Heat transfer enhancement in a spiral plate heat exchanger model using continuous rods

This study presents an innovative and simple way to increase the rate of heat transfer in a spiral plate heat exchanger model. Several circular cross-section rods, as continuous vortex generators, have been inserted within the spiral plate heat exchanger in the cross-stream plane. The vortex generators are located at various azimuth angles of α=30◦, 60◦, 90◦, and 120◦ with non-dimensional diameters of d/H=0.3, 0.4, and 0.5. Computations have been carried out numerically by means of the finite volume approach under different Dean numbers (De) ranging from 500 to 1500 in the laminar regime. The flow physics within the advanced spiral heat exchanger model has been discussed using several velocity and temperature contours. It was found that by inserting the continuous vortex generators in the cross-stream plane of a spiral plate heat exchanger, the unsteady flow develops within the channel in which the rate of unsteadiness is proportional to d/H and De directly and to azimuth angle inversely. The maximum heat transfer enhancement with respect to the conventional spiral plate heat exchanger (without continuous vortex generators) is found to be 341% for α=30◦, d/H=0.5, and De=1500. Additionally, values of pressure drop penalty and thermal-hydraulic performance have been determined accordingly.