江水源热泵套管式换热器换热效率的实验研究和模拟分析  

Experiment and Simulation on Heat Transfer Efficiency of Double-pipe Heat Exchanger for River Water-source Heat Pump

作　　者：周智勇[1,2] 王子云[3] 付祥钊[1] 王勇[1] 何华[1] 

机构地区：[1]重庆大学城市建设与环境工程学院,重庆400045 [2]华东交通大学土木建筑学院,南昌330013 [3]中铁二院工程集团有限责任公司,成都610031

出　　处：《土木建筑与环境工程》2009年第4期82-87,共6页Journal of Civil,Architectural & Environment Engineering

基　　金：十一五国家科技支撑计划项目(2006BAJ01A06-3)

摘　　要：利用长江水源的江水源热泵系统是重庆市可再生资源利用的重要形式,其换热器的性能对系统能效具有显著的影响,论文研究了使用半圆环形折返管的套管式换热器的换热效率。实验证明折返管曲率的增加可以有效地提高换热器的换热效率,与直管套管式换热器相比,当R/r=5时,其换热效率可提高2.5%。为分析半圆环形折返管的换热机理,论文利用计算流体力学(CFD)进行了流动、温度场和换热模拟。为保证在旋转流和大曲率情况下计算的准确性,模拟分析采用了修正后的RNGk-ε湍流模型,模拟分析的结果表明:折返管内存在者明显的二次流漩涡,它对边界层的扰动是造成换热器换热效率随着折返管曲率增加而提高的主要原因。论文综合实验和模拟分析结果,同时考虑江水的泥沙问题和换热效率,给出了半圆环形折返换管的适宜曲率。The river water-source heat pump system is an important technique to utilize renewable energy in Chongqing and heat exchanger can influence overall energy efficiency of system obviously. A test was carried out to study the heat transfer efficiency of double-pipe heat exchanger with semicircular reentrant tube. It was found that the heat transfer efficiency would increase while curvature of semicircular reentrant tube rose. And when the ratio of R to r was five, heat transfer efficiency for semicircular reentrant tube would be increased 2.5% than that of straight double-pipe heat exchanger. Flow, temperature field and heat transfer process of semicircular reentrant tube were simulated with computational fluid dynamics （CFD） tool to study the heat transfer mechanism. The modified RNG κ-ε Turbulence Model was adopted to ensure the accuracy of simulation analysis under the situation of rotary flow and great curvature. Thus, it was indicated that there was obvious secondary flow vertex in reentrant tube. And disturbance of vertex on boundary layer was the main reason for which heat transfer efficiency of double pipe heat exchanger would increase as curvature of semi-toroidal reentrant tube rose. Based on the experiment and simulation, the recommended curvature for reentrant tube was proposed with the consideration of sediment in river-water and heat transfer efficiency of heat exchanger.

关 键 词：换热器 半圆环折返管 换热效率 二次流漩涡 

分 类 号：TU831.4[建筑科学—供热、供燃气、通风及空调工程] TF066.2[冶金工程—冶金物理化学]