螺旋套管式换热器螺纹扰流及耦合传热数值模拟

Numerical Simulation of Screw Turbulence and Coupled Heat Transfer of Spiral Tube Heat Exchanger

考虑壳程流体和管程流体的耦合传热,对套管式换热器管程流体的流动特性和换热特性进行数值分析。对比不同模型的管程流体的Nu和f,发现了螺纹管传热的优越性,结合管程流体速度场、温度场的细观信息,揭示了管程流体的换热性能和流动特性,并分析了不同流体介质对其管程换热效果的影响。结果表明:内管采用螺纹管时,螺旋套管式换热器管程流体的换热性能明显优于光滑内管,在研究范围内,内管采用螺纹管的Nu是采用光管的1.76~1.9倍,流体受离心力、螺纹扰流和螺旋槽导流的复合作用,强化了管程流体的传热。在同一雷诺数下,30号透平油的Nu最大,约为空气的3.8~5.01倍,然后依次是水、水蒸气、空气。

Considering the coupled heat transfer between shell side fluid and tube side fluid,the flow characteristics and heat transfer characteristics of tube side fluid in casing heat exchanger were numerically analyzed.The advantages of heat transfer in threaded pipe were found by comparing the Nu and f of pipe flow fluid of different models.Combined with the mesoscopic information of velocity field and temperature field of pipe flow fluid,the heat transfer performance and flow characteristics of pipe flow fluid were revealed,and the influence of different fluid media on the heat transfer effect of pipe flow was analyzed.The results showed that the heat transfer performance of spiral tube heat exchanger fluid was better than that of smooth inner tube when threaded tube was used.In the research range,Nu of threaded tube in inner tube was 1.76~1.9 times that of smooth tube.The fluid was affected by centrifugal force,threaded turbulence and spiral groove diversion,which enhanced the heat transfer of pipe fluid.At the same Reynolds number,No.30 turbine oil had the largest Nu,which was about 3.8~5.01 times of air,followed by water,steam and air.