Experimental and Numerical Investigations on the Leakage Flow Characteristics of the Labyrinth Brush Seal

Abstract

The leakage rate of the labyrinth brush seal was experimentally measured and numerically investigated in this paper. Four different rotational speeds of 0, 1500, 2400 and 3000 rpm were utilized to investigate the effects on the leakage rate of the labyrinth brush seal. In addition, five different pressure ratios and two initial clearances were also adopted to study the influences of pressure ratio and clearance size on the leakage rate of the labyrinth brush seal. The leakage rates of the experimental labyrinth brush seal at different rotational speeds, pressure ratios, and initial clearances were also predicted using Reynolds-averaged Navier-Stokes (RANS) solutions coupling with a non-Darcian porous medium model. The rotor centrifugal growth and bristle blow-down effects were considered in the present numerical research. The rotor centrifugal growth at different rotational speeds was calculated using the finite element method (FEM). The variation of the sealing clearance size with rotor centrifugal growth and bristle blow-down was analyzed. The numerical leakage rate was in good agreement with the experimental data. The effects of rotational speeds, pressure ratios, and clearance sizes on the leakage flow characteristics of brush seals were also investigated based on the experimental data and numerical results. The detailed leakage flow fields and pressure distributions of the brush seals were also presented.