Numerical Investigation on the Effects of Cavity-Blowing Jet on Intermediate Turbine Duct Flowfield

Abstract

Intermediate turbine duct is an important part of engine, which guides the hot gas from upstream high-pressure turbine to downstream low-pressure turbine without much loss. To promise such goal, much work has been done to investigate flow mechanism in this kind of duct as well as its design criterion with numerical and experimental methods. Usually intermediate turbine duct simplified from real engine structure was adopted with upstream and downstream blades. However, cavity-blowing jet exists to disturb the duct flow field in real engine to change its performance. Naturally, the wall vortex pair would develop in different ways. In addition to that, the blowing jet flow rate changes at different engine representative operating conditions. This paper deals with the influence of cavity-blowing jet on the aerodynamic performance of an aggressive intermediate turbine duct. The objective is to reveal the physical mechanism of blowing jet ejected from the wheel-space and its effects on the duct flow field. First, ten cases with and without cavity are simulated simultaneously. On one hand, the influence of cavity structure without blowing jet on the flow field inside duct would be discussed. On the other hand, the effect of blowing jet rate on flow field could be analyzed to investigate the mechanisms at different engine operating conditions. Second, seventy other more configurations with different cavity inlet swirl angle have been discussed to study its influence on the flow mechanisms in the ducts.