Authors: Assistant Professor Dr. Suraj J Patil, Assistant Professor Somashekar R
Abstract: In industries, huge amounts of waste heat are produced; however, gas turbine exhaust heat can reach 400°C, but a heat exchanger can recover merely 40% to 60% of this because of its poor thermal and hydraulic performance. In this study, a design approach is proposed for an efficient heat exchanger using milli-tubes, segmental baffles, and optimized fin designs. Based on the results of experimental studies on six different geometries, heat exchangers incorporating milli-tubes (tube size: 1.4 mm, 8 baffles) were found to have a heat transfer coefficient of 52 W/m²·K, which is an improvement of 41% relative to the baseline case with relatively low pressure losses. According to numerical simulations validated with CFD, the offset fin design increased the Colburn j number up to 150% relative to a smooth tube; however, a pressure loss reduction of 30% to 65% was obtained.
