Enhancement of cooling process of hot blocks mounted inside a horizontal channel using flexible baffles — Alternative arrangement

In this paper, two heated blocks and three flexible baffles that are alternately placed on the upper and bottom sides of a rectangular channel are used to replicate the transient heat and air movement. The novelty of this research is the use of flexible baffles to destruct the thermal boundary layer with maintaining little pressure drop, and thus reducing the required pumping capacity. The finite thickness blocks are subject to a constant heat flux, while the baffles are very thin and deforms depending on the strength of the flow of coolant (air). Finite element method with arbitrary Lagrangian–Eulerian approach is used for solving such deforming domain problem. The problem is inspected transiently by varying the dimensionless time (τ=0.0 to 10) and two salient parameters which are Reynolds number Re=10−500, and baffle elasticity parameter E=105−108. Results show that the flexibility feature of the baffles contributes not only in directing the coolant towards the hot blocks, but also contributes in reducing the skin friction and pressure drop through the channel. At Re=150, the skin friction and pressure drop of the flexible baffles are 13.2% and 16.5%, respectively lesser than the rigid baffles. The improvement of Nusselt number with flexibility parameter is marginal and within a limited low Reynolds number, where the maximal improvement is about 3.4% at Re=150.