Windage Characteristics of a Compressor Stator Well Cavity

This article aims at the investigation of a generic compressor stator well cavity flowfield of a high pressure compressor stage. Swirl ratio, static pressure distributions are thoroughly investigated together with windage power for three different engine thrust levels and three different clearance levels at high thrust cases. An experimental test case from Kong et. al [3]–[4] has been selected to validate the numerical method at five rotational speeds and two pressure ratios employing measured/predicted labyrinth seal clearances. One-dimensional cavity solver with three cavity approach is also employed to compare the results with experimental data. Contrary to a rotorstator cavity with radial inflow, stator well cavity flow displays a reduction in swirl ratio throughout the entire well and increase in windage power loss with higher λT, essentially with more flow. This is because well cavities are too shallow and located at high radii with low swirl leakage inflow, where torques dominate and dictate swirl distributions. Upstream cavity on the right hand side of the seal and labyrinth seal cavity are found to determine the windage power loss and associated temperature rise. The effect of downstream cavity located on the left hand side of the labyrinth seal is found to be less important.