Geometry In-Dependent and Increasing Measuring Range of MEMS Flowmeter Using Constant Power Mode

The main challenge of thermal flow sensors is its performance range, which is directly dependent on the geometry and thermal power of the hot wire. This article presents a method to prevent saturation of the fluid flow sensor and increase its sensing range. For this purpose, in the initial state of the sensor, the current passing through it is changed step by step so that the temperature changes of the hot wire are within a certain range to prevent damage to it. After obtaining the distance of current steps corresponding to the flow speed range, the operational mode of the sensor is changed from constant current mode to constant power mode, and in this case, the current passing through the hot wire changes according to the fluid speed, which makes that the sensor is not damaged and the range of fluid velocity measurement is increased. Here, the sensor will be able to measure the fluid velocity up to ۶۰ m/s without depending on the geometry, and by fabrication a geometry of parallel wires with the same resistance, the life time and response time of the sensor can be increased, and these parameters will be reported later. The results show that with a specific geometry, the velocity of a fluid can be calculated in the range of ۰-۶۰ m/s, which covers most of the applications.

کلیدواژه ها:

Micro-electromechanical Systems ، Fluid Flow Sensor ، Anemometer ، Flowmeter ، Thermal Mechanism