气动发动机输出扭矩无因次分析

针对气动发动机的工作过程,利用能量方程、气体状态方程、连续性方程及运动过程方程建立气动发动机的非线性微分方程组.选取合适的基准量,对所建立的微分方程组进行无因次化,得到无因次化的数学模型.利用MATLAB/Simulink仿真工具,对无因次数学模型进行研究,得到各无因次量对气动发动机输出扭矩的影响.从仿真结果可以看出,气动发动机的无因次转速、进气门面积比例因子、排气门面积比例因子以及进气持续角度对气动发动机的无因次输出扭矩影响较大.当发动机转速升高扭矩急剧下降时,可以通过调整进气门面积比例因子、排气门面积比例因子以及进气持续角度使输出扭矩恒定.

Dimensionless study on outlet torque characteristics of an air powered engine

Aiming at the process of an air powered engine, the energy equation, gas state equation, continuity equation and momentum equation were used to set up non-linear differential equations of an air powered engine(APE). By selecting the appropriate reference values, the basic mathematical model was transformed to a dimensional expression. Using MATLAB/Simulink for simulation, the dimensionless outlet torque characteristics of APE were obtained. Through analysis, it can be seen that the dimensionless outlet torque of APE was mainly determined by the dimensionless crankshaft speed, the inlet effective area scaling coefficient, the outlet effective area scaling coefficient and the duration angle. The dimensionless outlet torque could be regulated by charging the inlet effective area, the outlet effective area and the duration angle to fit the change of crankshaft speed.