DOI: 10.1615/ICHMT.2012.ProcSevIntSympTurbHeatTransfPal
ISBN Print: 978-1-56700-302-4
ISSN: 2377-2816
CFD Simulations of The Impact of Radiation on Thermocouple Measurement of Hot Gas Jets
ABSTRAKT
Turbulent convective heat transfer and radiation are studied by means of CFD for a hot gas jet, impinging perpendicular on a flat surface. A small solid spherical bead, located in the jet centre, half way from the wall, represents a thermocouple sensitive point. The bead becomes so hot that it radiates some heat to the colder surroundings. This causes a difference between the jet temperature and the bead temperature. Bead sizes 0.25, 1.0 and 2.0mm are used in 500°C and 900°C jets. It is found that the mentioned temperature difference is significant and grows rapidly with jet temperature but decreases with jet velocity. The temperature difference increases also with the bead size. In order to reduce the radiation, a cylindrical thermal shield is accommodated around the bead, aligned with the jet. However, the improvement is marginal because it reduces the convection as well.