Evolutionary design of compact counterflow heat exchanger

Abstract

Abstract This investigation includes a geometric optimization for a compact heat exchanger built from hexagonal channels with the rely of Constructal design. A three-dimensional numerical analysis based on the finite volume method (FVM) are conducted to identify hydrodynamic and thermal behaviors of the counterflow arrays. We considered several configurations for the inactive channel emerged from packing the hexagonal channels within the compact heat exchanger, considering the easier access for the heat from the hot fluid to the cold fluid. The hexagonal arrays considered for the CFD study is first assumed to be well insulated. The hot and cold fluids (water) flow with variable Reynolds numbers; 10, 100, 200 and 300. The results are presented in term of heat transfer effectiveness, thermal conductance, and the thermal-to-flow performances ratio. The CFD code was verified with an experiment work to assess the accuracy of the current numerical analysis. Triangular channels (β = 1) employed in the inactive region showed better performance for the counterflow hexagonal bundle. High pressure drop is associated with the trapezoidal shape especially with smaller hydraulic diameter (small cross-sectional area).