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Cavitating venturi의 유량공급 특성에 관한 연구
강동혁(Donghyuk Kang),안규복(Kyubok Ahn),임병직(Byoungjik Lim),한상훈(Sanghoon Han),최환석(Hwan-Seok Choi),서성현(Seonghyeon Seo),김홍집(Hongjip Kim) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.5
본 연구에서는 하류의 압력 변동이 있을 때 cavitating venturi에 의한 유량 제어 성능을 평가하였다. 이를 위해 액체로켓엔진 연소시험설비에 적용할 cavitating venturi를 설계, 제작하였다. Cavitating venturi에 대한 실험과 수치해석을 수행하여 유량 특성을 분석하고 그 결과를 제시하였다. The flow rate control through cavitating venturi with downstream pressure fluctuation has been investigated. A set of cavitation venturies for a liquid rocket engine thrust chamber firing test facility have been designed and fabricated. The flow characteristics of the cavitation venturies have been investigated by experiment and computational analysis and the results have been presented.
황종빈,신이수,김주하 한국가시화정보학회 2023 한국가시화정보학회지 Vol.21 No.1
In this study, we investigate the effects of a single roughness element on Venturi cavitation. The single roughness element of hemispherical shape is installed at the throat inlet of a Venturi tube. Since the wake behind the roughness element induces an additional pressure drop, cavitation inception occurs at a higher Cavitation number for the Venturi model with the single roughness element than for the Venturi model with no roughness. Cavitation bubbles form along the wake of the roughness element and lengthen in the streamwise direction as the Cavitation number decreases, forming a longitudinal cavitation. With a further decrease in the Cavitation number, the longitudinal cavitation bubble merges with the sheet cavitation initiated from the exit edge of the Venturi tube throat, followed by the shedding of cloud cavitation. The merging of the longitudinal cavitation and sheet cavitation is accompanied by a sudden decrease in the discharge coefficient and an increase in the pressure loss coefficient as it chokes the flow inside the Venturi tube.
황종빈,신이수,김주하 한국가시화정보학회 2023 한국가시화정보학회지 Vol.21 No.2
In this study, we investigated how the performance of a Venturi changes when a hemispherical bump is applied to the divergent part of the Venturi tube and what causes the performance difference. The Venturi-tunnel experiment was conducted in the Reynolds number range of 0.2 × 105 – 1.2 × 105 and cavitation number range of 0.9 – 10. The bump was found to reduce the pressure loss coefficient and increase the discharge coefficient by shortening the cavitation length. The decrease in the cavitation length by the bump was explained by the strengthening of the re-entrant jet. The wake generated from the hemispherical bump seems to increase the adverse pressure gradient on the Venturi surface, thereby strengthening the re-entrant jet.
액체로켓엔진 연소시험설비에서의 캐비테이션 벤튜리 유량공급 특성
강동혁(Donghyuk Kang),안규복(Kyubok Ahn),임병직(Byoungjik Lim),한상훈(Sanghoon Han),최환석(Hwan-Seok Choi),서성현(Seonghyeon Seo),김홍집(Hongjip Kim) 한국추진공학회 2014 한국추진공학회지 Vol.18 No.3
The flow rate control of a cavitating venturi has been investigated with downstream pressure variation. A set of cavitating venturies for a liquid rocket engine thrust chamber firing test facility have been designed and manufactured. The flow characteristics of the cavitating venturies have been analyzed by experimental and computational methods. Results showed that constant mass flow rate condition was established by the cavitation inside the venturi. However, upstream pressure less than the actual design pressure of the cavitating venturi could not supply a constant flow rate.
Hee Jin Hwang,Jae Hyun Park,민준기 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.4
A cavitating venturi in the auxiliary feed water system of a nuclear power plant is a flow control device that limits the maximum flow rate in critical conditions. In this research, a numerical study was conducted to predict the characteristics of the cavitating flow in a venturi with various geometrical configurations. Assuming axisymmetric geometry and a steady state, equations of the flow field were solved numerically. The mixture model for the multi-phase flow and the standard k-ε turbulence model were adopted. The primary diffuser angle was varied to perform detailed parametric study. The flow and pressure variations, shape of the cavitation bubble, and corresponding flow control characteristics were summarized. Finally, the calculation results were analyzed to provide a physical basis for the design limits proposed in a previous patent. It is expected that the results of this study will be useful information for the future design of an optimized venturi.
윤원재(Wonjae Yoon),안규복(Kyubok Ahn) 한국추진공학회 2015 한국추진공학회지 Vol.19 No.4
A cavitation venturi is a device that allows a liquid flow rate to be fixed or locked independent of a downstream pressure and has been successfully used in a liquid rocket engine system which requires a stable propellant flow rate. In the present research, four cavitation venturis which have same dimensions except for converging inlet angle and diverging outlet angle, were designed and manufactured. Flow rates through each venturi and upstream/downstream pressures were measured by changing the pressures. From the experimental data, the discharge coefficients and critical pressure ratios were calculated for each venturi. It was found that the inlet and outlet angles of the cavitation venturi affected the discharge coefficient, and the outlet angle influenced on the critical pressure ratio.
윤정의(Jeong Eui Yun),김주호(Joo Ho Kim) 대한기계학회 2014 大韓機械學會論文集B Vol.38 No.10
본 연구는 벤츄리 시스템을 미세기포 생성을 위한 공기공급 장치로 개발하는데 그 목표를 두고 수행하였다. 이를 위해 상용유동해석 프로그램인 ANSYS CFX-15를 사용한 전산 유동해석을 통해 기하학적 형상변화가 벤츄리 관 내 유동특성들에 미치는 영향을 규명하였다 그리고 공급공기를 공급하는 공기 공급관의 위치, 크기, 개수 등을 변수로 2-유체 유동 해석을 수행하여 이들 설계 값들이 공기 공급특성에 미치는 효과를 규명하였다. 최종적으로 직경 비 =0.75의 벤츄리 확대관이 시작되는 위치에 공기 공급 구멍을 설치할 경우 가장 많은 공기가 벤츄리 관으로 유입되는 것을 확인할 수 있었으며, 유입공기 공급구멍 개수 및 직경과 벤츄리 관 내 공급되는 공기량 사이에는 선형적인 관계가 성립됨을 확인하였다. This study was conducted with the aim of developing a venturi-type air supply system for a microbubble generator. In order to determine the influence of the varying geometry of the venturi tube on the flow characteristics, a computational fluid dynamics (CFD) simulation was performed using the commercial CFD software ANSYS CFX-15. Furthermore, in order to elucidate the effects of variation in major design dimensions such as the air supply hole size, position of holes, and number of holes on the air supply characteristics, two-phase multiflow CFD analysis was performed. The analysis results showed that the starting point of expansion on the venturi tube with 0.75 is the best hole position and that the air supply hole size and the number of holes are linearly proportional to the amount of air.
다공성 재질의 목을 가진 벤츄리 관 공기방울 발생장치의 설계를 위한 유동해석
윤정의(Jeong-Eui Yun) 대한기계학회 2016 大韓機械學會論文集B Vol.40 No.10
본 연구는 다공성 재질의 목을 가진 벤츄리관 공기방울 발생장치의 설계를 위해 수행되었다. 주어진 공급 유량 조건 하에서 다공성 재질을 통해 공급되는 공기방울의 공급 성능 최대화를 위한 벤츄리관의 길이와 직경을 결정하기 위해 2상 전산유동해석에 기초한 최적화 설계를 수행하였다. 이러한 일련의 연구 수행 결과를 통해 다공성 재질을 통해 공급되는 공기방울의 공급 성능 최대화를 위한 공급유량과 이들 설계변수들 관계를 규명하였다. The goal of this study was to develop a venturi-type air bubble generator with a porous material throat. Using the two-phase multi-flow CFD analysis for the venturi tube, researchers determined the optimal design of major dimensions, such as the venturi throat length and diameter, in order to control the performance of the air bubble supply through the porous material throat in a venturi tube. Researchers then determined the relationship between the flow rate of supply water and the major design dimensions of the venturi-type air generator for maximizing the performance of the air bubble supply through the porous material throat in a venturi tube.
캐비테이팅 벤츄리의 수렴부 경사각 크기에 따른 내부 유동 형태 고찰
이공희(Gong Hee Lee),배준호(June Ho Bae) 대한설비공학회 2020 대한설비공학회 학술발표대회논문집 Vol.2020 No.6
In this study, simulation of cavitation flow inside a cavitating venturi was conducted with commercial CFD software, ANSYS CFX R19.1 to investigate the internal flow pattern depending on inclination angle magnitude in the convergent section of the cavitating venturi. It was found that cavitation flow pattern changed in the throat and diffusion section depending on the magnitude of this structural parameter.
Ogive-Cylinder 주위와 Venturi에서의 캐비테이션 전산 유동해석
이장춘(J.C. Lee),안보경(B.K. Ahn),김동훈(D.H. Kim),김찬기(C.K. Kim),박원규(W.G. Park) 한국전산유체공학회 2007 한국전산유체공학회 학술대회논문집 Vol.2007 No.-
A two-phase method in CFD has been developed and is applied to model the cavitation flow. The governing equation system is two-phase Navier-Stokes equation, comprised of the mixture mass, momentum and liquid-phase mass equation. It employs an implicite, dual time, preconditioned algorithm using finite difference scheme in curvilineal coordinates and Chien k-ε turbulence equation. The experimental cavitating flows around ogive-cylinder and venturi type objects are employed to test the solver. To prove the capabilities of the solver. several three-dimentional examples are presented.