INTRODUCTION

Heat exchanger has wide range of applications in distinct industries. Uniform heat transfer over complete length and circumference of tubes is of high importance in heat exchanger for its efficient working. CFD helps in evaluating Heat exchanger performance by properly capturing the turbulence within fluid flow and velocity + thermal boundary layers overheat Exchanger walls and by identifying the formation of recirculation & dead regions within Heat Exchanger. CFD helps for making an appropriate design modification in Heat Exchanger for improving the heat transfer ability.

CHALLENGES

• Meshing small gaps in between tubes and modelling of fins
• Appropriate selection of turbulence model for accurate capturing of turbulence.
• Proper capturing of turbulence and Velocity + Thermal boundary layers.
• Verifying heat transfer coefficient.

THE SOLUTION

Flow & thermal analysis of the heat exchanger was executed for determining heat transfer coefficient, recirculation & dead regions within the flow. Appropriate selection of turbulence model & close capturing of velocity + thermal boundary layers is of great importance while evaluating Heat Exchanger performance. Based on CFD simulation results ineffective area of tubes were identified, and appropriate modifications made for reducing the ineffective regions of tubes. Also a proper methodology developed in CFD for determining heat transfer coefficient over various walls.

Heat transfer coefficient obtained from CFD was compared with analytical heat transfer coefficient using Nusselt’s number. It showed that heat transfer coefficient value was not varying by more than 5 % from analytical value.

BENEFITS

• Identification of ineffective regions within Heat Exchanger.
• Reduced number of trials for design modifications.
• Cost effective solution for reduced number of trials with an appropriate design modifications.