利用CFD技术对管壳式换热器壳程结构的模拟分析

Simulation Analysis of Shell Structures of Shell and Tube Heat Exchanger Based on CFD Technology

以某公司所制造的水源热泵为基础,针对制冷量Q_0=180 kW的蒸发器的内部结构,利用CFD枝术对其壳程侧做了流场与热场的模拟分析,得到了具有一定价值的分析结果:1)原设计中不仅单弓形折流板的数量较多而且折流板较厚,占用了一定有效换热面积,势必影响了壳程水侧的换热效果扣造成了较大压降;2)由于进水管侧的水温与制冷剂的蒸发温度之间存在较大的温差,会在管板上产生较大的热应力,有造成管板与换热管的接触破坏的可能;3)通过对原设计的速度矢量分析,可以较为清楚地看到,原设计存在较多的流动死区,这些流动死区,会影响水侧换热。根据这些分析结果,提出了相应地解决方案。

Using CFD technology, a water source heat pump＇s evaporator shell with quantity Q0 = 180 kW is made of fluid flow and temperature field simulation and analysis. It＇s found that：1 ） In the original design, there are a lot of single segmental, with thick baffle plate that occupies some effect beat transfer area,influencing the shell side heat exchange effect and greatly dropping tbe water pressure;2 ） because of the temperature difference between water and the evaporation temperature of refrigerant, larger thermal stress is produced, with possibility of breakage in tube plate and tube heat exchanger;3 ） based on speed vector analysis of the original design, it＇s easy to find lots of dead zone in the original design, which will affect the water side heat exchanger. According to these results, corresponding solutions are put forward, establishing the improved evaporator model.