发动机短舱泄压过程瞬态仿真

发动机短舱泄压门的设计会影响到短舱的安全性，泄压是一个动态变化过程，与舱内外压力、外界气流马赫数及泄压门结构有关。基于Modelica语言建立了短舱泄压过程零维瞬态仿真数学模型，并通过计算流体力学（CFD）方法得到不同开启角度下所需泄压门排放质量流量和力矩系数，并将这些系数代入零维瞬态仿真数学模型，得到了短舱泄压过程中舱内压力、泄压门开启角度等关键参数随时间的变化关系，分析了泄压门开启舱内压力阈值及最大开启角度对泄压过程的影响。研究结果显示，降低泄压门开启舱内压力阈值会使泄压过程到达平衡阶段时间减小，但是对平衡阶段舱内压力和往复摆动角度/幅度无影响。适当降低最大开启角度可有效降低泄压平衡阶段往复摆动角度/幅度，而对初始阶段的泄压速率和平衡阶段的短舱内部压力基本无影响，但是随着最大开启角度进一步降低，则会导致泄压速率下降，并使平衡阶段短舱内部压力升高。 

Transient simulation on pressure relief process of engine nacelle

The design of the engine nacelle pressure relief door will affect the safety of the nacelle. The pressure relief is a dynamic process, which is related to the pressure inside and outside the nacelle, the freestream Mach number and the structure of the pressure relief door. Based on the Modelica language, a zero-dimensional transient simulation mathematical model of the nacelle pressure relief process was established, and the pressure relief door (PRD) discharge and moment coefficient under different opening angles were calculated via computational fluid dynamics (CFD). Then those coefficients were substituted into the zero-dimensional transient simulation model, and the variation relationship of key parameters such as the plenum compartment pressure and opening angle of the PRD with time during the pressure relief process is obtained. The influence of the plenum compartment pressure threshold and the maximum opening angle of the PRD on the pressure relief process was analyzed. The study results show that reducing the plenum compartment pressure threshold for PRD opening will reduce the time required for the pressure relief process reaching to the equilibrium stage, but has no effect on the plenum compartment pressure and reciprocating swing angle/amplitude at equilibrium stage; properly reducing the maximum opening angle can effectively reduce the PRD reciprocating swing angle/amplitude in the equilibrium stage, and has no effect on the pressure relief rate in the initial stage and the plenum compartment pressure in the equilibrium stage, but excessive reduction of the maximum opening angle will decrease the pressure relief rate in the initial stage and increase plenum compartment pressure in the equilibrium stage.