Investigation of Seal Cavity Leakage Flow Effect on Multistage Axial Compressor Aerodynamic Performance with a Circumferentially Averaged Method

Abstract

The seal cavity leakage flow has a considerable impact on the performance of the aeroengine, especially on the multistage compressor. Thus, a quasi-three-dimensional simulation program named CAM is developed basing on circumferentially averaged throughflow method. The program enables a rapid diagnosis for the performance degradation of multistage compressor caused by labyrinth wear. The coupling flow field between the seal cavity leakage flow and the main flow field at the root of the shrouded stator of a high-loading three-stage compressor with inlet guide vanes (IGV) was simulated by CAM and the results indicate that seal cavity leakage flow has a significant impact on the overall performance of the compressor. That is, for a 1% increase in the seal-tooth clearance-to-span ratio, the decrease in total pressure ratio was 2.6%, and the reduction in efficiency was 0.6%. Stage performance shows that the seal cavity leakage flow reduces the pressurization capacity of the current stator and the work capacity of the downstream rotor, but has little effect on the upstream blade row. Spanwise distribution of blade element performance shows that the leakage flow leads to an increased flow blockage near the hub, resulting in spanwise migration. The incidence of the stator and rear rotor then change through the entire span. The leakage flow leads to the flow blockage and migration and hence changes the incidence angle, which results in the deterioration of compressor performance.

Angle-Regulating Rule of Guide Vanes of Variable Geometry Turbine Adjusting Mechanism

“…The total dissipation rate of the guide vane's suction side and the outlet passage's wall decreased with the increased backflow clearance radius. Liang et al [17] studied the effect of the sealing chamber leakage flow rate on the performance of aviation engines. They found that when the sealing tooth gap span ratio increased by 1%, the total pressure ratio decreased by 2.6%, and the efficiency decreased by 0.6%.…”

Detailed Simulations of a Three-Stage Supercritical Carbon Dioxide Axial Compressor with a Focus on the Shrouded Stator Cavities Flow

“…Spalding's formula, with surface roughness as presented by Shabbir et al [20], was used to correlate terms of skin friction coefficients and Reynold's number and was then used to calculate the rise in temperature. Equations ( 8)- (13) shown below were used to calculate the approximate shear work and the corresponding rise in temperature.…”

“…He used CFD simulations to investigate the effects of the purge flow on the aero and thermal performances of a high-pressure turbine rotor and presents the co-relations between purge flow, cooling and sealing effectiveness, as well as losses. In another work, Liang et al [13] developed a quasi-three-dimensional simulation tool, based on the circumferentially averaged method, to study the effect of seal cavity leakage flow on the aerodynamic performance of a multistage axial compressor, concluding that such a flow has a significant impact on the overall compressor performance. In a recent work, Ghimire et al [6] used CFD simulations to investigate the effects on aerodynamic and thermal characteristics of an axial sCO 2 compressor due to seal cavity leakage flow, employing a steady state mixing plane approach with both adiabatic and non-adiabatic walls.…”

Numerical Heat Transfer and Fluid Flow: A Review of Contributions to the Special Issue

“…This is especially important if high-power generating machines are considered. Liang et al [26] proved that a 1% increase in seal-tooth clearance height causes a significant decrease in multistage axial compressor performance and efficiency. Some researchers are using CFDs to design seals of higher leak tightness.…”