Comparison on the heat transfer performance and entropy analysis on miniature loop thermosyphon with screen mesh wick and metal foam

Abstract

Comparison on the heat transfer performance (HTP) of copper screen mesh wick and metal foam inserted evaporator section of miniature loop thermosyphon is experimentally investigated. Porosity of both screen mesh wick and metal foams are fixed to be 63%. Experiments are con-ducted using DI water under vertical orientation for different heat loads (40 W-280 W) and filling ratios (FR = 20%, 30% and 40%). Results showed a decrease of 12.8% and 5.2% in thermal resistance and wall temperature respectively for the metal foam inserted evaporator. In addition 10.6% enhancement is noted for heat transfer coefficient at the evaporator region for 30% FR. Reduction of 4.6% in heat transfer irreversibility is also noted for metal foam inserted thermo-syphon compared to screen mesh wick condition. Increase in interstitial heat transfer between the fibers of metal foam and larger pore size of metal foams resulted in higher permeability compared to screen mesh wick are responsible for the enhancement in the overall HTP of metal foam inserted thermosyphon. Based on the observed results, the use of metal foams inserted thermo-syphon will be a better substitute for thermal management applications of electronic devices.