English

Bumrungthaichaichan Eakarach,Jaiklom Nattawat,Wattananusorn Santi,Namkanisorn Apinan

doi:10.5897/sre2015.6353

Abstract

In the present work, the effect of nozzle angle (22.5º, 45º and 67.5º) on mixing time for jet mixing tanks with the various ratios of liquid height (H) to tank diameter (D), including 0.5, 1, and 1.5, are studied by using computational fluid dynamics (CFD). The results revealed that CFD model with standard k-epsilon is successfully employed to predict the concentration profiles and mixing time by using the fine mesh and second order upwind scheme. The simulated results showed that the different jet nozzle angles result in different flow patterns. The results also indicate that the mixing time is mainly a function of the jet potential core length. Moreover, the jet path length or jet centerline velocity (jet kinetic energy) is considered as the secondary effect on mixing time, which depends on the tank geometry. Key words: Computational fluid dynamics (CFD), jet, mixing, turbulence, k-epsilon model.

Highlights

IntroductionThe jet mixer is the simplest mixing device, commonly used to achieve mixing in a storage tank
Mixing is one of the most important processes in chemical engineering
The computational fluid dynamics (CFD) model was developed to study the effect of jet nozzle angle on mixing time for different H/D

Summary

Introduction

The jet mixer is the simplest mixing device, commonly used to achieve mixing in a storage tank. In such a tank, the liquid is drawn into the pump and returns as high velocity jet through a nozzle into the tank. The liquid is drawn into the pump and returns as high velocity jet through a nozzle into the tank This jet entrains the surrounding liquid and generates the fluid circulation in the vessel. Jet mixed tanks are more efficient as compared to the conventional impeller mixers (Fossett, 1951). The jet mixing tanks are cheaper and easier to install, and may not require the additional support for the tank structure

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Conclusion