Analysis of Temperature and Heat Flow Characteristics in Underground Tunnel

2014 ◽  
Vol 548-549 ◽  
pp. 579-583
Author(s):  
Hai Min Xie ◽  
Mao De Li
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Heat Flow ◽  
Thermal Environment ◽  
Flow Characteristics ◽  
Surrounding Rock ◽  
Simplified Model ◽  
Radial Temperature ◽  
Underground Tunnel ◽  
Axial Temperature

This paper summarizes the two methods which are experimental research and numerical simulation to thermal environment of the tunnel. Then the latest developments of the thermal environment research at home and overseas are introduced. At last a simplified model of thermal environment of underground tunnel is established. Through CFD software, the radial temperature distribution of tunnel surrounding rock and the axial temperature distribution of air at winter and summer conditions are obtained which provide basis for further research on thermal environment of underground tunnel.

Analysis of Temperature and Heat Flow Characteristics in Underground Tunnel

2014 ◽  
Vol 955-959 ◽  
pp. 4083-4086 ◽  
Author(s):  
Hai Min Xie ◽  
Mao De Li
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Heat Flow ◽  
Thermal Environment ◽  
Flow Characteristics ◽  
Surrounding Rock ◽  
Simplified Model ◽  
Radial Temperature ◽  
Underground Tunnel ◽  
Axial Temperature

This paper summarizes the two methods which are experimental research and numerical simulation to thermal environment of the tunnel. Then the latest developments of the thermal environment research at home and overseas are introduced. At last a simplified model of thermal environment of underground tunnel is established. Through CFD software, the radial temperature distribution of tunnel surrounding rock and the axial temperature distribution of air at winter and summer conditions are obtained which provide basis for further research on thermal environment.

Analysis of Microheat Pipes With Axial Conduction in the Solid Wall

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Yew Mun Hung ◽  
Kek-Kiong Tio
Keyword(s):  
Temperature Distribution ◽  
Heat Transport ◽  
Thermal Effects ◽  
Solid Wall ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Working Fluid ◽  
Transport Capacity ◽  
Axial Temperature ◽  
Energy Equations

A one-dimensional, steady-state model of a triangular microheat pipe (MHP) is developed, with the main purpose of investigating the thermal effects of the solid wall on the heat transport capacity of an MHP. The energy equation of the solid wall is solved analytically to obtain the axial temperature distribution, the average of which over the entire length of the MHP is simply its operating temperature. Next, the liquid phase is coupled with the solid wall by a heat transfer coefficient. Then, the continuity, momentum, and energy equations of the liquid and vapor phases are, together with the Young–Laplace equation, solved numerically to yield the heat and fluid flow characteristics of the MHP. The heat transport capacity and the associated optimal charge level of the working fluid are predicted for different operating conditions. Comparison between the models with and without a solid wall reveals that the presence of the solid wall induces a change in the phase change heat transport by the working fluid, besides facilitating axial heat conduction in the solid wall. The analysis also highlights the effects of the thickness and thermal conductivity of the solid wall on its axial temperature distribution. Finally, while the contribution of the thermal effects of the solid wall on the heat transport capacity of the MHP is usually not dominant, it is, nevertheless, not negligible either.

Thermal Buckling and Snapping of a Circular Ring

1971 ◽  
Vol 93 (4) ◽  
pp. 1245-1254
Author(s):  
David Burgreen
Keyword(s):  
Temperature Distribution ◽  
Temperature Variation ◽  
Circular Ring ◽  
Thermal Buckling ◽  
Uniform Temperature ◽  
Radial Temperature ◽  
Axial Temperature ◽  
Axisymmetric Temperature

An analysis is made of the thermal buckling of flat rings and of shallow conical rings which are subjected to an axisymmetric temperature distribution. It is found that flat rings can buckle when there is a radial temperature variation only. Conical rings are subject to instability and snapping in the presence of either an axial temperature variation alone, or a combined axial and radial temperature variation, of the proper magnitude. Expressions are developed which give the temperatures at which buckling and snapping take place, as well as the temperature over-lap in a full thermostatic cycle of increasing and decreasing temperatures. Bimetallic conical rings at uniform temperature are examined, and snapping temperatures are determined for this type element.

scholarly journals Some Effects on the Temperature of the Mine Air at the Heading Face

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Van Quang NGUYEN ◽  
Van Thinh NGUYEN ◽  
Cao Khai NGUYEN ◽  
Van Chung PHAM
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Temperature Distribution ◽  
Air Temperature ◽  
Significant Influence ◽  
Thermal Environment ◽  
Simulation Method ◽  
Forced Ventilation ◽  
Ansys Cfx ◽  
Ventilation Method

Currently, with the increase in mining output leading to deeper mining levels, the volume ofheading face serving production has also increased. The thermal environment tends to worsen whendigging deep due to the geothermal's effect, which increases the air temperature at the heading face.According to QCVN01/2011-BCT, the temperature at the heading face is not allowed to exceed 300C. Toensure this, in Vietnam today, mainly forced ventilation method uses local fans to provide a clean amountof air to ensure a favorable environment for workers. With the forced ventilation method, the duct positionis usually arranged on the side, and the distance from the duct mouth to the heading face is determined toensure that l < 6√s. In this study, a numerical simulation method by Ansys CFX software is applied tostudy the influence of several factors such as duct position, air temperature of duct, and roughnesscharacteristics of roadway on the temperature of the mine air at the heading face. The models are set upwith six duct positions and four air temperature of duct parameters. Model 1 (y =1.1 m) is better thanmodels 2 to 6 in terms of temperature distribution and the lowest temperature values. Four models havedifferent wind temperatures, and we can see the significant influence of the inlet air temperature of theduct on the thermal environment of the heading face. The results show that with the model T = 297.15K,the temperature value on the roadway length is guaranteed as specified < 303K. The result is a referencefor determining the duct position and cool for the high-temperature heading face.

Effects of Different Vents Location on Flow Characteristics of Air Conditioning

2014 ◽  
Vol 662 ◽  
pp. 179-182
Author(s):  
Zhi Bin Luo
Keyword(s):  
Numerical Simulation ◽  
Thermal Environment ◽  
Flow Characteristics ◽  
Simulation Method ◽  
Physical Models ◽  
Flow And Heat Transfer ◽  
Wall Collision ◽  
Basic Equations ◽  
Transfer Problems ◽  
Two Jets

When using numerical simulation method for solving fluid flow and heat transfer problems, need to follow the basic equations. Each control equations generally use common form of expression, build a wall collision effects on indoor thermal environment situation jet and jet corner collision of two jets in the form of physical models under its numerical simulation were studied in the form of three jets collide.

scholarly journals Numerical Analysis of Thermal Environment in Deep Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Qi Li ◽  
Shuang You ◽  
HongGuang Ji ◽  
Huici Xu ◽  
Huan Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Temperature Field ◽  
Heat Exchange ◽  
Simulation Model ◽  
Thermal Environment ◽  
Surrounding Rock ◽  
Tunnel Length ◽  
Rock Body ◽  
Finite Element Software

To analyze heat effect in deep metal mines, it is crucial to understand the temperature field distribution around the mine tunnel. In this paper, a numerical model of the random mineral composition of the rock body is established based on finite element software to analyze the influence of the internal composition of the surrounding rock on the temperature field, and a numerical simulation model based on COMSOL finite element software is established based on the two heat exchange modes of heat conduction and heat convection in the surrounding rock. The results show that the numerical simulation results of a typical numerical simulation model using a single material are lower than the real situation; increasing the tunnel length does not increase the heat exchange efficiency between the rock wall and the air; increasing the wind velocity has a limited impact on the temperature field; the wind temperature more directly affects the mining surface; and the effect of wet air on the temperature field of the surrounding rock has a more substantial variation.

Numerical analysis of heat flow in oxy-ethylene flame cutting of steel plate

2016 ◽  
Vol 232 (4) ◽  
pp. 742-751 ◽  
Author(s):  
Kang-Yul Bae ◽  
Young-Soo Yang ◽  
Myung-Su Yi ◽  
Chang-Woo Park
Keyword(s):  
Numerical Simulation ◽  
Heat Flow ◽  
Heat Affected Zone ◽  
Steel Plate ◽  
Cutting Parameters ◽  
Cutting Process ◽  
Heat Sources ◽  
Power Functions ◽  
Severe Problem ◽  
Ethylene Flame

To manufacture a steel structure, in the first step, raw steel plate needs to be cut into proper sizes. Oxy-fuel flame is widely used in the cutting process due to its flexibility with respect to accessibility, plate thickness, cost, and material handling. However, the deformation caused by the cutting process frequently becomes a severe problem for the next process in the production of steel product. To decrease the deformation, the thermo-elasto-plastic behavior of the steel plate in the cutting process should be analyzed in advance. In this study, heat sources in oxy-ethylene flame cutting of steel plate were modeled first, and the heat flow in the steel plate was then analyzed by the models of the heat sources using a numerical simulation based on the finite element method. To verify the analysis by the numerical simulation including the models, a series of experiments were performed, and the temperature histories at several points on the steel plate during the cutting process were measured. Moreover, the predicted sizes of the heat-affected zone by the numerical simulations according to the variation in the cutting parameters were compared to the experimental results. The power functions of the relationship between the sizes of the heat-affected zone and cutting parameters were obtained by the recursion analysis using the correlation between the results and parameters. The results of the numerical simulation showed good agreement with those of the experiments, indicating that the proposed models of the heat sources and thermal analysis were feasible to analyze the heat flow in the steel plate during the cutting process.

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