Abstract

Secondary power system based on gas turbine engine is usually used for starting the aircraft main engine at ground and finds similar application in air during the emergency. The secondary power system comprises of an auxiliary power unit (APU) and an air starter. APU provides stand-alone power to the main engine subsystems and air to the air starter for starting main engine. The main rotor system of APU is to be designed for safe operation during the ground critical speed crossing and maneuver loading. The weight of such a rotor system is an important design criterion. In the current work, multi-objective optimization using hybrid genetic algorithm (HGA) is employed for simultaneously minimizing the response at critical speed, the response during maneuvering, and shaft weight of the APU rotor system used in secondary power system of an aircraft. The shaft considered is a stepped one and is modeled using Rayleigh beam elements with three disks. Effects due to gyroscopic effect are also included in the analysis. A Pareto front is generated, and subsequently, an optimal solution is selected for the problem. The comparison with typical two-objective optimization result, having response at critical speed and shaft weight as objectives and response during maneuvering as constraint, has shown that the novel three-objective optimization has provided the designer with improved design choices for the selection of final compromise solution.

摘要

基于燃气涡轮发动机的二次动力系统通常用于在地面启动飞机主机，并在紧急情况下在空中找到类似的应用。二次动力系统由辅助动力装置 (APU) 和空气启动器组成。APU 为主机子系统提供独立电源，并为空气启动器提供空气以启动主机。APU 的主旋翼系统设计用于在地面临界速度穿越和机动装载期间的安全运行。这种旋翼系统的重量是一个重要的设计标准。在目前的工作中，使用混合遗传算法（HGA）的多目标优化被用于同时最小化飞机二次动力系统中使用的APU旋翼系统的临界速度响应、机动响应和轴重。所考虑的轴是阶梯式的，并使用带有三个圆盘的瑞利梁单元进行建模。陀螺效应造成的影响也包括在分析中。生成一个帕累托前沿，然后为问题选择一个最优解。与典型的以临界速度和轴重响应为目标，机动响应为约束的两目标优化结果的比较表明，新颖的三目标优化为设计人员提供了改进的设计选择，用于最终折衷的选择解决方案。