基于共轭传热计算的换热器热应力分析

次级换热器属于机载环控系统的主要附件,负责冷却涡轮压气机后的高温高压空气。为了分析某次级换热器服役过程中产生的热应力,首先对其传热与流动进行数值模拟,建模时针对产品的结构特点划分为周期性单元以及侧板单元两类计算模型,并提出将周期性单元的周期边界结果传递到侧板单元中作为约束条件的数值模拟策略,通过侧板单元中的共轭传热计算得到了结构上的温度分布；然后对换热器整体进行分析,在侧板结构上加载所获取的温度场结果并设置其他约束条件得出热应力分布。对比实验数据发现,数值模拟结果误差均在10%以内,共轭传热数值模拟策略在航空换热器热应力分析中的有效性得到了验证。

Thermal Stress Analysis of Heat Exchanger Based on ConjugateHeat Transfer Calculation

The secondary heat exchanger is the main accessory of the airborne environmental control system and is re-sponsible for the high temperature and high-pressure air after cooling the turbo compressor. In order to ana-lyze the thermal stress generated during the service of a secondary heat exchanger. Firstly, the heat transfer and flow are numerically simulated. According to the structural characteristics of the product, the model is divided into two types: periodic unit and side plate unit. A numerical simulation strategy is proposed to trans-fer the periodic boundary results of periodic elements to the side plate unit as a constraint condition. The temperature distribution of the structure is obtained by conjugate heat transfer in the side plate unit; Then, the overall model of the heat exchanger is analyzed, and the obtained temperature field results are loaded on the side plate structure and other constraints are set to obtain the thermal stress distribution. Comparing the experimental data, the maximum error of numerical simulation results is about 10%, the effectiveness of the conjugate heat transfer numerical simulation strategy in the thermal stress analysis of aerospace heat ex-changers is verified.