• 제목/요약/키워드: diffuser

검색결과 790건 처리시간 0.026초

과급기의 고압력비 원심압축기 공력설계 및 시험평가 (Performance Test and Aerodynamic Design on the High Pressure Ratio Centrifugal Compressor of a Turbocharger)

  • 김홍원;류승협;이근식
    • 한국유체기계학회 논문집
    • /
    • 제17권6호
    • /
    • pp.13-20
    • /
    • 2014
  • It is necessary to design a compressor with high pressure ratio that satisfies the IMO(international maritime organization) NOx emission regulation for the marine diesel engine. Impeller was designed using the modified slip factor with the flow coefficient. The main purpose of this study is to investigate the sensitivity of the compressor performance by the vaned diffuser geometries. The first vaned diffuser type was based on a NACA airfoil, the second was channel diffuser, and the third was conformally transformated configuration of a NACA65(4A10)06 airfoil. The sensitivity of the performance was calculated using a commercial CFD program for three different diffuser geometries. The channel diffuser showed the wide range of operation and higher pressure characteristics, comparing with the others. This is attributed to the flow stability at diffuser. Combined with this results with impeller design, the optimized compressor was designed and verified by the test results.

산기식 물순환장치 설계인자 연구: 현장 댐 조건을 고려한 CFD 해석 중심 (A Study on Design Factors of Air Diffuser Systems in Reservoirs: Application of Field Conditions to the CFD Simulation)

  • 신상민;이승재;이상은;박희경;염경택
    • 상하수도학회지
    • /
    • 제25권2호
    • /
    • pp.161-169
    • /
    • 2011
  • This study aims at examining the design factors of the air diffuser system in a particular view of field conditions, and thus improving the procedures currently applied to design the system. First, the CFD model is built for an air diffuser system suitable for field conditions of real reservoirs. Then, the design factors, including destratification number, destratification radius and efficiency of the air diffuser system, are analyzed after a series of simulations over various field conditions. The result shows successful correlations of design factors with DN at the condition, and they lead to estimate of the destratification radius and efficiency of air diffuser system based on DN. It is finally concluded that the design factors are improved such that the air diffuser system is suitable for the field conditions of dam reservoirs.

Center Body 위치와 Cone 각도에 따른 Center Body Diffuser의 유동특성 및 시동에 대한 수치적 연구 (A Numerical Study of the Flow Characteristics and Starting Pressure of a Center Body Diffuser According to the Center Body Position and Cone Angle)

  • 이성훈;박진;김홍집
    • 한국추진공학회지
    • /
    • 제23권5호
    • /
    • pp.10-18
    • /
    • 2019
  • Center Body Diffuser (CBD)의 Center Body (CB) 형상에 의한 유동 특성 및 시동압력을 해석하였다. CB 위치와 Cone 각도의 변경을 통해 초음속 유동 특성 및 시동압력을 비교하였다. CB 위치를 변수로 하여 Diffuser 해석한 결과, 유동의 모멘텀의 형성에 따라 강한 경사충격파의 발생위치가 달라지는 것을 확인하였다. 또한 경사충격파가 발생할 경우, 초음속 유동의 방향이 디퓨저 벽면으로 유도되는 것을 확인하였다. Cone 각도 변화에 따른 경사충격파의 각도 차이로 인하여, CBD의 시동압력이 영향을 받는 것을 확인하였다.

New Diffuser Film Using Coating Technology for LCD Backlight

  • Hwang, Hee-Nam;Choi, Woong-Hyun;Lee, Ki-Ho;Kim, In-Sun
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
    • /
    • pp.1066-1067
    • /
    • 2004
  • New diffuser film for LCD backlight is developed. A diffuser film was manufactured through coating UV curable monomer on a plastic film. The diffuser layer coated on plastic film showed excellent optical transmittance.

  • PDF

원심압축기용 베인디퓨져의 탈설계점 성능연구 - 제1부 : 채널디퓨져 - (Investigation of Off-Design Performance of Vaned Diffusers in Centrifugal Compressors - Part I : A Channel-Wedge Diffuser -)

  • 오종식;현용익
    • 유체기계공업학회:학술대회논문집
    • /
    • 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
    • /
    • pp.83-90
    • /
    • 2001
  • Experimental and numerical investigations of the off·design performance of a simple channel-wedge diffuser in a small centrifugal compressor are presented. Surge and choke conditions as well as design point are considered using somewhat limited range of experimental data and also supplementary 3D CFD results. Some critical meanline design parameters' behavior is investigated numerically, to render the basis for improved modelings in the meanline performance prediction.

  • PDF

배기 매니폴드 확관부 형상 최적화에 관하여 (About the Shape Optimization of Ex-Manifold Diffuser)

  • 조석현
    • 대한기계학회논문집B
    • /
    • 제28권9호
    • /
    • pp.1133-1138
    • /
    • 2004
  • Shape optimization method was coupled with a conventional CFD analysis to find the optimal shape of ex-manifold diffuser which decreases the maldistribution of flow above the catalyst. Shape optimization results show that flow uniformity above the catalyst was increased about 28% fur the axi-symmetric case and about 18% for the asymmetric case. The axi-symmetric type can be applied to the diffuser of under floor catalyst and the asymmetric type can be applied to the diffuser of close coupled catalyst.

정지수체로 방류된 연직다중\ulcorner㈏\ulcorner최소희석률 (Minimum Dilution of Vertical Multijet Discharging into Stagnant Water)

  • 김홍식;서일원;유대영;서용원
    • 한국수자원학회논문집
    • /
    • 제32권2호
    • /
    • pp.153-162
    • /
    • 1999
  • 본 연구에서는 정지수체에서 다공확산관을 통해 방류된 연직다중의 혼합 및 희석 특성에 대해 규명하였다. 3차원 실험수조에서 실험을 통해 밝혀진 결과는 다음과 같다. 우선 다공확산관의 병합과정을 살펴보면 흐름의 안정조건에 따라 병합거리가 다소 차이가 있기는 하지만 {{{{ { z}_{ } }}}}/{{{{ {l}_{ } }}}}가 대략 3인 지점부터 병합이 시작되어 그 이후에는 평면부력?의 거동에 서서히 가까워짐을 알 수 있다. 최소희석률에 대해 분석해 본 결과, 방류운동량이 지배적인 영역, 천이영역, 그리고 부력이 지배적인 부력류영역으로 나누어 희석률 특성을 표현할 수 있음을 알 수 있었다. 본 연구의 실험결과 다공확산관의 경우 부력류영역의 희석률 상수가 평면확산관에 비해 15% 더 높게 나왔다. 그 이유는 다공확산관의 경우 병합 이전에는 개별의 경계면에서 주변수의 포획이 발생하여 희석이 증대되기 때문이다.

  • PDF

노즐-디류저 내에서의 저 Reynolds수 해독특성 해석 (Analysis of Low Reynolds Number Flow in Nozzle and Diffuser)

  • 송귀은;이준식
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2007년도 춘계학술대회B
    • /
    • pp.2672-2677
    • /
    • 2007
  • An investigation of low Reynolds number flow in nozzles and diffusers which are widely used in the valveless micropump is presented. Flow characteristics in the nozzle and diffuser are explained in view of viscous effect and flow oscillation induced by pumping membrane. These calculation results show that the rectification property of valveless micropump is due to a flow separation in the diffuser and the separation is largely originated from the flow oscillation. Under the assumptions of steady flow velocity profile and flow separation in the diffuser, simplified analytical models are provided to see the dependency of rectification on the micropump geometry. Geometric parameters of channel length, nozzle throat, chamber size, and converging/diverging angle are depicted through the analytical models in low Reynolds number flow, and the prediction and experimental results are compared. This theoretical study can be used to determine the optimum geometry of valveless micropump.

  • PDF

디퓨져/노즐을 이용한 압전형 마이크로 펌프의 입 . 출구 형상 차이에 따른 유동특성에 관한 수치해석적 연구 (Numerical Analysis about the Flow Characteristics for Different Figures of Inlet and Outlet in Diffuser/Nozzle based on Piezoelectric Micropump)

  • 김창녕;김진욱
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2007년도 춘계학술대회B
    • /
    • pp.3104-3109
    • /
    • 2007
  • The present study has been carried out to investigate the pumping characteristics for different figures of inlet and outlet in diffuser/nozzle based on piezoelectric micropump. Piezoelectric micropump system consists of several parts like a pumping chamber, diffuser/nozzle, piezoelectric element and tubes. Parts of the micropump connected with diffuser/nozzle and tubes have been analyzed.. The magnified parts have been classified into two different models based on their resistance. These models have been further classified into six models with each one having three different angles at the magnified parts. Each model has been compared and analyzed using the simulation tool, namely, CFD-ACE depending on their flow rates and characteristics.

  • PDF

전자파 잔향실 내의 필드 균일성 확보를 위한 Shroeder 방식의 Diffuser 설계 (Design of Schroeder Method Diffusers To obtain Field Uniformity Characteristics of Reverberation Chamber)

  • 이광순;이중근;정삼영;김혜광
    • 한국음향학회:학술대회논문집
    • /
    • 한국음향학회 2000년도 하계학술발표대회 논문집 제19권 1호
    • /
    • pp.211-214
    • /
    • 2000
  • 본 논문은 전자파 장해 및 복사내성 측정의 대용 시험시설로 활용될 수 있는 전자파 잔향실의 전자기장 특성에 관하여 연구하였다. 전자파 잔향실 내부 균일성을 확보하기 위하여, 음향효과의 극대화를 위해 인간의 가청 주파수대인 16-20,000Hz 범위, 음속(340 m/sec)에 적용하여 활용되고 있는 Shroeder Quadratic Residue Diffuser를 무선 주파수 대역 30 KHz -3 THz인 범위로 확장, 3가지 형태의 Diffuser를 설계하여 잔향실 내부에 적용하였다. FDTD(Finite-Difference Time-Domain) 수치해석 방식을 이용하여 잔향실 내부의 필드 특성을 조사한 결과 Diffuser를 부착한 3 가지 형태 모두 치대 tolerance $\pm$3dB 이내의 필드 균일도를 나타내었으며, Type 3, 대칭형 구조의 Diffuser 형태가 효율이 가장 우수하다는 결과를 나타내었다.

  • PDF