Melting of a phase change material in a horizontal annulus with discrete heat sources

Abstract

Phase change materials have found many industrial applications such as cooling of electronic devices and thermal energy storage. This paper investigates numerically the melting process of a phase change material in a two-dimensional horizontal annulus with different arrangements of two discrete heat sources. The sources are positioned on the inner cylinder of the annulus and assumed as constant-temperature boundary conditions. The remaining portion of the inner cylinder wall as well as the outer cylinder wall is considered to be insulated. The emphasis is mainly on the effects of the arrangement of the heat source pair on the fluid flow and heat transfer features. The governing equations are solved on a non-uniform O type mesh using a pressure-based finite volume method with an enthalpy porosity technique to trace the solid and liquid interface. The results are obtained at Ra=104 and presented in terms of streamlines, isotherms, melting phase front, liquid fraction and dimensionless heat flux. It is observed that, depending on the arrangement of heat sources, the liquid fraction increases both linearly and non-linearly with time but will slow down at the end of the melting process. It can also be concluded that proper arrangement of discrete heat sources has the great potential in improving the energy storage system. For instance, the arrangement C3 where the heat sources are located on the bottom part of the inner cylinder wall can expedite the melting process as compared to the other arrangements.

Investigasi Peleburan dan Pembekuan Phasa Change Material (PCM) Paraffin Wax Sebagai Thermal Energy Storage Pada Pipa

“…Sehingga jumlah panas sensibel yang dapat disimpan bergantung pada besarnya nilai panas spesifik, perubahan temperatur selama proses penyerapan dan pelepasan panas pada material, serta banyaknya material tersimpan didalam storage. Sistem penyimpanan panas laten telah menerima banyak perhatian dalam beberapa tahun karena kepadatan penyimpanan energi yang tinggi dan kemampuannya untuk menyediakan panas laten memerlukan berat jauh lebih kecil dan volume bahan untuk menyimpan sejumlah energi dibandingkan dengan system sensible heat storage [7]. Kapasitas penyimpanan panas dapat dihitung dengan persamaan [8] Gambar 1.…”

Interactions between hybrid nanosized particles and convection melting inside an enclosure with partially active walls: 2D lattice Boltzmann‐based numerical investigation

“…Previous research has been directed toward finding the optimized location of active parts in partially heated cavities. Mirzaei et al 11 studied the effects of different arrangements of two discrete heat sources located on the inner cylinder within a two‐dimensional (2D) horizontal cylindrical annulus on the PCM melting. It was reported that utilizing the appropriate arrangement of discrete heat sources had great potential to advance the energy storage system.…”

Improving the performance of finned latent heat thermal storage devices using a Cartesian grid solver and machine-learning optimization techniques

“…2) 1) 49 The two designs that are most effective in the charging process are designs 1 and 4, as they are able to begin the melting process more quickly and spread heat more efficiently through convection than the other two. Design 3 performed nearly as well, particularly in spreading heat throughout the device with its five-finned aluminum core, but the fact that the first fin is closer to the core inlet limited the effectiveness of the convective flow created near the core inlet.…”

“…And finally, the low diffusivity of the latent heat medium means that heat transfer within that medium will be heavily dominated by convection, leading to significantly different time and length scales for the movement of heat within the liquid (molten) salt, within the solid salt, and within the metal fins First, to deal with meshing problems, this work employs an adaptive locally refined octree Cartesian mesh [45] that both allows the grid to adapt to the changing mesh interface and eliminates the need to create a mesh for the multiple complex geometries that would be used in a design optimization process. Like much recent work [36,[46][47][48][49][50][51], the melting boundary here is tracked using the well-established enthalpy-porosity method [33,52]. But the present work differs in its approach to the computational grid.…”