Abstract: In order to suppress the infrared characteristics of turbofan engine exhaust system，the performance seeking control for minimum infrared characteristic mode based on infrared prediction model is proposed. Firstly, a simplified forecasting method of backward infrared radiation intensity of exhaust system is established. The prediction method which has credible simulation accuracy takes into account the infrared radiation of the high temperature components and the tail jet in the exhaust system, and the absorption of infrared radiation of the high temperature components by the tail jet. Secondly, based on the component level real-time simulation model of a turbofan engine, the cooling structure of the center cone and the inner wall of nozzle expansion section and infrared prediction module are added. Finally, based on this model，the optimization principle of the minimum infrared characteristic mode is explored, and the feasible sequential quadratic programming (FSQP) algorithm is selected to optimize the two working points of subsonic cruise state in real time by controlling the flow rate of high temperature wall cooling gas, the fuel quantity of the main combustion chamber and the throat area of the tail nozzle. The simulation results show that under the condition of constant thrust and other constraints, the forward and backward infrared radiation of exhaust system decreases by more than 30% and the infrared suppression effect is remarkable through the performance seeking control of minimum infrared characteristic mode.

Key words: Turbofan engine;Infrared characteristics;Performance seeking control;High temperature wall cooling;Exhaust system

摘要： 为抑制涡扇发动机排气系统的红外特征，提出一种基于红外预测模型的最小红外特征模式性能寻优控制。首先，建立一种排气系统正后向红外辐射强度简化预测模型，该预测方法考虑了排气系统内高温部件和尾喷流的红外辐射，以及尾喷流对高温部件红外辐射的吸收作用，具有可信的仿真精度；其次，基于涡扇发动机部件级实时仿真模型，增加了从外涵引气冷却中心锥和尾喷管扩张段内壁的冷却结构和红外预测模块；最后，基于该模型探索了最小红外特征模式的优化原理，并选用可行序列二次规划（FSQP）算法，通过控制高温壁面冷却气的流量，主燃烧室的燃油量以及尾喷管喉道面积，对两个亚声速巡航状态的工作点进行实时优化。仿真结果表明：在满足发动机推力恒定以及其他约束条件的前提下，发动机通过最小红外特征模式性能寻优控制，其排气系统后向红外辐射下降了30%以上，红外抑制效果显著。

关键词: 涡扇发动机;红外特征;性能寻优控制;高温壁面冷却;排气系统