Numerical simulation of heat transfer and phase change during freezing of potatoes with different shapes at the presence or absence of ultrasound irradiation

Abstract In this paper, transient analysis on heat transfer across the residential building roof having various materials like wood wool, phase change material and weathering tile is performed by numerical simulation technique. 2-dimensional roof model is created, checked for grid independency and validated with the experimental results. Three different roof structures are included in this study namely roof with (i). Concrete and weathering tile, (ii). Concrete, phase change material and weathering tile and (iii). Concrete, phase change material, wood wool and weathering tile. Roof type 3 restricts 13% of heat entering the room in comparison with roof having only concrete and weathering tile. Also the effect of various roof layers’ thickness in the roof type 3 is investigated and identified that the wood wool plays the major role in arresting the entry of heat in to the room. The average reduction of heat is about 10 % for an increase of a unit thickness of wood wool layer.

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Numerical simulation of vapor bubble growth on a vertical superheated wall using lattice Boltzmann method

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-08-2013-0263 ◽

2015 ◽

Vol 25 (5) ◽

pp. 1214-1230 ◽

Cited By ~ 7

Author(s):

Tao Sun ◽

Weizhong Li ◽

Bo Dong

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Phase Change ◽

Lattice Boltzmann Method ◽

Lattice Boltzmann ◽

Nucleate Boiling ◽

Numerical Results ◽

Heat Transfer Mechanism ◽

Content Type ◽

Boltzmann Method

Purpose – The purpose of this paper is to test the feasibility of lattice Boltzmann method (LBM) for numerical simulation of nucleate boiling and transition boiling. In addition, the processes of nucleate and transition boiling on vertical wall are simulated. The heat transfer mechanism is discussed based on the evolution of temperature field. Design/methodology/approach – In this paper, nucleate boiling and transition boiling are numerically investigated by LBM. A lattice Boltzmann (LB) multiphase model combining with a LB thermal model is used to predict the phase-change process. Findings – Numerical results are in good agreement with existing experimental results. Numerical results confirm the feasibility of the hybrid LBM for direct simulations of nucleate and transition boiling. The data exhibit correct parametric dependencies of bubble departure diameter compared with experimental correlation and relevant references. Research limitations/implications – All the simulations are performed in two-dimensions in this paper. In the future work, the boiling process will be simulated in three-dimensional. Practical implications – This study demonstrated a potential model that can be applied to the investigation of phase change heat transfer, which is one of the effective techniques for enhance the heat transfer in engineering. The numerical results can be considered as a basic work or a reference for generalizing LB method in the practical application about nucleate boiling and transition boiling. Originality/value – The hybrid LBM is first used for simulation of nucleate and transition boiling on vertical surface. Heat transfer mechanism during boiling is discussed based on the numerical results.

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Analysis of the Thermal Characteristics of a Composite Ceramic Product Filled with Phase Change Material

Buildings ◽

10.3390/buildings9100217 ◽

2019 ◽

Vol 9 (10) ◽

pp. 217 ◽

Cited By ~ 2

Author(s):

Joanna Krasoń ◽

Przemysław Miąsik ◽

Lech Lichołai ◽

Bernardeta Dębska ◽

Aleksander Starakiewicz

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Heat Transfer Coefficient ◽

Phase Change ◽

Transfer Coefficient ◽

Phase Change Material ◽

Thermal Characteristics ◽

Ceramic Product ◽

Change Material ◽

The Heat Transfer Coefficient

The article presents a comparative analysis carried out using three methods, determining the heat transfer coefficient U for a ceramic product modified with a phase change material (PCM). The purpose of the article is to determine the convergence of the resulting thermal characteristics, obtained using the experimental method, numerical simulation, and standard calculation method according to the requirements of PN-EN ISO 6946. The heat transfer coefficient is one of the basic parameters characterizing the thermal insulation of a building partition. Most often, for the thermal characteristics of the partition, we obtain from the manufacturer the value of the thermal conductivity coefficient λ for individual homogeneous materials or the heat transfer coefficient U for the finished (prefabricated) partition. In the case of a designed composite element modified with a phase change material or other material, it is not possible to obtain direct information on the above parameter. In such a case, one of the methods presented in this article should be used to determine the U factor. The U factor in all analyses was determined in stationary conditions. Research has shown a significant convergence of the resulting value of the heat transfer coefficient obtained by the assumed methods. Thanks to obtaining similar values, it is possible to continue tests of thermal characteristics of partitions by means of numerical simulation, limiting the number of experimental tests (due to the longer test time required) in assumed different partition configurations, in stationary and dynamic conditions.

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Phase Change Material Used for Masonry Joints: Numerical Simulation and Scale Test

Proceedings ◽

10.3390/proceedings2019034016 ◽

2019 ◽

Vol 34 (1) ◽

pp. 16

Author(s):

Jiang ◽

Liu ◽

Yuan

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Phase Change ◽

Phase Change Material ◽

Phase Change Materials ◽

Masonry Wall ◽

Wall Structure ◽

Thermal Coefficient ◽

New Form ◽

Change Material

In order to effectively improve the thermal performance of the thermal insulation masonry wall, the thermal bridge effect of the grey joint on the heat transfer of the wall structure was studied. A brand-new form of phase change material walls, which used phase change materials in the wall parts to build ash joints, was carried out. The application of phase change material mortar, which was different from conventional "Hamburger" phase change material walls, was demonstrated to be a useful tool to reduce the thermal coefficient of the masonry wall. Furthermore, the scale-down test and numerical simulation of the heat transfer coefficient of the phase change material wall with different distribution of ash joints were experimented and discussed, and the feasibility of the new-form phase change material wall within the error range was verified.

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