摘要
Abstract
Fuel cell powered Unmanned Aerial Vehicle(UAV),characterized by long endurance,low infrared radia-tion,low carbon emission,has become a promising technology for future UAV designs.Considering the high heat loads and small temperature difference during heat exchange,the present study develops a thermal management sys-tem and the corresponding control strategy of fuel cell for liquid hydrogen powered UAV.Utilizing the cold energy of liq-uid hydrogen for fuel cell cooling,the proposed thermal management system effectively provides a new idea for the fu-ture design and optimization of UAV thermal management.Based on the proposed thermal management system,a simulation study is conducted on the operation process of thermal management system under typical flight phases.The results indicate that:Based on the developed thermal management model,the temperature of fuel cell is effec-tively controlled for each flight phase.The maximum and minimum outlet temperature of the liquid coolant is 70℃and 14.6℃,respectively.The liquid coolant temperature at the fuel cell outlet can be maintained at 65℃during cruise.Meanwhile,the internal pressure of liquid hydrogen tank is stably maintained at 0.5±0.04 MPa.For the takeoff phase which the heat loads reach the maximum value,the expendable hydrogen is applied as heat sink for thermal manage-ment.This method can reduce the air intake area,and subsequently avoid the liquid coolant freezing at high altitude.Under the premise of consistent minimum temperature in the thermal management system,ethylene glycol aqueous solution carries less mass than water,has a greater temperature difference between the solidification point that has lower solidification risk,but consumes more liquid hydrogen during the climbing phase.Based on the simulation re-sults,the prediction model is proposed for the mass of consumed liquid hydrogen during takeoff.The model has sig-nificant guiding value in optimal design of fuel cell thermal management system for UAV.关键词
液氢/无人机/氢燃料电池/热管理系统/动态分析Key words
liquid hydrogen/UAV/PEMFC/thermal management system/dynamic analysis分类
航空航天
