• Title, Summary, Keyword: Jet fan

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Performance Improvement of High Speed Jet Fan

  • Choi, Young-Seok;Kim, Joon-Hyung;Lee, Kyoung-Yong;Yang, Sang-Ho
    • International Journal of Fluid Machinery and Systems
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    • v.3 no.1
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    • pp.39-49
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    • 2010
  • In this paper, a numerical study has been carried out to investigate the influence of jet fan design variables on the performance of a jet fan. In order to achieve an optimum jet fan design and to explain the interactions between the different geometric configurations in the jet fan, three-dimensional computational fluid dynamics and the DOE method have been applied. Several geometric variables, i.e., hub-tip ratio, meridional shape, rotor stagger angle, number of rotor-stator blades and stator geometry, were employed to improve the performance of the jet fan. The objective functions are defined as the exit velocity and total efficiency at the operating condition. Based on the results of computational analyses, the performance of the jet fan was significantly improved. The performance degradations when the jet fan is operated in the reverse direction are also discussed.

Study of the Smoke Control Characteristics for Fire Near Jet Fans (Jet fan 근접 화재 발생 시 제연 특성 연구)

  • Kim, Jong-Yoon;Seo, Tae-Beom;Lim, Kyung-Bum;Yoo, Ji-Oh;Rie, Dong-Ho
    • Fire Science and Engineering
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    • v.21 no.1
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    • pp.82-89
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    • 2007
  • In this research, we conducted a PIV-visualization experiment to smoke control from fires by using a neighboring Jet fan at minimum distance. We also compared our experiment results with FDS numerical analysis ones. As a result of quantitative data analysis of smoke control modes against fires in tunnel, we concluded that a neighboring Jet fan should be placed at least 25 m away from its fire source in order to produce satisfactory smoke control results. Jet fan showed the best smoke-controlling performance, if placed 50 m away from its fire source. It tended to show an overspeed around the center of tunnel when it is placed more than 75 away from its fire source.

분배계통에 따른 지하주차장 환기설비 성능의 예측

  • 김경환;이재헌;오명도;김종필
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.10
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    • pp.982-992
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    • 2001
  • In this paper, the performance of ventilation equipments in enclosed parking garages were investigated for several air distribution systems by numerical method. Air change effectiveness of the non-mixing system was 0.42. It meant that more supply air as much as the design supply air was needed to maintain good indoor air quality. In the high speed nozzle ventilating system which is most expensive one, air change effectiveness was 0.54. Therefore this system satisfied to ventilation design. In the jet fan ventilating systems, air change effectiveness for jet fan ventilating system-A with 18 jet fans and jet fan ventilating system-B with 6 jet fans in circulation mixing arrangement were 0.565 and 0.42 respectively. Jet fan ventilating system-C with 6 jet fans in transport mixing arrangement was 0.535. Jet fan ventilating system-A and jet fan ventilating system-C met the ventilation design. But velocity in jet fan ventilating system-A was over 2.0m/s which is inappropriate in human comfort. Therefore this system is not proper to ventilation. Jet fan ventilating system-C was the optimum one for enclosed parking garages among 5 systems examined in this paper.

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Effects of Silencer Design on the Performance of Jet-fan (제트홴 소음기 형상이 성능에 미치는 영향)

  • Oh, In-Gyu;Choi, Young-Seok;Kim, Joon-Hyung;Yang, Sang-Ho;Kwon, Oh-Myoung
    • The KSFM Journal of Fluid Machinery
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    • v.13 no.6
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    • pp.25-29
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    • 2010
  • In this paper, a numerical study has been carried out to investigate the influence of silencer design variables on the performance of a jet fan. In order to achieve an optimum jet fan design and to explain the interactions between the different geometric configurations in the jet fan, three-dimensional computational fluid dynamics and the Design of Experiments method have been applied. Two geometric variables, i.e., cap size and silencer length, were employed to improve the performance of the jet fan. The objective functions of the jet fan are defined as the effective velocity and total efficiency at the operating condition. Based on the results of computational analyses, the flow characteristics were discussed. The effect of silencer with a specific roughness on the performance was also discussed.

Study on the Design Concept of Impinging Jet Electronics Cooling by Using Axial Fan (축류 팬을 이용한 충돌제트 전자냉각 설계개념에 대한 연구)

  • Lee, Chan;Kil, Hyun-Gwon
    • The KSFM Journal of Fluid Machinery
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    • v.12 no.2
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    • pp.24-30
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    • 2009
  • Flow and noise analyses are conducted for examining a new design concept of impinging jet electronics cooling, and the analysis results are compared with conventional electronics cooling techniques. For the application of impinging jet electronics cooling method, the present study considers the air duct where air is supplied by axial fan and air flow from the duct is impinged vertically onto the electronic component heat source. Applying CFD simulation technique and fan noise model to the present cooling scheme, the cooling performance of the impinging jet as well as the operation condition and the noise characteristics of fan are investigated for various impinging jet nozzle conditions and fan models. Furthermore, the impinging jet electronics cooling analysis results are compared with the conventional parallel-flow cooling scheme to give the design concept and criteria of impinging jet cooling method.

NUMERICAL ANALYSIS OF TUNNEL FLOW INDUCED BY JET FAN (제트팬 운전에 의해 형성되는 터널내 유동에 대한 수치적 해석)

  • Kim, J.Y.
    • 한국전산유체공학회:학술대회논문집
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    • pp.10-13
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    • 2010
  • The flow field in road tunnel is influenced by some facts such as piston effect of vehicle's move, operation of ventilation facilities, natural wind and buoyancy effect of fire plume. Among those, jet fan is one of main ventilation facilities especially in longitudinal ventilation system of tunnel. In this study to analyze tunnel flow induced by operation of jet fan, numerical simulation has been carried out. The velocity distributions and streamlines in tunnel are examined to consider the three-dimensional characteristics of tunnel flow caused by jet fan.

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Numerical and Experimental Analysis of Tunnel Flow Induced by Jet Fan (제트홴에 의해 형성되는 터널내 유동의 실험 및 수치적 해석)

  • Kim, Jung-Yup;Yang, Sang-Ho
    • The KSFM Journal of Fluid Machinery
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    • v.13 no.3
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    • pp.59-64
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    • 2010
  • To analyze the three-dimensional flow in tunnel caused by operation of jet fan, both experimental and computational studies have been conducted. The experimental analysis of tunnel flow induced by jet fan is conducted on a real-scale apparatus with jet fan and tunnel, and air velocity at the monitoring points is measured for variation of fan's RPM. The three-dimensional numerical analysis including tunnel and jet fan is carried out for the same geometric configuration as the experimental analysis. The experimental and computational results are compared to examine the applicability of the numerical method.

Ventilation Analysis according to Jet Fan Location in Long Tunnel (장대형 터널 내 제트 팬 위치에 따른 환기해석)

  • Kang, Shin-Hyung;Byun, Ju-Suk;Lee, Jin-Ho
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.5
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    • pp.386-393
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    • 2007
  • This paper studies the ventilation characteristics according to the jet fan location at the long road tunnel using the CFD software 'FLUENT' which is based on the finite volume method. The tunnel model used in the analysis has a length of 1600m, a cross sectional area of $120m^3$, and is composed of 3 lanes and one way. The velocity profile, the distribution of CO concentration and the ventilation flow rate within the tunnel are analyzed, respectively. In the analysis, it is found that the dependence of the ventilation flow rate upon the jet fan location is small, but the CO concentration in the tunnel is at the lowest when the jet fans are installed near the tunnel outlet. An air stream right below the jet fan is almost inactive due to the strong stream injection near the jet fan. Thus, the pollution level below the jet fan must be higher than the other area.

A Study on Smoke Control Characteristic by the Effect off Jet Fan Installation Distance (제트팬 이격거리에 따른 연기제어특성에 관한 연구)

  • Kim, Jong-Yoon;Jeon, Yong-Han;Seo, Tae-Beom;Yoo, Ji-Oh;Rie, Dong-Ho
    • Fire Science and Engineering
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    • v.22 no.1
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    • pp.16-23
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    • 2008
  • In this research, the visualization experiment for a scaling tunnel was conducted to establish the optimum fire protection system in tunnel fires. In order to find the optimal operating condition of jet fan with the fire, the characteristics of smoke propagation was considered to find the optimal operating condition of jet fan at the time of tunnel fire, the concentration of smoke was measured experimentally for various jet fan position and it's operating condition. As a result, when jet fan in the vicinity of fire operates at the upstream, the back-layering of the smoke should be considered with separation distance from the fire source. The distance between the jet fan and the fire should be longer than 50 m. On the other hand, when the vicinity jet fan operates at the downstream, the back-layering of smoke does not occur, but stratification is not maintained because the smoke dispersion occurs at the downstream due to the operation of the jet fan.

Effects of the Distance between Jet Fans on the Ventilation Performance in a Road Tunnel (제트홴의 이격거리에 따른 터널내 환기특성에 관한 수치적 연구)

  • Kim, Jung-Yup
    • The KSFM Journal of Fluid Machinery
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    • v.14 no.4
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    • pp.25-30
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    • 2011
  • The jet fan is generally used to add thrust in the longitudinal ventilation system of road tunnel and the geometric conditions of jet fan such as the distance from tunnel wall have an effect on the performance of ventilation system. Numerical analyses on the flow in tunnel caused by operation of jet fan are presented to study the ventilation characteristics in tunnel. While the distance between jet fans in parallel installed in tunnel is changed 0.5 L/D to 3.0 L/D, the flowrate and mean velocity through tunnel are calculated for each cases. As the distance between jet fans increases, the flowrate through tunnel increases asymptotically and the momentum of tunnel flow is alike.