Numerical investigation of melting process with natural convection inside multi-tube horizontal cylinder by SPH method

The application of Phase Change Materials on Latent Heat Thermal Energy Storage has attracted wide focus on its thermal flow analysis. This study applied Smoothed Particle Hydrodynamics to the melting process inside a multi-tube horizontal container. The Lagrangian nature of the present method simplifies the moving boundary treatment and phase change calculation process, the melting and natural convection are solved by the enthalpy method and Boussinesq assumption, respectively. After the validation of the present method in a square cavity, the melting performance inside a multi-tube container is conducted. Two main factors, Rayleigh number and arrangement of the inner tubes, are calculated and analyzed. The results reveal that natural convection basically enhances the overall thermal performance. With a large Ra number, the melting speed is accelerated and the amount of stored energy is also increased. The melting rate is faster in the upper-half region than that in the lower-half region due to the Buoyancy force. Besides, under the multitube configuration, the thermal perfor-mance is more sensitive to the change of the distance than the angle between inner tubes. With a larger distance, the thermal stratification effect in the bottom of the container is weakened, and the melting time is shorter.

Automated summary

The present study uses Smoothed Particle Hydrodynamics to analyze the melting process inside a multi-tube horizontal container. The Lagrangian method simplifies the moving boundary and phase change calculations, while the enthalpy method and Boussinesq assumption are used to solve the melting and natural convection problems. The results show that natural convection enhances the overall thermal performance, and a higher Rayleigh number increases the melting speed and energy storage. The melting rate is faster in the upper region due to buoyancy force. The thermal performance is more sensitive to distance rather than the angle between inner tubes in the multi-tube configuration, with a larger distance leading to weakened stratification and shorter melting time.