Heat Transfer Enhancement in a Spiral Plate Heat Exchanger Model Using Continuous Rods

In this study, an innovative and simple method to increase the rate of heat transfer in a spiral plate heat exchanger model has been presented. For this purpose, several circular cross-section rods, as continuous vortex generators, were inserted within the spiral plate heat exchanger in the cross-stream plane. The vortex generators were 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 were 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, an unsteady flow developed within the channel. The rate of unsteadiness was directly proportional to d/H and De but inversely related to the azimuth angle. The maximum heat transfer enhancement with respect to the conventional spiral plate heat exchanger (without continuous vortex generators) was found to be 341% for α=30◦, d/H=0.5, and De=1500. Additionally, values of pressure drop penalty and thermal-hydraulic performance were determined accordingly