Computation fluid dynamics design of a plate fin heat exchanger with different transverse vortex generators for food processing

In this work, the performance of a plate heat exchanger with rectangular, rhombus, and elliptical vortex generators with 3, 5, and 7 mm width and 3, 6, and 9 mm height were investigated by means of computation fluid dynamics (CFD). Moreover, seven flow rates (from 0.01 to 1 ms−1) were tested and 196 CFD models were obtained. Heat transfer coefficient, pressure drop, Colburn j, and Fanning f factor were considered to evaluate the performance of the heat exchanger. The best heat exchange was obtained for rhombus wings and the highest Colburn j factor was obtained for 7 mm width and 6 mm height. The lowest pressure drop was obtained for 3 mm width and 3 mm height elliptical wings. Regarding surface reduction, the best result for all the geometries was with 5 mm width and 9 mm height, allowing a possible reduction of 25, 26, and 23% for rectangular, rhombus, and elliptical geometry. Practical applications: Plate heat exchangers are extensively used for continuous thermal processing of liquid foods without particles in suspension and with low viscosity. In the last decades, due to the increasing demand of high quality foods and energy saving, increasing the overall heat transfer performances of food processes became crucial for the sector. Computation fluid dynamics (CFD) technique can contribute to understanding food fluid flows inside heat exchangers and in supporting equipment design. Product and process quality can be improved with minimum cost and time investment. In this work CFD was used for studying the performances of a plate heat exchanger with different passive vortex generators presenting different shapes and dimensions. The simulated data allowed identifying the best geometry with the best balance between heat performance improvements and pressure losses. The proposed approach successfully applied to Newtonian fluid could be extended also to non-Newtonian liquid foods and to different plate heat exchanger design.