Thermal performance augmentation in the cooling zone of brick tunnel kiln with two types of guide vanes

The energy consumption in bricks and ceramics industry is of great importance. Therefore, the present work introduces an augmentation technique to improve the thermal performance during the cooling process in bricks tunnel kiln. A test rig by scale 1:4 has been designed and fabricated to simulate the cooling zone of tunnel kiln. Two types of guide vanes (side wall (SV) and U-shape (UV)) have been designed with attack angles (θ=120o, 135o, and 150o) in flow direction. Seven different settings within Reynolds number range of 13,609 ≤ Re ≤ 27,634 are tested in a suction-type tunnel kiln. Effect of brick setting arrangement, Reynolds number, guide vane type, and attack angle on the thermal performance is studied. The results reveal that the UV guide vanes influence the thermal performance more than SV guide vanes. The maximum enhancement in heat transfer rate to pumping power ratio (Qavg/PP) is about 25 for setting 7 in absence of vanes and 23 for (UV) with attack angles 150° and 135° at Re = 14,000. The present study introduces two correlations for average Nusselt number. Settings 4 and 1 provide a moderate production time with highest productivity while setting 2 has lowest productivity with small production time.