Starting and running performance of a pulsating heat pipe with micro encapsulated phase change material suspension

• Published in: Applied thermal engineering Vol. 212; p. 118626
• Main Authors: Shi, Weixiu, Chen, Hongdi, Pan, Lisheng, Wang, Qian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 25.07.2022
• Subjects: Micro encapsulated phase change material (MEPCM); Pulsating heat pipe (PHP); Running performance; Starting performance; Starting performance; Running performance; Pulsating heat pipe (PHP); Micro encapsulated phase change material (MEPCM)
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2022.118626

•MEPCM suspension at mass concentration of 0.5% is used as the working fluid of a PHP.•The heating power, filling ratio and inclination angle are all considered.•Heating power impacts on the starting and running characteristic.•The running of PHP deteriorates obviously by decreasing inclination angle. Pulsating heat pipe (PHP) is an efficient heat transfer technology. The micro encapsulated phase change material (MEPCM) suspension is a novel latent heat fluid with high heat storage density. The research on the PHP with MEPCM suspension is of great significance for expanding the types of working fluids and studying the operating performance. An experimental investigation of starting and running performance was carried out on a closed loop PHP with MEPCM suspension at mass concentration of 0.5%. The results show that the PHP charged with MEPCM suspension starts unstably with irregular oscillating under lower heating power of 30–90 W, while it runs stably after starting with heating power increasing to 120 W. The start-up time of PHP charged with MEPCM suspension first drops rapidly, then flattens from 50 s to 20 s with increasing heating power and it still maintains at 20 s with the increasing of heating power from 150 W during experiments, which indicates the influence on the start-up time from further increasing heating power becomes smaller on the condition that the heating power increases to a certain level. Compared with 70% of filling ratio, conditions with 35% and 50% of that showed better performance. Gravity is very important to overcome the viscous resistance of working fluids. The running performance of PHP was slightly affected by inclination angle which was greater than 60°. When it dropped to 30°, the running deteriorated obviously. However, the PHP with 35% of filling ratio couldn’t run normally at a small inclination angle of 30°.