• Title/Summary/Keyword: Fluid pipeline

Search Result 156, Processing Time 0.031 seconds

Calculation of Anchor's Terminal Velocity in the Water and Onshore Dropped Heights Using MDM Technique

  • Shin, Mun-Beom;Seo, Young-Kyo
    • Journal of Advanced Research in Ocean Engineering
    • /
    • v.3 no.2
    • /
    • pp.59-65
    • /
    • 2017
  • When an anchor is dropped into the sea, there exists a danger of collision on the pipeline and subsea cables in the seabed. This collision could cause huge environmental disasters and serious economic losses. In order to secure the safety of subsea structures such as pipelines and subsea cables from the external impact, it is necessary to estimate the exact external force through the anchor's terminal velocity on the water. FLUENT, a computational fluid dynamic program, was used to acquire the terminal velocity and drag coefficient computation. A half-symmetry condition was used in order to reduce the computational time and a moving deforming mesh technique also adapted to present hydrostatic pressure. The results were examined with the equation based on Newton's Second Law to check the error rate. In this study, three example cases were calculated by stockless anchors of 5.25 ton, 10.5 ton, and 15.4 ton, and for the onshore experiment dropped height was back calculated with the anchor's terminal velocity in the water.

Flow Network Analysis for the Flow Control of a Main Cooling Water System in the HANARO Fuel Test Loop (하나로 핵연료 시험 루프 주냉각수 계통의 유량 제어에 대한 유동 해석)

  • Park, Young-Chul;Lee, Yong-Sub;Chi, Dae-Yong
    • The KSFM Journal of Fluid Machinery
    • /
    • v.12 no.5
    • /
    • pp.7-12
    • /
    • 2009
  • A nuclear fuel test loop(after below, FTL) is installed in the IRI of an irradiation hole in HANARO for testing the neutron irradiation characteristics and thermo hydraulic characteristics of a fuel loaded in a light water power reactor or a heavy water power reactor. There is an in-pile section(IPS) and an out-pile section(OPS) in this test loop. When HANARO is operated normally, the fuel loaded into the IPS has a nuclear reaction heat generated by a neutron irradiation. To remove the generated heat and to maintain the operation conditions of the test fuel, a main cooling water system(MCWS) is installed in the OPS of the FTL. The MCWS is composed of a main cooler, a pressurizer, two circulation pumps, a main heater, an interconnection pipe line and instruments. The interconnection pipeline is a closed loop which is connected to an inlet and an outlet of the IPS respectively. The MCWS is under a cold function test during a start-up period. This paper describes the system flow network analysis results of the flow control of a main cooling water system in the HANARO fuel test loop. It was confirmed through the results that the flow was met the system design requirements.

Experimental Study of Check Valves in Pumping Systems with Air Entrainment

  • Lee, Thong-See;Low, Hong-Tong;Nguyen, Dinh-Tam;Rong, Wei;Neo, Avan
    • International Journal of Fluid Machinery and Systems
    • /
    • v.1 no.1
    • /
    • pp.140-147
    • /
    • 2008
  • An experiment setup was introduced to study dynamic behaviour of different types of check valves and the effects of air entrainment on the check valve performance under pressure transient condition. The experiment results show that the check valves with low inertia, assisted by springs or small traveling distance/angle gave better performance under pressure transient condition than check valves without these features. Air entrainment was found to affect both wave speed and reverse velocity. With the increase of the initial air void fraction in pipeline, the experiment results show that the wave speed was reduced, the reverse velocity was increased. The first peak pressure increased initially and then decreased with the increase of the initial air void fraction, the pressure surge periods were increased proportionally with air void fraction due to the greatly reduced wave speed. The study can be applied to help choosing suitable check valves for a particular pumping system.

A Study of Dynamic Response in a Pipeline for Design of Hydraulic Circut (유압회로 설계를위한 유압관로에서의 동특성연구)

  • Kim, Ji-Hwan;Kim, Kwang-Ho;Shin, You-Hwan;You, Young-Tae
    • Proceedings of the KSME Conference
    • /
    • 2003.04a
    • /
    • pp.2024-2030
    • /
    • 2003
  • Design for a quite operation of fluid power system requires the understanding of noise and vibration characteristics of the system. This paper presents a dynamic response for design of hydraulic circuit. Experimental investigations on the attenuation characteristics of pressure ripple in automotive power steering hydraulic pipe with dynamic response of hydraulic pipe line is examined. Also, a mathematical model of hydraulic pipe is proposed to support design of the hydraulic circuit and analyze the attenuation characteristics of pressure ripples in a hydraulic pipe line. And analyze the impedance characteristics to determine the postion to construct accumulator for attenuation the pressure pulsation. The experimental results show that the pulsation attenuation characteristics of hydraulic hoses is remarkably affected by the flexible metal tube inserted coaxially inside a hydraulic hose with a finite length as well as viscoelastic properties of hose wall. It is also shown that the predicted results by the model proposed here agree well with the measured results over a wied range of frequency;

  • PDF

Induction Heating Water Heater using Dual Mode Phase Shifted ZVS-PWM High Frequency Resonant Inverter (듀얼 모드 위상 시프트 ZVS PWM 제어 고주파 공진형 인버터를 이용한 IH 온수기)

  • Lee, Sang-Wook;Ryu, Yeoi-Joung;Woo, Kyung-Il;Park, Han-Seok
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.67 no.2
    • /
    • pp.82-89
    • /
    • 2018
  • This paper presents a novel prototype of dual mode control based phase shift ZVS PWM high frequency load resonant inverter with lossless snubber capacitors in addition to a single active auxiliary resonant snubber for electromagnetic induction heating(IH) foam metal based consumer fluid dual packs(DPA) heater. The operating principle in steady state and unique features of this voltage source soft switching high frequency inverter circuit topology are described in this paper. The lossless snubber and auxiliary active resonant snubber assisted constant frequency phase shift ZVS PWM high frequency load resonant inverter employing IGBT power modules actually is capable of achieving zero voltage soft commutation over a widely specified power regulation range from full power to low power. The steady state operating performances of this dual mode phase shift PWM series load resonant high frequency inverter are evaluated and discussed on the basis of simulation and experimental results for induction heated foam metal heater which is designed for compact and high efficient moving fluid heating appliance in the consumer pipeline systems.

The Voltage-fed High Frequency Resonant Inverter Using Induction Heated Dry Steam Generator

  • Kim, Chil-Ryong;Lee, Jong-Kurl;Jung, Sang-Hwa;Mun, Sang-Pil;Kim, Sang-Don;Nakaoka, Mutsuo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
    • /
    • 2008.05a
    • /
    • pp.415-418
    • /
    • 2008
  • This paper presents an innovative prototype of a new conceptual electromagnetic induction-based fluid beating appliance using voltage-fed type scries capacitor-compensated load resonant high-frequency IGBT inverter with a phase-shifted PWM and a power factor correction schemes. Its operating characteristics in steady-state are illustrated including unique features and evaluated on the basis of its computer simulation and experimental results of 10kw breadboard appliance for hot water producer and superheated steamer. The promising cost effective inverter-fed boiler appliances for electromagnetic induction-heated type fluid-heating in the pipeline systems are proposed for induction-heated boiler, super heat steamer, high temperature water producer, hot gas producer and metal catalyst heating for exhaust gas cleaning in engine, which are more suitable and acceptable for industrial, chemical, and consumer energy utilization for household and business from a practical point of view.

  • PDF

A hybrid method for predicting the dynamic response of free-span submarine pipelines

  • Li, Tongtong;Duan, Menglan;Liang, Wei;An, Chen
    • Ocean Systems Engineering
    • /
    • v.6 no.4
    • /
    • pp.363-375
    • /
    • 2016
  • Large numbers of submarine pipelines are laid as the world now is attaching great importance to offshore oil exploitation. Free spanning of submarine pipelines may be caused by seabed unevenness, change of topology, artificial supports, etc. By combining Iwan's wake oscillator model with the differential equation which describes the vibration behavior of free-span submarine pipelines, the pipe-fluid coupling equation is developed and solved in order to study the effect of both internal and external fluid on the vibration behavior of free-span submarine pipelines. Through generalized integral transform technique (GITT), the governing equation describing the transverse displacement is transformed into a system of second-order ordinary differential equations (ODEs) in temporal variable, eliminating the spatial variable. The MATHEMATICA built-in function NDSolve is then used to numerically solve the transformed ODE system. The good convergence of the eigenfunction expansions proved that this method is applicable for predicting the dynamic response of free-span pipelines subjected to both internal flow and external current.

Axial Thrust Control of High-speed Centrifugal Pump with Cavity Vanes (캐비티 베인이 있는 고속 원심펌프의 축추력 제어)

  • Kim, Dae-Jin;Choi, Chang-Ho;Noh, Jun-Gu;Kim, Jinhan
    • The KSFM Journal of Fluid Machinery
    • /
    • v.15 no.6
    • /
    • pp.46-50
    • /
    • 2012
  • A high-speed centrifugal pump requires more attention to the control of its axial thrust due to the high discharge pressure than a conventional industrial pump. Vanes employed toward the rear cavity of the impeller can be an effective device to control the axial thrust of the pump. The vanes disturb circumferential flow of the cavity and it can modify the axial force acting on the impeller. In this paper, three types of vanes are installed in the high-speed centrifugal pump for liquid rocket engines and the thrust of the pump is measured with an additional thrust measurement unit. According to the results, shapes of cavity vanes have effects on the axial thrust of the pump. As the height of vanes increases, the outlet pressure of the rear floating ring seal decreases which results in a decrease of the thrust. On the other hand, head of the pump is almost same regardless of cavity vanes. Also, the pressure drop of the bypass pipeline increases when vanes are removed.

Priliminary Numerical Simulation of the Torque Motor for a Servo Valve in the Fuel Supply System of APU (보조동력장치 연료 공급용 서보밸브 토크모터의 기초 수치모사 연구)

  • Chang, S.M.;Jeong, H.S.;Jang, G.W.;Yang, I.Y.;Lee, W.
    • Transactions of The Korea Fluid Power Systems Society
    • /
    • v.6 no.2
    • /
    • pp.1-6
    • /
    • 2009
  • The APU(Auxiliary Power Unit) needs a set of complex pipeline for the fuel supply system where some of the main valves controlling the flow rate consist of the servo valve worked with a torque motor. The input electric current produces an induced magnetic field almost perpendicular to the background magnetic filed generated by fixed permanent magnets. The induced torque deforms the tubular bushing, and directly rotates an armature, which can open and close the valve. In this study, we start from a basic analytic model using a simple electro-magneto-statics, and expand our model to the three-dimensional one computationally applying a commercial code named COMSOL. The result is compared with each other, and reasonable numerical data are obtained for the dynamic behavior and multi-physics system.

  • PDF

Seismic response of smart nanocomposite cylindrical shell conveying fluid flow using HDQ-Newmark methods

  • Zamani, Abbas;Kolahchi, Reza;Bidgoli, Mahmood Rabani
    • Computers and Concrete
    • /
    • v.20 no.6
    • /
    • pp.671-682
    • /
    • 2017
  • In this research, seismic response of pipes is examined by applying nanotechnology and piezoelectric materials. For this purpose, a pipe is considered which is reinforced by carbon nanotubes (CNTs) and covered with a piezoelectric layer. The structure is subjected to the dynamic loads caused by earthquake and the governing equations of the system are derived using mathematical model via cylindrical shell element and Mindlin theory. Navier-Stokes equation is employed to calculate the force due to the fluid in the pipe. Mori-Tanaka approach is used to estimate the equivalent material properties of the nanocomposite and to consider the effect of the CNTs agglomeration on the scismic response of the structure. Moreover, the dynamic displacement of the structure is extracted using harmonic differential quadrature method (HDQM) and Newmark method. The main goal of this research is the analysis of the seismic response using piezoelectric layer and nanotechnology. The results indicate that reinforcing the pipeline by CNTs leads to a reduction in the displacement of the structure during an earthquake. Also the negative voltage applied to the piezoelectric layer reduces the dynamic displacement.