串列双U型管束换热器压降与回热效率模型实验

为了研究串列双U型管束换热器的流动和传热特性,开展了模型实验,得到了串列双U型管束换热器布置方式对喷管通道流动压降和换热器回热效率的影响。结果表明:喷管通道流动压降随着换热器安装角的增大而增加,邻近喷管收敛状出口位置的换热器安装角对流动压降的影响最为显著,进口附近的换热器影响次之;相对通道内置单个换热器的情形,串列换热器中前置换热器安装角的变化对流动压降的影响有所减弱;较小的前置换热器安装角度导致其回热效率过低,从而导致平均回热效率难以改善;在本文研究的几种布置方式下,安装角为30°-17°-13°的串列换热器布置方式的流动和传热综合性能相对较优。

Model experiment on pressure drop and thermal recovery efficiency of tandem double-U-shaped-tube heat exchangers

In order to investigate the flow and heat transfer performances of tandem double-U-shaped-tube heat exchangers,model experiments are conducted.The effects of arrangement of the tandem heat exchangers on the nozzle pressure drop and recuperator effectiveness are obtained.The results show that the nozzle pressure drop is increased with the increase of heat exchanger inclined angle.The inclined angle of the last heat exchanger adjacent to the convergent nozzle exit has the most significant influence on the nozzle pressure drop,and the influence of the front heat exchanger adjacent to the nozzle inlet comes the second.In comparison with the situation where a single heat exchanger is placed inside the nozzle,the influence of the inclined angle of the front heat exchanger on pressure drop is slightly weakened when tandem heat exchangers is used.When the inclined angle of the front heat exchanger is small,the thermal recovery efficiency achieved by the front heat exchanger is very low,thus making it difficult to improve the overall thermal recovery efficiency of tandem heat exchangers.Among several arrangements of tandem heat exchangers in the present tests,the inclined angles of 30°-17°-13° corresponding to the three tandem heat exchangers appears to be more reasonable for obtaining the optimum comprehensive flow and heat transfer performance.