An experimental investigation of convective heat transfer of slurry PCM in a tube with butterfly tube inserts

In this study, the effect of adding of microencapsulated phase change material (MEPCM) to pure water base fluid as a working fluid was investigated. To this end, a laboratory apparatus was prepared and used. The main part of this setup is a tube which is called test section. This tube has a circular cross-section under a constant heat flux and is equipped with 6 thermocouples for measuring wall temperature at 6 different points as well as 2 thermocouples to measure the inlet and outlet flow temperature into the tube. The effect of butterfly tube inserts was also studied and the results were compared with each other. The results showed that adding phase change material to base fluid could improve the heat transfer rate up to 41%. Also, when the butterfly blades were placed in the test section, it was observed that the heat transfer rate increased to 234% for pure water and up to 180% for the slurry of 10 wt% of the phase change material. The blades increase the heat transfer by creating turbulence in the flow and eliminating the thermal boundary layer.