Numerical Investigation On Flow And Ingression Of Disc Cavity In The Presence Of Mainstream External Flow

In the modern gas turbine engines, it is very meaningful to improve the sealing system of disc cavity in order to increase the efficiency of turbine system. Minimum flow rate to prevent mainstream from ingressing into cavity summarized either by experiment or numerical simulation is critical to improve the sealing system of disc cavity.Software FLUENT6.1.2 was used to compute the axisymmetric flow as well as sealing characteristics in disc cavity system. Segregated steady implicit solver and the Realizable k-epsilon turbulent modal was used in the simulation. SIMPLE arithmetic with second order upwind format., were used in pressure velocity coupling.Rotor-stator disc cavity system and rotor-rotor disc cavity system were investigated in the paper. It is much more approaching the realistic condition to take the influence of mainstream external flow on disc cavity system into consideration. Numerical simulation was used to study the flow and sealing characteristics in disc cavity system in the presence of mainstream external flow. The minimum flow rates were calculated under different Rotational Reynolds number and External Reynolds number, and compare the calculated data with the experimental results shows that they match very well. The paper also analysed the influencing factors of minimum flow rate to prevent mainstream from ingressing into cavity and proposed that besides external Reynolds number and rotational Reynolds number, the pressure difference between mainstream and cavity is also an important factor to control the minimum flow rate. The minimum flow rate increases as the pressure difference increase under the same external Reynolds number and rotational Reynolds number. Additionally, the minimum flow rates of three different disc cavity systems were compared in the paper.Calculation of the minimum flow rate to prevent mainstream from ingressing into cavity by numerical simulation is a contribution to the design of the cooling system of disc cavity. It is meaningful to the subsequent investigation of mainstream ingression both experimentally and numerically.