A novel three-dimensional numerical model to simulate heat transfer inside a double U-tube borehole with two independent circuits

2021 ◽  
pp. 122243
Author(s):  
Saeed Kimiaei ◽  
Sina Kazemi-Ranjbar ◽  
Alireza Jalali ◽  
Pouria Ahmadi
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Three Dimensional

Automatic Integration in the Design of a Microturbine Compact Recuperator

2006 ◽  
Author(s):  
Marco Manzan ◽  
Diego Micheli ◽  
Stefano Pieri
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Exchange Rate ◽  
Heat Exchange ◽  
Numerical Model ◽  
Gas Turbine ◽  
Three Dimensional ◽  
Parametric Model ◽  
Automatic Integration ◽  
Successive Step

The first phase of the development of an automatic methodology for the design process of small gas turbine recuperators is presented. The different software tools are selected in order to be managed, in a successive step of the research, by means of a design-optimization platform, according to the concept of Multi Disciplinary Optimization (MDO). The methodology has been developed integrating a geometrical parametric model of the heat transfer surfaces, built inside an industrial CAD, a three dimensional meshing tool and a CFD solver. Final objectives of the research will be an optimization process designed to maximize the heat exchange rate and to minimize costs and fluid dynamics losses. The paper deals with the parameterization technique and the numerical model validation.

Microchannel Optimization for Heat Dissipation From a Solid Substrate

2008 ◽  
Author(s):  
C. B. Sobhan ◽  
P. S. Anoop ◽  
Kuriyan Arimboor ◽  
Thomas Abraham ◽  
G. P. Peterson
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Thermal Resistance ◽  
Computational Model ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Heat Dissipation ◽  
Three Dimensional ◽  
Solid Substrate ◽  
Nusselt Numbers

A computational model was developed to analyze and optimize the convective heat transfer for water flowing through rectangular microchannels fabricated in a silicon substrate. A baseline case was analyzed by solving the nondimensional governing equations. Using a quasi three-dimensional computational model, the velocity and temperature distributions were obtained and the numerical results were then used to determine the overall dimensionless thermal resistance for the convective heat transfer from the substrate to the fluid. To validate the numerical model, the average Nusselt numbers as determined by the numerical model were compared with experimental results available in the literature, for channels with comparable hydraulic diameters. The procedure for arriving at an optimum geometric configuration and arrangement of microchannels on the substrate, subject to given design constraints, so that the thermal resistance is at a minimum, is described and demonstrated using the computational model.

Numerical simulation of methane spreading in porous media after leaking from an underground pipe

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ji Wang ◽  
Yuting Yan ◽  
Junming Li
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Numerical Model ◽  
Natural Gas ◽  
Three Dimensional ◽  
Ground Surface ◽  
Air Transportation ◽  
Water Evaporation ◽  
Content Type ◽  
Gas Leak

Purpose Natural gas leak from underground pipelines could lead to serious damage and global warming, whose spreading in soil should be systematically investigated. This paper aims to propose a three-dimensional numerical model to analyze the methane–air transportation in soil. The results could help understand the diffusion process of natural gas in soil, which is essential for locating leak source and reducing damage after leak accident. Design/methodology/approach A numerical model using finite element method is proposed to simulate the methane spreading process in porous media after leaking from an underground pipe. Physical models, including fluids transportation in porous media, water evaporation and heat transfer, are taken into account. The numerical results are compared with experimental data to validate the reliability of the simulation model. The effects of methane leaking direction, non-uniform soil porosity, leaking pressure and convective mass transfer coefficient on ground surface are analyzed. Findings The methane mole fraction distribution in soil is significantly affected by the leaking direction. Horizontally and vertically non-uniform soil porosity has a stronger effect. Increasing leaking pressure causes increasing methane mole flux and flow rate on the ground surface. Originality/value Most existing gas diffusion models in porous media are for one- or two-dimensional simulation, which is not enough for predicting three-dimensional diffusion process after natural gas leak in soil. The heat transfer between gas and soil was also neglected by most researchers, which is very important for predicting the gas-spreading process affected by the soil moisture variation because of water evaporation. In this paper, a three-dimensional numerical model is proposed to further analyze the methane–air transportation in soil using finite element method, with the presence of water evaporation and heat transfer in soil.

Three-dimensional thermohydrodynamic investigation on the micro-groove textures in the main bearing of internal combustion engine for tribological performances

2020 ◽  
pp. 135065012094128
Author(s):  
Anvar Ahmadkhah ◽  
Amir Hassan Kakaee
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Carrying Capacity ◽  
Combustion Engine ◽  
Three Dimensional ◽  
Load Carrying Capacity ◽  
Bearing Surface ◽  
Main Bearing ◽  
Texture Surface ◽  
Load Carrying

A three-dimensional thermohydrodynamic numerical simulation study was used to investigate the impact of the micro-groove surface texturing on the tribological performances in the main bearing of the internal combustion engine. For this purpose, various number of grooves and groove height to the bearing surface were applied to determine the optimal texture surface parameters by comparing the load-carrying capacity and friction force in the engine main bearing. In the multiphysics numerical model, the three-dimensional Navier–Stokes equation was employed considering the cavitation mechanism based on the Elrod method in the solution. Using the transverse grooves on the bearing surface altered the cavitation response and film reformation. To validate the use of the current numerical model for analyzing the bearings, the obtained results were compared with those of the published theoretical papers, where a good agreement was obtained. The bearing performance was studied in thermal interface conditions to find the optimal set textures parameters that gave minimum fiction force with minimum loss in load-carrying capacity. The bearing with the optimal micro-groove texture parameter showed a reduction in friction (around 16%) with the minimum reduction in load-carrying capacity (around 6%) and the maximum reduction of the flow work (around 15%) compared with the untextured bearing surface. This paper focuses on the thermohydrodynamic investigation with a combination of thermal effects of the fluid film in the textured bearing. Meanwhile, the heat transfer characteristic, temperature distribution of solid bodies, and convection heat transfer coefficient in the contact surfaces of the textured bearing were investigated. The proposed multiphysics numerical model can be widely used for predicting the optimal texture surface parameters in different engineering systems modeling. Moreover, using the three-dimensional-based numerical model is more cost-effective compared with the experimental evaluation of the textured surface.

A three-dimensional numerical model of unsteady flow and heat transfer in ceramic honeycomb regenerator

2016 ◽  
Vol 108 ◽  
pp. 1243-1250 ◽  
Author(s):  
Yonghua You ◽  
Huang Huang ◽  
Guiwei Shao ◽  
Ji Hu ◽  
Xuecheng Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Unsteady Flow ◽  
Three Dimensional ◽  
Flow And Heat Transfer ◽  
Ceramic Honeycomb
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