• 제목/요약/키워드: Power-Flow Analysis

검색결과 2,220건 처리시간 0.024초

진동 동력 흐름 예측 기법을 이용한 소음 전달 경로 해석 및 차량의 실내소음저감에 관한 연구 (A Study on Noise Transfer Path Analysi for Sound Improvement of Vehicle Using the Vibrational Power Flow)

  • 이상권
    • 한국자동차공학회논문집
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    • 제9권2호
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    • pp.168-175
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    • 2001
  • Reduction of structure-borne noise of the compartment in a car is an important task in automotive engineering. Transfer path analysis using vibroacoustic reciprocity technique or multiple path decomposition method has generally been used for structure-borne noise path analysis. These methods are useful in solving particular problem but do net quantify the effectiveness of vibration isolation of each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow has been used for a simple isolation system or a laboratory based isolation system. It is often difficult to apply the vibrational power flow technique to the complex isolation system like a car. In this paper, a simple equation is derived for calculation of the vibrational power flow of an isolation system with multiple isolators such as a car. It is successfully applied to not only quantifying the relative contributions of eighteen isolators but also reducing structure-borne noise of a passenger car. According to the results, the main contributor of eighteen isolators is the rear roll mount of an engine. The reduced structure-borne noise level is about 5dBA.

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화력발전소용 1인치 볼 밸브 유량계수 Cv에 관한 유동해석 및 실험에 관한 연구 (Experiment and Flow Analysis of the Flow Coefficient Cv of a 1 inch Ball Valve for a Thermal Power Plant)

  • 강창원;이중섭;이치우
    • 한국기계가공학회지
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    • 제18권3호
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    • pp.109-115
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    • 2019
  • The purpose of this study was to analyze and test the flow rate of a 1-inch ball valve used in a thermal power plant. To identify the flow-rate characteristics, numerical analysis was conducted and an experimental apparatus of the valve flow rate coefficient was used to compare the flow coefficient Cv values. To determine the internal pressure distribution, the sites of opening ball valves and flow fields were investigated. In particular, a smaller the valve opening resulted in a more complicated the flow field of the ball. The valve flow characteristic test showed that the Cv value and flow rate increased with increasing valve-opening rate and the secondary function was performed. The pressure drop increased as the valve opening rate decreased. In addition, the experimental results for the flow analysis are similar to the numerical analysis results.

육상전원공급장치(AMP) 이용한 선내 전원 공급 시 계통 안정도 분석 (Transient Stability Analysis of Vessel Power System Using Alternative Marine Power)

  • 강승표;김장목;조현준
    • 해양환경안전학회지
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    • 제29권2호
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    • pp.215-222
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    • 2023
  • 세계적 선박 배출가스 저감에 대한 규제로 인해 항만 및 부두에서 육상전원공급장치(AMP, Alternative Marine Power)가 지속적으로 사용되고 있다. 국내 또한 항만 대기질 개선 특별법에 따라 AMP의 사용이 의무화되고 있고, 다양한 친환경선박과 연계하여 활용하도록 지속적인 시도를 하고 있다. 본 논문에서는 AMP를 통해 선내 전력을 공급하는 상황을 모델링 하여 AC Load Flow Analysis를 수행하였다. 이를 통해 선박에 전력이 공급될 때의 전기적 파라미터와 손실 등에 대해서 분석할 수 있다. 아울러 Transient Stability Analysis를 통해 계통의 사고 발생 시 선내 발전기를 통한 무정전전환에 대한 HSGT(High Speed Generation Transfer)의 한계값을 도출하고 이를 적용하였을 경우 결과에 대해 검토하였다.

정유압기계식 변속장치의 동력특성해석 (Power Characteristics Analysis of Hydro-Mechanical Transmission)

  • 성덕환;이근호;김현수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집B
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    • pp.519-524
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    • 2001
  • In this paper, power flow characteristics of a hydromechanical transmission(HMT) are investigated using network analysis. The HMT used in this study consist of a hydrostatic unit(HSU), planetary gear sets, clutches and brakes providing forward 4 speeds and backward 2 speeds. Since the HMT power flows showing a closed loop and the HSU efficiency varies depending on the pressure and speed, a systematic approach is required to analyze the power transmission characteristics of the HMT. In order to analyze the closed loop power flow and the HSU power loss which changes depending on the pressure and speed, network model is constructed for each speed range. In addition, an algorithm is proposed to calculate an accurate HSU loss corresponding to the experimental results. It is found from the network analysis that the torque and speed of each transmission element including the HSU can be obtained as well as direction of the power flow by the proposed algorithm. It is expected that the network analysis can be used in the design of relatively complicated transmission system such as HMT.

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변동비반영 발전경쟁시장에서 LNG-복합 화력발전소의 경제성 분석에 관한 연구 (A Study on the Economic Analysis of LNG Combined Cycle Thermal Power Plant in Cost Based Pool Electricity Markets)

  • 이천호;한석만;정구형;강동주;김발호
    • 전기학회논문지
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    • 제57권8호
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    • pp.1327-1333
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    • 2008
  • Since Cost Based Pool markets has been continued to power markets, Genco. needs economic analysis about investment in power plants. Particularly most Private Genco.s have presently a construction plan about LNG combined cycle thermal power plants. In this paper, we propose a economic analysis method of LNG combined cycle thermal power plants using Economic Dispatch and Optimal Power Flow in CBP markets. Also we develope computation model using it for decision making to build a plant. This method can consider a variation of power facility like power plants and transmission lines in CBP markets. Finally, this dissertation provides a relevant case study to confirm the effect of cost factor to economical efficiency.

진동파워흐름해석의 주파수 평균해석에 대한 연구 (Research on Frequency Average Analysis of vibrational Power Flow Analysis)

  • 이재민;홍석윤;박영호
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 춘계학술대회논문집
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    • pp.971-977
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    • 2005
  • Power Flow Analysis (PFA) is developed for the effective predictions of frequency-averaged vibrational response in medium-to-high frequency ranges. In PFA, the power coefficients of semi-infinite structure and for-field energy density are used to predict the vibrational responses of structures. Generally, at high frequencies, PFA can predict narrow-band frequency-averaged vibrational responses of built-up structures. However, in low- to medium frequency ranges, the dynamic responses obtained by PFA represent broad-band frequency-averaged vibrational energy densities. For the prediction of vibrational response variance in Power Flow Finite Element Method (PFFEM), the variances of input power and joint element matrix describing structural coupling relationship are derived. Finally, for the validity of developed formulation, numerical examples for two co-planer plates are performed and the vibrational response variance of the structure are compared with the results of classical and PFFEM solutions.

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냉열발전을 위한 극저온 체크밸브의 유동해석 (Flow Analysis of Cryogenic Check Valve for LNG)

  • 문정현
    • 동력기계공학회지
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    • 제20권1호
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    • pp.5-10
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    • 2016
  • Swing check valve is opened when the flow direction is forward, when the flow is reversed, the valve is automatically closed by back pressure. In this study, the internal flow field analysis of the valve was conducted by Fluent. The working fluid used in the study, using liquefied methane $-165^{\circ}C$ (CH4) and velocity field, pressure field, pressure drop coefficient were simulated by varying separately the opening divergence into four intervals from 0 to 100%. The approximate research result are as follow : When the opening divergence is smaller, it appears high pressure on the upstream side, this value is relaxed when the opening divergence is large. Flow rate coefficient of the valve shows a larger value as the degree of opening becomes larger, confirming that the check valve used in the study is in the effective flow rate counting range.

소형 digital computer를 이용한 대전력계통의 해석 (Analysis of Large Power System by Small Digital Computer)

  • 박영문;정재길
    • 전기의세계
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    • 제23권1호
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    • pp.61-68
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    • 1974
  • This paper attempts to develop the algorithms and computer program for load flow solution and faults analysis of large power system by small digital computer. The Conventional methods for load flow solution and fault analysis of large power system require too much amount of computer memory space and computing time. Therefore, this paper describes the methad for reducing the computer memory space and computing time as follows. (1) Load Flow Solution; This method is to store each primitive impedance of lines along with a list of bus numbers corresponding to the both terminals of lines, and to store only nonzero element of bus admittance matrix. (2) Faults Analysis: This method is to partition a large power system into several groups of subsystems, form individual bus impedance matrix, store them in the storage, and assemble the only required portion of them to original total system by algorithm.

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8단 자동변속기의 유성기어 가공을 위한 동력 흐름 해석 (2) : 4-8단 (Power Flow Analysis for Manufacturing of Planetary Gears in an 8-speed Automatic Transmission (II): 4-8 Speeds)

  • 이경진;김정민
    • 한국기계가공학회지
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    • 제15권5호
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    • pp.57-65
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    • 2016
  • The power flow of an 8-speed automatic transmission was analyzed using a lever analogy for the manufacturing of planetary gears. From the analysis, we found that the engine power was split between the first and second double-pinion planetary gears (DPPG1 and DPPG2), and was then passed to the DPPG3 for the fourth speed. For the fifth speed, the engine power was split between the DPPG1 and DPPG3. For the speeds 6-8, the engine power was passed only to SPPG2, while the seventh speed contained the power circulation.

식물성 절연유 변압기의 냉각특성 변화에 따른 최고점온도 특성 해석 (Characteristic Analysis of Hot Spot Temperature according to Cooling Performance Variation of Natural Ester Transformer)

  • 김지호;이향범
    • 전기학회논문지P
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    • 제64권4호
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    • pp.236-240
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    • 2015
  • Natural ester has a higher biodegradability, flash and fire points, and a greater permittivity compared to conventional mineral oils. However, natural ester also has a higher pour point, viscosity, and water content. These characteristics hamper circulation and the electrical properties of oil-filled transformer. Thus, this paper applied electromagnetic-thermal-flow coupled analysis method to predict temperature distribution inside 154kV single phase power transformer using natural ester. It modeled in the actual appearance for the tank and winding of the power transformer to improve the accuracy of analysis and applied heat flow analysis that considered hydromechanics and heat transfer at the same time. It calculated the power loss, the main cause of temperature rise, from winding and core with electromagnetic analysis then used for the heat source for the heat flow analysis. It then compared the reasonability of result of measurement analysis based on the result acquired from temperature rise test using FBG sensor on the power transformer.