scholarly journals Experimental Study on the Temperature Field of Cold Region Tunnel under Various Groundwater Seepage Velocities

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Shiding Cao ◽  
Taishan Lu ◽  
Bo Zheng ◽  
Guozhu Zhang
Keyword(s):  
Temperature Field ◽  
Coupling Effect ◽  
Calculation Model ◽  
Surrounding Rock ◽  
Laboratory Model ◽  
Interface Temperature ◽  
Cold Region ◽  
Seepage Velocity ◽  
Groundwater Seepage ◽  
Tunnel Cross Section

Groundwater seepage significantly affects the temperature field of a cold region tunnel. Laboratory model tests are carried out to evaluate its effects, yielding four main results. First, groundwater seepage can increase tunnel air temperature and decrease the thickness and length of the tunnel insulation layer. Second, groundwater seepage and tunnel ventilation exert a coupling effect on the surrounding rock temperature. This effect is related to the surrounding rock depth. Third, the influence of the groundwater seepage velocity on the temperature of the interface between the lining and surrounding rock demonstrates a spatial difference, and the groundwater seepage leads to an uneven temperature distribution at the interface between the lining and surrounding rock. Furthermore, under groundwater seepage, the shape and size of the tunnel cross section have significant effects on the interface temperature. Fourth, the cold region tunnel has an antifreezing capability that is mainly related to the frost heaving of the surrounding rock and the groundwater seepage velocity. This capability should be fully utilized in the design of cold region tunnels. The experimental data presented can be used to verify the reliability of the theoretical calculation model for tunnel temperatures in cold regions.

scholarly journals Investigation of the Thermal Performance of Energy Tunnel Equipped with the Insulation Layer Considering Ventilation and Groundwater Seepage

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Guozhu Zhang ◽  
Ziming Cao ◽  
Xu Zhao ◽  
Yongli Xie ◽  
Xiaohua Liu ◽  
...  
Keyword(s):  
Heat Exchange ◽  
Groundwater Flow ◽  
Exchange Rates ◽  
Thermal Performance ◽  
Surrounding Rock ◽  
Interface Temperature ◽  
Insulation Layer ◽  
Groundwater Seepage ◽  
Ground Heat Exchangers ◽  
Reduction Effect

The insulation layer is usually installed in the tunnel structure, whereas the influence of the insulation layer on the thermal behavior of energy tunnel ground heat exchangers (GHEs) is rarely investigated. The model tests were performed in this study to evaluate the heat transfer potential of the energy tunnel with the insulation layer under ventilation and groundwater seepage. The results can be obtained as follows: first, the fluctuations of air temperature and surrounding rock temperature at different locations are relevant to insulation layer, ventilation, and groundwater seepage. Second, the reduction effect of ventilation on the interface temperature of tunnel lining and surrounding rock is alleviated when using an insulation layer, and the interface temperature at upstream section of groundwater seepage is more easily affected by the energy tunnel GHEs. Third, the variation range of ground temperature is wider at the downstream section of groundwater flow. Moreover, the heat exchange rates of tunnel without the insulation layer improve by 5.82% and 6.45% with increasing wind speed at two groundwater flow velocities of 1 × 10 − 4 and 5 × 10 − 4  m/s, and there are only 2.03% and 0.77% enhancements of heat exchange rates by ventilation for the tunnel with the insulation layer. However, the thermal performance of the energy tunnel improved by groundwater is less relevant to the existence of the insulation layer. The relevant findings can provide an effective guidance for the following research and design of the energy tunnel.

scholarly journals Evolution regularity of temperature field of active heat insulation roadway considering thermal insulation spraying and grouting: A case study of Zhujidong Coal Mine, China

2021 ◽  
Vol 40 (1) ◽  
pp. 151-170
Author(s):  
Weijing Yao ◽  
Happiness Lyimo ◽  
Jianyong Pang
Keyword(s):  
Sensitivity Analysis ◽  
Temperature Field ◽  
Thermal Insulation ◽  
Wall Temperature ◽  
Heat Insulation ◽  
Surrounding Rock ◽  
Rock Temperature ◽  
Grouting Materials ◽  
Zone Radius ◽  
Thermal Conductivities

Abstract To study the active heat insulation roadways of high-temperature mines considering thermal insulation and injection, a high-temperature −965 m return air roadway of Zhujidong Coal Mine (Anhui Province, China) is selected as a prototype. The ANSYS numerical simulation method is used for the sensitivity analysis of heat insulation grouting layers with different thermal conductivities and zone ranges and heat insulation spray layers with different thermal conductivities and thicknesses; thus, their effects on the heat-adjusting zone radius, surrounding rock temperature field, and wall temperature are studied. The results show that the tunneling head temperature of the Zhujidong Mine is >27°C all year round, consequently causing serious heat damage. The heat insulation circle formed by thermal insulation spraying and grouting can effectively alleviate the disturbance of roadway airflow to the surrounding rock temperature field, thereby significantly reducing the heat-adjusting zone radius and wall temperature. The decrease in the thermal conductivities of the grouting and spray layers, expansion of the grouting layer zone, and increase in the spray layer thickness help effectively reduce the heat-adjusting zone radius and wall temperature. This trend decreases significantly with the ventilation time. A sensitivity analysis shows that the use of spraying and grouting materials of low thermal conductivity for thermal insulation is a primary factor in determining the temperature field distribution, while the range of the grouting layer zone and the spray layer thickness are secondary factors. The influence of the increased surrounding rock radial depth and ventilation time is negligible. Thus, the application of thermal insulation spraying and grouting is essential for the thermal environment control of mine roadways. Furthermore, the research and development of new spraying and grouting materials with good thermal insulation capabilities should be considered.

scholarly journals Study on the Temperature Field of Casting Process in ANSYS

2011 ◽  
Vol 2-3 ◽  
pp. 856-860
Author(s):  
Chang Li ◽  
Guang Bing Zhao ◽  
Shu Yu Zhang ◽  
Xing Han
Keyword(s):  
Temperature Field ◽  
Casting Process ◽  
Interface Temperature ◽  
Field Change ◽  
Ansys Software ◽  
Heat Process ◽  
Manufacture Process ◽  
Composite Interface ◽  
Non Linear ◽  
Changing Process

Cast molding is the main manufacture process in foundry, because the most disfigurements occurs in this step, while the foundry itself is a complex non-linear instantaneous transferring heat process, in which it should take the absorbing and releasing potential heat into account. In this paper, it simulates the temperature field changing process of the cast solidification in ANSYS software, gets the temperature field change rule for a typical cast, and analyzed the effect of different foundry technics parameters on composite interface temperature, which will provide numerical bases for optimizing foundry technics parameters in future.

Analysis of Temperature Field Based on Hollow Sucker Rod Hot Flushing Technology

2014 ◽  
Vol 1073-1076 ◽  
pp. 2257-2262
Author(s):  
Jie Yu Du ◽  
Jiang Xie ◽  
Yu Qi Zhao ◽  
Li Peng Zhang ◽  
Rui Bin Zhu
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Low Pressure ◽  
Calculation Model ◽  
Simulation System ◽  
Well Production ◽  
Transfer Theory ◽  
Heat Transfer Theory ◽  
Sucker Rod ◽  
Theory Calculation

The hot flushing is a major means of removing wax. For low pressure reservoir, it is possible to produce a large number of washing fluid flowing into the formation, which affects the well production recovery. The application of hollow sucker rod hot flushing technology can avoid fluid pouring back into the formation, and the wells can keep production. Based on the principle of hollow sucker rod hot flushing and heat transfer theory, calculation model of temperature field was established, and hollow sucker rod hot flushing simulation system was developed, which can guide flushing in oilfield.

Study on the Range of Freeze-Thaw of Surrounding Rock from a Cold-Region Tunnel and the Effects of Insulation Material

2011 ◽  
Vol 399-401 ◽  
pp. 2222-2225 ◽  
Author(s):  
Peng Qi ◽  
Jing Zhang ◽  
Zhi Rong Mei ◽  
Yue Xiu Wu
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Surrounding Rock ◽  
Insulation Material ◽  
The Finite Element Method ◽  
Cold Region ◽  
Coupled Problem ◽  
Fluid Transfer ◽  
Tunnel Depth ◽  
The Relationship

A mathematical models for the coupled problem is established by considering heat and mass transfer and phase change for rock mass at low temperature, according to the theory of heat and mass transfer for porous media. It is considered of the influences of fluid transfer on the heat conduction and the temperature gradient on the seepage. By adopting the finite element method, the numerical simulation is done to study the range of frost-thaw of surrounding rock and the effects of insulation material in cold regions, which analysis the influence of tunnel depth and surrounding rock class on the range of frost-thaw, the change law of the frost-thaw area of different insulation material and the relationship between the frost-thaw area and the thickness of insulation material.

scholarly journals Rebound Mechanism and Control of the Hard Main Roof in the Deep Mining Roadway in Huainan Mining Area

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Denghong Chen ◽  
Chao Li ◽  
Xinzhu Hua ◽  
Xiaoyu Lu ◽  
Yongqiang Yuan ◽  
...  
Keyword(s):  
Slope Angle ◽  
Bending Moment ◽  
Main Roof ◽  
Mining Area ◽  
Calculation Model ◽  
Surrounding Rock ◽  
Tensile Failure ◽  
Damage Area ◽  
Critical Range ◽  
Working Face

Taking the occurrence conditions of the hard main roof in the deep 13-1 coal mining roadway in Huainan mining area as the research object, based on the mechanical parameters of the surrounding rock and the stress state of the main roof obtained by numerical simulation, a simply supported beam calculation model was established based on the damage factor D, main roof support reaction RA, RB, and critical range C (9 m) and B (7 m) at the elastoplastic junction of the solid coal side and mining face side (hereinafter referred to as “junction”). Considering that the damage area still has a large bearing capacity, the vertical stress of the main roof at the junction is K1γH (0.05γh, 0.15γh, and 0.25γh) and K2γH (0.01γh, 0.10γh, and 0.2γh). The maximum deflection is 21 mm, 324 mm, and 627.6 mm, respectively. According to the criterion of tensile failure, the maximum bending moment of the top beam is 209 mN·m at the side of the working face 3.1 m away from the roadway side when K1 = 0.15 and K2 = 0.10, and the whole hard main roof is in tensile failure except the junction. To control the stability of the top beam and simplify the supporting reaction to limit the deformation of the slope angle, RC and RD are used to construct the statically indeterminate beam. By adding an anchor cable and advance self-moving support to the roadway side angle, the problem of difficult control of the surrounding rock with a large deformation of the side angle roof is solved, which provides a reference for roof control under similar conditions.

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