Main Fan Research Articles

Determination of reasonable working mode for main fan stations during pilot operation of fan station VO - 22/14AR in Lo Tri area, Thong Nhat coal mine

The article presents a review of the technical characteristics and an introduction to the appearance of fan station VO - 22/14AR when it is first put into operation in the Lo Tri area, Thong Nhat coal mine. When this new fan station comes into operation, it will affect the overall ventilation system of the mine. Therefore, it is necessary to check, calculate, evaluate and determine the reasonable working mode of two main fan stations 2K56 - No24 and VO - 22/14AR. The results show that for two fan stations 2K56 - No24 and VO - 22/14AR, the associated fans should be operated in impeller angles of 35 and 50 degrees, respectively. The impeller angles create an overall airflow Qbp of 236.8 m3/s and an air pressure Hbp of 390 mm H20 that fulfill the ventilation requirement of the mine.

Resilience estimation of critical infrastructure systems: Application of expert judgment

Resilience is an emerging concept whose application has increased significantly in managing engineering systems. In order to have an effective resilience management, first, an estimation of the system resilience should be undertaken. However, a lack of historical data and limited information are major challenges for system resilience estimation. The main reason is that most data collection systems are not designed for resilience assessment. Moreover, the available study dealing with resilience assessment have been used different indices to quantify the resilience of critical infrastructures including, robustness, recoverability, etc. These indices can be affected in a complex way by different factors such as operational conditions, protective practices, the recovery process, logistic process, etc. However, the available resilience studies are not so detailed regarding identifying and quantifying these influencing factors. Therefore, this paper aims to develop and apply a practical methodology to estimate resilience based on the combination of expert judgment and fuzzy set theory. By adopting this methodology, factors influencing resilience can be modeled effectively. Finally, the application of the proposed methodology is illustrated for the main fan system of an underground coal mine.

Modernization of two-stage main fans at the end of the service life

The authors analyze air velocities in the inlet of the installation composed of two-stage axial fans (aerodynamic design OV-84 of the Central Aerohydrodynamic Institute) and in the inlet elements of the fan. It is shown that air flow is considerably nonuniform at the fan inlet, and the nonuniformity reduces in the air passage of the fan. The fan can be modernized by replacing the two-stage rotor by a high-rate single-stage rotor as per the inlet guide vanes– impeller–flow straightener design. This modification allows the required uniformity of air flow at the impeller inlet and ensures a longer service life of the rotor bearing assembly owing to considerable decrease n the weight of the rotor.

On Signal Surveillance Analysis of Vibration Fault of Main Fan

The research idea of the coal mine main fan’s fault diagnosis is generally the surveillance of the vibration state of the main fan’s impeller and the drive motor’s rotor. The vibration characteristics under different faults are obtained to distinguish the fault categories by analyzing the obtained vibration signals.

Correction to: Innovative aerodynamic grain separation system for plant harvesting in sloped areas: problems, research and optimization of parameters

This article presents the main problems associated with cereal harvesting in sloping areas. The presented innovative aerodynamic system supporting the separating unit of combine harvester can be one of the ways to counteract the negative effects of harvesting machines work on slopes. The Monte Carlo numerical method, presented in this article, was applied in the optimization of an aerodynamic sieve separation process on an inclined terrain. The given variables are the transverse slope of separator α (of the sieve), longitudinal slope β and the output of the main and side fans. The Monte Carlo method makes it possible to determine an optimized set of parameters (α = 10°, β = 2.8°, δ = 9°), the output of the main fan (0.67 m3 s−1) and the output of the side fan (1.86 m3 s−1), allowing to obtain the best indicator values of 2.1% grain loss and 97.5% grain purity.

Architecture of a Cyber-Physical System for the Mining Enterprise Ventilation Control Based on the Internet of Things Platform

The article considers the architecture of the ventilation control system for underground mining enterprises, equipped with a digital twin with online functions such as simulation modeling and predictive analytics. The system is focused on the main fan unit (MFU) control taking into account changing parameters of external air supplied to mine shafts. In contrast to the existing ones, the proposed method of control takes into account the influence of these parameters on changes in the total volume of natural draught, on which the total volume of air supplied to the mine (mine) depends. It is known that ventilation systems of such enterprises consume from 30 to 50 % of all electricity consumed for the mining process. In this regard, the proposed control models can be used to optimize energy costs and energy savings in ventilation. The Internet of things (IoT) InfluxData of stack TICK is offered for the realization. The offered architecture of cyber-physical system (CPS) consists of four subsystems: physical object subsystem, network and computing infrastructure IoT, digital twin, user interface. Architecture of CPS provides data processing from energy meters, control controllers and sensors of air environment parameters, implemented in blocks of on-line and off-line calculations. The digital twin of the ventilation system is made with the use of a time series database and a database of attributes that store information on changes in equipment parameters by time, air indicators, performance indicators, statistics on accidents and fan runtime, CPS characteristics, etc. CPS of the given architecture means connection of additional data sources, providing calculations of rational volumes of air delivery taking into account safety norms and requirements of energy efficiency.

Study formulate a reasonable working mode of the main fans in Nam Mau coal mine, Uongbi-QuangNinh

The ventilation for underground coal mines and to the general underground mining work is indispensable. For pit coal mines in Quang Ninh is usually done by the main fans is located on the ground. Today, Nam Mau coal mines use three main fan stations operating in parallel to ventilate the mine. This fan has three stations of different capacities but is interconnected via the mine pits. Thus, during the operation occurred between three mutual “bracing” winds fan stations causing decreased fan performance and not satisfying my ventilation requirements. This paper analyzed, calculated, and determined each fan’s operating mode and reasonable fans when operating in parallel to improve fans’ performance and improve the efficiency ventilation for Nam Mau coal mine.

Flood Hazard Mapping in Alluvial Fans with Computational Modeling

Floods occurring in alluvial fans are very peculiar and hazardous, due to the mobility of the channel in the regions. Such mobility increases the uncertainty of the course to be occupied by the water or the debris flow, which makes hazard mapping more complex. Since the flow in alluvial fans is three-dimensional, the flood mapping in these regions without hydrological data can be unfeasible. Then, at first the present study applied to the Upper Mampituba river basin characterized with three main alluvial fans (Molha Coco and Malacara Fans (MCMFs) and Boi Fan), southern Brazil, three models: Hydrological Engineering Center – River Analysis System 2D (HEC-RAS), FAN Model and Height Above The Nearest Drainage (HAND). The FAN and HAND models are considered geomorphological models and comparatively simpler. Then the combination between these two models was applied to generate flood hazard maps. The proposed combination model presented results more coherent with alluvial fan feature, representing satisfactorily the flood extent of the most recent event occurred in the study area (showing good performance metrics: statistical F (%) 72.65, General Accuracy (%) 79.82, FIT(%) 38.44 and False Alarm Rate (%) 20.50).

Numerical analysis of natural gas pressure during coal and gas outbursts

AbstractAny disturbance in the ventilation system of a mine during a coal and gas outburst can lead to secondary disasters. This is because, on the one hand, the expansion power of the outburst source makes the airflow in the ventilation system countercurrent, causing the gas in this system to exceed the allowable limit. On the other hand, the airflow density changes because of the outburst and the consequent airflow mixing in the mine roadway, thereby changing the natural wind pressure. From this, the concept of natural gas wind pressure is proposed, and a calculation method for this pressure in a 3D model mine ventilation system is derived. For the “11.10” major coal and gas outburst that occurred in Shizhuang Coal Mine in Qujing, Yunnan Province, the entire process of the counter flow and gas dispersion flow in the main and auxiliary shafts is analyzed using the TF1M 3D simulation program, including the dynamic change in the natural wind pressure in the mine in each stage. The simulation shows that during the gas outburst period, the natural gas pressure of the countercurrent circuit is greater than that of the main fan. Between 140 s and 225 s following the outburst, the natural wind pressure once overcomes the fan pressure and reverses the airflow in the 1824 transport roadway, and the gas is withdrawn from the 1727 service point. Evidently, the natural pressure of the gas produced by the outburst affects the mine ventilation system. In the event of a coal and gas outburst in a private village coal mine, if the natural gas wind pressure can be reasonably utilized and the main fan stopped or the entire mine reversed in time, casualties may be minimized. Scholars studying coal and gas outburst mines should pay attention to mine airflow disorder due to the varying natural gas wind pressure when an outburst occurs and perform simulation drills of the outburst beforehand. Thus, a scientific emergency management plan for mine disaster prevention and reduction can be formulated.

Innovative aerodynamic grain separation system for plant harvesting in sloped areas: problems, research and optimization of parameters

This article presents the main problems associated with cereal harvesting in sloping areas. The presented innovative aerodynamic system supporting the separating unit of combine harvester can be one of the ways to counteract the negative effects of harvesting machines work on slopes. The Monte Carlo numerical method, presented in this article, was applied in the optimization of an aerodynamic sieve separation process on an inclined terrain. The given variables are the transverse slope of separator α (of the sieve), longitudinal slope β and the output of the main and side fans. The Monte Carlo method makes it possible to determine an optimized set of parameters (α = 10°, β = 2.8°, δ = 9°), the output of the main fan (0.67 m3 s−1) and the output of the side fan (1.86 m3 s−1), allowing to obtain the best indicator values of 2.1% grain loss and 97.5% grain purity.

Automated ventilation control in mines. Challenges, state of the art, areas for improvement

The article is divided into three main parts. The first part provides an overview of the existing literature on theoretical methods for calculating the optimal air distribution in mines according to the criteria of energy efficiency and providing all sections of mines with the required amount of air. It is shown that by the current moment there are many different formulations of the problem of searching the optimal air distribution, many different approaches and methods for optimizing air distribution have been developed. The case of a single (main) fan is most fully investigated, while for many fans a number of issues still remain unresolved.
 The second part is devoted to the review of existing methods and examples of the automated mine ventilation control systems implementation in Russia and abroad. Two of the most well-known concepts for the development of such systems are automated ventilation control systems (AVCS) in Russia and the CIS countries and Ventilation on demand (VOD) abroad. The main strategies of ventilation management in the framework of the AVCS and VOD concepts are described and also the key differences between them are shown. One of the key differences between AVCS and VOD today is the automatic determination of the operation parameters of fan units and ventilation doors using the optimal control algorithm, which is an integral part of the AVCS.
 The third part of the article describes the optimal control algorithm developed by the team of the Mining Institute of the Ural Branch of the Russian Academy of Sciences with the participation of the authors of the article. In this algorithm, the search for optimal air distribution is carried out by the system in a fully automated mode in real time using algorithms programmed into the microcontrollers of fans and ventilation doors. Minimization of energy consumption is achieved due to the most efficient selection of the fan speed and the rate of ventilation doors opening and also due to the air distribution shift control and the partial air recirculation systems introduction.
 It is noted that currently the available literature poorly covers the issue related to emergency operation modes ventilation systems of mines and also with the adaptation of automated control systems to different mining methods. According to the authors, further development of automated ventilation control systems should be carried out, in particular, in these two areas.

Test and analysis of air flow rate adaptive performance in a distributed fan ventilation system

In this study, adaptive branch fan performance in a distributed fan ventilation system was tested. The results demonstrate that the adaptive branch fan stabilises the branch air flow rate within a certain air pressure range corresponding to the branch duct inlet, and this range becomes increasingly narrow as the fan control signal is adjusted to reduce the speed of the fan. The adaptive branch fan is less affected by the main fan and other branch fans in the distributed fan ventilation system because it has a good self-adaptive ability of ventilation duct resistance characteristics and anti-interference ability of the air flow rate. Furthermore, the hydraulic characteristics of the branch fans in the distributed fan ventilation system were analysed. The new performance characterisation parameters and method for modifying the engineering design for the adaptive branch fan were presented. Practical application: This study investigates the adaptive performance of the branch fan in a distributed fan ventilation system. Our results demonstrate that the new branch fan can stabilise the air flow rate in a mechanical ventilation system. More importantly, we not only propose performance characterisation parameters of the adaptive branch fan that are important for understanding the operation of a mechanical ventilation system, but also present a method of engineering design application. This study can guide the design and operation of mechanical ventilation systems.

МОДЕЛЬНІ ДОСЛІДЖЕННЯ З ВИЯВЛЕННЯ ЕНЕРГОЕФЕКТИВНИХ РЕЖИМІВ ФУНКЦІОНУВАННЯ ГОЛОВНИХ ВЕНТИЛЯЦІЙНИХ УСТАНОВОК ШАХТ

Purpose. The paper analyzes the system and methods of starting synchronous electric motors of fans of the main ventilation of iron ore mines. It is concluded that it is necessary to modernize the method of starting a synchronous electric motor, despite the fact that the installed direct start-up system has a number of disadvantages, and negatively affects the energy indicators of the electromechanical complex of the main ventilation fan of mines. The priority direction in solving the complex of the above problems is the use of modern achievements in the field of semiconductor conversion technology, in terms of the development of effective circuits and methods for starting and controlling a synchronous electric drive. Originality. The method of separate regulation of size and frequency of output voltage of the multilevel converter of a clock at quasi-frequency start of the synchronous electric drive is offered, limits admissible values of starting currents to admissible values. Methodology. Simulation of transient processes of starting a synchronous electric motor with step-by-step changes in voltage and frequency of supply, which made it possible to determine the energy efficiency of this method. Result. A new method of starting with a step-by-step change in the voltage and frequency of a synchronous motor is proposed. The modeling of the proposed starting method for a synchronous electric motor with a fan torque on the motor shaft was carried out, while it allowed to get rid of the main drawback, namely, a large starting current and made it possible to increase the energy efficiency of the electromechanical complex of the main ventilation fans due to the fact that the consumed active energy during start-up will decrease approximately 50% compared to a direct starting system. Practical value. The proposed method and the obtained results of the study made it possible to prove that the effectiveness of the proposed method is very high and this will save most of the electrical energy when starting the fans of the main ventilation of iron ore mines. Figures 15, references 15

River, alluvial fan and landslide interactions in a tributary junction setting: Implications for tectonic controls on Quaternary fluvial landscape development (Central Anatolian Plateau northern margin, Turkey)

Along the western flank of the northern margin (Central Pontides) of the Central Anatolian Plateau, the humidity from the Black Sea is much higher than the central and eastern flanks and creates a complex relationship between surface and tectonic processes by triggering intense mass wasting activity and aggradation within narrow valleys. We identified three incised fill terrace levels and used Optically Stimulated Luminescence (OSL) dating to calculate fluvial sediment ages and cosmogenic 36Cl exposure dating to calculate limestone boulders exposure ages across the terrace surface. Stratigraphical interpretations and OSL ages of the lowest levels revealed that a fluvial fill terrace formed in the main valley at 275.6 ± 12.8 ka and was overlain by a main river-tributary junction alluvial fan that was abandoned at 39.5 ± 3.5 ka. The results collectively show the influence of climate, topography, hillslope processes, and lithology on aggradation-incision patterns of main rivers. Prolonged aggradation can prevent the channel equilibrium required to calculate rock uplift rates while also causing a new base-level and aggradation upstream. This effect can be exacerbated in uplifting mountainous regions with limited depositional areas. Bedrock incision rates based on the fluvial terrace age were between 0.15 and 0.2 mm/a since 39.5 ± 3.5 ka. However, the high aggradation within this segment of the main valley prevented incision of the channel bedrock for long periods, causing a potential underestimation of the rock uplift rate calculation. Our local period of aggradation appears to be related to increased aggradation and decreased bedrock incision rates measured 14 km upstream that were previously assumed to be the result of decreased tectonic uplift rates. This demonstrates the importance of corroborating strath terrace incision rate estimations with ages and incision rates of downstream fill terraces, if present, to check for potential interference with the tectonic signal.

Performance analysis of turbo-electric propulsion system with fuselage boundary layer ingestion

A propulsion system analysis of an aircraft concept featuring a fuselage tail cone integrated turbo-electrically powered fan is presented. The aircraft has two underwing podded geared turbofan engines and an aft-fuselage mounted boundary layer ingesting fan. The fuselage fan is driven by an electric motor that is powered by power offtake from the main power plants under the wing. A long-range tube-and-wing aircraft with a year 2050 entry into service is used as a reference. A coupled multidisciplinary method for system level assessment of the turbo-electric boundary-layer ingesting propulsion system is presented. A correlation-based method is used to predict fuselage drag and a series of optimizations are carried out for a range of fuselage fan diameters. The optimal level of ingested drag is 30%-57% of the total fuselage drag, resulting in a net reduction in mission fuel burn of 0.6%-3.6% depending on technology assumptions. Further analysis reveals that installation effects, mainly increased mass, offset some of the gains of boundary layer ingestion for the smallest fuselage fan sizes. For larger fan sizes, it is instead the losses in the electric machinery together with the lower efficiency of the fuselage fan, compared to the main engine fan, that compensate for the gains from boundary layer ingestion. However, the by far strongest effect for determining the optimal level of ingested drag is that it is very difficult to obtain a net benefit from ingesting the half of the total fuselage drag contained in the outer part of the boundary layer. The benefit is outweighed by losses in the electric transmission system, installation effects and efficiency deficits of having an aft-mounted fan instead of larger size under-wing main engines. This is true also under the assumption of radical technology such as superconducting electric machinery. It is concluded that the studied aircraft architecture, despite having a high theoretical potential, faces a large difficulty in beneficially ingesting the significant amount of the fuselage drag contained in the outer part of the boundary layer. This severely limits its potential to substantially reduce the fuel burn compared to a conventional twin-engine tube-and-wing aircraft in the year 2050 timeframe.

Numerical Simulation of Impact Loads of Main Fan Blades in Gas Explosion

The shock wave generated by a severe gas explosion accident can damage the main fan, and the toxic and harmful gases in the well cannot be discharged in time, leading to the expansion of disaster accidents. Therefore, it is meaningful to study impact loads of main fan blades in gas explosion. In this paper, a full-scale three-dimensional numerical simulation model has been established based on No. 2 Yangchangwan Coal Mine in China. The propagation of shock wave in shaft and air tunnel and the dynamic process of main fan blade subjected to shock load when gas explosion of different volume occurs in heading face have been simulated. The overpressure on the blade at different times, the overpressure distribution on the blade, and the relationship between the overpressure and the explosion intensity have been obtained. The results showed that the time when the explosion shock wave reached, each blade of the wind turbine was basically the same, and the time when each blade reached, the maximum overpressure was basically the same. With the increase of gas explosion volume, occurrence time of overpressure and maximum overpressure time on the fan blade were shortened, and the time interval between them was also shortened. There is a little difference in the overpressure of each blade. Fan blade directly above the hub was subject to the highest overpressure, and fan blade directly below the hub was subject to the lowest overpressure. The overpressure of the maximum overpressure blade was 5.44% to 6.77% higher than that of the minimum overpressure blade. The distribution of overpressure on each fan blade was uneven, and the overpressures on blade edges were the lowest. The overpressure on the fan blades showed a corrugated distribution along the radial direction. There was 12.06% to 15.40% difference between the maximum and minimum overpressure section on the fan blade.

Underground booster fan placement strategies

ABSTRACT Booster fans assist main fans by boosting the air pressure of the ventilation air. Correct placement of underground booster fans in a mine is a critical decision since it not only influences the mine’s operational capacity in terms of costs and efficiency, but also affects safety and environmental conditions. There are many booster fan installations around mines that are inappropriate, resulting in system failure (fan stall), major negative impacts on mine production, or extensive air leakage that has compromised the economics of the operation. In some cases, recirculation of contaminants has seriously compromised safety. This article provides guidelines for proper design and siting of booster fans underground to achieve an economic ventilation system and create safe work conditions and efficient atmospheric conditions. Procedures for the planning, installation, operation, and maintenance of booster fans are also presented. A case study illustrating the design and siting of a major booster fan installation in a potash mine is presented, supported by computational fluid dynamics analysis.

Rationale for main fans service life in the conditions of changing load

Research aim is to study basic regularities in functional condition change of main fans included in the confi guration of main mine ventilation installations depending on the technological service conditions. The research also aims to determine the standard service life of main fans with the account of the diff erential analysis of the destructive factors, structural features, intensity and modes of operation of ventilation plants. 108 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 6. 2020 ISSN 0536-1028 Research methodology. Based on the analysis of main fan installations structure and differential analysis of technological factors affecting the functional efficiency of main fans, a mathematical model has been proposed which determines the standard and residual life of the main fan with the account of the changing load. Results and analysis. As a result of studying the impact of destructive factors on the main functional parts of the main fan, an equation has been proposed, which takes into account the physical properties of the material the fan elements are made of together with the quantitative effect of the external physical factors on the machine’s operation. Research results show that the resource of the main fans should be determined based on the useful life of the machine’s major component, i.e. mainshaft, with the account of the machine’s operation mode. Conclusions and scope of results. Circuit designs of mine ventilation plants predetermine the main fans service life. The service life should be established at the stage of the detail design with the account of the differential analysis of the destructive factors, structural features, intensity and operation modes of ventilation plants. The proposed methodology for main mine fans residual life determination is applied in expert organizations and Guidances on the determination of residual life of main mine fans which operate under the excess of the standard service life. The methodology may also be applied by project organizations to determine the design service life for the constructed main ventilation installations.

A new component maps correction method using variable geometric parameters

Accurate engine performance models are important for model-based performance evaluation of aero engine. The accuracy of the model often depends on engine component maps, so there is a need for a method that can accurately correct the component maps of the model over a wide range. In this paper, a new method for modifying component maps is proposed, this method combines the correction of the scaling factors with the solution process of the off-design working point, and uses the adjustment of the variable geometric parameters of the engine to change the position of the working line, in order to obtain more correction results and guarantee high accuracy in a wider range. The method is validated by taking the main fan of the Adaptive Cycle Engine (ACE), an ideal power unit for a new generation of multi-purpose and ultra-wide working range aircraft, as an example. The results show that the maximum error between the corrected component maps and the target maps is less than 1%. New possibility for more precise component maps can be realized in this paper.

Study on status and solution to improve the ventilation system of Quang Hanh coal mine

Quang Hanh coal mine is currently operating at two areas with 11 longwalls having the annual production of 1.5 million tonnes. In recent years, the mine has used 4 conjugate fan stations for air ventilation. To assess the quality of ventilation operation at the Quang Hanh coal mine, the paper surveyed the ventilation quality at longwall faces, roadway faces, ventilation works and main fans. The results show that the ventilation at longwall and roadway faces basically satisfies the requirements. However, in some areas, the fresh air has not been sufficiently supplied, the temparature and humidity are high, the air leakage is serious, and the total intake air lacks an amount of 26.4 m3/s (8%). Based on these the findings, the paper the proposes proper solutions to the air ventilation system at the Quang Hanh coal mine in the near future.