Effects of thermal radiation on natural convection in two connected circular cylinders suspended by NEPCM and porous media

The natural convection of NEPCM was delivered in the dosed cavity constructed from two circular cylinders. The contributions of the NEPCM particles in heat transfer are achieved by the phase change. The partial differential equations that govern a nanofluid motion and heat transport are solved by a time fractional derivative of ISPH method. The impacts of the pertinent parameters, thermal radiation parameter Rd = 0 - 3, Rayleigh number Ra = 10(3) - 10(6), Darcy parameter Da = 10(-2) - 10(-5), Fusion temperature theta(f) = 0.05 - 0.8, length of a hot source L-Hot = 0.4 - 1, and fractional time-derivative alpha = 0.95 - 1 on the nanofluid flow and heat transfer are discussed. The main findings indicated that the Rayleigh number is representing a well role in improving the nanofluid movements and intensity of the temperature within the two circular cylinders. The phase change zone is reducing by an increase in Rayleigh number. The higher nanofluid speed and heat transfer are higher at the top cylinder compared to the bottom cylinder. Increasing the length of a hot source enhances the temperature strength within a cavity.