CFD simulation of convective heat transfer in vessel with mechanical agitation for milk

Abstract

Computational fluid dynamics (CFD) analysis using ANSYS Fluent software has been carried out to investigate velocity profiles and thermal characteristics of milk during heating under mechanically agitated condition. In earlier article experimental data on forced convection heat transfer coefficient $\left(\stackrel{-}{\mathrm{h}}\right)$ and correlations of the form $\mathrm{N}\mathrm{u}=\mathrm{a}\cdot {\mathrm{R}\mathrm{e}}^{\mathrm{b}}\cdot {\mathrm{P}\mathrm{r}}^{0.33}$ for cow milk, standardised milk and full cream milk in Baffled vessel and Unbaffled vessel with scraping, using Propeller, Flat Six Blade Turbine (FBT), Inclined Six Blade Turbine (IBT) and Paddle impellers were reported. It was noted milk in Baffled vessel with Paddle impeller provided highest $\stackrel{-}{\mathrm{h}}$ even at lower rotational speeds followed by Propeller, FBT and IBT impellers. In Unbaffled vessel with scraping, Propeller provided the highest $\stackrel{-}{\mathrm{h}}$ followed by FBT and IBT impellers. Hence, the present investigation has been carried out to validate and understand how different velocity of flow currents and their magnitude influence the heat transfer coefficient values in CFD simulation. It also justifies the relative performance of the impellers delineated in the earlier paper. In addition, theoretical values of heat transfer coefficients computed using CFD shows close agreement with experimental values.