Thermal performance analysis of an underground closed chamber with human body heat sources under natural convection

Zhang, Zujing; Day, Rodney; Wang, Kequan; Wu, Hongwei; Yuan, Yanping

doi:10.1016/j.applthermaleng.2018.09.068

Cited by 18 publications

(10 citation statements)

References 38 publications

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“…In the current work, a computational model of a fifty-person MRC was developed. For the purpose of validation, the internal size of the MRC is 20 m in length, 3 m in height, and 4 m in width was selected, which is consist with the available experimental work [11]. It is known that the thickness of the heat-regulating circle of the surrounding rock for MRC within 96 h is approximately 2 m. [19] In the current MRC model, the thickness of the wall is 2.…”

Section: Computational Model and Meshmentioning

confidence: 99%

“…Therefore, the heat generated by the MRC's carbon dioxide scrubbing system will not be considered since the CO 2 is removed from the MRC by the airflow when ventilation is supplied for MRC. It is recognized that the heat flux of a human body surface is 60 W/m 2 since the calorie generated by an adult man sitting in a room is approximately 120 W [11,14,38,47] . The velocity at each of the ten air inlets is 6 m/s since the fresh air supply rate in an MRC is specified to be 0.3 m 3 /min per person [48] .…”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

“…However, high temperature and high concentration harmful gas issue accompanied with the accident becomes a problem in MRC due to human metabolism and harmful elements. [10,11] As one of the basic conditions for safe survival, it is crucial to control the air temperature in the MRC. It should be noted that cooling a MRC is challenging since the electrical power supply is often interrupted during and after an accident as well as the risk of re-explosion still exists.…”

Section: Introductionmentioning

confidence: 99%

“…Gao et al [24~26] systematically studied the temperature controlling characteristics of the PCM cooling plate and PCM cooling seat used in a fifty-person MRC, considering the coupled heat transfer characteristics between surrounding rock, air, and PCM. Most recently, Zhang et al [11] analyzed the thermal performance of a MRC and proposed a new analytical method to predict the air temperature in a MRC under natural convection. They concluded that the temperature in the MRC rises linearly with the square root of the heating time and the air temperature increasing trend becomes slow with the increase of the thermal conductivity, density and specific heat capacity of the rock.…”

Section: Introductionmentioning

confidence: 99%

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Thermal performance of a mine refuge chamber with human body heat sources under ventilation

Zhang

Wang

et al. 2019

Applied Thermal Engineering

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This paper investigated the dynamic coupling heat transfer characteristics of rock and air in a Mine Refuge Chamber (MRC) under ventilation. In the current work, a comprehensive fiftyperson MRC model combining human-body heat sources and ventilation is established, the proposed model is validated against available experimental data with deviation less than 4%. Furthermore, sensitivity analysis is performed to investigate the influence of several control parameters such as heating rate, ventilation and wall area in a MRC through using numerical simulation. Results indicated that: (ⅰ) the heat transfer process in a MRC will reach a stage of air temperature slow increase (ATSI) in less than 0.5 h. The air temperature rises linearly with the square root of time during the ATSI stage; (ⅱ) for a MRC built in a sandstone seam with an initial rock temperature of less than 27 °C, the average air temperature will not exceed 35 °C in 96 h when the ventilation volume rate is 0.3 m 3 /min per person; (ⅲ) the rate of temperature rise in MRC is proportional to the rate of heat generation, but it is inversely proportional to the thermal conductivity, density and thermal capacity of the rock, as well as the ventilation volume rate and the wall area; (ⅳ) an empirical correlation for the MRC average air temperature is developed while the supply air temperature equals to the initial rock temperature. Keywords：Underground; Mine refuge chamber; Air temperature prediction; Ventilation; Heat transfer coefficient; Human body heat sources. Nomenclature a Constant in K expression V Ventilation volume for MRC, m 3 /h A w Wall area of MRC, m 2 x, y Coordinate direction vector b Constant in K expression Subscripts B Temperature variable, °C a Air c Constant in K expression num Numerical data C a Specific heat capacity of air, J/(kg• K) exp Experimental data C p Specific heat capacity of rock, J/(kg• K) Greek symbols d Constant in K expression α Surface heat transfer coefficient, W/(m 2 • K) i, j Constant in B expression Θ Difference k Constant in B expression ρ Density of rock, kg/m 3 K Rate for air temperature increasing, °C/s 0.5 ρ a Density of air, kg/m 3 l Constant in B expression λ Thermal conductivity of rock, W/(m• K) L Temperature variable, °C τ Heat time, h L c Perimeter of cross-section tunnel, m Acronyms m, n Constant in K expression ATSI Air temperature slow increase p Pressure, Pa CE Critical equilibrium Q Total heat generation rate in MRC, W MRC Mine refuge chamber r 0 equivalent radius of cross-section tunnel, m MMRC Movable mine rescue capsules T Temperature, °C PCM Phase change materials T 0 Initial rock temperature, °C

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Section: Computational Model and Meshmentioning

confidence: 99%

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal performance of a mine refuge chamber with human body heat sources under ventilation

Zhang

Wang

et al. 2019

Applied Thermal Engineering

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“…High ground temperature is the main cause of thermal damage to the mine. In addition to high ground temperature, other factors, including air compression heat, dissipation of high-power mechanical and electrical equipment operation heat, heat release from coal rock oxidation, can also result in thermal damage [3,4]. Nowadays, the harm from thermal damage can be comparable yo disasters such as gas, water inrush, fire, dusts, and coal mining roof.…”

Section: Introductionmentioning

confidence: 99%

Foundation Research on Physicochemical Properties of Mine Insulation Materials

et al. 2020

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The known cooling methods for the high-temperature operating environment of a mine mainly include ventilation, refrigeration, heat insulation, and individual protection. Among them, the superior performance and wide application of the heat insulation materials have attracted the attention of the coal mining industry. In this paper, three types of mineral insulation materials were prepared using basalt fiber, glass fiber, vitrified microbeads in combination with cement, sand, high-strength ceramsite, water, etc. In addition, the thermal conductivity and compressive strength of the prepared specimens were assessed. The results show that the test specimen containing basalt fiber had a great thermal insulation effect and achieved the required compressive strength. Furthermore, according to the COMSOL simulation results, the test specimen containing basalt fiber had a better thermal insulation effect than the ordinary concrete materials. Therefore, the research results of this article have guiding significance to search for new mine thermal insulation materials.

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