Design and manufacturing of MEMS thermal film sensor and its application for experimental fluid dynamics

The present MEMS thermal film sensor is featured with platinum as sensing material, deposited on polyimide layer as flexible substrate. In the fabrication process, only four masks were used for defining the patterns of the thermal sensors, structure base and conducting wires, respectively. The polyimide layer was deposited on a thin aluminum layer, which was served as a sacrificial layer; subsequently, a flexible skin, i. e., the polyimide layer, would be released after metal etching. Each of the sensors shows the linear temperature-dependence characteristic, with the coefficient of resistance (TCR) about 0.247% /°C. Furthermore, in this report it is demonstrated that the self-made MEMS thermal film sensors could be successfully applied on curved surfaces of models for experiments in low-speed and transonic wind tunnels. The temporal and spatial characteristics are noted outstanding, evidenced by examining the unsteady, three-dimensional flow separation of interest.