Cooled dual element thermocouple computer and flow velocity measurement method

摘要

Embodiments of a flowmeter and velocity measurement method are described, which include preferably a dual element thermocouple that is immersed in a flowing fluid and a computer that processes, validates, and calculates data to arrive at a velocity measurement for fluids at low flow rates. A temperature differential is created by the Peltier effect when electric current is applied to one thermocouple pair in the dual element thermocouple, and this temperature differential causes heat transfer to occur between the fluid and the thermocouple. The temperature response of the cooled junction of the thermocouple is preferably measured using the second pair of the dual element thermocouple while the electric current is pulsed on and off. The temperature response, including the initial temperature of the probe junction immediately after the current is turned off, and including several junction temperature points thereafter, is correlated to fluid velocity using a calibration equation relating the junction's temperature suppression and observed time constant.