基于空气绝热的飞机空气导管绝热设计

在分析现有飞机泄漏探测系统性能的基础上,提出了一种基于多层绝热的飞机空气导管泄漏探测结构.推导了该种多层绝热的工程计算方法,并对不同管径的导管进行了绝热层设计计算.其次,为了验证该计算方法的准确性,搭建了高温压力管道空气绝热试验平台,获得了不同温度下空气绝热层的外表面温度.同时,采用数值分析方法进一步考察了导流洞数量及导流洞直径对绝热设计计算的影响.最后,根据导流洞对绝热设计的影响进行了结构优化.研究结果表明:该结构与传统的泄漏探测系统相比具有对泄漏的高温气流具有快速导流作用,保证泄漏探测系统能及时探测到泄漏信号并作出报警响应;绝热层外表面温度的计算值比试验值偏大,最大误差为23.08%.随着导流洞孔径和个数的增加,绝热层外表面的平均温度减少,并且导流洞个数的增加对绝热层外表面温度的影响较大.该研究结果为飞机空气导管的国产化提供参考依据. 

Insulation design of aircraft pneumatic duct system based on air insulation

Based on the study of the performance of existing duct leakage detection system of commercial aircraft, an improved leakage detection system based on multilayer insulation design method was proposed. Also, the calculation method of multilayer insulation design was derived with engineering calculation method and the calculation of the insulation with different diameters was conducted. Meanwhile, in order to testify the accuracy of the method, the leakage detection experiment platform was built, and the outside surface temperature of air insulation in different air temperatures was obtained. Also, the influences of the number and the diameter of the diversion channel on the insulation calculation were investigated by numerical simulation. Finally, an optimized structure of the air detection system was proposed. The results show that the improved leakage detection system with quick diversion performance is superior to the traditional leakage detection system since the leakage signal can be detected in time and the alarm system can react quickly. Besides, the outside surface temperature of the insulation is averagely 23.08 percent larger than that of test, and decreases with the diameter and the number of the diversion channel. Also, as the number of the diversion channel increases, the influence of the diversion channel is more remarkable. This work could be helpful to domestic design of China's civil-aircraft ducting system.