R410A在5 mm管内的沸腾换热及压降特性
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摘要
为了研究制冷剂R410A在5 mm内螺纹铜管内的沸腾换热及压降特性,以磁驱泵提供循环动力、均匀缠绕在测试段上的电加热丝提供热量以及冷水机组提供循环冷量的方式搭建了测试实验台,并对R410A在5 mm内螺纹管内的流动沸腾换热系数及压降进行了测试.分析讨论了不同蒸发温度下,制冷剂质量流量密度和管壁热流密度对管内制冷剂流动沸腾换热系数以及压降特性的影响.研究结果表明:5mm内螺纹管内R410A的流动沸腾换热系数分别在质量流量密度位于191.28和344.3kg/(m2·s)处达到峰值;其流动沸腾换热系数随着管壁热流密度增大最初呈现增大的趋势,在热流密度>30 kW/m2后逐渐平稳;而R410A在5 mm内螺纹管内的压降均随质量流量密度和管壁热流密度的增大而增大,其中压降和管壁热流密度的关系呈较为明显的线性变化.
In order to study the characteristics of boiling heat transfer and pressure drop of R410 A in the 5 mm diameter inner-grooved copper tube,the experiment table was established where a magnetic pump was used to provide power of the system cycle,coils of electric heating wires which were well-distributed on the copper tube were used to supply heat and a water chilling unit was used to supply cold for the cycle.Characteristics of boiling heat transfer and pressure drop of R410 A was measured in the experiment table.The effect of the mass flux and heat flux on the boiling heat transfer coefficient and pressure drop under different boiling temperatures was analyzed and discussed.The conclusion indicates that:in the 5 mm diameter inner-grooved copper tube,boiling heat transfer coefficient of R410 A reaches its peak value while the mass flux is 191.28 and 344.3 kg/(m2·s) respectively;boiling heat transfer coefficient increases at the beginning while heat flux rises and gets stable when heat flux reaches 30 kW/m2;pressure drop increases while both heat flux and mass flux rises,and the effect of heat flux on pressure drop presents an obvious linear relationship.
In order to study the characteristics of boiling heat transfer and pressure drop of R410 A in the 5 mm diameter inner-grooved copper tube,the experiment table was established where a magnetic pump was used to provide power of the system cycle,coils of electric heating wires which were well-distributed on the copper tube were used to supply heat and a water chilling unit was used to supply cold for the cycle.Characteristics of boiling heat transfer and pressure drop of R410 A was measured in the experiment table.The effect of the mass flux and heat flux on the boiling heat transfer coefficient and pressure drop under different boiling temperatures was analyzed and discussed.The conclusion indicates that:in the 5 mm diameter inner-grooved copper tube,boiling heat transfer coefficient of R410 A reaches its peak value while the mass flux is 191.28 and 344.3 kg/(m2·s) respectively;boiling heat transfer coefficient increases at the beginning while heat flux rises and gets stable when heat flux reaches 30 kW/m2;pressure drop increases while both heat flux and mass flux rises,and the effect of heat flux on pressure drop presents an obvious linear relationship.
引文
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[2]HU H,DING G,HUANG X,et al.Pressure drop during horizontal flow boiling of R410A/oil mixture in 5 mm and 3 mm smooth tubes[J].Applied Thermal Engineering,2009,29(16):3353-3365.
[3]HUANG X,DING G,HU H,et al.Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and4 mm outside diameter horizontal microfin tubes[J].Experimental Thermal and Fluid Science,2010,34(7):845-856.
[4]HE G,LIU Y,CAI D,et al.Experimental investigation on flow boiling heat transfer performance of a new near azeotropic refrigerant mixture R290/R32 in horizontal tubes[J].International Journal of Heat and Mass Transfer,2016,102:561-573.
[5]JIANG J,HE G,LIU Y,et al.Flow boiling heat transfer characteristics and pressure drop of ammonia-lithium nitrate solution in a smooth horizontal tube[J].International Journal of Heat and Mass Transfer,2017,108(Part A):220-231.
[6]ANDRZEJCZYK R,MUSZYNSKI T,DORAO CA.Experimental investigations on adiabatic frictional pressure drops of R134a during flow in 5 mm diameter channel[J].Experimental Thermal and Fluid Science,2017,83:78-87.
[7]胡海涛,丁国良,黄翔超,等.小管径铜管内含油制冷剂流动冷凝换热与压降特性的实验研究[J].制冷技术,2012:10-14.
[8]黄理浩,陶乐仁,郑志皋,等.R410A在管内冷凝换热及压降的实验研究[J].低温与超导,2011,39:31-34.
[9]刘荣,陶乐仁,高立博,等.R410A在内螺纹管内无润滑油沸腾换热实验研究[J].制冷学报,2011,32:20-24.
[10]韦伟.车用热泵小管径换热器开发与性能研究[D].上海:上海交通大学机械与动力工程学院,2013.
[11]张建国,陶乐仁,王金锋,等.R410A在水平内螺纹管中沸腾换热实验研究[J].低温与超导,2009:42-46.
[12]苟秋平,吴扬,邓斌.小管径铜管在家用热泵热水器蒸发器中的应用研究[J].制冷技术,2013:21-23.
[13]任滔,丁国良,韩维哲,等.空调器中采用小管径的影响分析及研发思路[J].制冷技术,2012:49-52.
[14]王婷婷,任滔,丁国良,等.小管径空调器的优化设计[J].制冷技术,2012:1-4.
[15]冼志健,王开发.小管径铜管换热器的性能及成本分析[J].制冷与空调,2013:65-66.
[16]徐啟华,潘保远.小管径换热器对空调可靠性的影响[J].制冷与空调,2015:76-77.
[17]尤顺义,张静,林灿洪,等.小管径内螺纹铜管在空调系统中的应用[J].制冷技术,2010:22-25.
[18]MURATA K,HASHIZUME K.Forced convective boiling of nonazeotropic refrigerant mixtures inside tubes[J].Journal of Heat Transfer,1993,115(3):680-689.