• Title/Summary/Keyword: design low-flow

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Low-Noise Design of Passage of Idle Speed Control Actuator in Automotive Engines Using Scaling Laws for Noise Prediction (소음예측 비례식을 이용한 자동차 엔진 공회전 속도 제어 장치 유로의 저소음 디자인)

  • Cheong, Cheol-Ung;Kim, Jae-Hyun;Park, Yong-Hwan;Lee, Soo-Gab
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.283-290
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    • 2007
  • Recently, plastic products in air-intake parts of automotive engines have become very popular due to advantages that include reduced weight, constricted cost, and lower intake air temperature. However, flow-induced noise in air-intake parts becomes a more serious problem for plastic intake-manifolds than for conventional aluminum-made manifolds. This is due to the fact that plastic manifolds transmit more noise owing to their lower material density. Internal aerodynamic noise from an Idle Speed control Actuator (ISA) is qualitatively analyzed by using a scaling law, which is expressed with some flow parameters such as pressure drop, maximum flow velocity, and turbulence kinetic energy. First, basic flow characteristics through ISA passage are identified with the flow predictions obtained by applying Computational Fluid Dynamics techniques. Then, the effects on ISA passage noise of each design factors including the duct turning shape and vane geometries are assessed. Based on these results, the preliminary low noise design for the ISA passage are proposed. The current method for the prediction of internal aerodynamic noise consists of the steady CFD and the scaling laws for the noise prediction. This combination is most cost-effective, compared with other methods, and therefore is believed to be suited for the preliminary design tool in the industrial field.

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Low-noise Design of Passage of Idle Speed Control Actuator In Automotive Engines Using Scaling Laws for Noise Prediction (소음예측 비례식을 이용한 자동차 엔진 공회전 속도 제어 장치 유로의 저소음 설계)

  • Cheong, Cheol-Ung;Kim, Jae-Hyun;Kim, Sung-Tae;Park, Yong-Hwan;Lee, Soo-Gab
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.8
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    • pp.683-692
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    • 2007
  • Recently, plastic products in air-intake parts of automotive engines have become very popular due to advantages that include reduced weight, constricted cost, and lower intake air temperature. However, flow-induced noise in air-intake parts becomes a more serious problem for plastic intake-manifolds than for conventional aluminum-made manifolds. This is due to the fact that plastic manifolds transmit more noise owing to their lower material density. Internal aerodynamic noise from an idle speed control actuator(ISA) is qualitatively analyzed by using a scaling law, which is expressed with some flow parameters such as pressure drop, maximum flow velocity, and turbulence kinetic energy. First, basic flow characteristics through ISA passage are identified with the flow predictions obtained by applying computational fluid dynamics techniques. Then, the effects on ISA passage noise of each design factors including the duct turning shape and vane geometries are assessed. Based on these results, the preliminary low noise design for the ISA passage are proposed. The current method for the prediction of internal aerodynamic noise consists of the steady CFD and the scaling laws for the noise prediction. This combination is most cost-effective, compared with other methods, and therefore is believed to be suited for the preliminary design tool in the industrial field.

Mechanical Load Performance Measurements of a Low Temperature Differential Stirling Engine with Water-Sprayed Heat Transfer according to Supply Water Flow Rates and Temperatures (스프레이 열전달을 이용한 저온도차 스털링 엔진의 고온수 공급 유량 및 온도에 따른 기계 부하성능 실험)

  • Sim, Kyuho;Jeong, Min-Seong;Lee, Yoon-Pyo;Jang, Seon-Jun
    • The KSFM Journal of Fluid Machinery
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    • v.18 no.1
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    • pp.29-36
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    • 2015
  • Recently, Stirling engines are emerging as a key device for power conversion of renewable energy or waste energy. This study develops a LTDSE(Low Temperature Differential Stirling Engine) using a water spray for higher heat transfer and performs load performance tests for various flow rates and temperatures of hot water spray for variable engine loads emulated by a mechanical friction device. Internal temperature and pressure, working frequency and inlet and outlet temperature of the supply water are measured. As a result, the increases in flow rate and temperature of hot water respectively enhance the power output, efficiency and the working frequency, while the increasing engine load leads to decreases in working frequency but increases in the pressure amplitude. Eventually, it is revealed there exists a maximum shaft power of the test engine.

The Standard of Sump Design in Pump Station (펌프장내 흡수정 설계 기준)

  • Roh, H.W.;Oh, O.S.;Lee, Y.H.
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.589-592
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    • 2005
  • In general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Unfortunately in order to design the sump station, the reasonable code or the standards weren't presented yet in Korea. Thus, some researchers had often referred the HI code, JSME code or CEN code to design the sump station. This study aims to prescribe the standard of sump design which were matched well the Korean pump station. Thus, the HI code and TSJ code would be interpreted fully to Korean language, the part of interpreted clauses of the western codes would be selected to compose the standard.

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Shape Optimization of Axial Flow Fan Blade Using Surrogate Model (대리모델을 사용한 축류송풍기 블레이드의 형상 최적화)

  • Kim, Jin-Hyuk;Choi, Jae-Ho;Kim, Kwang-Yong
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2440-2443
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    • 2008
  • This paper presents a three dimensional shape optimization procedure for a low-speed axial flow fan blade with a weighted average surrogate model. Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model are discretized by finite volume approximations. Six variables from airfoil profile and lean are selected as design variables. 3D RANS solver is used to evaluate the objective functions of total pressure efficiency. Surrogate approximation models for optimization have been employed to find the optimal design of fan blade. A search algorithm is used to find the optimal design in the design space from the constructed surrogate models for the objective function. The total pressure efficiency is increased by 0.31% with the weighted average surrogate model.

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Vortices within a Three-Dimensional Separation in an Axial Flow Stator of a Diagonal Flow Fan

  • Kinoue, Yoichi;Shiomi, Norimasa;Setoguchi, Toshiaki
    • International Journal of Fluid Machinery and Systems
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    • v.4 no.2
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    • pp.262-270
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    • 2011
  • Experimental and numerical investigations were conducted for an internal flow in an axial flow stator of a diagonal flow fan. A corner separation near the hub surface and the suction surface of a stator blade was focused on, and further, three-dimensional vortices in separated flow were investigated by the numerical analysis. At low flow rate of 80% of the design flow rate, a corner separation of the stator between the suction surface and the hub surface can be found in both experimental and calculated results. Separation vortices are observed in the limiting streamline patterns both on the blade suction and on the hub surfaces at 80% of the design flow rate in the calculated results. It also can be observed in the streamline pattern that both vortices from the blade suction surface and from the hub surface keep vortex structures up to far locations from these wall surfaces. An attempt to explain the vortices within a three-dimensional separation is introduced by using vortex filaments.

Landscape Planting Design for Yeoyido Flood Plain Park in Han-river (한강 여의도지구 수변공원 식재설계)

  • 이준복
    • Journal of the Korean Institute of Landscape Architecture
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    • v.31 no.5
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    • pp.86-95
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    • 2003
  • It had been strictly prohibited to plant in waterway according to Korea laws and regulations. It was then made possible to plant by the modification law and regulation of 10/30/1997. In 2000, the Seoul metropolis government planted in the Yeoyido flood plain park in Han river by way of showing the model case. This planting design is for the Yeoyido flood plain park along the Han river, in Seoul. The design requirements were to create a pleasant rest area, to improve the surrounding landscape, and to create diverse ecological habitats by planting within the stability of flood flow. This design emphasizes the following design requirements that has positive effect on stabilizing flood flow. First, planting suitable in a area was determined by the speed of a current of less than 0.7m/sec under various numerical value simulations. Second, plants were selected in existing trees of the present and the past Han river, as well as the questionnaire results from landscape professional engineers and professors. Shade plants were planted in the large visiting areas so as to offer pleasant shade in the summer, the ecological planting pattern was applied in the area with low speed of flood flow, so as to aid the restoration of the natural ecological environment. It was found that the foresaid planting design verified the stability of flood flow and wind by overturn limit moment calculation. It is expected that this plan would serve environmentally friendly planting plans in flood plain park.

Improvement of the Design Process of LID Retrofit Testbed for Effect Analysis of the Water Cycle (LID Retrofit 시범단지 설계 절차 개선)

  • Jung, Jong-Suk;Lim, Jung-Min;Hyun, Kyoung-Hak
    • Land and Housing Review
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    • v.8 no.4
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    • pp.267-274
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    • 2017
  • Since LID design process for the urban regeneration has not yet been established in Korea, this study was extablished in LID design process through reterauture reviews and expert opinions. But the extablished LID design processes have many limitations to be applied to proper LID facilities to the site because of not considering characteristics and water flow of the site. To solve the limitations of existing design processes, it is necessary for analysis of water flow through GIS analysis at the site. After analysis of water flow, it is important to find areas cut off water flow and to install LID facilities at those points. Through these considerations, this study present the improved LID design process to apply to urban regeneration.

ANALYSES ON FLOW FIELDS AND PERFORMANCE OF A CROSS-FLOW FAN WITH VARIOUS SETTING ANGLES OF A STABILIZER

  • Kim D. W.;Kim H. S.;Park S. K.;Kim Youn J
    • Journal of computational fluids engineering
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    • v.10 no.1
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    • pp.107-112
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    • 2005
  • A cross-flow fan is generally used on the region within the low static pressure difference and the high flow rate. It relatively makes high dynamic pressure at low rotating speed because a working fluid passes through an impeller blade twice and blades have a forward curved shape. At off-design points, there are a rapid pressure head reduction, a noise increase and an unsteady flow. Those phenomena are remarkably influenced by the setting angle of a stabilizer. Therefore, it should be considered how the setting angle of a stabilizer affects on the performance and the flow fields of a cross-flow fan. It is also required to investigate the effect of the volumetric flow rate before occurring stall. Two-dimensional, unsteady governing equations are solved using a commercial code, STAR-CD, which uses FVM. PISO algorithm, sliding grid system and standard k - ε turbulence model are also adopted. Pressure and velocity profiles with various setting angles are graphically depicted. Furthermore, the meridional velocity profiles around the impeller are plotted with different flow rates for a given rotating speed.

Fabrication and Performance Demonstration of the 20kW Class Inverted-type Cross-flow Turbine Based on Computational Fluid Dynamics Analysis (전산유체역학 해석에 기반한 20kW급 도립형 횡류수차의 제작 및 성능 실증)

  • Ham, Sangwoo;Choi, Ji-Woong;Jeong, Changho;Kim, Taeyun;Choi, Sangin;Jin, Glenn Young;Lee, Jeong Wan;Ha, Hojin
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.2
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    • pp.107-119
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    • 2021
  • The cross-flow turbine is one of the most famous and widely used hydraulic power systems for a long time. The cross-flow turbine is especially popular in many countries and remote regions where off-grided because of its many benefits such as low cost, high efficiency at low head, simple structure, and easy maintenance. However, most modern turbines, including the cross-flow turbine, are unsuitable for the ultra-low head situation, known as less than 3m water head or zero head with over 0.5m/s flow velocity. In this study, we demonstrated a 20kW class inverted-type cross-flow turbine's performance. First, we reevaluated our previous studies and introduced how to design the inverted-type cross-flow turbine. Secondly, we fabricated the 20kW class inverted-type cross-flow turbine for the performance test. And then, we designed a testbed and installed the turbine system in the demonstration facility. In the end, we compare the demonstration with its previous CFD results. The comparing result shows that both CFD and real model fitted on guide vane angle at 10 degrees. At the demonstration, we achieved 42% turbine efficiency at runner speed 125 RPM.