scholarly journals Three-Dimensional Numerical Simulation of Geothermal Field of Buried Pipe Group Coupled with Heat and Permeable Groundwater

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3698 ◽  
Author(s):  
Xinbo Lei ◽  
Xiuhua Zheng ◽  
Chenyang Duan ◽  
Jianhong Ye ◽  
Kang Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Three Dimensional ◽  
Heat Pumps ◽  
Geothermal Field ◽  
Ground Temperature ◽  
Transfer Model ◽  
Buried Pipe ◽  
Ground Source Heat Pumps

The flow of groundwater and the interaction of buried pipe groups will affect the heat transfer efficiency and the distribution of the ground temperature field, thus affecting the design and operation of ground source heat pumps. Three-dimensional numerical simulation is an effective method to study the buried pipe heat exchanger and ground temperature distribution. According to the heat transfer control equation of non-isothermal pipe flow and porous media, combined with the influence of permeable groundwater and tube group, a heat-transfer coupled heat transfer model of the buried pipe group was established, and the accuracy of the model was verified by the sandbox test and on-site thermal response test. By processing the layout of the buried pipe in the borehole to reduce the number of meshes and improve the meshing quality, a three-dimensional numerical model of the buried pipe cluster at the site scale was established. Additionally, the ground temperature field under the thermal-osmotic coupling of the buried pipe group during groundwater flow was simulated and the influence of the head difference and hydraulic conductivity on the temperature field around the buried pipe group was calculated and analyzed. The results showed that the research on the influence of the tube group and permeable groundwater on the heat transfer and ground temperature field of a buried pipe simulated by COMSOL software is an advanced method.

Numerical Simulating the Ground Coefficient of Thermal Conductivity in Severe Cold Region

2014 ◽  
Vol 960-961 ◽  
pp. 366-369 ◽  
Author(s):  
Li Bai ◽  
Yan Wang ◽  
Ya Wei Hua
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Temperature Field ◽  
Ground Temperature ◽  
Actual Data ◽  
Transfer Model ◽  
Cold Region ◽  
Unsteady Heat Transfer ◽  
Buried Pipe ◽  
Coefficient Of Thermal Conductivity

The ground coefficient of thermal conductivity is one of the most important parameters of simulating the ground temperature field. The ground coefficient of thermal conductivity of the severe cold region is investigated in this article. Firstly, calculating the ground thermal conductivity with considering the moisture content and porosity; then measuring the thermal conductivity of the 1.5 Meter depth; finally, simulating the unsteady heat transfer model of the shallow buried pipe and the ground with the Matlab software; it founded that the calculation data and the actual data differ only 0.31,but the corresponding ground temperature field vary widely. Thus, it can be concluded that the more precise temperature field of the ground can be simulated with the actual data of ground coefficient of thermal conductivity.

Heat Transfer Model and Analysis of Oil-Immersed Electrical Transformers with Heat Pipe Radiator

2012 ◽  
Vol 516-517 ◽  
pp. 312-315
Author(s):  
Guang Hua Li ◽  
Hong Lei Liu ◽  
De Jian Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Heat Pipe ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Cooling Device ◽  
Transformer Design ◽  
Electrical Transformers ◽  
Good Agreement

This paper has formulated a heat transfer model for analyzing the cooling properties of a heat pipe cooling device of oil-immersed electrical transformer. Based on the model, the oil temperature field of a 30 KVA oil-immersed transformer has been numerical simulated, and experiments also had been conducted. Results showed that the numerical simulation has good agreement with experiment results. Results also showed that heat pipe radiator is feasible for oil-immersed electrical transformer cooling. The model can be used to analyze the oil temperature distribution properties in an oil-immersed electrical transformer with heat pipe cooling device, and provide theoretical guide for transformer design and improvement.

Numerical Simulation on Process of Flow and Heat Transfer in Upright Magnesium Reducing Furnace

2011 ◽  
Vol 383-390 ◽  
pp. 6657-6662 ◽  
Author(s):  
Jun Xiao Feng ◽  
Qi Bo Cheng ◽  
Si Jing Yu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Flue Gas ◽  
Gas Flow ◽  
Three Dimensional ◽  
Reaction Heat ◽  
Flow And Heat Transfer ◽  
Major Factors ◽  
High Chemical Reaction

Based on the analysis of structural characteristic superiority, the process of combustion, flue gas flow and heat transfer in the upright magnesium reducing furnace, the three dimensional mathematical model is devoloped. And numerical simulation is performed further with the commercial software FLUENT. Finally, the flow and temperature field in furnace and temperature field in reducing pot have been obtained. The results indicate that the upright magnesium reducing furnace has perfect flue gas flow field and temperature field to meet the challenge of the magnesium reducing process; the major factors that affect the magnesium reducing reaction are the low thermal conductivity of slag and the high chemical reaction heat absorption.

Application of Artificial Neural Networks to Predict Heat Transfer From Buried Pipe for Ground Source Heat Pump Applications

2013 ◽  
Author(s):  
Hakan Demir ◽  
Ş. Özgür Atayılmaz ◽  
Özden Agra ◽  
Ahmet Selim Dalkılıç
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Study ◽  
Energy Resource ◽  
Heat Pumps ◽  
Burial Depth ◽  
Buried Pipe ◽  
Ground Source Heat Pumps ◽  
Ground Source ◽  
Artificial Neural

The earth is an energy resource which has more suitable and stable temperatures than air. Ground Source Heat Pumps (GSHPs) were developed to use ground energy for residential heating. The most important part of a GSHP is the Ground Heat Exchanger (GHE) that consists of pipes buried in the soil and is used for transferring heat between the soil and the heat exchanger of the GSHP. Soil composition, density, moisture and burial depth of pipes affect the size of a GHE. Design of GSHP systems in different regions of US and Europe is performed using data from an experimental model. However, there are many more techniques including some complex calculations for sizing GHEs. An experimental study was carried out to investigate heat transfer in soil. A three-layer network is used for predicting heat transfer from a buried pipe. Measured fluid inlet temperatures were used in the artificial neural network model and the fluid outlet temperatures were obtained. The number of the neurons in the hidden layer was determined by a trial and error process together with cross-validation of the experimental data taken from literature evaluating the performance of the network and standard sensitivity analysis. Also, the results of the trained network were compared with the numerical study.

Numerical Simulation of Hot Rolled Coil Temperature Field in Hot Coil Box

2011 ◽  
Vol 338 ◽  
pp. 572-575
Author(s):  
Gui Jie Zhang ◽  
Kang Li ◽  
Ying Zi Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Coil Temperature ◽  
Hot Rolled ◽  
Strip Coil ◽  
Good Agreement

The heat transfer model was developed and the heat transfer of the strip coil stay in the hot coil box was analyzed. The temperature distribution of the strip coil was investigated use the model. The measured results are in good agreement with the calculated ones, has a guiding significance to further improve the technology.

Three Dimensional Transient Heat Transfer Model for Steel Billet Heating in Reheat Furnace

2012 ◽  
Author(s):  
Satish Kumar Dubey ◽  
Neelesh Agarwal ◽  
P. Srinivasan
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Oxide Scale ◽  
Three Dimensional ◽  
Heat Transfer Model ◽  
Heat Diffusion ◽  
Transient Heat Transfer ◽  
Transfer Model ◽  
Scale Thickness ◽  
Reheating Process

In steel rolling mills reheat furnaces are used to heat the billets prior to rolling processes. Reheating is one of the most energy intensive processes in the steel industries. Inadequate temperature measuring techniques and extremely complex analytical solution for temperature filed calculations demands suitable numerical model. In the present work a three dimensional transient heat transfer model is developed for billet heating in reheat furnaces. Conduction heat transfer within the billets is modeled using Finite Difference Method (FDM). Fully implicit spatial discretization approximation was used for three dimensional heat diffusion equation of billet. The three dimensional model takes into account the temperature dependent thermo physical properties, reaction heat effect and growing oxide layer. Algorithm is implemented in MATLAB® to solve three dimensional discretization equations. Model is capable of predicting the temperature field for billet and oxide scale thickness for any residence time. The predicted results are in reasonable concurrence with available data. The main objective of this work is to predict billet temperature field and oxide scale thickness for the various residence times, which may be vital for development of energy efficient optimization strategy for reheating process.

Random Heat Temperature Field Model Analysis on Buried Pipe of Ground Source Heat Pump

2011 ◽  
Vol 383-390 ◽  
pp. 6626-6631
Author(s):  
Cheng Ju Huang ◽  
Chang Sheng Guan ◽  
Kai Xia
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Heat Pump ◽  
Design Theory ◽  
Transfer Model ◽  
Ground Source Heat Pump ◽  
Buried Pipe ◽  
Reliability Design ◽  
Ground Source ◽  
Temperature Field Model

The random properties on buried pipe of ground-source heat pump (GSHP) is analyzed, the equation of Kelvin one-dimensional line source of heat transfer model is discussed. The model randomness is analyzed also, and the GSHP buried pipe to random excess temperature field, space-time statistics and the correlation of features are studied. The engineering example shows that heat transfer in buried pipe has relationship with the distance from the pipe center and run time of the system, and also the heat transfer between buried pipes can not be ignored. The method in this paper has great significance for improving the reliability design theory and reducing the construction cost of GSHP buried pipe in this paper.

Thermal Analysis and Research of Multi-Chip Component Substrate Based on Different Thermal Conductivity Models

2012 ◽  
Vol 217-219 ◽  
pp. 2523-2527
Author(s):  
Ming Xiang Zang ◽  
Pei Luo ◽  
Yuan Ming Xiao ◽  
Jian Guo Jiang
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Temperature Field ◽  
Three Dimensional ◽  
Stable State ◽  
Transfer Model ◽  
Three Dimension ◽  
Fourier Model ◽  
Substrate Model ◽  
Conductivity Models

With the development of electronic packaging technology, the time criterion and the space criterion of heat transfer have been becoming smaller and smaller, which results in the stronger Non-Fourier effect．Using the classical Fourier model to analyze the heat transfer of the substrate will inevitably make the result deviate from the actual conditions greatly. However, using the Non-Fourier model could closely describe the real situation. This paper regards the Fourier model and the Non-Fourier model separately, sets up their own mathematics-physics equations to the heat-transfer model of three-dimension multi-chip module(MCM) substrate，adopts finite difference method(FDM) to solve the corresponding equations，and get the temperature field of the three-dimensional substrate model. To test the accuracy of the results, meanwhile, the thermal analysis software ANSYS ICEPAK is used to calculate the same model. The results indicate that，compared with the classical Fourier model，the results of Non-Fourier model have great advantages：the temperature value is higher, the time is longer for temperature field to enter the stable state, changing of the temperature is faster and the phenomenon of thermal coupling is stronger too.

Transient, Three-Dimensional Heat Transfer Model for Partially Stabilized Zirconia Undergoing Laser-Assisted Machining

1999 ◽  
Author(s):  
Frank E. Pfefferkorn ◽  
Frank P. Incropera ◽  
Yung C. Shin
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Laser Radiation ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Depth Of Cut ◽  
Transfer Model ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
Laser Assisted Machining

Abstract A three-dimensional, unsteady heat transfer model has been developed for predicting the temperature field in partially stabilized zirconia (PSZ) undergoing laser-assisted machining (LAM). PSZ is a semi-transparent ceramic which volumetrically absorbs, emits and scatters radiation across a spectral region extending from approximately 0.5 to 8 μm. As a first approximation, it is treated as optically thick within this spectral band, and the high density of scattering centers, as well as the random orientation of grain boundaries, permits the assumption of isotropic scattering. Accordingly, the Rosseland diffusion approximation is used to model internal radiative transfer. Since most of the CO2 laser radiation (λ = 10.6 μm) is absorbed in the first layer of control volumes adjacent to the surface, incident laser radiation is treated as a surface phenomenon. The equivalent radiation conductivity of PSZ is strongly temperature dependent and enhances thermal energy transfer within regions of the workpiece which are close to the location of laser irradiation. However, the effective thermal conductivity of PSZ remains relatively low, even at the highest temperatures achieved during LAM, and is responsible for large temperature gradients near the irradiated surface of the workpiece. For representative operating conditions, comparative calculations are performed with and without the radiation model to assess the influence of volumetric radiation effects on the temperature field. Numerical simulations are also performed to consider the effect of operating conditions, such as the laser power, laser/tool feed and depth-of-cut, on thermal conditions in close proximity to the material removal zone. The results are contrasted with those for silicon nitride, which is an opaque ceramic that exhibits quasi-plastic deformation when its temperature is raised above a threshold value at the depth-of-cut and can therefore be machined with a cutting tool.

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