热交换器式热量表中热交换器的优化设计研究

Research of Optimal Design of Heat Exchanger in Heat Exchanger Heat Meter

在热交换器式热量表中,热交换器相当于流量计,只需测量热交换器进出口温度,就可以计算出流量和热量,有效避免了由于水质问题引起的流量计丧失准确性及损坏问题;但是由于热交换器模型比较复杂,很难用解析法得到流量与温度之间的关系式,对热交换器结构的设计和优化造成了困难;针对上述问题,借助CFD数值模拟软件,建立热交换器的三维模型,在并行计算平台上进行了求解,从而得到了热交换器流量和温差比的关系,并结合模式搜索法对热交换器的结构进行了优化;仿真结果表明,采用该优化方法后,热交换器的性能评价指标R2得到了有效的提高;参照优化后的模型参数,设计和加工了热交换器,并进行了实验验证,实验结果表明,热交换器的R2为0.989,与仿真结果0.987吻合的很好,表明了该优化方法的有效性,且具有较好的实用性和推广价值。

In heat exchanger heat meter, heat exchanger is equivalent to a flowmeter. Flow and heat can be calculated by measuring inlet and outlet temperature of heat exchanger. It greatly prevents the flowmeter from the problems of inaccuracy and damage which are caused by quality of water. However, due to the complexity of the heat exchanger model, it is difficult to get an expression between flow and tempera ture through analytic methods. This makes a great difficulty to design and optimize the structure of heat exchanger. To solve the problem a- bove, we establish a three--dimensional model of heat exchanger by means of CFD numerical simulation software. By solving it in parallel computing platform, we get the relationship between flow and temperature, and optimize the structure of the heat exchanger by means of pat tern search method. Simulation results show that after using this optimization method, the performance evaluation R2 of heat exchanger has been effectively improved. Basing on the optimized model parameters, we design and process the heat exchanger. The experiment conclude that the R2 of heat exchanger is 0. 989 which is consistent with the simulation data 0. 987 very well. It shows that the optimization method is effective, practical and valuable.