An Experimental Investigation and Numerical Study of Paraffin Wax Melting in a Shell and Tube Thermal Storage System


Raid S. Fahad, Maathe A. Theeb, Dhamyaa S. Khudhur*, Muhanad Nazar Mustafa Al-Sabbagh


Mechanical Engineering Department, College of Engineering, Mustansiriyah University, Baghdad, Iraq

Corresponding Author Email: [email protected]

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At the present time, the use of the phase-changing materials is considered as an important and commonly used topic. The melting of a phase-change material was studied and determined around a vertically spaced, vertical cylindrical heat set experimentally. Experiments were implemented during both melting and circulation to examine the tube surface temperature effects on heat transfer. The processes were elucidated on the observation’s basis of temporal changes in the solid/ liquid interface and measurements of distribution of the temperature in the phase change material. The results demonstrated that the temperature of the lower tube surface has highly influenced on the solid/ liquid connect, melting and limitation of the liquid from the upper tube. In the numerical section, ANSYS Fluent Software was used at flow rate (0.007kg/s, 0.01562 kg/s, 0.02343 kg/s and 0.0546 kg/s) and various charging times to characterize the trend and the behaviour of the PCM inside the shell and tube heat exchanger. The results exhibited that the multiple liquid zones may promote in the phase change material around them, and the temperature fluctuations, solubility, and intervals must be properly elected for efficiently utilize of phase change materials in the thermal potential energy storage unit. The results also demonstrated that during the fusion process, the coefficient of the heat transfer between both the heat transfer fluid and the phase-change material is influenced by the mass flow rate more than that during the solidification operation. It was also found that the heat raises during the fusion process by 25%, while during the solidification process, it raises by 11%. In the case of augmentation or diminution, the rate of the heat flow raises by 28oC of the inlet temperature of heat transfer fluid. Moreover, the results of this work exhibited that the total fusion time reduces by 31% by raising the temperature of the inlet water from (58ºC to 60ºC). The natural convection effects that alter the behaviour of the storage tank have an important role during the charging process, particularly during the horizontally arrangement of the tubes.