Influence of thermowells on accuracy of temperature measurements for flowing gases in low-pressure and high-pressure pipelines

The following contribution deals with temperature measuring errors which may occur when recording the gas temperature within pipes that are equipped with thermowells. Using a simple one-dimensional heat flow model, the temperature difference between the gas and temperature sensor will be determined and confirmed by means of measuring results and CFD-simulations. In addition, measuring errors caused by the gas flow against the thermowell are analysed. A calculation example demonstrates how to check the thermodynamic design of a thermowell.