Flow and Heat Transfer Characteristics in High Porosity Metal Foams

摘要

In this study，flow and heat transfer characteristics in high porosity metal foams were examined theoretically，numerically and experimentally. High porosity metal foams are promising materials to be used for a high efficiency heat exchanger. Theoretical and Numerical approaches were developed based on the Darcy-Brinkman equation and Forchheimer-Darcy equation，respectively with a modified energy equation to predict velocity and temperature profiles in a rectangular channel filled with metal foams. To examine effect of thickness of metal foam fibre，metal foam was assumed Weaire-Phelan structure and Navier-Stokes equation was employed for computational fluid dynamics.The Forchheimer-Darcy modification was employed with the experimental results to determine flow characteristics，the permeability and the inertial coefficient. Nusselt number was derived from a volumetric heat transfer coefficient based on the local wall and fluid temperatures. To validate the numerical prediction，an experimental study was carried out to investigate flow and heat transfer characteristics in metal foams. For this study，the test section channels were filled with several metal foam samples (copper and nickel) with different pore per inch (ppi) and air was used as a coolant fluid. Temperature distribution and pressure drop along the test section were measured for a range of coolant flow rates. The velocity profile becomes more flat with increasing porosity of metal forms. Predicted pressure drop and heat transfer agree well with those obtained from experiment.

目录

封面

声明

英文摘要

目录

1. Introduction

1.1 Metal foam

1.2 Literature review

1.3 Background knowledge

1.4 Objectives

2. Theoretical analysis

2.1 Velocity distribution

2.2 Pressure drop

2.3 Heat transfer characteristics

3. Numerical analysis

3.1 Mathematical formulation

3.2 Pressure drop

3.3 Heat transfer performance

4. CFD Analysis

4.1 Metal foam geometry modeling

4.2 Numerical method and boundary conditions

4.3 Comparison between previous study and present CFD analysis

4.4 Effect of thickness of metal foam fibre

5. Experimental validation

5.1 Experimental setup

5.2 Test section

5.3 Pressure drop

5.4 Heat transfer performance

5.5 Comparison between theoretical and experimental results

6. Conclusions

参考文献

致谢