Temperature difference type thermal volume flow sensor with constant temperature gradient

摘要

A thermal mass flow sensor in which heat transfer to and from a fluid flowing through a sensor conduit is optimized by establishing a symmetrical triangular temperature distribution along a heated length of the sensor conduit. The sensor conduit is heated by a pair of distributed heat sources and a concentrated heat source located between the distributed heat sources. The heater density of the sensor conduit increases linearly from the outer ends of the distributed heat sources towards the center of the heated length of the sensor conduit, and spikes to a substantially greater value at a point corresponding to the centrally located concentrated heat source. The temperature distribution function along the flow sensor tube is a substantially symmetric triangular function.