Flowmeter based on heat dissipation principles

A flowmeter was built using the heat dissipation principle. The objective is to keep the body (sensor) at some value of temperature (setpoint) higher than the temperature of the fluid in which the flow is being measured. The energy balance for the sensor once the setpoint is reached states that the dissipated heat, which is a function of the fluid speed, is equal to the supplied energy to the heating element in the sensor, because the supplied energy to the sensor is known then the fluid speed can be computed using a equation correlating the variables involved. The flowmeter was calibrated using a commercial flowmeter based on ultrasonic principles. The calibration procedure shows that the flowmeter response is linear and repeatable. This flowmeter has potential to be used in liquids, specially in dirty liquids where hot-wire sensors should not be used.