• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.390-393
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• 1998

직기에 있는 5대 운동 메카니즘[1] 중에서 고속화가 가장 어려운 것으로는 개구운동과 위입운동을 들 수 있다. 그런데, 위입운동의 효과적인 고속 위입방법을 개발하려는 노력의 결과로 Water Jet Air Jet Rapier, Projectile 등의 방법들이 이미 개발되어 현재, Water Jet 및 Air Jet 직기인 경우에는 1,500 rpm에 이르는 위입운동의 고속화가 이루어진 상태에 있다. (중략)

• 한국기계연구소 소보
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• s.20
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• pp.5-11
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• 1990

Most water cannon machines use compressed gas to accelerate a piston which extrudes water through a cumulation nozzle. Very high jet stagnation-pressures can be achieved by using a specially-shaped nozzle which is initially filled with air or vacuum. The objective of this study was to establish the basic technology of water cannon using exponential type nozzle. An experimental water cannon including high pressure components such as exponential nozzle and 300atm air resrvior were designed and tested. Parameters that influence the performance of the system and jet characteristics were examined.

• Journal of Mechanical Science and Technology
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• v.17 no.5
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• pp.740-750
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• 2003

It has been observed that the cooling capacity of an impinging water jet is affected by the seasonal conditions in large-scale steel manufacturing processes. To confirm this phenomenon, cooling experiments utilizing a hot steel plate cooled by a laminar jet were conducted for two initial ambient air temperatures (10$^{\circ}C$ and 40$^{\circ}C$) in a closed chamber, performing an inverse heat conduction method for quantitative comparison. This study reveals that the cooling capacity at an air temperature of 10$^{\circ}C$ is lower than the heat extracted at 40$^{\circ}C$. The amount of total extracted heat at 10$^{\circ}C$ is 15% less than at 40$^{\circ}C$ , These results Indicate the quantity of water vapor, absorbed until saturation, affects the mechanism of boiling heat transfer.

• Fashion & Textile Research Journal
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• v.7 no.1
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• pp.101-105
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• 2005

This study surveys the warp and weft tension differences between projectile and air-jet looms and analyses the mechanical properties of worsted fabrics for garment with relation of these loom characteristics using KES-FB system. The paper is divided by two parts. In the 1st paper, the worsted fabric is woven as 5 harness satin weave using 1/40 Nm sirofil worsted warp yarn and 1/30 Nm worsted weft yarn by projectile(Sulzer) and air-jet looms(Picanol PAT and OMNI), respectively. The weavability is also analysed by measuring warp tension variation according to the warp position and weft tension of 3 kinds of looms. The relationship between shed amount and the warp tension is surveyed, and the relationship between end breaks and warp and weft tensions is also discussed.

• Fashion & Textile Research Journal
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• v.7 no.1
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• pp.106-110
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• 2005

This research surveys the mechanical properties of worsted fabrics for garment according to the loom characteristics and fabric positions with relation to the warp and weft weaving tensions on the projectile and air-jet looms, which is previously surveyed in the 1st paper. For this purpose, the grey fabrics are processed in dyeing and finishing processes. The mechanical properties of the finished fabrics are measured and discussed with relation to the warp and weft weaving tensions of projectile and air-jet looms and the variations of the fabric mechanical properties according to the fabric positions are also surveyed for investigating the homogeneity of the tailorability and fabric hand.

• Textile Coloration and Finishing
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• v.13 no.1
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• pp.61-67
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• 2001

In this study, the fabrics were woven with worsted grams of Nm 2/72 and the structure of 5 harness satin on rapier and air-jet loom with different weft insertion mechanism and then fabrics were finished in the same processes. Also the physical properties were measured with KES-FB system and discussed with the characteristics of looms for comparing the difference of physical properties of the worsted fabrics which were woven with two different looms under the same structure. Pot shearing and compression properties, then showed similar behavior and the fabric finishing processes were seemed to affect much more than the difference of the loom types. For the surface roughness, the rapier fabrics showed higher irregularity than the air-jet fabrics.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.1
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• pp.33-39
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• 1990

This study has been conducted by experiments for distribution of concentration of helium gas, which is jetted into stationary atmosphere at the normal temperature and pressure. It is able to obtain the data for concentration of helium and air mixtures by the use of hot wire probe which has fast response. At an up stream, the concentration gradient which is attained is steep. At a down stream, the mixing time of helium and air is gradually shortened with the lapse of time in front of a jet. The arrival frequency of a jet in an unsteady area is mostly constant from 0% to 100% up to 80mm, but the time which is reaching to 100% is gradually to lengthen as a descending downstream. After starting a jet and the point of 90%, the mixing time is especially to lengthen. This reason comes from the turbulent intensity which causes for mixing of helium and air. This time difference which causes according to lengthen a jet should be considered in the design of combustion chamber.

• Journal of ILASS-Korea
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• v.1 no.4
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• pp.46-53
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• 1996

The present study is aiming at improving the performance of main nozzle of an air jet loom with a modified reed and auxiliary nozzles. The double coaxial pipe jets consisting of a central air jet and an annular air jet have been experimentally investigated. The duter jet has a potential core and a constant velocity. The inner jet through an inner long pipe is induced by the subatmospheric pressure near the inner nozzle edge, and the jet velocity of an inner pipe is always lower than that of a outer pipe. The static pressures of the main nozzle over a wide range of the nozzle tank pressure were measured, and the nozzle velocity and Mach numbers were analytically calculated. Experiment81 results indicate that the critical condition of Mach number of unity to occur at the two positions in a main nozzle; one of them is the needle tip and the other is the acceleration tube exit An increase in the tank pressure causes the critical throat condition to occur at the two positions above. The velocity of acceleration-tube exit is maximum at the critical length L* and flow patter in acceleration-tube over critical lengh remains unstable.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.111-120
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• 2008

A particle image velocimetry (PIV) technique was employed to investigate the effects of blowing jet on the flow characteristics over stationary and pitch-oscillating airfoils. The Reynolds number was $7.84{\times}10^5$ based on the chord length. It was found that for stationary airfoil cases, continuous and pulsating blowing jets successfully reduced separated wake region at high angles of attack. A comparison study of two different types of jet blowing indicated that pulsating jet is more effective than continuous jet for flow separation control. Pulsating leading-edge blowing postpones flow separation and increased stall angle of attack by $2^{\circ}{\sim}3^{\circ}$. For pitch-oscillating airfoil cases, the PIV results showed that blowing jet efficiently delays the separation onset point during pitch-up stroke, whereas it does not prevent flow separation during pitch-down stroke, even at angles of attack smaller than static ones.

• Journal of Environmental Science International
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• v.32 no.11
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• pp.801-809
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• 2023

The purpose of this study is to predict the reflection distance following to the pulsing pressure, total air supplying, filter bag size using numercial analysis techniques and use it as an efficient operation condition and economic data for off-line type pulse air jet bag filter. In this research, filtration area 6 m² condition, calculate filter resistance coefficient for simulation through the main experiments using coke dust. Ansys fluent V19.0 apply to CFD simulation, and analysis pulsing characteristics about pulsing pressure, filtration velocity and nozzle diameter. The maximum reflecting distance of off-line type pulse air jet bag filter is 1,000 mm regardless of total air supplying at over the 42 L/m² conditions, that indicates off-line type can extend filter bag length 1,000 mm than on-line type. In order to effective primary and secondary pulsing of off-line type pulse air jet bag filter, over the 5 bar of pulsing pressure and over the 42 L/m² of total air supplying are needed.