民用飞机预冷器设计点选取方法研究

预冷器是民用飞机气源系统温度调节的重要部件，若发生超温将导致系统自动关闭，影响下游机翼防冰系统和空调等系统用气需求，对飞机安全性有重要影响，因此研究预冷器设计点满足温度调节需求对气源系统设计有着重要意义。首先分析了预冷器换热性能影响关系，进而对其性能影响因素进行分析，主要包括环境条件信息，飞机状态信息，气源系统引气构型。然后根据经验公式对某机型不同工况条件下预冷器换热功率因子进行计算。计算结果表明在严酷引气构型双发单引气条件下，极热天巡航或待机状态下，低高度、低马赫数、低重量条件为预冷器设计点。通过计算严酷工况下预冷器热边出口温度，对预冷器设计点进行校核，计算结果表明预冷器热边出口温度均满足预冷器预期温度，说明预冷器设计点选取满足设计需求。

Design point selection method of pre-cooler for civil aircraft

The pre-cooler is an important part of the temperature adjustment of the pneumatic system of the civil aircraft. Over temperature of the system will lead to automatic shutdown of the system, which will affect the demand of downstream wing anti-icing system and air conditioning system, and have a significant impact on the safety of aircraft. Therefore, the research on the pre-cooler design point is of great significance to the design of the pneumatic system. Firstly, this article analyzes the influence relationship of the heat transfer performance of the pre-cooler, and then analyzes the factors affecting the performance of the pre-cooler, including environmental conditions information, aircraft state information and air source configuration. Then, according to the empirical formula, the heat transfer power factor of precooler under different conditions of a certain model was calculated. The calculation results show that low altitude, low Mach number, and low weight are the pre-cooler design points under the dual-engine single-bleed configuration, in extremely hot day, under cruise or holding operating conditions. In addition, this paper verifies the design point of the precooler by calculating the hot side outlet temperature of pre-cooler under harsh working conditions. The calculation results show that the hot edge outlet temperature of the pre-cooler meets the expected temperature of the precooler, indicating that the selection of the design points of the pre-cooler meets the design requirements.