,采用CFD软件对内螺旋连续式换热器和传统弓形式换热器的换热进行数值模拟。结合场协同理论及数值分析,研究了两者之间的温度场、流速场、压力场对换热效率的影响。结果表明:相较于传统弓形式换热器,内螺旋连续式换热器在流量较小的情况下流速场中有射流、扰流、二次流存在,有更少的流动死区、更大的换热面积,同时扰流的存在加大了换热系数。综合数值模拟与分析得出,在流量较小的情况下,通过增大换热面积与换热系数,内螺旋连续式换热器明显比传统弓形式换热器效率高,换热效率提高约12%。该分析为低流量情况下换热器的传热效率、强化传热的研究提供了有效理论依据。
In order to improve the heat transfer efficiency of heat exchanger at low flow rate, the heat transfer of internal spiral continuous heat exchanger and traditional bow heat exchanger was simulated by CFD software based on finite element simulation technology, and combined with the field synergy theory and numerical analysis, the effects of temperature field, velocity field and pressure field on heat transfer efficiency were studied. The results show that compared with the traditional bow heat exchanger, there are jet flow, turbulence, secondary flow, less dead zone and larger heat transfer area in the flow field of the internal spiral continuous heat exchanger, and the turbulence increases the heat transfer coefficient. The results of numerical simulation and analysis show that, when the flow rate is small, the efficiency of the internal spiral continuous heat exchanger is obviously higher than that of the traditional bow heat exchanger, and the heat transfer efficiency increases by about 12% by increasing the heat transfer area and the heat transfer coefficient. The analysis provides an effective theoretical basis for the study of heat transfer efficiency and heat transfer enhancement in the case of low flow rate.
In order to improve the heat transfer efficiency of heat exchanger at low flow rate, the heat transfer of internal spiral continuous heat exchanger and traditional bow heat exchanger was simulated by CFD software based on finite element simulation technology, and combined with the field synergy theory and numerical analysis, the effects of temperature field, velocity field and pressure field on heat transfer efficiency were studied. The results show that compared with the traditional bow heat exchanger, there are jet flow, turbulence, secondary flow, less dead zone and larger heat transfer area in the flow field of the internal spiral continuous heat exchanger, and the turbulence increases the heat transfer coefficient. The results of numerical simulation and analysis show that, when the flow rate is small, the efficiency of the internal spiral continuous heat exchanger is obviously higher than that of the traditional bow heat exchanger, and the heat transfer efficiency increases by about 12% by increasing the heat transfer area and the heat transfer coefficient. The analysis provides an effective theoretical basis for the study of heat transfer efficiency and heat transfer enhancement in the case of low flow rate.
引文
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[2] Chokphoemphun S,Pimsarn M,Thianpong C,et al.Thermal performance of tubular heat exchanger with multiple twisted-tape inserts[J].Chinese Journal of Chemical Engineering,2015,23(5):755-762.
[3] Park H C,Choi H S,Lee J E.Heat transfer of bio-oil in a direct contact heat exchanger during condensation[J].Korean Journal of Chemical Engineering,2016,33(4):1159-1169.
[4] 仇嘉,魏文建,张绍志,等.基于CFD数值模拟的板式换热器分配性能研究[J].机械工程学报,2010,46(14):130-137.QIU Jia,WEI Wen-jian,ZHANG Shao-zhi,et al.Research on performance of distributors used in plate heat exchangers based on CFD numerical simulation[J].Journal of Mechanical Engineering,2010,46(14):130-137.
[5] 许晓红.双壳程外螺旋内斜百叶片管壳式换热器的传热和阻力性能研究[D].太原:太原理工大学,2018.XU xiao-hong.Heat transfer and flow resistance performance of double shellpass shell-and-tube heat exchanger combined with helical baffles in the outer shell pass and louver baffles in the inner shell pass[D].Taiyuan:Taiyuan University of Technology,2018.
[6] 王晨,桑芝富.不同螺旋折流板换热器壳侧流动的数值研究[J].石油机械,2008(10):12-15+96.WANG Chen,SANG Zhi-fu.Numerical study of shell-side flow of heat exchanger of different helical baffle[J].China Petroleum Machinery,2008(10):12-15+96.
[7] Jafari Nasr M R,Shafeghat A.Fluid flow analysis and extension of rapid design algorithm for helical baffle heat exchangers[J].Applied Thermal Engineering,2008,28(11/12):1324-1332.
[8] 李晓敏,王立军,王河.管壳式换热器流体与传热模拟分析[J].真空科学与技术学报,2018,38(10):919-923.LI Xiao-min,WANG Li-jun,WANG He.Flow field profiles of shell-and-tube heat exchanger:a simulation study[J].Chinese Journal of Vacuum Science and Technology,2018,38(10):919-923.
[9] Li H,Kottke V.Analysis of local shellside heat and mass transfer in the shell-and-tube heat exchanger with disc-and-doughnut baffles[J].International Journal of Heat and Mass Transfer,1999,42(18):3509-3521.
[10] 谢洪虎,江楠.连续形螺旋折流板管壳式换热器强化传热机理的数值模拟[J].石油化工设备,2009,38(S1):6-11.XIE Hong-hu,JIANG Nan.Numerical simulation and discussion of the enhanced heat transfer mechanism in continuous spiral-shaped baf fle shell and tube heat exchangers[J].Petro-Chemical Equipment,2009,38(S1):6-11.
[11] 崔玉清,赵爽,吴卫伟.一种连续型螺旋折流板换热器的设计[J].有色冶金节能,2016,32(4):27-30.CUI Yu-qing,ZHAO Shuang,WU Wei-wei.Design of one continuous helical baffle type heat exchanger[J].Energy Saving of Non-ferrous Metallurgy,2016,32(4):27-30.
[12] 崔海亭,姚中鹏,赵欣.螺旋槽纹管研究及应用[J].石油化工设备,2001,30(2):34-36.CUI Hai-ting,YAO Zhong-peng,ZHAO Xin.Research and application of spirally corrugated tube[J].Petro-Chemical Equipment,2001,30(2):34-36.
[13] Zimparov V.Enhancement of heat transfer by a combination of a single-start spirally corrugated tubes with a twisted tape[J].Experimental Thermal and Fluid Science,2002,25(7):535-546.
[14] Ambekar A S,Sivakumar R,Anantharaman N,et al.CFD simulation study of shell and tube heat exchangers with different baffle segment configurations[J].Applied Thermal Engineering,2016,108:999-1007.
[15] Peng B,Wang Q W,Zhang C,et al.An experimental study of shell-and-tube heat exchangers with continuous helical baffles[J].Journal of Heat Transfer,2007,129(10):1425-1431.