An analysis of selected jet fans used in chambers of KGHM mines with respect to the air stream range

Drenda, J.; Domagała, Lech; Musioł, D.; Pach, Grzegorz; Różański, Zenon

doi:10.1016/j.tust.2018.08.033

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…(Hudeček et al, 2013;Nguyen et al, 2009;Szlązak et al, 2013;Drenda et al, 2016;Jeswiet & Szekeres, 2016). Therefore, sufficient air quantity in the district is essential to reduce these kinds of hazard (Koptoń & Wierzbiński, 2014;Drenda et al, 2018). According to Krausego (Krause & Smolinski, 2013) air quantity in a longwall should be considered as third important factor influencing methane hazard.…”

Section: Introductionmentioning

confidence: 99%

Archives of Mining Sciences

Pach

2020

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Subnetwork with two nodes shared with entire ventilation network can be separated as its part. For the network under common ventilation conditions, one of these nodes will become the subnetwork starting node, while the other will be the subnetwork end node. According to the graphs theory, such a piece of the network can be considered as a subgraph of the graph representing the entire ventilation network. A special feature of that subgraph is lack of predecessors of the subnetwork starting node and lack of successors of the subnetwork end node. Ventilation district of a mine may be often treated as a subnetwork. Vicinity is a part of the network which is not separated as subnetwork. In the case of a ventilation district its vicinity forces air flow through the district. The alternative characteristic curve of the vicinity can therefore be compared to the characteristics curve of a fictional fan that forces the airflow in the district.The alternative characteristics (later in the text: the characteristics) of the vicinity of the ventilation district in an underground mine strongly influence air quantity and therefore play a crucial role in the reduction of methane, fire and thermal hazards. The role of these characteristics and proper selection of their approximating function were presented in the article.The reduction of resistance of an intake stopping (having influence on entire resistance of a ventilation district) produces increased airflow in the district. This changes of airflow in the district caused by a variation in internal resistance (e.g. by opening an internal regulation stopping) depends on the characteristic of the vicinity of the district. Proper selection of its approximating function is also important for this matter.The methods of determination of the alternative characteristic curve of the district vicinity are presented. From these procedures it was possible to obtain the results of air quantities and differences in isentropic potentials between an inlet and an outlet to/from the ventilation district. Following this, the characteristics were determined by graphic and analytic methods. It was proved that, in contrast to flat vicinity characteristics, steep ones have a smaller influence on the airflow modification in the district (which are caused by a regulation of the district resistance). The characteristic curve of the vicinity determines the ability to regulate air quantity and velocity in the district.

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Section: Introductionmentioning

confidence: 99%

Archives of Mining Sciences

Pach

2020

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“…Ventilation is essential to ensure a safe evacuation environment when hazards occur in the underground space [3,4]. In tunnel fires, the longitudinal ventilation system has been widely used to control smoke over the past years, which can prevent the smoke from spreading upstream in tunnel fires.…”

Section: Introductionmentioning

confidence: 99%

A Study on Ceiling Temperature Distribution and Critical Exhaust Volumetric Flow Rate in a Long-Distance Subway Tunnel Fire with a Two-Point Extraction Ventilation System

Zhao

Yuan

et al. 2019

Energies

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Smoke control is a crucial issue in a long-distance subway tunnel fire, and a two-point extraction ventilation system is an effective way to solve this problem, due to the characteristics of controlling the smoke in a limited area and removing high-temperature and toxic smoke in time. In this study, the ceiling temperature distribution and the critical exhaust volumetric flow rate to control the smoke in the zone between two extraction vents were investigated in a long-distance subway tunnel fire with a two-point extraction ventilation system. Experiments were carried out in a 1/20 reduced-scale tunnel model based on Froude modeling. Factors, including the heat release rate (HRR), the extraction vent length, the internal distance between two extraction vents and exhaust volumetric flow rate, were studied. Smoke temperature below the ceiling, exhaust volumetric flow rate and smoke spreading configurations were measured. The ceiling temperature distribution was analyzed. Meanwhile, an empirical equation was developed to predict the critical exhaust volumetric flow rate based on the one-dimensional theory, experimental phenomenon and the analysis of forces acting at the smoke underneath the extraction vent. The coefficients in the empirical equation were determined by experimental data. Compared with the experimental results, the developed empirical equation can predict the critical exhaust volumetric flow rate well. Research outcomes in this study will be beneficial to the design and application of two-point extraction ventilation system for a long-distance subway tunnel fire.

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“…This is reflected in the fact that ventilation velocity is not fully considered. J Drenda et al 21 carried out a ventilation velocity about 1 to 3 m/s, which is 20 m from the fan outlet, in the mining of Polish copper ores. Kro´l et al 22 investigated the normal and reversed velocity of air flows in tunnel with longitudinal ventilation.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study of maximum ceiling temperature in a tunnel

Bai

2019

Advances in Mechanical Engineering

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Maximum ceiling temperatures in a tunnel with different ventilation velocities with three heat release fires are studied experimentally and theoretically. This article investigates the ventilation velocity effects on maximum ceiling temperature combustible materials around ignition source in tunnel fires. Several fire experimental tests are conducted with longitudinal ventilation velocity changes in a small-scale tunnel (23 m in length, 2 m in width, and 0.98 m in height), where three heat release fires (237, 340, and 567 kW) and their corresponding values in the real tunnel are 20, 30, and 50 MW, respectively. This article modifies the current temperature prediction model taking the ignition materials near the fire source into account in tunnels. Results show that the ceiling maximum temperature increases, corresponding to the burn time when other experimental conditions remain unchanged for a given fire heat level source. The ceiling temperature reduces quickly when the ventilation velocity is increased from 0.5 to 2.0 m/s. Moreover, this article proposes an equation that can be used to estimate the ceiling maximum temperature variation value with three heat release fires in tunnels. Finally, experimental results are also compared with the tunnel ceiling temperature attenuation equations established by Alpert, Heskestad, and Ingason. The equation proposed in this article appears to provide better estimates of ceiling temperature variation than the Kurioka model developed in their scaled experiments. The prediction agrees well with the experimental and measured data by the modified equations of this article.

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An analysis of selected jet fans used in chambers of KGHM mines with respect to the air stream range

Cited by 5 publications

References 8 publications

Archives of Mining Sciences

Archives of Mining Sciences

A Study on Ceiling Temperature Distribution and Critical Exhaust Volumetric Flow Rate in a Long-Distance Subway Tunnel Fire with a Two-Point Extraction Ventilation System

Experimental and numerical study of maximum ceiling temperature in a tunnel

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