An Approach to Thermocouple Measurements that Reduces Uncertainties Associated with Radiative Corrections

摘要

The measurement of gas temperature forms an integral part of most combustion studies. The use of thermocouples presents an inexpensive, robust and relatively easy way to accomplish this. However, radiative and conductive heat losses present significant challenges to accurate measurements. In order to minimize uncertainties associated with correcting for heat losses, a novel approach has been developed for thermocouple measurements of flame temperature wherein the heat loss is minimized by spinning the thermocouple. In addition to minimizing the required correction by increasing the heat transfer coefficient, this approach provides for a well-known heat transfer coefficient, thus improving the accuracy of the radiation correction. The results are compared to models using established heat transfer correlations. The results show a significant decrease in the required radiation corrections and good agreement with the model. Additionally, the technique has a high level of spatial accuracy compared to conventional aspirated thermocouples. The results suggest that this technique is a viable alternative to conventional approaches to measuring temperatures in highly radiating flame environments.