Experimental Study on Flow Boiling Heat Transfer Characteristics of Microencapsulated Phase Change Material Suspension

Due to its core phase change characteristics, microencapsulated phase change material (MPCM) can make many base fluids have better heat transfer characteristics. In this paper, the flow boiling heat transfer characteristics of fluorinated liquid-based microencapsulated phase change material suspension (MPCMS) through vertical transparent quartz channel were studied. The effects of MPCM core phase change temperature and suspension flow velocity on boiling heat transfer coefficient and critical heat flux were discussed, respectively. The results show that the appropriate concentration of MPCMS can enhance both the boiling heat transfer coefficient and the critical heat flux. The strengthening effect becomes weak with the increase of suspension flow velocity. The maximum strengthening rates of critical heat flux appear at 0.05 m/s, which are 25% (MPCMS (70°C)), 16% (MPCMS (58°C)) and 10% (MPCMS (28°C)). The phase change temperature of the MPCM core has important effects on the boiling heat transfer coefficient and the critical heat flux. The results showed that the MPCM with core phase change temperature higher than the boiling temperature of base fluid has the best enhancement effect. Different bubble behavior in vertical tube with different heat flux can be observed by high-speed photography system. The particle core phase change in MPCMS inhibits the aggregation of bubbles and forms many small bubbles to enhance heat transfer. The work lays a foundation for further exploring the industrial application of MPCMS.