The Investigation of the Effect of Contact Frequency upon Thermal Contact Conductance

Thermal Contact Conductance (TCC) between an exhaust valve and its seat is one of the important parameters to be estimated in an internal combustion engine. An experimental study presented here to acquire temperature in some interior points to be used as inputs to an inverse analysis. An actual exhaust valve and its seat are utilized in a designed and constructed setup. Conjugate Gradient Method (CGM) with adjoin problem for function estimation is used for estimation of TCC. The method converges very rapidly and is not so sensitive to the measurement errors. Contact frequency is one the factors which have a significant influence on TCC. The results obtained from current inverse method as well as those obtained from linear extrapolation method show that the thermal contact conductance decreases as the contact frequency increases. The results obtained from both sets of results are also in good agreement.

Keywords:

Thermal contact conductance , conjugates gradient method , contact frequency , exhaust valve , seat