• Title, Summary, Keyword: Inlet Part

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평행류 열교환기의 헤더부 형상 최적화

  • 오석진;이관수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.10
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    • pp.1017-1024
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    • 2001
  • The optimum shape of header part in a PFHE (parallel-flow heat exchanger) is studied. The optimal values of each geometric parameter are proposed according to their order of influence with varying the four important parameters (the injection angle of working fluid ($\Theta$), the shape of inlet(S), the location of inlet ($y_c/D_{in}$) and the height of the protruding flat tube ( $y_{b/}$ $D_{in}$ )). The optimal geometric parameters are as follows:$\Theta= -21^{\circ}C,\; S=Type\; A \;an\;y_b/D_{in}$/=0. The heat transfer rate of the optimum model, compared to that of the reference model, is increased by about 55%. The optimal geometric parameters ran be applicable to the Reynolds number ranging from 5,000 to 20,000.0.

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A Numerical Study on Axial Inlet Cyclone for Diesel Engine (디젤 엔진용 싸이클론 내부 수치 해석)

  • Kim, S.K.;Son, C.S.;Kim, I.K.
    • Journal of the Korea Society For Power System Engineering
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    • v.10 no.2
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    • pp.16-21
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    • 2006
  • On this study, numerical analysis was performed for the 3 dimensional flow field of gas and particle phase for axial inlet cyclone, a part of dust collector. We applied FVM to visualize the gas phase. The flow was solved using ${\kappa}-{\varepsilon}$ turbulence model. The major parameters considered in this study were helical guide vane, inner diameter, length. Particle trajectory calculations were performed for the particle sizes of $5{\mu}m{\sim}75{\mu}m$. The distribution curve of particle sizes was made of Rosin-Rammler function. The simulation results show various gas flows, particle trajectories on numerical models.

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Internal Flow of a Two-Bladed Helical Inducer at an Extremely Low Flow Rate

  • Watanabe, Satoshi;Inoue, Naoki;Ishizaka, Koichi;Furukawa, Akinori;Kim, Jun-Ho
    • International Journal of Fluid Machinery and Systems
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    • v.3 no.2
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    • pp.129-136
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    • 2010
  • The attachment of inducer upstream of main impeller is an effective method to improve the suction performance of turbopump. However, various types of cavitation instabilities are known to occur even at the designed flow rate as well as in the partial flow rate region. The cavitation surge occurring at partial flow rates is known to be strongly associated with the inlet back flow. In the present study, in order to understand the detailed structure of internal flow of inducer, we firstly carried out the experimental and numerical studies of non-cavitating flow, focusing on the flow field near the inlet throat section and inside the blade passage of a two bladed inducer at a partial flow rate. The steady flow simulation with cavitation model was also made to investigate the difference of flow field between in the cavitating and no-cavitating conditions.

The characteristics of static pressure recovery in a conical diffuser with a swirling flow (선회류 유입에 대한 원추디퓨저의 정압회복 특성)

  • Jeong, Hyo-Min;Jeong, Han-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.7
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    • pp.937-945
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    • 1998
  • The purpose of this paper is to investigate the relationship between pressure recovery and turbulent characteristic value of velocity and pressure, in the case where a swirling flow streams into a conical diffuser. The results of both measurements of the wall pressure fluctuation and velocity fluctuation revealed them to role the large part of the total pressure loss of the flow. The cause of the fluctuation of flow was showed to be the flow separation at the inlet of diffuser at low intensity of swirl, but the flow of diffuser center was instable at high intensity of swirl. The static pressure recovery depends strongly on the magnitude of the turbulent energy in the diffuser, and that this magnitude of the turbulent energy varies as the intensity of swirl at the diffuser inlet.

Evaluation of Component Performance of a Commercial Micro Gas Turbine (상용 마이크로 가스터빈의 구성부 성능분석)

  • Lee, J.J.;Yun, J.E.;Kim, T.S.
    • 유체기계공업학회:학술대회논문집
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    • pp.331-337
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    • 2005
  • This study aims at evaluation of component performance of a commercial micro gas turbine by detailed measurements of various system parameters. A test facility to measure performance of a micro gas turbine was set up. Performance parameters such as turbine exit temperature, exhaust gas temperature, engine inlet temperature, compressor discharge pressure and fuel flow rate were measured. Variations in measured data and estimated performance parameters were analyzed. In addition to overall engine performance, component characteristic parameters including the turbine inlet temperature, the compressor efficiency, the turbine efficiency, the recuperator effectiveness were estimated. Behaviors of the estimated characteristic parameters with operating condition change were examined.

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Application of Generalized Experimental Data Correlation in Centrifugal Compressor Design (원시험 데이터 일반화를 적용한 원심압축기 설계)

  • Cho, Gyu-Sik;Kim, Jin-Han;Yang, Soo-Seok;Lee, Dae-Sung;Mileshin, Victor I.
    • The KSFM Journal of Fluid Machinery
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    • v.3 no.4
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    • pp.38-43
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    • 2000
  • Recently, KARI(Korea Aerospace Research Institute, Korea) and CIAM(Central Institute of Aviation Motors, Russia) have made an effort in developing a centrifugal compressor for a small gas turbine engine as part of a collaboration program. This compressor has been designed as a sub-component for an axial-centrifugal compression system for a small turbo-shaft engine aiming adiabatic efficiency higher than 0.81. The geometrical design requirement imposes restrictions to have high inlet hub-to-tip ratio and inlet swirl flow. In this study, the compressor has been designed using the generalized experimental data established from those compressors having pressure ratio of 3.7 to 5. From this generalized empirical correlation, desirable values of design parameters could be obtained. Subsequently, quasi-3D and 3D viscous flow analyses have been performed to ensure the adopted methodology. It is expected that the centrifugal compressor provides total pressure ratio of 4.89, corrected mass flow-rate of 1.64kg/sec, and adiabatic efficiency of 0.815 with inlet hub-to-tip ratio of 0.641. These relatively high total pressure ratio and inlet hub-to-tip ratio are the main distinctive features in this design. Besides, one of the main features of this centrifugal compressor is the adoption of a double-row bladed diffuser to effectively decelerate the transonic flow leaving the impeller. The compressor has been manufactured and will be tested in the near future.

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Investigation of Flow and Heat Transfer Characteristics of Plate Heat Exchanger Taking into Account Entrance Effects and Variation in Corrugation Height (입구영향 및 주름높이의 변화를 고려한 판형열교환기의 유동 및 열전달 특성)

  • Moh, Jeong-Hah
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.11
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    • pp.965-973
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    • 2010
  • Numerical analysis has been carried out to investigate the heat transfer characteristics of a plate heat exchanger. The multi-cell models with inlet part and outlet part are used for performing numerical simulation. The plate heat exchanger is characterized by chevron angle of $15^{\circ}$, corrugation pitch of 24mm and corrugation height 6~12mm. The length of the inlet-part considered in the analysis ranges from 24.8 to 124mm and Reynolds numbers range from 1,000 to 10,000. The correlations such as friction factor and Colburn factor are compared with previous experimental data. The results can be utilized for designing the plate heat exchanger.

Optimization of Injection Molding of Bobbin Part based on CAE (CAE를 이용한 보빈 성형품의 사출성형 최적화)

  • Kwon, Y.S.;Cho, Y.S.;Kim, B.G.;Min, B.H.;Jeong, Y.D.
    • Journal of the Korea Society For Power System Engineering
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    • v.6 no.2
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    • pp.68-72
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    • 2002
  • Design of experiment was applied to analyze the shrinkage characteristics of the bobbin molded by injection molding. Among lots of design and processing conditions, the thickness of a bobbin and cooling conditions of a mold were considered. The temperature difference between top and bottom parts of the bobbin was considered as the objective to minimize the shrinkage of a bobbin. Optimal thickness of a bobbin was 2.0mm at the part of body and 1.5mm at the part of wing, respectively. Optimal cooling conditions such as cooling time and coolant inlet temperature were 12 second and $12^{\circ}C$, respectively.

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A Design Study of Aerodynamic Noise Reduction in Centrifugal Compressor Part I : Performance Analysis and Noise Prediction (원심압축기의 공력소음 저감에 관한 설계연구 Part I : 성능해석 및 소음예측)

  • Sun, Hyosung;Lee, Soogab
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.9
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    • pp.785-791
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    • 2004
  • The objective of this research is to suggest anoise prediction method for a centrifugal compressor. It is focused on the Blade Passing Frequency component which is regarded as the main part of the rotating impeller noise. Navier-Stokes solver is used to simulate the flow-field of the centrifugal compressor, and the time-dependent pressure data are calculated to perform the near-field noise prediction by using Ffowcs Williams - Hawkings formulation. Indirect Boundary Element Method is applied to consider the noise propagation effect. Pressure fluctuations of the inlet and the outlet in the centrifugal compressor impeller are presented and the sound pressure level prediction results are compared with the experimental data.

Disposable Microfluidic Infusion Pump using Elastomeric Blister Actuator (탄성 블리스터 액츄에이터를 이용한 일회용 미세유체 주입펌프)

  • Jang, Woong Ki;Kim, Hyung Jin;Kim, Byeong Hee;Seo, Young Ho
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.22 no.2
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    • pp.235-240
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    • 2013
  • This paper presents a disposable microfluidic infusion pump using the restoring force of elastomeric membrane of Polydimethylsiloxane. Microfluidic infusion pump consists of hydraulic resistance control part, elastomeric blister actuator part, drug inlet and outlet. Expanded elastomeric blister actuator continuously pushes liquid in the chamber to outlet. At same time, microchannel diameter near the outlet was controlled by thin elastomeric membrane in hydraulic resistance control part. Eventually flow rate of infused liquid is controlled by air pressure. In experimental study, the amount of the filled liquid in the blister is precisely controlled by the height of the blister. Flow rate of infused liquid could be controlled, that is, controlled release of the drug over time was possible by adjusting hydraulic resistance and restoring pressure with the blister actuator.