基于NSGA-Ⅱ的燃气轮机排气引射装置多目标优化设计

Multi-objective optimization design of gas turbine exhaust ejection device based on NSGA-Ⅱalgorithm

[目的]排气引射装置是舰船燃气轮机进排气系统的重要组成部分,保证排气引射装置的排气与引射性能对船舶的正常运行至关重要。[方法]针对某型燃气轮机排气引射装置的结构特点,选取8个关键的设计参数作为优化变量,2个关键性能指标作为目标函数,通过单因素影响分析,获得目标函数与各设计变量之间的变化规律,确定与目标函数相关性较大的2个设计变量。然后在此基础上,基于多目标优化遗传算法NSGA-Ⅱ对设计参数进行优化,并将选定的优化方案放入燃气轮机进排气系统一体化模型中进行验证。[结果]结果显示,相比原方案,优化后的排气引射装置能显著提升燃气轮机箱装体的引射率,满足排气引射量的设计要求,但同时也会导致排气蜗壳出口总压增加。[结论]所做研究对燃气轮机排气引射装置的设计与优化具有一定的参考价值。

[Objective]The exhaust ejection device is an important part of a ship’s gas turbine intake and exhaust system.It is very important to ensure the exhaust and ejection performance of the exhaust ejection device for the normal operation of the ship.[Methods]According to the characteristics of this type of gas turbine exhaust ejection device,this paper selects eight relevant structural parameters and two objective functions in order to analyze the parameter correlation,and determines the two design variables that have the greatest correlation with the objective function.On this basis,the design parameters are optimized based on the multi-objective optimization genetic algorithm NSGA-Ⅱ,and the selected optimization scheme is applied to a gas turbine intake and exhaust system assembly model for verification.[Results]The results show that,compared with the original scheme,the optimized exhaust ejection device has a significantly improved ejection flow rate of the gas turbine casing,meeting the design requirements of the exhaust ejection amount,but this also leads to an increase in exhaust back pressure.[Conclusion]The research approaches and results obtained in this paper have certain reference value for the design and optimization of gas turbine exhaust ejection devices.