• Title/Summary/Keyword: 축동력

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Effect of Air Admission on Pressure Pulsation in a Francis Turbine (급기가 프란시스 수차의 수압 맥동에 미치는 영향)

  • Jeon, Yunheung;Park, Sihoon;Choi, Hansu;Park, Jungwan
    • New & Renewable Energy
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    • v.10 no.4
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    • pp.9-15
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    • 2014
  • In this study pressure and shaft torque pulsation were measured with variation of head and flow during the model test for a 15 MW Francis Turbine. Pressure pulsations were measured at the inlet of the spiral casing and 4 points in the cone of the diffuser and shaft torque pulsation at the upper position of the turbine. The maximum amplitude of pressure pulsation appeared 2.03% of the maximum rated head with the frequency of 25% of the rated revolution and at the guide vane opening of $10^{\circ}$. Shaft torque pulsation appeared 0.01% of the rated shaft torque, fairly low value. Air was admitted through the cone and pressure pulsation gradually decreased with increase of air flow and kept nearly constant after 5% of the rated flow. A new Francis turbine of which specific speed is 115 m-kW had been designed to rehabilitate the old one and the model test was performed at EPFL. The commercial code, STAR-$CCM^+$ was used for numerical simulation of flow.

Conceptual design of scroll expander-compressor for Stirling engine (스크롤 방식 스털링 엔진용 스크롤 압축기-팽창기 개념 설계)

  • Kim, Woo-Young;Kim, Hyun-Jin;Kim, Young-Min;Lee, Sang-Tae
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.397-403
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    • 2007
  • In this paper, conceptual design of scroll expander-compressor for Stirling engine utilizing solar energy as heat source has been carried out. Orbiting scroll member was designed to have a double-sided structure to reduce the overall scroll size and to cancel out the axial forces on the orbiting scroll base plate. Diameter of designed scroll base plate was about 251 mm for the expander, and it was about 218 mm for the compressor. With operating condition such as temperature range of $400^{\circ}C/20^{\circ}C$, pressure range of 6 MPa/2 MPa, and shaft speed of 2700 rpm, the shaft output of the designed scroll expander was calculated to be 49.8 kW, while input power for the scroll compressor was 38.6 kW, yielding 11.2 kW for the output power of the Stirling engine. Overall efficiencies of the scroll expander and compressor were 93.73% and 92.87%, respectively.

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A Study on the Pump Performance Analysis by Modifying the Impeller for a Seawater Pump using CFD (임펠러 가공량에 따른 펌프성능의 해석적 연구)

  • Chang, Young Ki;Song, Woo Seok
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.8 no.3
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    • pp.23-27
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    • 2012
  • A seawater pumps in the nuclear power plant is responsible for providing cooling water to other components all the time. Because of the depreciation, the seawater pump with current impeller consumes too much power for maintaining the total head. Therefore the objective of this study is to reduce power with maintaining certain the total head by cutting the current impeller. By using a commercial CFD code, FLUENT, the overall performance of seawater pump with current and modified impeller was simulated. Also Affinity law was applied at pumps with various impeller diameter and evaluated the validity of the affinity law. The numerical results show that the pump efficiency is quite irrelevant to the diameters of the impellers and the pump efficiency becomes worse over the designed flow rate. And affinity law result and numerical one show good agreements at small change of impeller diameter. One of the impeller diameters was decided to modify and was applied to the nuclear power plant with the numerical study above.

Measurement and Assessment on the Shaft Power Measurement of Diesel Engine using Strain Gauge in Marine Vessel (선박에서 스트레인 게이지를 이용한 디젤엔진의 축 동력 측정과 평가)

  • Lee, Don-Chool;Song, Myong-Ho;Kim, Sang-Hwan
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.8
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    • pp.1152-1161
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    • 2009
  • The power measurement of main propulsion system on the new vessels can be classified with the direct method acquired from the shaft's strain using strain gauge and the indirect method converted and summed from all of cylinders combustion pressure using mechanical or electrical pickup device during the sea trial. This power is fluctuated by external factors which was influenced by various sea motions with long time interval and by internal factors which was influenced by varying torques of torsional vibration and bending moment, due to mis-aligned shaft and whirling vibration with short time interval. In this paper, the statistical analysis method for the shaft power measurement and assessment using strain gauge in marine vessels are introduced. And these are identified by the low speed two stroke diesel engine model and four stroke medium speed diesel engine model including reduction gear.

Prediction of Hydraulic Performance of a Scaled-Down Model of SMART Reactor Coolant Pump (스마트 원자로냉각재펌프의 축소모형에 대한 수력성능 예측)

  • Kwon, Sun-Guk;Park, Jin-Seok;Yu, Je-Yong;Lee, Won-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.8
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    • pp.1059-1065
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    • 2010
  • An analysis was conducted to predict the hydraulic performance of a reactor coolant pump (RCP) of SMART at the off-design as well as design points. In order to reduce the analysis time efficiently, a single passage containing an impeller and a diffuser was considered as the computational domain. A stage scheme was used to perform a circumferential averaging of the flux on the impeller-diffuser interface. The pressure difference between the inlet and outlet of the pump was determined and was used to compute the head, efficiency, and break horse power (BHP) of a scaled-down model under conditions of steady-state incompressible flow. The predicted curves of the hydraulic performance of an RCP were similar to the typical characteristic curves of a conventional mixed-flow pump. The complex internal fluid flow of a pump, including the internal recirculation loss due to reverse flow, was observed at a low flow rate.

Effects of Impeller Shape of Submersible Nonclogging Pump on its Performance (비 막힘형 수중 펌프 임펠러 형상이 펌프 성능에 미치는 영향)

  • Yun, Jeong-Eui
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.12
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    • pp.1201-1207
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    • 2012
  • This study was performed to develop a high-efficiency submersible nonclogging pump impeller. Toward this end, we simulated the effect of some parameters such as the outlet position of a blade ($h_I$), outlet width of a blade ($b_2$), and hub profile on the pump efficiency by using the commercial codes ANSYS CFX and BladeGen. The results showed that the pump efficiency was proportional up to $h_I$= 38 mm and $b_2$= 55 mm. It remained constant over these values. However, the head and shaft power were proportional to $h_I$ and $b_2$ in the simulated ranges. The effects of hub profile changes on the pump efficiency were relatively small compared to those of the other parameters.

The Development of Rotoless Electronic Circulating Pump System with Internal Three Way Valve for Boiler - Objective for the 1st Year : Development of New Housing with Internal Three Way Valve - (보일러용 3way valve내장형 rotoless 전자식순환펌프 시스템의 개발 - 1차년도 목표 : 3way valve 내장형 하우징의 개발 -)

  • Han, J.W.;Kum, S.M.;Ryu, B.H.;Lee, C.E.;Ohu, S.C.;Yim, J.S.
    • Solar Energy
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    • v.16 no.2
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    • pp.97-112
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    • 1996
  • The purpose of research is to complement the circulating pump of gas boiler for the domestic and to develop a pump housing with internal three way valve: Housing and three way valve have been apart in the existing pump system. Based on the experimental result on can-typed circulating pump with existing housing, a new housing with internal three way valve was designed and manufactured. The performance of can-typed circulating pump with the new housing, and the performance of circulating pump of boiler system were tested. As a result ot the test, the new housing with internal three way valve has been excellent in respect of pump performance, weight and manufacturing cost. So It is expected to have an effect of import substitution.

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Prediction of GHP Performance Using Cycle Analysis (사이클 해석을 통한 GHP 성능 예측)

  • Cha, Woo Ho;Choi, Song;Chung, Baik Young;Kim, Byung Soon;Jeon, Si Moon
    • Transactions of the KSME C: Technology and Education
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    • v.3 no.1
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    • pp.15-21
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    • 2015
  • In this paper a prediction method of GHP performance is proposed for increasing design accuracy. Two compressors with different capacity and 2311cc gas engine are used for prediction and the target capacity of GHP is 25HP. For predicting GHP performance at first the operation points are randomly selected and then as compared with compressor performance date and heat exchanger characteristic, more accurate operating points are decided through recursive calculation. Lastly engine performance date is used for calculating gas consumption volume. Predicting heating mode performance of GHP, evaporator is separated to the two section of absorbing heat in outdoor air and in engine. From the experimental results, it was found that the simulation model is good for the predicting GHP efficiency and the difference of predicted and measured efficiency is less than 5%.

Experimental Study on the Performance Characteristics of a Scroll Expander for 1kW-class Organic Rankine Cycle (1kW급 유기랭킨사이클용 스크롤 팽창기의 성능 특성에 관한 실험적 연구)

  • Kim, Dokyun;Yun, Eunkoo;Yoon, Sang Youl;Kim, Kyung Chun
    • Journal of the Korean Institute of Gas
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    • v.19 no.4
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    • pp.41-48
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    • 2015
  • The performance characteristics of a scroll expander is the most important variable for the performance of organic Rankine cycle system. In this paper, the performance characteristics of a scroll expander was identified using 1kW class organic Rankine cycle system with various operating conditions. The ORC system is composed of an evaporator, a scroll expander, a condenser and a working fluid feed pump that uses R245fa as working fluid. The hot water temperature was controlled from $80^{\circ}C$ to $115^{\circ}C$ by the 50kW-class electric water-heater. The maximum isentropic efficiency of the scroll expander was measured about 77%, and the shaft power was measured from 0.5 kW to 1.8 kW according to heat source temperatures.

Air-Water Two-Phase Flow Test Facility of a Single Stage Closed-type Centrifugal Pump (단단 밀폐형 원심펌프의 기액이상류 성능시험 설비)

  • Kim, S. Y.;Lee, S. L.;Kim, Y. T.;Kim, S. D.;Lee, Y. S.;Lee, Y. H.
    • 유체기계공업학회:학술대회논문집
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    • 2004.12a
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    • pp.49-53
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    • 2004
  • LabVIEW is mostly preferred to use in experiment, measurement and control as one of the useful thing in America and Europe. So, We tried performance experiment of a single-stage closed-type centrifugal pump by using the LabVIEW. The pump rpm and the shaft torque are measured by rpm sensor and torque sensor The test pump's maximum rpm, head, kW are 1,750, 13m, and 1.5kW, respectively The casing is made up with transparency acrylic for confirmation the flow patterns. We installed experimental equipment for air water two phase flow. This paper tries to analyze the single-phase flow characteristics through this air water two phase flow experimental apparatus. The performance results of a single-stage closed-type centrifugal pump satisfied reappearance and coincide well with head and coefficients according to the change of rpm.

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