A numerical investigation of conjugate forced heat transfer for a micro thermal flow sensor

A steady-state analysis of heat transfer process for a micro thermal flow sensor is presented. A conjugate forced convection-conduction heat transfer model is built to describe the heat transfer process of the micro thermal flow sensor, the heat conduction in substrate and heat convection in fluid are both taken into account. A numerical solution involved with the finite difference scheme is developed and applied to the heat transfer model. The numerical results indicate that the heat conduction in substrate has great influence on the sensor's performance and cannot be ignored in the analysis. The influence of the sensing element position on the sensor's performance is also investigated, and it is shown that different position pairs have desirable sensing performance at different flow rates, which means one micro thermal flow sensor can use multiple sensing element pairs to measure different flow rates.