How to establish a general fuel tank thermodynamic model that meets the requirements of airworthiness certification and how to obtain the equilibrium temperature difference △T and time constant τ in the Monte Carlo evaluation model after obtaining the fuel temperature change law within specific flight envelope are the bottleneck issues need to be solved urgently in the airworthiness certification process of fuel tank flammability. This paper builds the fuel temperature simulation calculation model on the MATLAB/Simulink software platform to obtain the fuel temperature change law and obtains the high-order functional expression of the fuel temperature change law in each stage by means of MATLAB polynomial piecewise fitting function. The exponential attenuation equation stipulated in the Monte Carlo evaluation model is used to characterize the change law of fuel temperature. Among which the total ambient temperature (TAT) is obtained by the method specified in the evaluation model, and the equilibrium temperature difference and time constant are obtained by the improved genetic algorithm. The equilibrium temperature difference and time constant obtained by the inversion are input into Monte Carlo model for calculation, the calculated temperature data and the actual measured flight data are compared to verify the reliability of the method.

如何建立满足适航审定要求的通用油箱热力学模型，在获得特定飞行包线内的燃油温度变化规律后，如何在蒙特卡罗评价模型中求出平衡温差△T和时间常数τ是瓶颈燃油箱可燃性适航审定过程中亟待解决的问题。本文在MATLAB/Simulink软件平台上建立燃油温度仿真计算模型，得到燃油温度变化规律，并借助MATLAB多项式分段拟合函数得到各阶段燃油温度变化规律的高阶函数表达式。采用蒙特卡罗评价模型中规定的指数衰减方程来刻画燃油温度的变化规律。其中总环境温度(TAT)通过评价模型中规定的方法得到，平衡温差和时间常数通过改进遗传算法得到。将反演得到的平衡温差和时间常数输入蒙特卡罗模型进行计算，将计算温度数据与实测飞行数据进行对比，验证了该方法的可靠性。