Three-Dimensional Flow-Heat Coupling Model of a Wavy-Tilt-Dam Mechanical Seal

A three-dimensional flow-heat coupling model of a wavy-tilt-dam (WTD) mechanical seal is established to study the heat transfer in both the fluid and the solid domains. The upwind scheme is used to ensure the convergence of the numerical calculation. The inlet temperature boundary condition is discussed and two modified inlet boundary condition methods are proposed to eliminate the noncontinuity of the film inlet temperature. The method where the temperature gradient in the radial direction is assumed constant gives more reasonable results than the method where the temperature is assumed to vary linearly along the film thickness direction. The results show that the highest temperature is located near the inlet due to the waves, which will cause a backflow along the converging spaces formed between the rotor and seal faces (convex segments of the wave) in the circumferential direction. The thermal deformation in the radial direction is larger than the deformation that is caused by waves in the circumferential direction. In addition the deformation will increase the taper, which will result in an increase in the minimum film thickness. A parametric study shows that the maximum temperature of the film will decrease as the wave number increases. The rotor speed and pressure difference will obviously affect the performance of the WTD seal.