Mines are continually expanding in size and depth,leading to an increased reliance on localised subsurface ventilation systems.The use of underground auxiliary fans is a favoured method to increase and control airflow...Mines are continually expanding in size and depth,leading to an increased reliance on localised subsurface ventilation systems.The use of underground auxiliary fans is a favoured method to increase and control airflow in working areas.However,the effectiveness of auxiliary fans in this regard is not clear.This paper evaluated the performance of these underground fan systems in four different South African deeplevel gold mines.A total auxiliary fan system efficiency of 5%was found across six systems,with the average fan efficiency of 33 fans at 38%.The results showed that these fans deviate significantly from their design operating points.Therefore,there are significant shortcomings in current underground fan practices.Our detailed investigations led to the conclusion that the assemblage of underground auxiliary fan systems results in significant energy inefficiencies.Therefore,maintaining good underground fan practice such as optimal fan selection,ducting design and maintenance is crucial for the efficacy of a mine ventilation network.展开更多
Ventilation fans are one of the most important pieces of equipment in coal mines. Their performance plays an important role in the safety of staff and production. Given the actual requirements of coal mine production,...Ventilation fans are one of the most important pieces of equipment in coal mines. Their performance plays an important role in the safety of staff and production. Given the actual requirements of coal mine production,we instituted a research project on the measurement methods of key performance parameters such as wind pressure,amount of ventilation and power. At the end a virtual instrument for mine ventilation fans performance evaluation was developed using a USB interface. The practical performance and analytical results of our experiments show that it is feasible,reliable and effective to use the proposed instrumentation for mine ventilation performance evaluation.展开更多
In large mines,single fan is usually not enough to ventilate all the working areas.Single mine-fan approach cannot be directly applied to multiple-fan networks because the present of multiple pressures and air quantit...In large mines,single fan is usually not enough to ventilate all the working areas.Single mine-fan approach cannot be directly applied to multiple-fan networks because the present of multiple pressures and air quantities associated with each fan in the network.Accordingly,each fan in a multiple-fan system has its own mine characteristic curve,or a subsystem curve.Under some consideration,the conventional concept of a mine characteristic curve of a single-fan system can be directly extended to that of a particular fan within a multiple-fan system.In this paper the mutual effect of the fans on each other and their effect on the stability of the ventilation network were investigated by Hardy Cross algorithm combined with a switching-parameters technique.To show the validity and reliability of this algorithm,the stability of the ventilation system of Abu-Tartur Mine(one of the largest underground mine in Egypt)has been studied.展开更多
Recirculation is prohibited in many coal mining countries because of the fear that the re-use of return air would allow the build-up of air contaminants at the workings. The incorrect design and location of a booster ...Recirculation is prohibited in many coal mining countries because of the fear that the re-use of return air would allow the build-up of air contaminants at the workings. The incorrect design and location of a booster fan in any ventilation network can create unsafe condition due to recirculation. The current approach to investigating recirculation using simulation software requires manual effort which becomes tedious in a complex and a large network. An algorithm-based C++ program was designed to detect the recirculation in a booster fan ventilation networks. This program needed an input file prepared from output file generated by any ventilation simulator. This program created an output file for recirculation. This program demonstrated the strong capability to detect the recirculation in a sample network and a coal mine ventilation network. The outcomes of this program were documented in this paper.展开更多
The causes of an offensive odor in the kitchens,bathrooms,and toilets of residential apartments in multi-story buildings with natural ventilation in Tomsk,Russia,are discussed in this paper.This problem exists in othe...The causes of an offensive odor in the kitchens,bathrooms,and toilets of residential apartments in multi-story buildings with natural ventilation in Tomsk,Russia,are discussed in this paper.This problem exists in other cities and countries.Wall electric fans can be installed in ventilation grills in kitchens,bathrooms,and toilets of apartments in multi-story residential buildings.Typically,these fans turn on with the light in the bathroom or toilet,so the problem is periodic.Forced airflow from a fan in one apartment disrupts the natural outflow of air in the ventilation system of a residential building designed and built according to building codes and regulations and can cause an unpleasant smell in neighboring apartments.In many cases,it is difficult to determine which apartments have fans and force the neighbors to remove them.Locally,on the scale of one apartment,the problem is solved by installing an air check valve in the ventilation grill,which will block the nuisance airflow from the ventilation system into the bathroom.Globally,the problem is solved by modification and subsequent compliance with building codes and regulations,the implementation of which is controlled by local authorities.展开更多
A more efficient mine ventilation system, the ventilation-on-demand （VOD） system, has been proposed and tested in Canadian mines recently. In order to supply the required air volumes to the production areas of a min...A more efficient mine ventilation system, the ventilation-on-demand （VOD） system, has been proposed and tested in Canadian mines recently. In order to supply the required air volumes to the production areas of a mine, operators need to know the cause and effect of any changes requested from the VOD system. The sensitivity analysis is developed through generating a cause and effect matrix of sensitivity factors on given parameter changes in a ventilation system. This new utility, which was incorporated in the 3D-CANVENT mine ventilation simulator, is able to predict the airflow distributions in a ventilation network when underground conditions and ventilation controls are changed. For a primary ventilation system, the software can determine the optimal operating speed of the main fans to satisfy the airflow requirements in underground workings without necessarily using booster fans and regulators locally. An optimized fan operating speed time-table would assure variable demand-based fresh air delivery to the production areas effectively, while generating significant savings in energy consumption and operating cost.展开更多
In mine ventilation network calculation, the total ventilatiou perameters, such as total specific resistance and total natural veutilatiou pressure of an overall mine ventilation system, play an important role on sele...In mine ventilation network calculation, the total ventilatiou perameters, such as total specific resistance and total natural veutilatiou pressure of an overall mine ventilation system, play an important role on selecting main fan and regulating its operating point. This paper explains the critical effect of network’ s total parameter calculation on the above two aspects and presents a new method, the junction pressure composing method(JPC method), which can be applied to calculate the total resistance.of an overall, complex and multi-fan ventilation network. Based on the total ressistance and airflow rate of main fan, total specific resistance of a natwork is easily calculated. This method gets rid of those shortcomings in the route airflow working mathod(RAW method), greatly improves computing speed and adaptability, and can calculate the total parameters of a mine ventilation network rapidly and conveniently. This method is proved to be correct and reliable by example tests.展开更多
Seoul metropolitan subway network is known to be the one of the most heavily used transportation means in the world. The subway cabins are naturally ventilated when the cabin doors are opened and through the gaps caus...Seoul metropolitan subway network is known to be the one of the most heavily used transportation means in the world. The subway cabins are naturally ventilated when the cabin doors are opened and through the gaps caused by the incomplete air-tightening of cabin bodies. Although, subway trains are equipped with a mechanical exhaust fan, the apparatus is rarely operated due to the problem of heating/cooling efficiency especially in the summer and winter seasons. In this study, we analyzed the transient CO2 （carbon dioxide） concentration level during the journey of a subway cabin when a heavy load of passengers of up to 200% of designed capacity using a CFD （computational fluid dynamics） analysis. With an increased journey time, the CO2 concentration increased by up to 5,000 ppm depending on passenger load. Through the operation of a mechanical exhaust fan, the high concentration of CO2 decreased down to 1,500 ppm. The effect of the exhaust fan operating on the dilution of indoor air was estimated by comparison with a closed cabin. In addition, the energy consumption for cooling in summer time was assessed for exhaust fan operations.展开更多
基金ETA Operations (Pty) Ltd funded this research work
文摘Mines are continually expanding in size and depth,leading to an increased reliance on localised subsurface ventilation systems.The use of underground auxiliary fans is a favoured method to increase and control airflow in working areas.However,the effectiveness of auxiliary fans in this regard is not clear.This paper evaluated the performance of these underground fan systems in four different South African deeplevel gold mines.A total auxiliary fan system efficiency of 5%was found across six systems,with the average fan efficiency of 33 fans at 38%.The results showed that these fans deviate significantly from their design operating points.Therefore,there are significant shortcomings in current underground fan practices.Our detailed investigations led to the conclusion that the assemblage of underground auxiliary fan systems results in significant energy inefficiencies.Therefore,maintaining good underground fan practice such as optimal fan selection,ducting design and maintenance is crucial for the efficacy of a mine ventilation network.
基金Project 2007E237 supported by the Science Fund Program of Shaanxi Province of China
文摘Ventilation fans are one of the most important pieces of equipment in coal mines. Their performance plays an important role in the safety of staff and production. Given the actual requirements of coal mine production,we instituted a research project on the measurement methods of key performance parameters such as wind pressure,amount of ventilation and power. At the end a virtual instrument for mine ventilation fans performance evaluation was developed using a USB interface. The practical performance and analytical results of our experiments show that it is feasible,reliable and effective to use the proposed instrumentation for mine ventilation performance evaluation.
文摘In large mines,single fan is usually not enough to ventilate all the working areas.Single mine-fan approach cannot be directly applied to multiple-fan networks because the present of multiple pressures and air quantities associated with each fan in the network.Accordingly,each fan in a multiple-fan system has its own mine characteristic curve,or a subsystem curve.Under some consideration,the conventional concept of a mine characteristic curve of a single-fan system can be directly extended to that of a particular fan within a multiple-fan system.In this paper the mutual effect of the fans on each other and their effect on the stability of the ventilation network were investigated by Hardy Cross algorithm combined with a switching-parameters technique.To show the validity and reliability of this algorithm,the stability of the ventilation system of Abu-Tartur Mine(one of the largest underground mine in Egypt)has been studied.
基金the National Institute for Occupational Safety and Health of USA for providing financial support for this project
文摘Recirculation is prohibited in many coal mining countries because of the fear that the re-use of return air would allow the build-up of air contaminants at the workings. The incorrect design and location of a booster fan in any ventilation network can create unsafe condition due to recirculation. The current approach to investigating recirculation using simulation software requires manual effort which becomes tedious in a complex and a large network. An algorithm-based C++ program was designed to detect the recirculation in a booster fan ventilation networks. This program needed an input file prepared from output file generated by any ventilation simulator. This program created an output file for recirculation. This program demonstrated the strong capability to detect the recirculation in a sample network and a coal mine ventilation network. The outcomes of this program were documented in this paper.
基金support from the Government of the Russian Federation (Mega grant No.075-15-2021-612 of June 4,2021) for funding scientific research in Russia.
文摘The causes of an offensive odor in the kitchens,bathrooms,and toilets of residential apartments in multi-story buildings with natural ventilation in Tomsk,Russia,are discussed in this paper.This problem exists in other cities and countries.Wall electric fans can be installed in ventilation grills in kitchens,bathrooms,and toilets of apartments in multi-story residential buildings.Typically,these fans turn on with the light in the bathroom or toilet,so the problem is periodic.Forced airflow from a fan in one apartment disrupts the natural outflow of air in the ventilation system of a residential building designed and built according to building codes and regulations and can cause an unpleasant smell in neighboring apartments.In many cases,it is difficult to determine which apartments have fans and force the neighbors to remove them.Locally,on the scale of one apartment,the problem is solved by installing an air check valve in the ventilation grill,which will block the nuisance airflow from the ventilation system into the bathroom.Globally,the problem is solved by modification and subsequent compliance with building codes and regulations,the implementation of which is controlled by local authorities.
文摘A more efficient mine ventilation system, the ventilation-on-demand （VOD） system, has been proposed and tested in Canadian mines recently. In order to supply the required air volumes to the production areas of a mine, operators need to know the cause and effect of any changes requested from the VOD system. The sensitivity analysis is developed through generating a cause and effect matrix of sensitivity factors on given parameter changes in a ventilation system. This new utility, which was incorporated in the 3D-CANVENT mine ventilation simulator, is able to predict the airflow distributions in a ventilation network when underground conditions and ventilation controls are changed. For a primary ventilation system, the software can determine the optimal operating speed of the main fans to satisfy the airflow requirements in underground workings without necessarily using booster fans and regulators locally. An optimized fan operating speed time-table would assure variable demand-based fresh air delivery to the production areas effectively, while generating significant savings in energy consumption and operating cost.
文摘In mine ventilation network calculation, the total ventilatiou perameters, such as total specific resistance and total natural veutilatiou pressure of an overall mine ventilation system, play an important role on selecting main fan and regulating its operating point. This paper explains the critical effect of network’ s total parameter calculation on the above two aspects and presents a new method, the junction pressure composing method(JPC method), which can be applied to calculate the total resistance.of an overall, complex and multi-fan ventilation network. Based on the total ressistance and airflow rate of main fan, total specific resistance of a natwork is easily calculated. This method gets rid of those shortcomings in the route airflow working mathod(RAW method), greatly improves computing speed and adaptability, and can calculate the total parameters of a mine ventilation network rapidly and conveniently. This method is proved to be correct and reliable by example tests.
文摘Seoul metropolitan subway network is known to be the one of the most heavily used transportation means in the world. The subway cabins are naturally ventilated when the cabin doors are opened and through the gaps caused by the incomplete air-tightening of cabin bodies. Although, subway trains are equipped with a mechanical exhaust fan, the apparatus is rarely operated due to the problem of heating/cooling efficiency especially in the summer and winter seasons. In this study, we analyzed the transient CO2 （carbon dioxide） concentration level during the journey of a subway cabin when a heavy load of passengers of up to 200% of designed capacity using a CFD （computational fluid dynamics） analysis. With an increased journey time, the CO2 concentration increased by up to 5,000 ppm depending on passenger load. Through the operation of a mechanical exhaust fan, the high concentration of CO2 decreased down to 1,500 ppm. The effect of the exhaust fan operating on the dilution of indoor air was estimated by comparison with a closed cabin. In addition, the energy consumption for cooling in summer time was assessed for exhaust fan operations.
