An Experimental and Theoretical Study of Brush Seal and Shaft Thermal Interaction

This paper presents a detailed experimental study and theoretical analysis of the thermal interactions of brush seal, shaft and airflow. The tests were performed in the Oxford University Brush Seal Test Facility. The facility, which was originally designed for the brush seal aerodynamic study, has been enhanced for thermal measurements. A variety of brush seals, typically applicable to aero and power generation gas and steam turbines, have been tested. The thermal interaction caused by changes in rotor and housing alignment was also studied. In the tests, in addition to the conventional aerodynamic parameters, such as the pressure, mass flow and torque, the temperatures of the rotor were measured and heat generated in the bristle/rotor contact were deduced using the finite element analysis. A theoretical analysis of the system was developed which predicts the heat transfer to the airflow from the bristle pack. This analysis is used to give a correlation to predict heat input to the rotor. The study provides valuable design information for the use of brush seals.