TRANSIENT CONTACT HEAT TRANSFER COEFFICIENTS FROM INFRARED TEMPERATURE MEASUREMENTS
The heat transfer between two bodies in contact is often reduced by thermal contact resistance, which typically is expressed either as contact resistance or as a contact heat transfer coefficient. For the prediction and optimisation of the thermal behaviour of components with thermal stress knowledge about the contact heat transfer is crucial.
An experimental approach to measure the actual contact heat transfer coefficient for given boundary parameters is introduced. The procedure is based on time-dependent infrared temperature measurements of two bodies in contact. The contact heat transfer coefficient is not measured directly, but results from the solution of the related inverse problem using the conjugate gradient method. In comparison to direct heat flux measurements under steady state conditions a transient method is applied here. Two bodies initially at two different temperatures are brought into contact and the surface temperature histories are recorded with a high speed infrared camera.
The results show good agreement for simulated temperature data and give also sound results for real measurements. A comparison to data from literature is not possible as the validity of existing models is far less than the loads applied here.