A Computational Study of Convection Currents of Liquid in a High Pressure Processing (HPP) using CFD

Abstract

The profiles of temperature, velocity and pressure at the beginning of liquid compression under extreme High Pressure (HP) in a 3D cylinder are simulated and presented in this work. The computational domain is a cylindrical basket with 38 mm diameter and 290 mm height. These dimensions are same with those used in the experimental work for the HPP unit used in this work. The simulation has been done on direct processing of water as a liquid model at 500 MPa pressure level and with 970 s holding time. A Computational Fluid Dynamics (CFD) package (PHOENICS) is used to solve the governing equations of continuity, momentum and energy. The CFD package is based on a Finite Volume Method (FVM) of solution. The results of the simulation shows the influence of both forced and free convection flow, on the distribution o temperature in the liquid at the early stages of compression. The convection formation is created due to the differences in velocities between the pumping fluid passing the cylinder inlet at 10-2 to 10-3 m/s and the treatment chamber velocity at 10-8-10-9 m/s. The calculated temperature at different cylinder heights are validated and found of good agreement with experimentally work measured.