Evaluation on Rain-Defense Performance of Temperature Sensors

Abstract

Rain-defense performance of temperature sensors is of concern in many important fields, while there has been no suitable method to evaluate their performance before. To solve this problem, an experiment is described in this paper. The experimental device used is a conventional temperature calibration wind tunnel. To simulate the practical environment as rainfall of 8 mm per hour, a water tank is set above the open experimental section of the wind tunnel, at the bottom of which many small holes are drilled so that rain can run down. Three new-type temperature sensors and an old-type temperature sensor are calibrated in the wind tunnel. The calibration method is similar to the recovery characteristic and dynamic characteristic calibration except that the environment here is a mixture of spray and air. As the authentic total temperature is unable to be obtained, an equivalent recovery factor is defined, which uses the total temperature outside the calibrated sensor to participate in the calculation instead of the authentic local total temperature. And through dynamic characteristic calibration, the time constant of the sensor is also obtained. During the calibration experiment, the gas Mach number, water temperature, and attack angle of the temperature sensors are varied. The result shows that the equivalent recovery factor of the new sensor design is lower than that of the old sensor design, which proved that the rain-defense performance of the new sensor design is better than the old sensor design, and some other comparisons can also demonstrate this point. Associating the design structure of the temperature sensor with the experimental result, the evaluation method is shown to be reasonable and feasible.