http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
공동현상 가시화 실험을 통한 절환밸브 바텀플러그 형상 최적화
김태안(Tae An Kim),이명곤(Myeong Gon Lee),한승호(Seung Ho Han) 대한기계학회 2016 大韓機械學會論文集A Vol.40 No.11
자동차 엔진과 변속기 블록 등의 가공과정에서 잔류하는 기름때를 제거하기 위한 부품 세척장비는 정교한 제어장치 없이도 정확한 수류방향 절환이 원활히 이루지는 3 방향 절환밸브를 사용한다. 그러나, 밸브의 복잡한 유로 및 바텀플러그 형상으로 인해 유속변화가 심하게 발생하여 공동현상이 나타날 수 있다. 본 연구에서는 3 방향 절환밸브 내의 유동특성을 해석적으로 평가하였으며, 바텀플러그 하부에서 나타나는 공동현상을 공동화지표와 POC(Percent of cavitation)를 도입하여 정량화하였다. 공동현상의 저감을 위해 바텀플러그 형상을 매개변수화하고, 해석의 수렴성 개선과 해석시간을 단축시킬 수 있는 단순 유한요소모델을 이용하여 유동해석을 통한 형상최적설계를 실시하였다. 또한, 연구팀에서 보유하고 있는 유동시험설비와 ISA-RP75.23 규격에 맞게 제작된 시편을 이용하여 공동현상 가시화 실험을 실시하여 해석결과를 검증하였다. A three-way reversing valve, which provides rapid and accurate changes in the water flow direction without requiring any precise control device, is used in automotive washing machines to remove oil and dirt that remain on the machined engine and transmission blocks. Because of the complicated shape of the bottom-plug, however, cavitation occurs in the plug. In this study, the cavitation index and POC (percent of cavitation) were used to quantitatively evaluate the cavitation effect occurring in the bottom-plug on the downstream side. An optimal shape design was conducted via parametric study with a simple CAE model to avoid time-consuming CFD analysis and hard-to-achieve convergence. To verify the results of the numerical analysis, a flow visualization test was conducted using a specimen prepared according to ISA-RP75.23. In this test, the flow characteristics, such as cavitation occurring on the downstream side, were investigated using flow test equipment that included a valve, pump, flow control system, and high-speed camera.
직분식 가솔린 엔진에서 피스톤 캐비티 반경에 따른 연료 거동 분석
김태안(Tae-An Kim),강정중(Jeong-Jung Kang),김덕줄(Duck-Jool Kim) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
This study was performed to investigate the behavior of vapor phase of fuel mixtures with different piston<br/> cavity diameters in a optically accessible engine. The images of vapor phases were measured in the motoring<br/> engine using exciplex fluorescence method. The conventional engine was modified as GDI engine with swirl<br/> flow. Fuel was injected into atmospheric nitrogen to prevent quenching phenomenon by oxygen. Injection<br/> pressure is 5.1MPa. Two dimensional spray fluorescence image of vapor phases was acquired to analyze spray<br/> behavior and fuel distribution inside of cylinder. Three injection timings were set at BTDC 180°, 90°and<br/> 60°. With a fuel injection timing of BTDC 60°, fuel-rich mixture was concentrated in near the cavity<br/> center. With a fuel injection timing of BTDC 90°, fuel-rich mixture level in the center region was highest in<br/> the S-type during the late compression stroke. With a fuel injection timing of BTDC 180°, fuel was not<br/> affected in a piston cavity and generally distributed as homogeneous mixture.
김태안(Tae An Kim),이광기(Kwang Ki Lee),김형우(Hyung Woo Kim),한승호(Seung Ho Han) 대한기계학회 2018 大韓機械學會論文集A Vol.42 No.1
API 609는 배관 사이에 설치되는 버터플라이밸브의 구매사양을 규정하는 가장 널리 사용되는 국제적인 코드로서, ASME 코드에서 정의하고 있는 구조상세, 세부 치수, 비파괴검사 및 성능시험을 인용하고 있다. 관련 기업이 선박해양 플랜트 시공 및 설계시 요구되는 사양을 만족하는 버터플라이밸브를 생산하는 경우, 상기한 코드에서 제공하는 설계지침에 따라 제품을 설계, 생산하여야 한다. 본 연구에서는 API 609 코드를 분석하여 재료의 선정과 형상치수를 정의하고, 코드에서 제시하고 있는 경계조건과 응답적합성을 확인하여 설계 프로세스를 개발하였다. 총 7단계로 이루어진 설계 프로세스는 Python script로 구현되어 자동화되었으며, Rhinoceros Grasshopper 기반의 Xml-template를 이용하여 3차원 CAD 파일이 생성되었다. 개발된 설계 프로세스의 자동화 과정을 통해, 버터플라이밸브의 3차원 CAD을 손쉽게 생성할 수 있으며, 아울러 유한요소 모델의 전처리과정이 대폭 생략된 CAE 해석이 가능하였다. API standard 609 provides a purchase specification for butterfly valves designed for installation between flanges, as defined in several ASME codes, which specify certain details, the features and nondestructive requirements including testing. If industries want to manufacture butterfly valves meeting standards as demanded by the plant engineering market, they should follow the design guidelines provided in the related API and ASME codes. In the present study, the design process of the butterfly valve according to API standard 609 was developed and implemented to create a 3-dimensional feature of the butterfly valve. This can be utilized in CAE analysis without any complicated pre-process of FE-modeling. The design process consists of seven steps, from the selection of class to the determination of the maximal disc diameter. Each step can be automated by using the Python script. Consequently, CAD data of the designed butterfly valve can be created using Xml-templates on the basis of a Grasshopper in Rhinoceros.
전기삼투효과를 이용한 미세혼합기 혼합 특성에 관한 연구
김태안(Tae-An Kim),김윤제(Youn J. Kim) 한국유체기계학회 2008 유체기계 연구개발 발표회 논문집 Vol.2008 No.-
In order to achieve the fast mixing, new type electrokinetic mixer wth Tr type channel is introduced. It takes two fluids from inlets and combines them into a single channel. The fluids then enter the mixing chamber with the different inner and outer radii. Electric potentials on the four microelectrodes are sinusoidal in time with two different maximum voltage of 0.1 V and 0.2 V, and frequency 4 ㎐ and 8 ㎐. Zeta potential of -0.1 V and -0.2 V is used. Working fluid is water and each inlet had different initial concentration values. The incompressible Navier-Stokes equation is solved in the channel, with the slip boundary condition on the inner and outer walls of the mixing chamber. Convection-diffusion equation is used to describe the concentration of the dissolved substances in the fluid. The pressure, concentration and flow fields in the channel are calculated and results are graphically depicted with various flow and electric conditions.
직분식 가솔린 기관에서 혼합기 형성에 미치는 분사시기와 캐비티의 영향
김태안(Tae-an Kim),강정중(Jeong-jung Kang),김덕줄(Duck-jool Kim) 한국자동차공학회 2003 한국자동차공학회 지부 학술대회 논문집 Vol.2003 No.10
This study was performed to. investigate the behavior of liquid and vapor phase of fuel mixtures with different piston cavity diameters in a optically accessible engine. The conventional engine was modified as DI gasoline engine with swirl flow. Fuel was injected into atmospheric nitrogen to prevent quenching phenomenon by oxygen. Injection pressure is 5.1 MPa. Two dimensional spray fluorescence image of vapor phases was acquired to analyze spray behavior and fuel distribution inside of cylinder. Three injection timings were set at BTDC 180˚ , 90˚ and 60˚ . The results obtained are as follows. With a fuel injection timings of BTDC 60˚ , fuel-rich mixture was concentrated in near the cavity center. With a fuel injection timings of BTDC 90˚ , fuel-rich mixture level in the center region was the highest in S-type(d/D = 0.35). With a fuel injection timings of BTDC 180˚ , fuel was not affected in a piston cavity and generally distributed as homogeneous mixture in the cylinder.