Dynamic performance of a thin film temperature sensor in a lubricated contact

A thin film temperature sensor integrated onto mechanical component surface is promising for real-time machine condition monitoring. In this article, a one-dimensional heat conduction model has been developed to study the dynamic performance of the thin film sensor designed for monitoring the temperature distribution in an elastohydrodynamic lubrication contact. A control volume approach was used to numerically analyse the effects of sensor film thickness (from 0.1 to 100 μm), sensing materials, and substrate materials on the transient time response of the thin film sensor. The numerical model was evaluated by an analytical solution in a semi-infinite domain. The sensor time constant is obtained on the basis of a constant heat load and sensor sensitivity is studied when a typical elastohydrodynamic pressure distribution in a lubricated contact is applied. Faster response time and short time delay of a thin film sensor are expected in a higher conductivity of substrate. It is also clear that the response time decreases with increasing sensor film thickness and with increasing conductivity of the substrate. The results show that when the thickness of the sensor is < 1 μm, the sensor is feasible to capture transient temperature profile in real time for machine health monitoring under various operating conditions. One of the experimental validations given in this article has proven the robustness of the developed model.