Experimental Investigation of Contact Heat Transfer at High Pressures

Abstract

- Besides the mechanical description of technical systems, a thermal modelling is frequently required. In this context, contact heat transfer coefficients are essential boundary conditions for the thermal simulation of technical systems consisting of several individual components. This parameter is mainly influenced by the surface structure and roughness of the contact partners as well as the applied contact pressure. However, although the influencing parameters are well known, an analytical determination is quite difficult. Therefore, an experimental quantification is mandatory. So far, experiments in literature have primarily focused on the investigation of contact heat transfers at moderate loads up to 100 MPa. Nevertheless, there are some applications where solids are in contact at very high pressure and resulting heat transfer between them plays an essential role, such as the interface between the tool and the workpiece during machining. The aim of this work is to present a novel experimental methodology to determine contact heat transfers at high loads. In this approach, infrared thermography is used to measure the temperature data, which is consequently used to solve an inverse problem using the conjugate gradient method, which provides the corresponding contact heat transfer coefficients. Furthermore, first experimental results for a load-dependent heat transfer for loads between 200 and 1200 MPa are presented and occurring effects are discussed.