冷却通道对引射器红外辐射特性影响的研究

Influence of a cooling channel on the infrared radiation performance of an ejector

为降低燃气轮机排气系统中的引射器排气温度,从而减少排出燃气的红外辐射强度,本文提出了一种具有冷却通道的亚音速引射器结构,并提出了评价冷却通道引射器的综合系数。在原有的引射器喷嘴内增加冷却通道,使冷气直接与主流中心位置的高温气体掺混,破坏排气包覆性分布,达到提高主流温度均匀性、降低中心温度的目的。本文运用数值模拟的方法,研究引射器内冷却通道数量、冷却通道进深和排气通道的排布对引射器内阻力特性、换热特性、出口温度分布特性的综合影响。研究结果表明:单排冷却通道排布时,通道数量与换热特性成正比,与阻力损失成反比;双排冷却通道排布时,阻力损失降低。双排12通道引射器可有效降低出流总温,均匀主流温度,综合系数最高。

An ejector of a gas turbine exhaust system reduces the temperature of the exhaust stream and decreases the infrared radiation intensity of exhaust gas.This paper presents a subsonic ejector structure with a cooling channel and a comprehensive performance factor for evaluating a cooling channel ejector.A cooling channel is added to the nozzle of the original ejector,and the coolant mixes with the high-temperature gas directly at the center of the mainstream,which can destroy the distribution of exhaust cladding,improve the uniformity of the mainstream temperature,and reduce the temperature in the center.This paper adopts a numerical simulation method to study the comprehensive influence of the number and depth of cooling channels and the layout of exhaust channels on the resistance,heat transfer,and outlet temperature distribution characteristics of the ejector.Reportedly,the number of channels is directly proportional to the heat transfer characteristics and inversely proportional to the resistance loss when single-row cooling channels are arranged.When double-row cooling channels are arranged,the resistance loss is reduced.An ejector with double rows and 12 channels can effectively reduce the total outflow temperature and uniform mainstream temperature,manifesting the highest comprehensive performance coefficient.