scholarly journals Modeling the Influence of Dust-Removing Extraction Fan’S Parameters on the Dust Control Effects in the Tunnel

2016 ◽  
Vol 5 (2) ◽  
pp. 18 ◽  
Author(s):  
Qingguo Wang ◽  
Deming Wang ◽  
Hetang Wang
Keyword(s):  
Cfd Simulation ◽  
Dust Control ◽  
Test Results ◽  
Ventilation Mode ◽  
Forced Ventilation ◽  
Migration Process ◽  
Optimal Arrangement ◽  
Air Supply ◽  
Mechanized Tunnelling ◽  
Migration Law

<p class="emsd"><a name="OLE_LINK1"></a><span lang="EN-GB">In the process of comprehensive mechanized tunnelling in coal mines, forced ventilation is usually adopted to supply air in China. But this ventilation mode could cause the dust rise and diffuse more easily, which has threaten the mine workers’ health seriously. To solve this problem, </span><a name="OLE_LINK8"></a><span lang="EN-GB">dust-removing extraction fan</span><span lang="EN-GB"> is generally used to suck and purify dusty air in mines. However, the optimal arrangement scheme for dust control is rarely systematically studied. In this paper, we took the tunnel in Donghuantuo Mine as an example and use CFD simulation technology to analyze the dust migration law and dust control effects under different conditions. An unsteady state solution is used to simulate the process and the simulation have realized the visualization of dust migration process with time and the results are as follows. Firstly, it’s better for dust control to <a name="OLE_LINK15"></a>arrange the inlet of the dust-removing extraction fan to the air return side rather than to the center of the tunnel. Secondly, the dust control effects decrease with the distance between inlet of the dust-removing extraction fan and heading face increases. Thirdly, as the amount of air suction is larger than air supply, the dust control efforts would get worse. Field test results are similar <a name="OLE_LINK9"></a>with that obtained from simulation under the optimal arrangement, which proves the reliability of simulation.</span></p>

scholarly journals Preliminary Study on Pollution Isolation of Civil Air Defence Underground Engineering

2020 ◽  
Vol 194 ◽  
pp. 04045
Author(s):  
Ji Yunzhe ◽  
Wang Xiaojie ◽  
Li Jintian
Keyword(s):  
Pressure Difference ◽  
Cfd Simulation ◽  
Pollution Source ◽  
Ventilation Mode ◽  
Underground Engineering ◽  
Isolation Room ◽  
Air Supply ◽  
Emergency Ventilation ◽  
Clean Area ◽  
Preliminary Study

In order to control the airborne spread of pollutants in civil air defences underground projects, the pollution source rooms are isolated. In this paper, CFD simulation technology is used to compare the effect of different positions of air supply and exhaust outlets on the removal of contaminants in the polluted isolation room. Pressure difference control is proposed to prevent the diffusion of polluted air from the isolation room to the clean area, and the realization of pressure difference control under emergency ventilation mode is discussed.

Numerical Simulation Study on Air-Flow Migration Law about Vortex Air Curtain of Plane Wall Fan Drum

2012 ◽  
Vol 241-244 ◽  
pp. 1285-1292
Author(s):  
Gang Zhou ◽  
Sen Cao ◽  
De Ming Wang ◽  
Wei Min Cheng ◽  
Wen Nie
Keyword(s):  
Numerical Simulation ◽  
Control System ◽  
Simple Algorithm ◽  
Plane Wall ◽  
Dust Control ◽  
High Concentration ◽  
Air Curtain ◽  
Working Face ◽  
Simulation Results ◽  
Migration Law

Vortex air curtain of plane wall fan drum can control the diffusion of air stripping dust effectively. In order to solve the high-concentration dust problem in fully mechanized excavation face, formation mechanism of vortex air curtain was analyzed. According to fluid mechanical control equations of gas phase flow, mathematical model was established to solve air migration law of vortex air curtain in fully mechanized excavation face. By using Simple algorithm based on collocated grid and fluent software, numerical simulation of air spatial migration law of closed-end dust control in fully mechanized excavation face was carried out. The simulation results show that vortex air curtain dust control system can form dust control fan drum along driving head to the front of the roadheader driver. According to the simulation results and actual conditions of working face field, vortex air curtain suction dust control system consisted of plane wall fan drum and exhausted dust purification device in fully mechanized excavation face was designed, and after it was applied in fully mechanized excavation face, the dust concentration decreased effectively in the working face field.

The Simulation Research on Air Drag Reduction of Tail Dome on Vans

2013 ◽  
Vol 345 ◽  
pp. 48-53
Author(s):  
Li Feng Cao ◽  
Xiao Peng Xie ◽  
Jian Hao Zeng ◽  
Heng Huang
Keyword(s):  
Drag Reduction ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Test Results ◽  
Three Dimensional Model ◽  
Simulation Test ◽  
Simulation Research ◽  
Wind Resistance ◽  
Pressure Drag ◽  
Variable Speed Motor

In this paper, three different types of tail domes were designed based on the mechanism of reducing pressure drag between the front and rear of vans, and it takes the van without a dome as a comparison to discuss the drag reduction effects of three different sizes. The three-dimensional model of the van is established in PRO/E, and the pressure and velocity distribution of the van model were analyzed in Fluent; In addition, the wind resistance test of the van model is proceed in the variable speed motor wind resistance simulation test device. The results of CFD simulation have good consistency with the experimental test results, and it verifies the conclusion that the tail dome is good for drag reduction. It provides basis and reference for the optimization of drag reduction for the vans.

Influence of Ventilation Mode on Exhaust of Propellant Vapor in a Confined Space

2014 ◽  
Vol 1073-1076 ◽  
pp. 374-377
Author(s):  
Jia Zhao Chen ◽  
Yu Xiang Zhang ◽  
Chao Ning
Keyword(s):  
Confined Space ◽  
Ventilation Mode ◽  
Forced Ventilation

Exhaust of propellant vapor in a confined space in case of forced ventilation was simulated by use of software Fluent. Calculated several situations, such as different vent position, vent number, and ventilation speed. The result shows that the lower of vent position, the more obvious the exhaust effect, and the more the vent number, the better the exhaust effect, and the higher the ventilation speed, the rapider the decrease of concentration of propellant vapor.

iGPS Measurement Network Multi-Station Arrangement Design

2013 ◽  
Vol 443 ◽  
pp. 223-227 ◽  
Author(s):  
Na Zhou ◽  
Zhi Yong An ◽  
Li Juan Li ◽  
Yun Zhu
Keyword(s):  
Measurement Accuracy ◽  
Measurement Unit ◽  
Baseline Length ◽  
Position Tracking ◽  
Test Results ◽  
Simulation Design ◽  
Intersection Angle ◽  
Optimal Arrangement ◽  
Accuracy Requirement ◽  
Measurement Principle

In order to meet the measurement accuracy requirement of some patrol device iGPS position tracking experiment, the most rational, economic configuration and optimal arrangement of iGPS are needed to find. It presented the iGPS dual-transmitter measurement principle based on non-coplanar intersection principle, and also their uncertainty analysis. From the measurement unit of iGPS networkthe dual-transmitter measurement uncertainty simulation results, the relations between measurement accuracy and the intersection angle, azimuth angle, pitch angle and baseline length are studied, which provides a reference for arrangement of multi-transmitter of iGPS. The iGPS multi-transmitter arrangement simulation design of some patrol device iGPS position tracking experiment is put forward. The calibration test results show that: the measurement accuracy of station arrangement design is less than 0.4mm, and satisfied the experiment requirement.

scholarly journals CFD simulation analysis on integrated operation of range-hood and make-up air supply for cooking-generated particulate matter

2019 ◽  
Vol 111 ◽  
pp. 04048
Author(s):  
Hyungkeun Kim ◽  
Kyungmo Kang ◽  
Yun-Gyu Lee ◽  
Taeyeon Kim
Keyword(s):  
Particulate Matter ◽  
Case Studies ◽  
Cfd Simulation ◽  
Simulation Analysis ◽  
Supply System ◽  
Airflow Rate ◽  
Cfd Simulations ◽  
Flow Angle ◽  
Air Supply ◽  
Integrated Operation

One of the most important problems of cooking-generated particulate matter (PM) is that it rapidly disperses when the range hood is in operation during cooking. To improve the performance of the range hood and prevent the dispersion of PM, a supply of make-up air equivalent to the airflow rate of the range hood should be provided. In this regard, we place an auxiliary supply system as a make-up supply to solve such problems. The objective of this study is to evaluate the performance of the make-up air supply system and the range hood. To evaluate this system, several case studies were performed involving CFD simulations. The auxiliary supply system is optimized through three types of variables (size of diffuser, distance from the source, and flow angle). An increase in the length of the diffuser causes PM dispersion to decrease. The installation of the diffuser at a certain distance from the emission source is effective in preventing dispersion of cooking-generated PM. In the building analyzed in this study, supplying the make-up air at an angle of 10° was observed to be most effective.

Air bearings in high precision systems

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
I. Cracaoanu ◽  
F. Bremer
Keyword(s):  
Surface Topography ◽  
High Precision ◽  
Air Bearing ◽  
Test Results ◽  
Air Bearings ◽  
Bearing Surface ◽  
Operational Parameters ◽  
Low Friction ◽  
Air Supply ◽  
Precision System

In high precision system applications low friction levels between components are desirable. Moving heavy parts at high speeds and accelerations without friction is possible by using air bearings. The main failure ofthe air bearings is the wear phenomenon (modification of surface topography) that occurs due to crash into the counterpart when air supply is interrupted. The aim of this research is to investigate different types of air bearings for a large number of crashes using real operational parameters from the field: speed, acceleration, load and supply air pressure. The real crash phenomenon in a high precision machine hasbeen replicated using a test setup. During testing, evolution of air bearing surface topography and air bearing characteristics (gap and flow) after different number of crashes are investigated. Test results showthat some air bearings are not reaching the specified number of crashes due to large defects that occur on the bearing surface. Some specific relations were found between crash defects and parameters such asthe air gap size and the direct contact between opposing surfaces. The preferred type of air bearings shows good performance even above the maximum specified number of crashes. This behavior can be explainedby low friction level during crash tests between the opposing surfaces. The test results from this investigation produced a reliable candidate for air bearings in the high precision system application.

scholarly journals Pointing, Tracking, Guiding, and Dome Seeing at the AAT

1984 ◽  
Vol 79 ◽  
pp. 415-416
Author(s):  
P.R. Gillingham
Keyword(s):  
Flow Direction ◽  
Polar Axis ◽  
Forced Ventilation ◽  
Tracking Errors ◽  
Air Temperatures ◽  
Air Supply ◽  
Temperature Excess ◽  
And Function ◽  
Drive And Control ◽  
And Control

AbstractThe Anglo-Australian Telescope (AAT), though based on the design for the Kitt Peak and Cerro Tololo 4 metre telescopes, differs in many significant respects. E.g. its declination axis is offset from the polar axis and its polar axis structure is much stiffer. Also the computer was, from the outset, more closely integrated with the telescope drive and control than was previous practice. The sound structural design, good gearing, and accurate mirror supports, together with thorough computer calibration, allowed the AAT to set new standards in pointing by the time it was fully operational in 1975. Good pointing saves time in acquisition, greatly aids day time observing, and leads to good blind tracking. Currently, calibrations covering the whole observable sky give rms radial residuals very near 2 arc sec. Blind tracking errors are generally within ± 1 arc sec for 1 hour or more and natural frequency oscillations less than 0.1 arc sec peak to peak. Better tracking is, of course, available using the offset autoguiders, which employ image dissectors and function on stars to about 15m. Intensified SEC Videcon television cameras are used for acquisition and for guiding with light reflected from spectrograph slit jaws.Initially, the AAT seeing suffered from poor matching of inside and outside air temperatures because the intended active cooling of dome air was cut from the installation to save funds, leaving an inadequate capacity for forced ventilation. Correlation of observed seeing with dome temperature excess indicated degradation of about 1/2 arc sec/°C. In 1980 the forced ventilation was upgraded to change the dome air in less than 4 minutes, with optional flow direction, upwards (exhausting out the observing aperture) or downwards. Measurements of seeing within the dome, but with the dome open, now show degradations typically 0.4 and 0.6 arc sec diameter with upwards and downwards ventilation respectively. Stellar seeing measurements, including routine observations in which the ventilation direction was alternated nightly, have also indicated superiority of the upwards flow. Taking advantage of this, filters can now be installed on the air supply to keep the optics cleaner.

Emission Performance of a Diesel Engine with Pressure-Wave Supercharger

2011 ◽  
Vol 383-390 ◽  
pp. 6168-6173
Author(s):  
Yan Lei ◽  
Hong Guang Zhang ◽  
Da Sen Zhou ◽  
Xiao Lei Bai
Keyword(s):  
Diesel Engine ◽  
Experimental Test ◽  
Pressure Wave ◽  
Engine Speed ◽  
3D Model ◽  
Cfd Simulation ◽  
Test Results ◽  
Turbocharged Diesel Engine ◽  
Emission Performance ◽  
Simulation Results

Pressure-wave supercharger (PWS) is one technical way to boost the engine intake air pressure. PWS has several advantages such as less emission (especially NOx emission), rapid response when load changes, higher torque even at low engine speed. In this research a 493 diesel engine is charged by a pressure-wave supercharger (PWS). The emission performance of the PWS diesel engine is mainly investigated. Together with experimental test, the CFD simulation is completed basing on a 3D model of the PWS rotor channel. The CFD simulation results show that the inner EGR phenomenon happens especially when PWS runs at middle PWS rotational speed with part load. The test results demonstrate that the PWS diesel engine performs well with less NOx and soot emissions than the turbocharged diesel engine.

Effect of Flow Field on Cutting Fluid Penetration during Minimum Quantity Lubrication (MQL) Machining

2011 ◽  
Vol 188 ◽  
pp. 61-66 ◽  
Author(s):  
W.J. Zheng ◽  
Hong Jie Pei ◽  
Gui Cheng Wang ◽  
C.G. Shen
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Wedge Angle ◽  
Minimum Quantity Lubrication ◽  
Cutting Fluid ◽  
Minimum Quantity ◽  
Supply Pressure ◽  
Air Supply ◽  
Computational Fluid Dynamics Cfd ◽  
Fluid Penetration

In order to study the mechanism of cutting fluid penetration during minimum quantity lubrication (MQL) machining, the flow field in cutting area was investigated through both theoretical analysis and computational fluid dynamics (CFD) simulation on the basis of cutting experiments. Combining the capillary model of cutting fluid penetration, the flow field in the wedge-shaped area beside major flank of the tool was analyzed in detail. It was found that the flow pressure at the wedge angle was lower than the outer. It was favorable for cutting fluid to penetrate into the main cutting edge. Besides, the air supply pressure of MQL has great impact on cutting fluid droplet track. Proper air supply pressure was in favor of cutting fluid penetration.

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