涡喷发动机对湍流型动态畸变响应的试验研究

 本文介绍涡喷发动机对湍流型动态畸变的响应。湍流型动态畸变是用发动机进口截面的叶根或叶尖挡板造成的,挡板的周向范围为180°,这个范围内的堵塞比为50％。这两种动态畸变发生器分别在发动机进口截面的叶根或叶尖部分产生相当强烈的湍流型动态畸变,在发动机转速（n）=1.0时,都会引起涡喷发动机出现“漂移型”喘振。本试验还对小一导（涡轮第一级导面器出口截面减小12％）的涡喷发动机进行研究,试验结果表明,（n）=0.9,同样挡板所造成的湍流型动态畸变也引起发动机“漂移型”喘振。（n）=0.87时,在“净”进气条件下,发动机出现的不稳定为深喘振,而在网格造成的进气畸变下,发动机出现的为古典喘振。这些结果表明,除了转速之外,发动机的不稳定性态还与进气条件有关。

AN EXPERIMENTAL INVESTIGATION ON RESPONSE OF TURBOJET ENGINE TO THE TURBULENCE-TYPE OF DYNAMIC INLET DISTORTION

The response of turbojet engine to the turbulence-type of dynamic inlet total pressure distortion is discussed in this paper. The turbulence-type of dynamic inlet distortion is generated by a blockage plate with 180° circumferential extent and 50% blockage ratio in the blade-tip or blade-hub region of the inlet section. The dynamic distortion generators with either a tip-plate or a hub-plate can set up a very strong pressure fluctuation region respectively at the tip or the hub of the blade. The measurements show that the Amplitude Probability Density （APD） of fluctuating total pressure approximately follows the Normal Distribution, and thus the dynamic distortion generated by the plate is a turbulence-type.The results from testing also show that: （ 1 ） the turbulence-type of dynamic inlet distortion always cause in the engine a "drift-mode" of surge at 100% engine speed, and at 90% engine speed in the case of a decrease about 12% in the first stage turbine-nozzle area; （ 2 ）the inlet distortion generated by the screen produces a "classical-mode" or "deep-mode" of surge; （ 3 ） the degree of the inlet distortion by the screen can change the mode of surge, for example, either when the inlet flow changes from "clean" to distorted at n = 0.87 or when the degree of distortion D = （Ptav. -Ptmin）/Ptav.] varies from 0.132 to 0.173 at n = 0.9, a deep-mode surge may be turned into a classical mode; （ 4 ） a decrease in turbine-nozzle area also can change the mode of surge; （5） the engine speed can affect the unstable behaviour of the compressor. At 71.6% engine speed, the instability of the compressor always appears as an overall rotating stall, and at n@0.87, the engine instability is a surge.