Theoretical and Experimental Investigation on Tip Forces and Temperature Distributions of the Brush Seal Coupled Aerodynamic Force

Abstract

Based on a type of three-dimensional slice model of a brush seal combined with the commercial CFD software FLUENT, the study calculated the leakage flow of the brush seal. The aerodynamic forces applied on upstream and downstream bristles are analyzed and reduced to a smaller amount of point forces for analysis convenience. The frictional coefficient between the bristle material Haynes 25 and rotor material ICrMMnMNi are tested. Tip forces including normal reaction and frictional forces caused by aerodynamic forces are quantitatively investigated under conditions with and without frictions using the torque balance principle and nonlinear beam theory (by ANSYS simulations), respectively. Torques, frictional heats, and the temperature distributions of the rotor and bristle pack are studied further. Details and characteristics of the flow and temperature distributions inside the bristle pack are presented. In the experiments, besides traditional tests, such as leakage and torque tests, an infrared camera is employed to capture temperature distributions at the interface of the rotor, bristle pack and nearby zones under various pressure differentials and rotation speeds. The three-dimensional slice model is firstly verified by calculating the leakages, torques and temperature distributions of the brush seal and confirmed via experimentation. The influence of various frictional coefficients and pressure differentials on tip forces, torque and temperature distributions are also examined.

Theoretical and experimental investigation on maximum pressure loads of labyrinth seal’s teeth

“…[1][2][3] As traditional annular gas seals, their major advantages are that they can be used for higher pressure gradients compared with other seals, like brush seals and finger seals. 4,5 Labyrinth seal is most typically used as impeller seals, shaft seals, and balance piston seals in centrifugal compressors. In centrifugal compressors, its working efficiency can be raised by 2% if the seal clearance can be reduced by 50%.…”

Using a three-dimensional tube bundle model to investigate the leakage flow characteristics of the rotating brush seal

“…Sun 31 used the tetrahedral and hexahedral mesh to discrete the fluid and solid domains of the brush seal, respectively. In the numerical study of friction heat effect for the brush seal, Huang 29 used tetrahedral mesh to discrete the fluid domain of the brush seal. In this article, multi-block structured mesh is used to discrete the computational domain of the rotating brush seal.…”

“…The expected trends of the axial deflections for the bristles were obtained. Huang 29 used the three-dimensional tube bundle model of the brush seal to calculate the leakage flow characteristics and temperature distribution within the bristle pack. The aerodynamic forces acting on upstream and downstream bristles were analyzed.…”

Leakage performance of hybrid brush seals under high differential pressure conditions

“…HUANG Shouqing [5] investigated the influence of the amount of brush filament rows on spillage as well as the details and patterns of flow in the brush filament gap and temperature distribution in the brush and filament gap. Deville Lilas [6] conducted experiments on a 38 mm diameter brush seal under operating conditions with an air pressure difference of 7 bar and a rotation frequency of 500 Hz to verify the effect of radial interference on seal performance, and the experimental results showed the important effect of radial interference on leakage.…”