Abstract A numerical analysis has been performed on a real-scale infrared suppression device to estimate the air entrainment and corresponding temperature drop of the exhaust gases flowing through it. The analysis of the IRS device is done for the exhaust of a gas turbine plant installed on a naval warship. The operational data used in the analysis has been taken from LM2500 series gas turbine from GE. The numerical method solves the three dimensional, incompressible Navier-Stokes equations, the mass continuity equation and the two-equation based eddy viscosity model for the turbulent k-epsilon equations along with the energy equation in the flow field. The effect of using different number of nozzles at the gas turbine exit on the air entrainment and the exit plume temperature has been discussed. The results show that the maximum air entrainment and minimum plume temperature can be achieved by using four to six numbers of nozzles. The air entrainment and the exit plume temperature are also affected by the pitch circle diameter of the nozzle placement. The maximum air entrainment and minimum exit temperature is achieved at a pitch circle diameter of 1.6 m. The air entrainment considerably increases with the nozzle-exit Reynolds number (Re). The higher Reynolds number also ensures the minimum plume temperature at the exit of IRS device. Air entrainment gradually reduces with the nozzle protrusion. The highest entrainment is observed when the nozzles are flush with the bottom plane of the IRS device. However, the nozzle protrusion does not affect the exit plume temperature significantly. The funnel overlap height adversely affects the performance of the IRS device i.e. the air entrainment continuously decreases with increasing funnel overlap height. Moreover, increasing funnel overlap also causes the exit plume temperature to rise considerably.

中文翻译：

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真实尺度锥形红外抑制（IRS）装置的空气夹带和出口温度数值分析

摘要 对实际尺度的红外抑制装置进行了数值分析，以估计流经该装置的废气的夹带量和相应的温降。IRS 装置的分析是针对安装在海军军舰上的燃气轮机装置的废气进行的。分析中使用的运行数据取自 GE 的 LM2500 系列燃气轮机。数值方法求解三维不可压缩纳维-斯托克斯方程、质量连续性方程和基于二维方程的涡流粘度模型，用于湍流 k-ε 方程以及流场中的能量方程。讨论了在燃气轮机出口使用不同数量的喷嘴对空气夹带和出口烟羽温度的影响。结果表明，使用 4 到 6 个喷嘴可以实现最大的空气夹带和最小的烟羽温度。空气夹带和出口烟羽温度也受喷嘴位置的节圆直径的影响。节圆直径为 1.6 m 时可实现最大空气夹带和最小出口温度。空气夹带随着喷嘴出口雷诺数 (Re) 的增加而显着增加。较高的雷诺数也确保了 IRS 设备出口处的最低烟羽温度。随着喷嘴突出，空气夹带逐渐减少。当喷嘴与 IRS 设备的底部平面齐平时，观察到最高的夹带量。然而，喷嘴突起不会显着影响出口烟羽温度。漏斗重叠高度不利地影响IRS装置的性能，即随着漏斗重叠高度的增加，夹带空气不断减少。此外，增加漏斗重叠也会导致出口烟羽温度显着升高。