A New Calibrator for Improved Performance of Hot-Wires

Abstract

A new calibrator for hot-wires has been developed to meet requirements for high efficiency, high accuracy and low turbulence calibrations. The calibrator is a free jet type and true differential pressure is measured across the exit nozzle and used with isentropic relations to estimate actual velocity. The calibrator itself is portable and can be installed in front of the hot-wire probe in many cases. It works with most noncorrosive gases at standard air tools pressure.