高温高湿环境下机载蒸发循环系统动态特性

为探究高温高湿环境对机载蒸发循环系统的影响,基于AMESim平台构建了系统仿真模型,并结合直升机典型飞行剖面,通过比例积分方法控制压缩机转速,实现此环境下系统性能的动态仿真。结果表明,环境温度或湿度越高,系统制冷量越大、COP越小、座舱达到设定温度所需时间越长。高湿环境还会显著增加蒸发器的制冷剂侧压力损失并降低其换热效率。此外,飞行剖面对系统性能的影响较大。地面待飞阶段和爬升阶段,各特性变化较剧烈;巡航阶段,变化均较小;下降阶段,除COP持续下降外,其他特性由于飞行速度和环境温度对座舱热负荷的耦合作用先升后降,飞行阶段内存在明显的峰值;地面停车阶段各参数均趋于稳定。

Dynamic Characteristics of Airborne Vapor Cycle System Under Hot and Humid Environment

In order to explore the influence of hot and humid environment on the airborne vapor cycle system, a simulation model was established based on the AMESim platform. The compressor rotation speed was controlled by the proportional-integral method, and the system characteristics were dynamically simulated under a typical helicopter flight profile. The re?sults show that the ambient temperature and relative humidity have significant influence on the system characteristics. The higher the ambient temperature is or the relative humidity is, the greater the refrigerating capacity is, the smaller the COP is, and the longer it takes to reach the setting temperature. High relative humidity significantly increase the pressure loss of the evaporator and reduce its heat exchange efficiency. Moreover, the flight profile has great influence onsystem characteristics. The system characteristics change dramatically in the ground standby phase and climbing phase,but a little in the cruising phase. In the descending phase, all characteristics increase first and then decrease due to thecoupling effect of flight velocity and ambient temperature on the cabin thermal load, except the COP which keeps declin?ing. Thus, peaks of some characteristics appear in this phase. All characteristics tend to be stable in the ground parkingphase.