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알루미나계 수도밸브용 세라믹디스크의 가속수명시험 및 수명 모델 개발
최형석 한국신뢰성학회 2022 신뢰성응용연구 Vol.22 No.4
Purpose: An accelerated life test (ALT) plan was devised after investigating the potential failure mechanisms of a ceramic disk material for a water valve. Moreover, ALT was implemented to establish a life distribution and acceleration model. Methods: The thermal shock behavior of the ceramic disk was predicted using finite element method. To reproduce the disk, a jig was fabricated and then the ALT was performed. After the test, failure analysis was conducted through optical microscopy and surface roughness measurement. Results: The life distribution of the ceramic disk for the water valve was confirmed to have a Weibull distribution with a shape parameter of 1.5. Moreover, because the operating condition was thermal shock acceleration, the acceleration model was suitable when the Coffin-Manson model with a material constant of 6.6 was applied. Conclusion: The analysis of the average values and standard deviations of the surface roughness of failed products using ALT showed that the more severe the environment, the greater the wear of the ceramic disk. This indicated that ALT was well planned and implemented.
디스크 방식 체크 밸브의 스프링력을 고려한 CFD 해석 기법 연구
정윤상(Yun-Sang Jeong),조준영(Jun-Young Cho),김성근(Sung-Kun Kim) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11
In general, check valves are intended to prevent reverse flow and various types of check valves have been developed and are used in various industrial fields. One of them, the disk type check valve is equipped with a spring operating in the opposite direction to the fluid flow at the bottom of the valve disk to close the valve with spring force to prevent fluid from flowing in. Although the structure is simple and suitable for miniaturization, differential pressure and flow loss occur due to spring force in a normal flow state. This paper presents the method of CFD analysis that can consider the flow loss caused by spring force when performing CFD analysis to predict the performance of a disk type check valve. In order to verify the validity of the proposed method of CFD analysis, a flow test was performed and compared with the test and CFD analysis results.
원심력기반 3차원 관성밸브 모델링을 통한 정밀 미세유체제어
강동희(Dong Hee Kang),김나경(Na Kyong Kim),강현욱(Hyun Wook Kang) 한국가시화정보학회 2021 한국가시화정보학회지 Vol.19 No.1
A three-dimensional slope valve component is used for controlling micro volume of liquid on a centrifugal force-based microfluidic disk platform, also called a lab-on-a-disk. The modeling factor of the slope valve component is determined to centrifugal force for liquid passing the crest of a slope valve via variation of slope length and angle as well as the radius to start point of slope valve. The centrifugal force is calculated by the equilibrium equation of the capillary and gravitational forces according to the microchannel surface roughness and the liquid volume, respectively. As a result, the slope valve is analyzed by the minimum angular velocity for liquid passing at crest point and the ratio between the length of micro liquid and slope length to obtain the factors for optimal slope angle modeling.
디스크 방식 체크 밸브의 스프링력을 고려한 CFD 해석 기법 연구
정윤상(Yun-Sang Jeong),조준영(Jun-Young Cho),김성근(Sung-Kun Kim) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11
In general, check valves are intended to prevent reverse flow and various types of check valves have been developed and are used in various industrial fields. One of them, the disk type check valve is equipped with a spring operating in the opposite direction to the fluid flow at the bottom of the valve disk to close the valve with spring force to prevent fluid from flowing in. Although the structure is simple and suitable for miniaturization, differential pressure and flow loss occur due to spring force in a normal flow state. This paper presents the method of CFD analysis that can consider the flow loss caused by spring force when performing CFD analysis to predict the performance of a disk type check valve. In order to verify the validity of the proposed method of CFD analysis, a flow test was performed and compared with the test and CFD analysis results.
고성호(S.H. Ko),곽영균(Y. K. Kwack),이상현(S. H. Lee),강민구(M. K. Kang) 한국전산유체공학회 2007 한국전산유체공학회 학술대회논문집 Vol.2007 No.-
A three dimensional numerical analysis has been made for the cone disk control valve and the flat disk control valve. The simulation of the incompressible flow in the each control vale are performed by using the commercial code. Six flow cases of each control valve are investigated.
배관용 틸팅디스크 체크밸브의 손실저항 절감에 관한 연구
김정환(J. H. Kim),박재현(J. H. Park),이현식(H. S. Lee),남시환(S. H. Nam),황성홍(S. H. Hwang) 한국마린엔지니어링학회 2006 한국마린엔지니어링학회 학술대회 논문집 Vol.2006 No.-
In generally, under the influence of over-pressure drop, serious problems such as cavitation, choked flow, flashing and vibration has been coming around the tilting disk check valve. A PIV experiment to examine the cause of energy loss has been performed and the improvement configuration of valve seat based on this visualization results is proposed. In the visualization results, flows in the piping system became instability under the influence of the shape of boss. This unstable flows induces sudden pressure drop in the piping system. So, we change the configuration of boss as a streamlined design to be stabilized the flows. A pressure measurement has been performed to know that the influence of the configuration change. In result, the rate of pressure loss reduction is about 22% at the position of No. 2 and 24.2% at the position of No. 6 in comparison with pre-improved shape.
밸브 닫힘각 변화에 따른 버터플라이밸브의 손실계수 평가
이지근(Jeekeun Lee),노병준(Byungjoon Rho),최희주(Heejoo Choi) 한국항공우주학회 2008 韓國航空宇宙學會誌 Vol.36 No.1
밸브 디스크 직경이 25.4 ㎜ 인 소형 버터플라이밸브의 유동특성이 다양한 밸브 닫힘각에 대해 실험적으로 연구되었다. 밸브 디스크각이 작은 경우 유량조절특성을 향상시키기 위해 주어지는 밸브 닫힘각을 0°, 5°, 10°, 20°, 30°로 변화시켜 밸브 디스크각에 따른 손실계수를 측정하였다. 또한 밸브선단 형상이 손실계수 변화에 미치는 영향을 조사하였다. 밸브 닫힘각이 증가함에 따라 최대손실계수는 감소하며, 밸브 닫힘각 0°~5°에서 가장 큰 감소를 나타냄을 알 수 있었다. 밸브 디스크 형상에 따른 손실계수는 밸브 닫힘각이 0°인 경우 날카로운 모서리를 갖는 디스크가 더 큰 손실계수를 나타낸 반면, 닫힘각 10°의 경우 날카로운 모서리를 갖는 디스크의 경우가 더 낮은 손실계수를 나타냄을 알 수 있었다. In this study, flow characteristics of a small-sized butterfly valve with the valve disk diameter of 25.4 ㎜ have been investigated experimentally for the valve closed angles. In order to examine the flow characteristics of the butterfly valve, loss coefficient (K<SUB>v</SUB>) was obtained at the valve closed angles of 0°, 5°, 10°, 20° and 30°. In addition, the effects of the valve disk edge shape were examined. As the result of the experiment, the maximum loss coefficient (K<SUB>vmax</SUB>) was decreased with the increase of the valve closed angle, and it had the maximum decrease ratio at the valve disk angles of 0°~5°. The valve disk edge shape have an effect on the loss coefficient of the valve around the small valve closed angle.
E-EGR Valve 내부 Carbon Deposit 억제를 위한 형상연구
이현창(Lee Hyun-Chang),이태곤(Lee, Tae-Gon),박우철(Park Woo-Chul) 한국산학기술학회 2010 한국산학기술학회논문지 Vol.11 No.12
E-EGR Valve 고장의 원인이 되는 내부 퇴적물 축적을 최소화하기 위한 새로운 Valve 형상을 제안하고자 한다. 전산유체 해석을 통하여 다양한 형상에 대하여 유속과 유량을 관찰하였으며, 밸브 상부에 라운드를 추가한 Valve 디자인 변형을 통하여 유량손실 없이 Valve 내의 유속을 약 10% 향상시킬 수 있었다. New E-EGR valve design to suppress a carbon deposit causing a trouble in the valve by improving gas flow velocity is proposed. With CFD simulations of various shapes of valve disk and rod, the velocities and quantities of flowing fluid are observed. The proposed unique design of having round grooves on the disk head shows the improved performance of flow velocity about 10 % without sacrificing the flow quantity.
Zong Chaoyong,Shi Maolin,Li Qingye,Xue Tianhang,Song Xueguan,Li Xiaofeng,Chen Dianjing 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4
Pressure relief valve (PRV) is one of the important control valves used in nuclear power plants, and its sealing performance is crucial to ensure the safety and function of the entire pressure system. For the sealing performance improving purpose, an explicit function that accounts for all design parameters and can accurately describe the relationship between the multi-design parameters and the seal performance is essential, which is also the challenge of the valve seal design and/or optimization work. On this basis, a surrogate model-based design optimization is carried out in this paper. To obtain the basic data required by the surrogate model, both the Finite Element Model (FEM) and the Computational Fluid Dynamics (CFD) based numerical models were successively established, and thereby both the contact stresses of valve static sealing and dynamic impact (between valve disk and nozzle) could be predicted. With these basic data, the polynomial chaos expansion (PCE) surrogate model which can not only be used for inputs-outputs relationship construction, but also produce the sensitivity of different design parameters were developed. Based on the PCE surrogate model, a new design scheme was obtained after optimization, in which the valve sealing stress is increased by 24.42% while keeping the maximum impact stress lower than 90% of the material allowable stress. The result confirms the ability and feasibility of the method proposed in this paper, and should also be suitable for performance design optimizations of control valves with similar structures.
Idea Factory를 통한 산학 협력 연구 활동(소재의 적절한 선정을 통한 버터플라이 밸브 디스크의 최적화 모델링)
김윤해,박창욱,배창원,김한솔,정민교 한국공학교육학회 2016 공학교육연구 Vol.19 No.6
This research is one of the Industry-University cooperation in idea factory of Korea Maritime and Ocean University. Idea factory of Korea Maritime and Ocean University is trying to train creative talented students and discover ingenious ideas. The contents are consisted of the possibility for the replacement of a metal valve disk to composite valve disk in butterfly valve based on the diversification. Purpose in this study is to predict failure field by each fly by appling Tsai-Wu Failure Index.