Sensing elements space design of hot-film sensor array considering thermal crosstalk

The flexible hot-film sensor array fabricated on polymer substrate with MEMS technology holds great importance for investigating and controlling flow separation and transition in the applications of fluid mechanics. The principle of these sensors is convective heat transfer from the sensing elements into the fluid. However, the heat dissipated into the fluid through forced convective will possibly has thermal crosstalk on the down-stream sensing elements. For this reason, the optimal space between two adjacent sensing elements needs to be considered in sensor array design. In this paper, FEM (Finite Element Method) simulations were performed to estimate the corresponding temperature distribution in the vicinity of the sensing element. We got the minimum non-thermal crosstalk spaces between two adjacent sensing elements in an array with various shear stress and sensing element working temperature. Moreover, both wind and water tunnel experiments were conducted to study the thermal crosstalk in a sensor array, and experimental results were agreed with the simulation results.