Thermal Resistance Characteristics Research On Rod Fastening Rotor Junction Surface Base On The Fractal Contact Theory

As the most important part of gas turbine components,there are lots of joint surfaces of the rod fastening rotor,and the whole frame is discontinuous,which makes the dynamics and thermodynamics analysis more complicated than the whole rotor.This paper is based on the fractal contacting theory.Using theoretical analysis and experimental verification,the dynamic characteristic of rod fastening rotor was analyzed and the thermal resistance characteristics research on rod fastening rotor junction surface has been done.According to the fractal contacting theory,the static friction coefficient between the joint interfaces of the plates of the rod fastening rotor was researched by numerical simulation and testing method,The variation of the static friction coefficient of the plates of the rod fastening rotor with different roughness under different normal load is studied.The changes of the critical speed of the system with the pretension of the rod,the roughness of the wheel junction surface and the temperature of the rotor were studied.It is found that when the roughness is certain,the critical speed increases with the increase of the pretension of the rod,and the critical speed increases with the decrease of the roughness when the pretension of the rod is fixed,and the rotor temperature rises and the critical speed of the system will decrease under the same roughness and the pretension of the pull rod.Taking the contact thermal resistance of the connecting rod of the rotor rotor as the research object.A fractal model of contact thermal resistance of the joint interfaces of the plates of the rod fastening rotor is established.The change rule of contact thermal resistance of the wheel joint surface with the pull rod preload,the wheel surface roughness and the joint surface temperature is analyzed.The temperature field distribution of rod bar rotor under different working conditions is calculated by finite element software.The experimental platform was designed to measure the variation of the temperature distribution of the rod fastening rotor,and the applicability of the theoretical model was checked.It is found that the heat transfer coefficient of the contact surface increases with the increase of the pretension of the rod,and decreases with the increase of the surface roughness of the wheel,and increases first,then decreases,and then increases with the increase of the surface temperature.