孔型参数对流体孔型密封泄漏特性和转子耗功的影响

To evaluate the sealing performance of the hole-pattern seals in liquid turbomachines and provide a comprehensive selection criterion of the critical geometry parameters (hole depth and hole diameter) for the design of liquid hole-pattern seals, the mesh auto-generation method and numerical solution method for the prediction of the steady leakage flow in the hole-pattern seals were proposed and validated using the 3D steady Reynolds-averaged Navier-Stokes(RANS) equations. The influences of the hole depth and hole diameter on the seal leakage characteristics and rotor power loss were numerically investigated for a hole-pattern seal of water fluid. The leakage flow rate, rotor drag torque, and flow fields in the hole cavities were calculated and analyzed for liquid hole-pattern seals with various hole depths (H=0.5-15 mm) and five hole diameters (D=3, 6, 9, 12, 16 mm) at two rotational speeds (n=2 000, 6 000 r/min). Numerical results show that the present numerical methods possess better accuracy for the prediction of leakage flow rate of the liquid hole-pattern seal. The leakage flow rate of the liquid hole-pattern seal decreases linearly with the rotational speed. From a view of seal leakage performance, the ratio of hole depth to hole diameter (A_R), which significantly influences the structure of the vortex system in the hole cavity, is the most critical design parameter for liquid hole-pattern seals. With the increase of A_R, the leakage flow rate firstly decreases and then increases. There is an optimum region for A_R (0.5-0.6), where the liquid hole-pattern seal possesses the best sealing performance with minimum leakage. For the liquid hole-pattern seals with different hole diameters, the rotor power loss obviously decreases with the increase of A_R.