Analyzing and simulating heat transfer and designing a shell and tube heat exchanger for the pasteurization process...

Pasteurization is a vital process to destroy harmful enzymes. This process is very critical to obtain quality tomato paste. In this study, Computational Fluid Dynamics (CFD) has been used to design a shell and tube heat exchanger on an industrial scale and to simulate heat transfer in order to visualize this process and present it to the industry. In this research, a three-dimensional CFD model was simulated using ANSYS FLUENT commercial software. Also, using the Herschel-Bulkley model, the behavior of viscosity in the pasteurization process of tomato paste has been explained. In this stage of the production line, the tomato paste enters a shell and tube heat exchanger at 65 °C and reaches 80 °C at the outlet. Compared with the experimental data, the output temperature of tomato paste predicted by CFD simulation reached 79 °C. In addition, thermophysical properties of tomato paste were measured, and these exact values were used for simulation. Also, the evaluation of this heat exchanger with three hot water inlet mass flow rates has been done in order to provide the results to the factory to avoid spending more energy. And the simulation results showed that the output temperature of tomato paste at three different mass flow rates did not change less than the mass flow rates measured in the factory, and also the output visualizations from this research can be suitable for presenting to the industry and benefiting from them.