• 제목/요약/키워드: flow-induced vibration

검색결과 447건 처리시간 0.024초

한국표준원전 증기발생기의 관막음 집중 영역 근방에서의 유체유발진동 특성해석 (Characteristics of Flow-induced Vibration for KSNP Steam Generator Tube at Concentrated Tube Plugging Zone)

  • 유기완;조봉호;박치용;박수기
    • 한국소음진동공학회논문집
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    • 제13권6호
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    • pp.452-459
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    • 2003
  • The characteristics of fluid-elastic instability and effects of turbulent excitations for the KSNP steam generator tubes were investigated numerically. The information for the thermal-hydraulic data of the steam generator has been obtained by using the ATHOS3-MOD1 code and the flow-induced vibration(FIV) analysis has been conducted by using the PIAT(program for Integrity assessment of SG tube) code. The KSNP steam generator has the concentrated plugging zone at the vicinity of the stay cylinder inside the SG. To investigate the cause of the concentrated tube plugging zone, the FIV analysis has been performed for various column and row number of the steam generator tubes. From the results of FIV analysis the stability ratio due to the fluid-elastic instability and vibrational amplitude due to the turbulent excitation in the concentrated plugged zone have a trend of larger values than those of the outer concentrated tube Plugging zone.

핵연료 조사시험용 캡슐 구조물의 좌굴 및 진동특성 (Buckling and Vibration Characteristics of the Capsule for Nuclear Fuel Irradiation Test)

  • 강영환;김봉구;류정수;김영진;최명환
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 춘계학술대회논문집
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    • pp.125-130
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    • 2004
  • The vibration and buckling characteristics of the capsule for fuel irradiation test are studied. The natural frequencies of the capsule in air and under water are obtained by modal testing and finite element(FE) analysis using ANSYS program, and accelerations with flow are measured to estimate the compatibility with the operation requirement of the HANARO reactor. The experimental fundamental frequency of the capsule in the x and z direction is 8.5Hz and 8.75Hz in air, and 7.5Hz and 7.75Hz under water, respectively. The maximum amplitude of accelerations under the normal operating condition is measured as 11.0m/s$^2$ that is within the allowable vibrational limit(18.99m/s$^2$) of the reactor structure. Also, the maximum displacement at 100% flow is calculated as 0.13mm which is not interference with other nearby structures. FE analysis results show that the natural frequencies are found to be similar to those of the modal testing when three supporting parts are considered as simply supported conditions. From the buckling analysis, when the loading tool is applied, the critical buckling load of the capsule is 233N.

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역스월 유로 입력을 가지는 밸런스 슬리브를 적용한 고압 다단 펌프의 진동 특성 (Vibration Characteristics of High Pressure Multi-Stage Pump with Anti-Swirl Injection Balance Sleeve)

  • 곽현덕;이용복;김창호;이봉주
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 춘계학술대회논문집
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    • pp.214-219
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    • 2002
  • As the tangential flow inside the clearance of tribe elements such as bearings and seals is increased as the shaft speed increases, the system stability will be decreased due to the increment of the instability parameter. To reduce the tangential flow inside the clearance of the balance sleeve, anti-swirl injection mechanism is applied. The balance sleeve is used in resisting the axial force induced by impeller in high pressure multi-stage pump. In this paper, total three cases are experimentally investigated; original balance steeve, anti-swirl injection balance steeve with 0 axial degree and anti-swirl injection balance sleeve with 30 axial degree. Experiments are focused in the comparison of vibration level and leakage flow rate. The results clearly shows that the anti-swirl injection balance sleeve with 0 axial degree improves the vibration characteristics. However, the anti-swirl injection balance sleeve with 30 degree aggravates the vibration characteristics. In the standpoint of leakage performance, both anti-swirl injection balance sleeves show the better result than the original balance sleeve.

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핵연료 조사시험용 캡슐 구조물의 좌굴 및 진동특성 (Buckling and Vibration Characteristics of the Capsule for Nuclear Fuel Irradiation Test)

  • 강영환;김봉구;류정수;김영진;최명환
    • 한국소음진동공학회논문집
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    • 제14권8호
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    • pp.741-748
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    • 2004
  • The vibration and buckling characteristics of the capsule for fuel irradiation test are studied. The natural frequencies of the capsule in air and under water are obtained by modal testing and finite element (FE) analysis using ANSYS program, and accelerations with flow are measured to estimate the compatibility with the operation requirement of the HANARO reactor. The experimental fundamental frequencies of the capsule in the x and z direction are 8.5 Hz and 8.75 Hz in air, and 7.5 Hz and 7.75 Hz under water, respectively. The maximum amplitude of accelerations under the normal operating condition is measured as 11.0 m/s$^2$ that is within the allowable vibrational limit(18.99 m/s$^2$) of the reactor structure. Also, the maximum displacement at 100% flow is calculated as 0.13 mm which is not interference with other nearby structures. FE analysis results show that the natural frequencies are found to be similar to those of the modal testing when three supporting parts are considered as simply supported conditions. From the buckling analysis, when the loading tool is applied, the critical buckling load of the capsule is 233 N.

역스월 유로 입력을 가지는 밸런스 슬리브를 적용한 고압 다단 펌프의 진동 특성 (Vibration Characteristics of High Pressure Multi-stage Pump with Anti-swirl Injection Balance Sleeve)

  • 곽현덕;이용복;김창호;이봉주
    • 한국소음진동공학회논문집
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    • 제12권8호
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    • pp.632-638
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    • 2002
  • As the tangential flow inside the clearance of tribo elements such as bearings and seals is increased as the shaft speed increases, the system stability will be decreased due to the increment of the instability parameter. To reduce the tangential flow inside the clearance of the balance sleeve, anti-swirl injection mechanism is applied. The balance sleeve is used in resisting the axial force induced by impeller in high pressure multi-stage pump. In this paper, total three cases are experimentally investigated; original balance sleeve, anti-swirl injection balance sleeve with 0 axial degree and anti-swirl injection balance sleeve with 30 axial degree. Experiments are focused in the comparison of vibration level and leakage flow rate. The results clearly shows that the anti-swirl injection balance sleeve with 0 axial degree improves the vibration characteristics. However, the anti-swirl injection balance sleeve with 30 degree aggravates the vibration characteristics. In the standpoint of leakage performance, both anti-swirl injection balance sleeves show the better result than the original balance sleeve.

경수로 핵연료집합체 진동의 실험적 고찰 (An Experimental Study on PWR Nuclear Fuel Assembly Vibration)

  • 장영기;김규태;조규종
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.82-87
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    • 2003
  • Nuclear fuel with a big slenderness ratio is susceptible to flow-induced vibration under very severe conditions of high temperature, high flow and exposure to irradiation in nuclear reactor. The fuel assembly should, therefore, be designed to escape any resonance due to the vibration during the reactor operation, in particular, in case of the design changes. In addition, the amplitudes due to the grid vibration, the fuel rod vibration and the fuel assembly vibration should be minimized to reduce the grid-to-rod fretting wear. Fuel assembly vibration tests in air at room temperature and in water at high temperature have been performed to investigate fuel vibration behaviors. The frequency and damping during the test in air have been compared to those in water. Through the hydraulic test, the advanced assembly has been evaluated not to be susceptible to any resonance. In addition, the test data from the tests can be used to make fuel model and to evaluate grid-to-rod fretting wear.

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동심원 환내의 정상.비정상 회전 유동 (Steady and Unsteady Rotating Flows between Concentric Cylinders)

  • 심우건
    • 소음진동
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    • 제7권4호
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    • pp.613-620
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    • 1997
  • Steady and unsteady flows between rotating cylinders are of interest on lubrication, convective heat transfer and flow-induced vibration in large rotating machinery. Steady rotating flow is generated by rotating cylinder with constant velocity while the unsteady rotating flow by oscillating cylinder with homogeneoysly oscillating velocity. An analytical method is developed based on the simple radial coordinate transformation for the steady and unsteady rotating flows in concentric annulus. The governing equations are simplified from Navier-Stokes equatins. Considering the skin friction based on the radial variation of circumferential flow velocity, the torques acting on the fixed and the rotating cylinder are evaluated in terms of added-inertia and added-damping torque coefficients. The coefficients are found to be influenced by the oscillatory Reynolds number and the radius ratio of two cylinders; however, the effect of the oscillatory Reynolds number on the coefficients is minor in case of relatively low radius ratio.

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맥동류에 의한 파이프 계의 진동응답에 관한 연구 (A Study on the Vibration Responses of Piping Systems by Pulsation Flow)

  • 이동명;최명진
    • 한국음향학회지
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    • 제16권6호
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    • pp.68-75
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    • 1997
  • 본 연구에서는 맥동류에 의한 파이프 계의 진동응답을 고찰하기 위해 전달행렬법을 사용하였다. 유속과 압력을 시간과 위치의 함수로 다루어 유체와 파이프간의 상호작용을 파동방정식으로 정립하고, 각 파동방정식으로부터 전달행렬을 직접 유도하였다. 맥동류로부터 유발되는 파이프 계의 동적응답은 맥동으로부터 발생하는 변동유속과 압력에 의존되는 것으로 나타났으며, 공진 근처에서 맥놀이 현상이 관찰되었다. 파이프 계의 동적거동은 파이프 내부의 유동양상과 동일한 응답특성을 나타내고, 내부 유동유체에 의해 결정된다.

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Scale effect를 고려한 탄소나노튜브의 유체유발진동 (Scale Effect on the Flow-Induced Vibration of Carbon Nanotubes Conveying Fluids)

  • 최종운;김성균;박상윤;김영준;송오섭
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2011년도 추계학술대회 논문집
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    • pp.147-152
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    • 2011
  • In this paper, static and oscillatory loss of stability of carbon nanotube conveying fluid and modelled as a thin-walled beam is investigated. Analytically nonlocal effect, transverse shear and rotary inertia are incorporated in this study. The governing equations and the boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Variations of critical flow velocity for analytically nonlocal effect, partially nonlocal effect and local effect of carbon nanopipes are investigated and pertinent conclusion is outlined.

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선배열 예인 음탐기의 음향 모듈을 따라 전파하는 축대칭 진동에 기인한 음향 센서 자체 소음 해석 (Self Noise Analysis of Towed Array Sonar Induced by Axisymmetric Vibrations Propagating Along Fluid-filled Elastic Hoses)

  • 유정수;신현경;안형택;권오조
    • 한국소음진동공학회논문집
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    • 제21권5호
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    • pp.437-446
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    • 2011
  • Performance of array sonars towed underwater is limited due to the self-noise induced mainly by the strumming vibration of the towing cable and also turbulent flow around the acoustic sensor module. The vibration of the towing cable generates axisymmetric waves that propagate along the acoustic module of the array sonar and produce self-noise. The present study aims to investigate the characteristics of the self-noise induced by the axisymmetric vibrations of the acoustic module. The waves of interest are the bulge and extensional waves propagating along the fluid-filled elastic hose. Dispersion relations of these waves are predicted by means of the numerical simulation to evaluate the wave speeds. The self-noise induced by the axisymmetric waves are formulated taking into account the damping of the elastic hose and the effect of the damping is investigated.