Introduction

Vaporizers are devices which heat and vaporize a working fluid. In many cases, they are like industrial boilers except that they do not build up high pressures. Vaporizer units are most used for low pressure heat transfer by incorporating the vaporized steam as the heat exchange fluid. They can also be used to vaporize liquid fuels or cryogenic liquids. Vaporizers are used for one of two basic purposes to generate a vapor or to transfer heat. CFD enables to capture the details of heat transfer across the tubes of vaporizer by modelling conduction, convection mode of heat transfer.

Challenges

• Meshing of vaporizer with prisms around fins for capturing boundary layer effect.
• Modelling heat transfer mode of conduction.

SOLUTION

Flow & thermal analysis of the vaporizer was executed for determining prominently flow path, temperature distribution and velocity distribution along tube flow path. Appropriate inlet and outlet boundary conditions were applied along with suitable turbulence model in steady state. CFD analysis was carried out on 1/4th of the complete model to save the computational time. We simulated two cases in which one case was without sunshade above vaporizer and other case was with sunshade placed at a certain height above vaporizer. From the results of above two cases, it was concluded that sunshade was having negligible effect on flow rate. This was because the placement of sunshade was allowing the flow to easily enter vaporizer from sides. CFD results also showed that temperature was increasing as we moved away from walls due to conductive heat transfer.

BENEFITS

• Flow rate prediction of air through vaporizer for various cases.
• Flow path around the tube arrangements of vaporizer.
• Reduced number of trials for design.