Heat transfer augmentation in heat sink with fin-bars inserted in cooling channel

Abstract

Adding obstacles and obstructing fluid flow in cooling channel to induce whirl velocity enhances thermal performance in heat sinks. An analysis is presented of conjugate heat transfer in a heat sink with transversely inserted bars in the flow channel. The numerical study seeks to maximise the dimensionless thermal conductance subject to constant total volume. The study contrasts a standard heat sink without a bar with cooling channel inserts with one, two, three, and 4 bars. To improve the surface area for heat transfer, the extended surfaces are placed longitudinally at various points in the cooling channel. A high-density heat flux is applied at the bottom wall of the heat sink and coolant with an inlet velocity vin between 4.26 and 7.26 m/s is pumped in a forced convective laminar condition to eliminate the heat. A computational fluid dynamic (CFD) code incorporated in Ansys fluent is used to solve the mathematical models. The numerical analysis indicates that the configuration featuring 3 bars inserted at the roof of the cooling channel exhibits the highest global thermal conductance, achieving a 53 % increase over other configurations. All configurations with 3 bars inserted up, down, left and right, maintain a constant pump power of 3.5 W across a Reynolds number range of 857–1461. Bars positioned at the roof of the cooling channel experience the lowest outlet and inner wall temperatures, whereas those at the floor exhibit the highest temperatures. The optimised design meets the highest porosity limit of 0.8.

Keywords

• Numerical analysis
• Heat transfer enhancement
• Heat sink
• Inserted bars