Abstract: A mass flowmeter for measuring the velocity of a fluid uses an active and a compensating sensor. The sensors generate heat when supplied with electrical power. A first heat sink is located a first gap from the first sensor in a direction substantially perpendicular to the direction of fluid flow. A second heat sink located a second gap from the second sensor in a direction substantially perpendicular to the direction of fluid flow. The dimension of the second gap is different from the dimension of the first gap. Electrical power supplied to the sensors causes a thermal flux to flow across the first gap from the first sensor to the first heat sink, and causes a thermal flux to flow from the second sensor across the second gap to the second heat sink. A measuring circuit computes the temperature rise of each of the sensors when supplied with power over the ambient temperature of the fluid.

Abstract: A mass flowmeter for measuring velocity of a flowing fluid employs a thermal sensor. The sensor generates heat when supplied with electrical power. A heat sink is located in the fluid flow directly across from the sensor perpendicular to the flowing fluid. Electrical power is supplied to the sensor to cause a thermal flux to flow from the sensor to the heat sink. The flowing fluid modulates this flux. A circuit measures the temperature of the sensor and computes the velocity of the flowing fluid from that measurement.