航空发动机起动过程摩擦阻力矩计算分析

扭矩特性分析是航空发动机起动仿真数学模型建立的重要环节,其中摩擦阻力矩因缺少相应的经验公式难以确定。为了得到起动过程的摩擦阻力矩,借助于某型发动机台架试车数据,根据转速变化率与扭矩的关系,在冷态和热态2种条件下分别对转速变化率和阻力矩进行计算,得到了冷、热态下发动机起动过程摩擦阻力矩,并分析了大气温度对冷态阻力矩的影响规律。以此建立起动过程数值仿真模型,完成了摩擦阻力矩对起动过程转速的影响分析。计算结果表明:摩擦阻力矩随着发动机转速的增加呈减小趋势;在冷态条件下,随着大气温度的降低,摩擦阻力矩逐渐增大;起动过程转速变化率随之减小。

Calculation and Analysis of Friction Resistance Moment in Aeroengine Starting Process

The analysis of torque characteristics was an important part of the establishing mathematical model of aeroengine starting simulation.The friction resistance moment was difficult to be determined because of the lack of the corresponding empirical formula.In order to obtain the friction resistance moment in the starting process,according to the relationship between the rotating speed and the torque,the rotating speed and the resistance moment were calculated by an engine bench test data under the cold and hot conditions.The friction resistance moment in the engine starting process was obtained under the cold and hot conditions,and the influence law of atmospheric temperature on the cold condition resistance moment was analyzed.The numerical simulation model of starting process was established,and the influence of friction torque on starting speed was analyzed.The calculation results show that the friction torque decreases with the increase of engine speed.Under the cold condition,the friction torque increases gradually with the decrease of atmospheric temperature,then the rotating speed decreases in the starting process.