Experimental measurement and numerical simulation to determine characteristics of an infrared tube system

Abstract

The heat flux emitted from infrared radiant tube heaters (RTH) was studied under controlled conditions using a special transducer-type sensor. An enclosed area of the floor below the RTH was marked off to provide a measurement grid extending the length of the RTH. The RTH used for these tests had a firing rate of 200,000 BTU/H (58.62 KW) and the length of the radiant tube was 70 ft (21.34 m). Heat flux measurements were taken with the RTH at different heights up to 12 ft (3.66 m) from the floor. Computational fluid dynamics (CFD) was also used to predict the measured data of the heat flux distribution on the floor and there was substantial agreement between the experimental and CFD results. It was confirmed by the measurements taken that maximum and average heat fluxes do decrease with increasing the height of the RTH. Locations on the floor below an infrared tube heater to achieve an acceptable average thermal comfort have been shown and recommendations have been made accordingly. Both measurements and simulation graphs showed that the maximum heat flux for the RTH is not directly below the centreline of the RTH but is located on opposite sides of the centerline.