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.

Numerical Investigation of Water Supply Pipe Optimal Buried Depth in Severe Cold Region

2014 ◽  
Vol 955-959 ◽  
pp. 3365-3368
Author(s):  
Li Bai ◽  
Yan Wang ◽  
Xiao Long Liu
Keyword(s):  
Water Supply ◽  
Ground Temperature ◽  
Frost Heave ◽  
Transfer Model ◽  
Insulation Layer ◽  
Cold Region ◽  
Unsteady Heat Transfer ◽  
Buried Pipe ◽  
Buried Pipes ◽  
Supply Pipe

Frost heave often causes damage to rural water supply pipes in severe cold region, therefore, the anti-frost technology of shallow buried pipe with insulation layer was proposed in this article. Firstly, by analyzing the calculation of frost heave and measuring the ground temperature of the different depth, the optimal buried depth was founded preliminarily. Secondly, establishing the unsteady heat transfer model with the Matlab software, the ground temperature field were simulated when the pipe depth differs. Thus, the conclusion is that the optimal depth is 1.5m for the buried pipes with little atmospheric disturbance effect and the thaw circle is larger

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.

Heat-Transfer Stability of Porous Fibrous Composition under Different Condition

2014 ◽  
Vol 1004-1005 ◽  
pp. 557-561
Author(s):  
Yu Juan Wang ◽  
Hai Zhen Chen ◽  
Jin Mei Wang ◽  
Mei Zhen Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Process ◽  
Surface Condition ◽  
Transfer Model ◽  
Unsteady Heat Transfer ◽  
One Dimensional ◽  
The One ◽  
Thermal Difference ◽  
Key Parameter

In this paper, the influences of different conditions on heat-transfer stability of porous fibrous composition were analyzed by the one-dimensional unsteady heat transfer model. It was resulted that the surface condition of composition was key parameter for heat performance during different thermal process. Great humidity and thermal difference caused the heat transfer fluctuating of material covering, and then changed the thermal conductivity. For the insulation materials under low temperature, the heat performance was sharply fluctuated nearby 0°C.

Numerical Heat Transfer Model of Buried Pipe and Ground Thermal Conductivity Measurement

2011 ◽  
Vol 99-100 ◽  
pp. 112-115
Author(s):  
Ming Zhi Yu ◽  
Lei Zhang ◽  
Xiao Fei Yu ◽  
Zhao Hong Fang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Estimation Method ◽  
Conductivity Measurement ◽  
Heat Transfer Model ◽  
Parameters Estimation ◽  
Transfer Model ◽  
Buried Pipe ◽  
Geothermal Heat ◽  
Numerical Heat Transfer

A two dimensional numerical heat transfer model of buried geothermal heat exchanger has been established by finite element method. This model is used to analyse the heat transfer between buried vertical pipes and the ground, and determine the ground thermal properties together with parameters estimation method. The ground thermal conductivity of an actual project was measured and the analysis shows that the results can be used for engineering design.

The Simulation Study on Buried Ground-Source Heat Pipe Transient Temperature Field Distribution

2011 ◽  
Vol 383-390 ◽  
pp. 6621-6625
Author(s):  
Chang Sheng Guan ◽  
Zhao Wan
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Field Distribution ◽  
Optimization Design ◽  
Transient Temperature ◽  
Transfer Model ◽  
Temperature Field Distribution ◽  
Heat Transfer Efficiency ◽  
Ground Source ◽  
Coefficient Of Thermal Conductivity

In order to provides the theory basis for the optimization design of ground source heat pump underground U-shaped buried tube, ANSYS software was used to simulate the temperature field distribution of GSHP buried tube summer cooling process. The dynamic simulation was base on analyzing the GSHP heat exchanger unsteady heat transfer model. Comparing the temperature field distribution radius in different soil heat transfer rate, the simulation results show that the buried tube heat transfer efficiency increases with soil coefficient of thermal conductivity, soil hot effect radius increased over time and tend to be gentle.

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.

scholarly journals Conjugate heat transfer performance of stepped lid-driven cavity with Al2O3/water nanofluid under forced and mixed convection

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Naveen Janjanam ◽  
Rajesh Nimmagadda ◽  
Lazarus Godson Asirvatham ◽  
R. Harish ◽  
Somchai Wongwises
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Mixed Convection ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Performance ◽  
Pure Water ◽  
Interface Temperature ◽  
Transfer Model ◽  
Transfer Performance ◽  
Driven Cavity

AbstractTwo-dimensional conjugate heat transfer performance of stepped lid-driven cavity was numerically investigated in the present study under forced and mixed convection in laminar regime. Pure water and Aluminium oxide (Al2O3)/water nanofluid with three different nanoparticle volume concentrations were considered. All the numerical simulations were performed in ANSYS FLUENT using homogeneous heat transfer model for Reynolds number, Re = 100 to 500 and Grashof number, Gr = 5000, 13,000 and 20,000. Effective thermal conductivity of the Al2O3/water nanofluid was evaluated by considering the Brownian motion of nanoparticles which results in 20.56% higher value for 3 vol.% Al2O3/water nanofluid in comparison with the lowest thermal conductivity value obtained in the present study. A solid region made up of silicon is present underneath the fluid region of the cavity in three geometrical configurations (forward step, backward step and no step) which results in conjugate heat transfer. For higher Re values (Re = 500), no much difference in the average Nusselt number (Nuavg) is observed between forced and mixed convection. Whereas, for Re = 100 and Gr = 20,000, Nuavg value of mixed convection is 24% higher than that of forced convection. Out of all the three configurations, at Re = 100, forward step with mixed convection results in higher heat transfer performance as the obtained interface temperature is lower than all other cases. Moreover, at Re = 500, 3 vol.% Al2O3/water nanofluid enhances the heat transfer performance by 23.63% in comparison with pure water for mixed convection with Gr = 20,000 in forward step.

Study on Effective Radial Thermal Conductivity of Gas Flow through a Methanol Reactor

2015 ◽  
Vol 13 (1) ◽  
pp. 103-112 ◽  
Author(s):  
Kun Lei ◽  
Hongfang Ma ◽  
Haitao Zhang ◽  
Weiyong Ying ◽  
Dingye Fang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Reynolds Number ◽  
Temperature Distribution ◽  
Large Scale ◽  
Gas Flow ◽  
Fixed Bed ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Particle Reynolds Number

Abstract The heat conduction performance of the methanol synthesis reactor is significant for the development of large-scale methanol production. The present work has measured the temperature distribution in the fixed bed at air volumetric flow rate 2.4–7 m3 · h−1, inlet air temperature 160–200°C and heating tube temperature 210–270°C. The effective radial thermal conductivity and effective wall heat transfer coefficient were derived based on the steady-state measurements and the two-dimensional heat transfer model. A correlation was proposed based on the experimental data, which related well the Nusselt number and the effective radial thermal conductivity to the particle Reynolds number ranging from 59.2 to 175.8. The heat transfer model combined with the correlation was used to calculate the temperature profiles. A comparison with the predicated temperature and the measurements was illustrated and the results showed that the predication agreed very well with the experimental results. All the absolute values of the relative errors were less than 10%, and the model was verified by experiments. Comparing the correlations of both this work with previously published showed that there are considerable discrepancies among them due to different experimental conditions. The influence of the particle Reynolds number on the temperature distribution inside the bed was also discussed and it was shown that improving particle Reynolds number contributed to enhance heat transfer in the fixed bed.

A Study Regarding the Unsteady Heat Transfer and Phase Change

2014 ◽  
Vol 659 ◽  
pp. 353-358
Author(s):  
Gelu Coman ◽  
Cristian Iosifescu ◽  
Valeriu Damian
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Finite Elements ◽  
Experimental Research ◽  
Theoretical Study ◽  
Ice Formation ◽  
Unsteady Heat Transfer ◽  
Cooling Pipes

The paper presents the experimental and theoretical study for temperature distribution around the cooling pipes of an ice rink pad. The heat transfer in the skating rink track is nonstationary and phase changing. In case of skating rinks equipped with pipe registers, the temperature field during the ice formation process can’t be modeled by analytical methods. The experimental research was targeted on finding the temperatures in several points of the pad and also details on ice shape and quality around the pipes. The temperatures measured on the skating ring surface using thermocouples is impossible due to the larger diameter of the thermocouple bulb compared with the air-water surfaces thickness. For this reason we used to measure the temperature by thermography method, thus reducing the errors The experimental results were compared against the numerical modeling using finite elements.

Research on Heat Transfer Characteristics of Nano-Porous Silica Aerogel Material and its Application on Mars Surface Mission

2014 ◽  
Vol 924 ◽  
pp. 329-335 ◽  
Author(s):  
Cong Hang Li ◽  
Shi Chen Jiang ◽  
Zheng Ping Yao ◽  
Song Sheng ◽  
Xin Jian Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Silica Aerogel ◽  
Thermal Environment ◽  
Porous Silica ◽  
Heat Transfer Model ◽  
Heat Radiation ◽  
Transfer Model ◽  
Ambient Conditions ◽  
Coupled Heat Transfer

Based on the nanoporous network structure features of silica aerogel, the gas-solid coupled heat transfer model of silica aerogel is analyzed, and the calculation formulas of the gas-solid coupled, the gas thermal conductivity and the heat radiation within the aerogel are derived. The thermal conductivity of pure silica aerogel is calculated according to the derived heat transfer model and is also experimentally measured. Moreover, measurements on the thermal conductivities of silica aerogel composites with different densities at ambient conditions are performed. And finally, a novel design of silica aerogel based integrated structure and thermal insulation used for withstanding the harsh thermal environment on the Martin surface is presented.

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