Temperature Measurement With Radiation Correction for Very High Temperature Gas

When a thermocouple is placed in a high temperature gas-flow stream, the measured temperature could be biased from the true gas temperature due to a large radiation heat transfer from a thermocouple surface to its surroundings. In this study, two thermocouples of unequal diameters of 1/8 inch and 1/16 inch were used to correct the radiation effect. This method is called the reduced radiation error (RRE). The test results show that the radiation on the thermocouple sheath tubes is the source of the error in the gas temperature measurement, and the RRE method is very effective for radiation correction under negligible conditions with the conductive dissipation through the sheath tubes.