• Title/Summary/Keyword: Number of blades

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Selection of Optimal Number of Francis Runner Blades for a Sediment Laden Micro Hydropower Plant in Nepal

  • Baidar, Binaya;Chitrakar, Sailesh;Koirala, Ravi;Neopane, Hari Prasad
    • International Journal of Fluid Machinery and Systems
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    • v.8 no.4
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    • pp.294-303
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    • 2015
  • The present study is conducted to identify a better design and optimal number of Francis runner blades for sediment laden high head micro hydropower site, Tara Khola in the Baglung district of Nepal. The runner is designed with in-house code and Computational Fluid Dynamics (CFD) analysis is performed to evaluate the performance with three configurations; 11, 13 and 17 numbers of runner blades. The three sets of runners were also investigated for the sediment erosion tendency. The runner with 13 blades shows better performance at design as well as in variable discharge conditions. 96.2% efficiency is obtained from the runner with 13 blades at the design point, and the runners with 17 and 11 blades have 88.25% and 76.63% efficiencies respectively. Further, the runner with 13 blades has better manufacturability than the runner with 17 blades as it has long and highly curved blade with small gaps between the blades, but it comes with 65% more erosion tendency than in the runner with 17 blades.

Analysis of the Sir Flow due to the Number of Electric Fan Blades (선풍기의 날개 수에 따른 공기 유동해석)

  • Cho, Jae-Ung;Han, Moon-Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.1
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    • pp.107-112
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    • 2012
  • Air flow and its pressure at electric fan according to three, four and five blades are analyzed in this study. As the number of blades increases at the same condition of specification, air tends to converge and becomes natural wind but higher power is consumed. And the velocity of wind is decreased as the space between winds becomes narrow. The turbulent flow is happened in the center of the body of revolution and the kinetic energy becomes largest in case of three blades. The pressure is decreased than atmospheric pressure from fan to outlet. As the number of blades increases, the pressure drop becomes smaller and is smallest in case of the fan with three blades. As the study result, The electric fan with three blades is thought to be effective in view of power consumption and design.

The Study of Wind Blower Characteristics Using a Blade Type Corona Motor (코로나 모터를 이용한 송풍장치의 특성 연구)

  • Jung, Jae-Seung;Kim, Hyung-Pyo;Kim, Jin-Gyu
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.11
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    • pp.76-81
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    • 2013
  • In this paper, a corona motor with blade type electrodes has been employed as a wind blower. The rotation speed was influenced significantly by the polarity of applied voltage and the number of blades. Therefore the effect of polarity of applied voltage and the number of blades on the electrical and mechanical fundamental properties of corona motor were investigated experimentally. The rotation speed decreased for increasing of number of blades, because the mass of blades increased. But the amount of air blow increased despite decreasing of the rotation speed, because air volume is not only influenced by rotation speed but also the number of blades and ionic wind which generated between blade tips and a induction electrode. Although space occupied by blades of the corona motor is smaller than the whole area of the blast pipe, wind rises a whole range of a wind blower for such reasons.

Performance analysis of hubless rim-driven thruster based on the number of blades: a CFD approach (날개수에 따른 허브리스 림 추진기의 성능 분석 : CFD를 이용한 접근)

  • Hyoung-Ho KIM;Chang-Je LEE
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.60 no.1
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    • pp.80-86
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    • 2024
  • We analyzed the performance of hubless rim propellers based on the number of blades, maintaining a fixed pitch ratio and expanded area ratio, using computational fluid dynamics (CFD). Thrust coefficient, torque coefficient and efficiency according to the number of blades were analyzed. In addition, the pressure distribution on the discharge and suction sides of the blade was analyzed. As the advance ratio increases, the thrust coefficient decreases. The highest thrust was shown when the advance ratio was lowest. For the three, four, five and six-blades, the torque coefficient tended to decrease as the advance ratio increased. In the case of seven and eight-blades, the torque coefficient tended to increase as the advance ratio increased. The maximum efficiency was found when the advance ratio was 0.8. When the three-blade, it showed high efficiency at all advance ratios. A high pressure distribution was observed at the leading edge of the discharge blade, and a low pressure distribution was observed at the trailing edge. Applying a hubless rim-driven thruster with the three-blade can generate higher thrust and increase work efficiency.

An Experimental Investigation of Noise Reduction by Blades in a Duct (회전 날개에 의한 덕트 소음 저감에 관한 실험적 고찰)

  • 최성배;이재곤
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.5
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    • pp.357-363
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    • 2003
  • There have been lots of studies on noise transmission analysis and noise reduction In ducts. In order to reduce the noise transmission in ducts. active noise cancellation techniques have often been employed and a rotation shaft with blades has sometimes been suggested. These Ideas were not successfully commercialized because of the limitation of real life such as size or application difficulties. This study investigated how a rotational shaft with blades could reduce the noise transmission in a duct. To do so, an assembly of the shaft and the $haft housing was built In the middle of a duct. and the clearance between the blades and the housing was 0.2 mm. The noise reduction was experimentally evaluated with respect to the number of blades. the rotation speed, and the rotation or stop. This paper showed that the noise reduction resulted in about 14∼19 dBA regardless of the three test conditions only If the blades always blocked the duct. And. the noise reduction increased due to the higher number of blades and the lower speed of the shaft.

Effects of number of blades on the performance of the turbopump inducer (터보펌프용 인듀서 블레이드 수가 성능에 미치는 영향에 대한 연구)

  • Choi, Chang-Ho;Kim, Jin-Han
    • The KSFM Journal of Fluid Machinery
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    • v.12 no.2
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    • pp.52-57
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    • 2009
  • The effects of number of blades on the hydraulic performance of the inducer were studied using a computational method. Inducers with number of blades from 2 to 4 were used for computations and the hydraulic performances of the inducers were compared. The computational results showed that the hydraulic performance decreased due to the increase of the skin friction loss at blade passages as the blade number increased. The results also showed that the strength of the backflow became weak because of the decrease of unfavorable pressure gradient as the blade number increased.

Modeling of Blades to Enhance Self-Power Generation in Pipe Flow (자가발전효율 향상을 위한 유수관내 블레이드 형상의 모델링 및 해석)

  • Yeo, In-Hwan;Kim, Do-Yoon;Paik, Jong-Hoo;Lee, Young-Jin;Shin, Min-Chul;Park, Jae-Woo
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.3
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    • pp.277-285
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    • 2010
  • We examined the optimal shape of blades and efficiency of a self-power generator when the self-power generator using flow of the water in pipe as the power source was installed. Selected factors were the shape of blades, the number of blades, pitch angle, and the existence of separator. GAMBIT2.4 was used as a modeling program, FLUENT6.3, which is computational fluid dynamics simulation program, was used as an analytical model. In the case of a viscous model, k-epsilon standard model was chosen. As a result, when the number of blades was increased, the efficiency and maximum moment were enhanced slightly. The pitch of blades went up, and maximum moment was also increased. The optimal pitch of blade was 62.5 degree and the efficiency was increased by 30%. The efficiency was also increased when a separator was installed.

Structural Design and Analysis of Composite Cyclocopter Rotor Blades (복합재료 사이클로콥터 로터 블레이드의 구조 설계 및 해석)

  • Hwang In Seong;Hwang Chang Sup;Yun Chul Yong;Kim Seung Jo
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.91-94
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    • 2004
  • A cyclocopter with the cycloidal blades system can be the type of UAV which can combine the high-speed characteristics of the conventional airplane with the low-speed characteristics of the helicopter. The cycloidal blades system, which can be described as a horizontal rotary wing, offers powerful thrust levels, and a unique ability to change the direction of the thrust almost instantly. Rotor blades are designed to withstand tremendous transverse centrifugal loadings, and responding to a number of aerodynamic harmonic vibratory forcing frequencies. To reduce the weight and increase the strength, the blades are made of composite materials. The blades consist of the skin, spar, and trailing stiffener. In this study, static and dynamic behaviors of cyclocopter rotor blades are analyzed by using MSC/NASTRAN.

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A Turbine-Blade-Balancing Problem with Some Locking Blades (고정형 블레이드가 있는 터빈의 블레이드 균형화 문제)

  • Choi, Won-Joon
    • IE interfaces
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    • v.14 no.2
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    • pp.140-147
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    • 2001
  • In the turbine-blade manufacturing industry, turbine-blades are machined and then are assembled to form a circular roll of blades. The roll of blades should be balanced as much as possible, since otherwise the efficiency of the turbine generator might be damaged. A locking blade is a blade whose location is fixed and a non-locking blade is a blade whose location can be freely changed. In this paper, we study methods for balancing the weights of the rotating blades for a turbine where some blades are locking blades. The turbine-blade balancing problem is formulated into a mixed-integer programming problem, which turns out to be NP-hard. A heuristic method based on the number partitioning algorithm is developed and the computational experiments show very promising results.

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A Heuristic Algorithm for a Turbine-Blade-Balancing Problem (터빈 블레이드 균형화를 위한 발견적 기법)

  • 최원준
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2000.04a
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    • pp.193-196
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    • 2000
  • In the turbine-blade manufacturing industry, turbine-blades are machined and then are assembled to form a circular roll of blades. The roll of blades should be balanced as much as possible, since otherwise the efficiency of the turbine generator might degrade. We propose a heuristic method for balancing blades based on the number partitioning algorithm. The proposed method outperformed existing methods remarkably in terms of the accuracy with a negligible increase in the running time.

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