Natural convection from a heated T-open pipe of nanoencapsulated phase change material in a cavity

Purpose This paper aims to study the natural convection from a heated T-open pipe of nanoencapsulated phase change material in a cavity. The impact of the presence of nanoencapsulated phase change materials (NEPCM) in water was studied on the thermal behavior of these novel nanoliquids in the presence of natural convection flows. The entropy generation for these nanoliquids was also investigated. Design/methodology/approach The NEPCM is modeled as a lumped phase change nanoparticle with a phase change material core and a polymer shell. The governing equations for a uniform mixture of NEPCM-water are written based on the conservation of mass, energy and also fluid motion. The natural convection effects were also taken into account. The finite element method was used to solve the governing equations. The entropy generation was also computed and studied. Findings Increasing the aspect ratio (AR) from 0.05 to 0.2 enhanced the average Nusselt number by 9%, while total entropy generation rose by 13%, indicating improved convective heat transfer near the bottom wall due to increased surface area. Enhancing the NEPCM nano particles volume fraction from 0 to 0.05 led to a 15% increase in heat transfer efficiency and a 9% rise in entropy, with negligible change in flow patterns. Growing the NEPCM fusion temperature from 0.1 to 0.5 slightly improved the Nusselt number by 5% and increased entropy by 3%, showing minor thermal gains with limited hydrodynamic impact. Practical implications NEPCMs have demonstrated significant potential in heat and mass transfer for cooling systems and thermal energy storage. Encapsulation technology has been widely used to improve the stability, specificity and bioavailability of essential food ingredients, as well as the performance of NEPCM suspensions in cooling applications. Additionally, the NEPCM suspensions use the latent heat of nanoparticles and can effectively control surface temperatures. Originality/value The natural convection heat transfer and the entropy generation of NEPCM suspension are addressed in an enclosure with T-open heated walls for the first time.