Equivalent thin-layer temperature field model (ETTM) for bolted rotors to describe interface temperature jump

Abstract

Improving the accuracy and efficiency of predicting the temperature field is a crucial requirement for iteratively calculating and online monitoring the temperature field, particularly for combined structures. The heat flow movement is impeded by incomplete interface contact, resulting in a temperature jump. To address this, the equivalent thin-layer temperature field model (ETTM) is proposed to replace the interface thermal contact conductance (TCC) model. Firstly, the fractal TCC model of a bolt connection is derived based on fractal geometry. Subsequently, the contact surface of the circumferential bolt connection is considered to be the parallel connection of multiple bolt thermal resistances. The TCC of the equivalent thin-layer is obtained. Building on this, the ETTM of the built-up rotor structure is developed. Finally, a temperature field model of the bolted rotor is derived. The validity of models is verified by comparing the model proposed in this paper with the previous research findings and ANSYS analysis results. Numerical simulation results reveal that TCC is influenced by several factors: contact pressure, the nominal contact area within the fractal domain, fractal dimension, fractal roughness, and the root mean square (RMS) height. Furthermore, the effects of the thickness of the thin layer model and the thermal conductivity of the material on heat transfer are examined. Ultimately, the findings indicate that heat transfer at the interface is significantly impeded by thermal contact resistance across various temperature boundary conditions. Notably, lower contact pressure intensifies this impedance.