The need for improved methods of measuring total temperature in low-density moving gas streams has been emphasized by the rapidly increasing use of gas-turbine engines for aircraft propulsion at high altitudes. Recent experience with various types of pyrometers has shown that increased errors of measurement and a reduced rate of response to temperature changes become apparent as the gas density is reduced. A design of suction pyrometer is presented in which sonic gas velocity is maintained over the thermocouple element at all operating conditions, thus insuring the maximum rate of heat transfer to the thermocouple from the gas, and enabling a simple correction for impact error to be applied to the indicated reading in order to derive the total temperature of the gas stream. The rapid rate of response to temperature change obtained with this pyrometer is a fundamental necessity in any control mechanism in which gas temperature is the operating criterion.

This content is only available via PDF.
You do not currently have access to this content.