Optimizing Heat Transfer: Corrugated Backward First Step Integration with Obstacles for Enhanced Performance

In this study, we investigate how heat transfer enhancement can be achieved in backward facing step (BFS) channels with corrugated bottoms and strategically placed obstacles via using water as base fluid. Simulations were performed using the Finite Volume Method (FVM) and SIMPLE method. The upstream dimension is 200 mm, the downstream dimension is 300 mm, and height varies from 10 mm at the inlet to 20 mm at the outlet. Four obstacle configurations were analyzed: Model A of 2.5 mm obstacle; Model B of 5 mm obstacle; Model C of 5 mm obstacle at 30°; Model D of three 5 mm obstacles. Reynolds numbers (Re) from 5000 to 20,000 and a constant heat flux of 40 kW/m² were studied. Model B with a trapezoidal corrugated bottom and 5 mm obstacle 215 mm from the inlet had the Nusselt number (Nu) and optimized performance evaluation criteria (PEC) demonstrated up to a 90% improvement over smooth BFS and 20% over trapezoidal BFS in heat transfer. Increasing turbulence and recirculation also helped improve fluid mixing and wall heat transfer through effective obstacle positioning. For BFS channels, Model B offered the best trade off of heat transfer enhancement and frictional losses, and thus represented the best design for thermal performance optimization.