• Journal of Industrial Technology
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• v.26 no.A
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• pp.3-15
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• 2006

To determine the optimum ventilation systems during long tunnel excavation, the velocity vector profile and the contaminant's distribution at working place are studied using 2-D, 3-D numerical analysis. The main results can be summarized as follow; In case of long tunnels, blower-exhaust-mixture types which enable to use soft blast ducts is most appropriate in terms of ventilation and economical efficiency. Of the same ventilation types, ventilation efficiency has a difference according to blast ducts and the distance between fan and working place. The 3-D numerical result shows that arranging blower and exhaust ducts in the right and left corners of the tunnel respectively is effective to discharge contaminant. The result of the real measurement shows that CO concentration can be reduced to below 50 ppm, which is regulation value, as 16-minutes fan operation goes on.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.9 s.102
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• pp.1060-1069
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• 2005

Silencers are engineering devices that are designed to attenuate sound waves propagating in a flowing medium. The muffler type silencer has a series of chambers in parallel or series utilizing the reflection and expansion characteristics of the expansion chambers, sidetubes, branch resonators, and tailpipes to attenuate the sound. To Improve the performance of industrial blower silencer of muffler type which is employed in petrochemical plant, this paper seeks its optimal arrangement of buffs by experimental method and suggests optimal arrangement of buffs. Experimental results show that the optimal one suggested can reduce the noise level as much as 14 dB (or 18 dB(A)) in the laboratory and as much as 4 dB(A) compared to that of the existing silencer on the ground.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.192-199
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• 2020

The blower erosion phenomenon was investigated to develop a long-life blower with a volume flow rate of 10,000 ㎥/min with the required total pressure efficiency of 83% or more. The blower performance and blower erosion were predicted through numerical analysis by computational fluid dynamics(CFD). The conditions used for numerical analysis were an air volume of 16,200 ㎥/min, a rotation speed of 893 rpm, and a temperature of 330℃. The specific gravity, particle size, and amount of the dust was 3.15, 90 ㎛~212 ㎛, and is 265 kg/min, respectively. To examine the effects of a dust deflector on erosion, erosion analysis was performed by comparing the models with and without a dust deflector. Numerical analysis showed that when the dust deflector is installed, the average tended to decrease by 167% in the impeller and 133% in the boss. CFD using the Finne's model for erosion revealed a parallel restitution coefficient of 1 and a perpendicular restitution coefficient of 0.1. The blower performance of case 5 was 691.7 mmAq, and the efficiency was 83.3% when the rotation speed and the air volume flow rate were 880 rpm and 16,200 ㎥/min, respectively.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.128-132
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• 2008

The noise levels and individual employee noise exposure levels within a factory will determine the need for hearing conservation program. The difficulty in not having an effective hearing conservation program is the risk of hearing loss that employees may sustain. In the last few years the claims for hearing loss compensation have grown due to class action litigation brought against the employer and companies that have equipment in the factory alleged to have caused hearing loss. The Blower in the factory generates the noise of 98.3dB(A) in the frequency range of 2,000Hz, which may cause occupational hearing loss. By designing close type enclosures which are made of absorption material, about 24.4dB(A) reduction has been in the factory. It is demonstrated that this kind of enclosures can be effectively used to reduce the noise in the factory.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.331-334
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• 2006

Air foil bearings have been attempted for application to industrial turbo machines, since they have several advantages over oil bearings in terms of endurance, simplicity, environment-friendliness, efficiency, sound and vibration, and small turbo machines with air foil bearings are in the market as the result. Recently, researches on widening the application spectrum of air foil bearings are in progress worldwide. In this paper, a 300 HP class turbo blower using air foil bearings is introduced. The turbo blower has a high speed PMSM(Permanent Magnet Synchronous Motor) driving a compressor, and air flow rate is designed to be $180\;m^3/min$ at pressure ratio of 1.6. The maximum rotational speed is set to 17,000 RPM to maximize the total efficiency with the result that the weight of rotor assembly is 26kg, which is expected to be the largest turbo machine with air foil bearings ever developed in the world.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4659-4664
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• 2014

The noise produced in a factory is a cause of the noise complaint of the surrounding residential areas. In addition, it affects the work efficiency and health of workers. This paper presents the results of a basic study to reduce the noise generated from the blower, which is often used in the factory of a small and medium scale, using an active noise controller (ANC) in three-dimensional space. For this purpose, the simulator program, which can compare various parameters of the original noise and controlled noise, such as sound pressure levels, power spectra, and equivalent noise levels, was developed. The noise data was recorded at 17 points around a turbo fan blower currently being operated in a small-medium size factory. The simulation results showed that the power spectrum was reduced by a maximum of 40dB in the low frequency band and the average equivalent noise level attenuation was 12.6dB.

• Asian Journal of Atmospheric Environment
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• v.10 no.4
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• pp.226-231
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• 2016

In order to remove fog often causes various troubles in our daily lives, the novel defog blower equipped the roller brush made of recycled horse's mane hair was developed. This work presents the overview of new defog devices and the experimental data obtained at two different kinds of defogging experiments. In the model experiment carried out at the enclosed cleanroom ($W5.9m{\times}L5.1m{\times}H2.4m$) targeted a vinyl house, fog was dissipated in less than 30 seconds in case with wind entrainment and two minutes 45 seconds in case without wind entrainment after running of the newly designed defog blower. When the demisting blower was run in a duct, it has an excellent mist sweeping qualities as well as a great removal effect for the background particles (89.5% and 65.4% scavenging rates for fine and coarse particles, respectively). It can be therefore said that the mist eliminator presented in this paper is ideal for use in the sealing space like a vinyl house and the industrial sites where required to remove both harmful mist and particle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.115-121
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• 2017

The efficiency of railway track cleaning vehicle for eliminating fine particulate matter (PM10 and PM2.5) in a subway tunnel depends strongly on the structure of the air blowing and suction system installed under the train. To increase the efficiency of underbody suction system, this paper proposes a novel method to use the Coanda effect for the air blower and dust suction module. In particular, through Computational Fluid Dynamics (CFD) analysis, the flow control device induced by the Coanda effect enables an increase in the overall flow velocity and to stabilize the flow distribution of the suction module at a control angle of $90^{\circ}$. In addition, the flow velocity drop at the edge of the air knife-type blower can be improved by placing small inserts at the edge of the blower. Those 4 modular designs of the dust suction system can help remove the dust accumulated on the track and tunnel by optimizing the blowing and suction flows.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.125-127
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• 2003

The single phase switched reluctance motor(SRM) is more simpler and robust in the structure than poly phase SRM. It has the merits that it reduces the switching elements and the energy density per volume is very high. Recently, it has been researched and developed in various types and starting method due to the technique of power electronics and the computer added design. The single phase SRM is tried to apply to many industrial appliance field to substitutethe the induction motor by the single phase SRM. On the previous studies, we decided the design parameters of the single phase SRM for the blower driver to adapt the design method of the conventional machine and the poly phase SRM. In this studies, it is proposed the conditions to decide the optimal pole arcs because the stator and rotor pole arcs is very important in the characteristics of the single phase SRM. For this reason, it is analysed the characteristics of current on/off angle vs. pole arc, pole arcs vs. average torque.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.177-182
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• 2002

In the paper, the development of high-speed industrial turbo blowers with foil air bearings is presented as a first successful commercialization in the world. Their target market is various from wastewater treatment to cement factory processes which require compressed air ranging between 0.6 and 0.8 bar gauge. Employing the state-of·the-art technology of the high-speed BLDC motors, the bump-type foil air bearings and the high- efficient turbo impellers/diffusers, so much compact, efficient and silent blower machines of a single stage are now available in the market, aiming to replace the existing inefficient, bulky and noisy ones, such as roots blowers. The first production lines are established fur 25,75 and 150 hp class blowers. Rotational speeds from about 20,000 to 80,000 rpm are realized directly from the high-speed BLDC motors without any gear boxes, and no lubrication oil is required. A brief introduction of design, manufacture and test results is presented fur mechanical, electrical and aerodynamic performance.