Effect of Environmental Temperature on the Sensitivity of the Airflow Level Posture Sensor

In this paper, the effect mechanism of environmental temperature on the sensitivity of the airflow level posture sensor is explained. Using ANSYS-FLOTRAN CFD program, the temperature field and the stream field in sensing element of the sensor under the effect of the different temperatures with tilt angle of 10deg/S, has been obtained by a series of procedure, such as model building, meshing, loads applying and equation solving. The results are as follow: In a constant input of tile angle, the temperature field and the stream field in sensing element of the sensor change in different ambient temperatures; With the increase in temperature, airflow rate in sensing element declines, Conversely, with the ambient temperature decreases, airflow rate in sensing element increases wholly; With the increase in temperature, the airflow rate difference of two detecting hot wires decreases, detecting bridge´s output voltage decreases, the sensitivity of the sensor reduces too; Conversely, with the ambient temperature decreases, the airflow rate difference of two detecting hot wires increases, detecting bridge´s output voltage increases, the sensitivity increases too; The sensitivity of the sensor with an average temperature change rate is 0.55 mV/deg/S/square. This paper provides the theoretical and experimental basis for the further temperature compensation, reducing the temperature drift of the airflow level posture sensor.