低参数下试验回路主热交换器换热能力分析

燃料组件在高温高压试验回路中的稳态辐照考验是揭示燃料抗辐照性能以及验证新型燃料组件在投入工程应用前安全性的必经阶段。针对高温高压稳态考验，研究了低参数工况对高温高压试验回路主热交换器换热能力的影响，研究表明，两台主热交换器并联运行时的总换热功率并非总是高于单台独立运行，在一次水入口相对流量40%和温度330℃下，两台主热交换器并联运行的功率反而较单台运行时低3.9%～4.3%。同时存在一个流量转折点，在该流量转折点之上，两台主热交换器并联运行才具有实质意义。建立了通过分段拟合求解流量转折点的方法，整体求解了在不同一次水入口温度下的流量转折点，通过拟合求解与计算求解获得的流量转折点平均差异为0.6%,而对应的换热功率平均偏差为1.8%。并且进一步提出在低参数运行工况下，可以采用主热交换器串联的方式解决换热功率不足的问题，在一次水入口温度250℃时，串联运行时的换热功率要较单台或两台并联运行时的最大功率平均高出77.5%。

Analysis of the Heat Exchange Capability of the Main Heat Exchanger in the Test Loop under Low Parameters

The steady-state irradiation test of the fuel assembly in the test loop with high temperature and pressure is a necessary stage to reveal the anti-irradiation performance of the fuel and verify the safety of the new fuel assembly before it is put into engineering application. The influence of low parameter conditions on the heat transfer capacity of the main heat exchanger in the test loop during steady-state irradiation was studied. It is shown that the heat transfer power of two regenerative heat exchangers in parallel operation is not always higher than that of a single independent operation. When the relative flow of the primary water inlet is 40% and the temperature is 330°C, the power of two main heat exchangers operating in parallel is 3.9%~4.3% lower than that of a single unit. There is a flow turning point, and only above this flow turning point, the parallel operation of two regenerative heat exchangers is of practical significance. A method for solving the flow turning point through segmented fitting was established and the flow turning point at different primary water inlet temperatures was solved. The average difference between the flow turning point obtained by the fitting solution and the calculation solution is 0.6%, and the average deviation of heat transfer power is 1.8%. It is further proposed that the main heat exchanger can be connected in series to solve the problem of insufficient heat exchange power. When the primary water inlet temperature is 250°C, the heat exchange power in series operation is 77.5% higher than maximum power in parallel or in a single unit operation.