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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The KSFM Journal of Fluid Machinery
Journal Basic Information
Journal DOI :
Korean Fluid Machinery Association
Editor in Chief :
Volume & Issues
Volume 14, Issue 6 - Dec 2011
Volume 14, Issue 5 - Oct 2011
Volume 14, Issue 4 - Aug 2011
Volume 14, Issue 3 - Jun 2011
Volume 14, Issue 2 - Apr 2011
Volume 14, Issue 1 - Feb 2011
Selecting the target year
Performance Measurement of a Tubular Type Turbine System for Small Hydropower by Field Test
Hwang, Yeong-Ho ; Lee, Young-Ho ; Choi, Young-Do ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 5~10
DOI : 10.5293/kfma..2011.14.6.005
Recently, small hydropower attracts attention because of its renewable, clean and abundant energy resources to develop. Therefore, a tubular type hydro turbine is proposed for small hydropower in this study because the turbine has relatively simple structure and high possibility of applying to small hydropower. The purpose of this study is to investigate the performance characteristics of the turbine by field test. Field test iss conducted using one tubular turbine system as well as serial arrangement system by two tubular turbines taking into consideration of actual operation conditions. The results show that efficiency of test turbine changes considerably by the runner vane angle. Best efficiency of one turbine arrangement is higher than that of two turbine serial arrangement.
Study of Waterhammer Suppression Technique due to Valve Closing on Water Supply Pipeline
Park, Jong-Ho ; Park, Han-Yung ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 11~17
DOI : 10.5293/kfma..2011.14.6.011
The cause of waterhammer phenomenon due to valve closing which is installed on pipeline is clarified in this study. Also if waterhammer phenomenon occurs on simple pipeline, expensive facilities like pressure relief valve is adapted to protect pipeline from waterhammer so far. But this study shows that waterhammer phenomenon can be suppressed by just simple modification of valve control sequence, and this technique is verified by simulation and site experiment.
Experiments on Single-Disk Pumps for the Transportation of Micro-scale Water Life
Zhang, Z.Q. ; Chang, S.M. ; Jeong, Y.H. ; Yang, J.S. ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 18~25
DOI : 10.5293/kfma..2011.14.6.018
A boundary-layer pump with a single disk has been experimented to obtain its characteristic curve by changing the impeller of a centrifugal pump to a single disk. The primary objective to use of these types of pumps is to avoid hurting water life during transportation unnecessarily. The change of impeller should degrade the performance of pump, so we used the method to increase the roughness on the disk with sandpaper and mesh. The enhancement of shear force from the rotation of disk to the internal flow brought an augmentation of momentum transport, and the characteristics were far improved from the original single-disk pump without decreasing the survival rate of water life in the case of Pseudobagrus fulvidraco (bullhead fish). However, in the case of Artemia cyst (zooplankton), the survival rate was very degraded due to the micro scale smaller than turbulent eddy size. The result of this study could be used for the design of transportation and bio-filtering of water lying on a specific bandwidth of its scale of size.
A Study on the Reversal Flow Time due to Blackout
Park, Jong-Ho ; Park, Han-Yung ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 26~34
DOI : 10.5293/kfma..2011.14.6.026
Waterhammer and slamming phenomena can occur when power is cut off due to reversal flow in pipeline and sudden close of check valve. Therefore analysis of reversal flow time, which means the time of reversal flow in pipeline due to pumping station blackout, is needed to protect facilities from waterhammer economically and efficiently. However systematic study on reversal flow time has not been done yet. So theory of reversal flow time analysis is proposed and verified with experiment using several parameters like pump specific speed, motor pole number, and characteristic curve of pipeline in this study.
Development of a Numerical Model for Cake Layer Formation Process on Membrane
Kim, Kyung-Ho ; Shin, Jae-Ho ; Lee, Sang-Hwan ; Lee, Ju-Hee ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 35~44
DOI : 10.5293/kfma..2011.14.6.035
Membrane filtration has become firmly established as a primary process for ensuring the purity, safety and efficiency of treatment of water or effluents. Several researches have been performed to develop and design membrane systems in order to increase the accuracy and performance of the processes. In this study, a lattice Boltzmann method for the cake layer has been developed using particle dynamics based on an immersed boundary method and the cake layer formation process on membrane has been numerically simulated. Case studies including various particle sizes were also performed for a microfiltration process. The growth rate of the cake layer thickness and the permeation flow rate along the membranes were predicted. The results of this study agreed well with that of previous experiments. Effects of various particle diameters on the membrane performance were studied. The cake layer of a large particle tended to be growing fast and the permeation flow going down rapidly at the beginning. The layer thickness of a small particle increased constantly and the flow rate was smaller than that of the large particle at the end of simulation time.
Direct Numerical Simulation of the Nucleate Pool Boiling Using the Multiphase Lattice Boltzmann Method : Preliminary Study
Ryu, Seung-Yeob ; Ko, Sung-Ho ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 45~53
DOI : 10.5293/kfma..2011.14.6.045
Multiphase lattice Boltzmann method (LBM) has been used to simulate the nucleate pool boiling directly. For the phase change model, the thermal model and the Stefan boundary condition were introduced to the isothermal LBM. The phase change model was validated by the bubble growth in a superheated liquid under no gravity. The bubble growth on and departure from a superheated wall has been simulated successfully. The preliminary results showed that the detail process of nucleate pool boiling was in good agreement with the experimental results.
Hydrodynamic Characteristics of Vaned-Diffuser and Return-Channel for a Multistage Centrifugal Pump
Oh, Hyoung-Woo ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 54~60
DOI : 10.5293/kfma..2011.14.6.054
This paper presents the steady-state performance analysis of the first stage of a multistage centrifugal pump, composed of a shrouded-impeller, a vaned-diffuser and a return-channel, using the commercially available computational fluid dynamics (CFD) code, ANSYS CFX. The detailed flow fields in the vaned-diffuser with outlet in its side wall and the return-channel are investigated by the CFD code adopted in the present study. The effect of the vaned-diffuser with a downstream crossover bend and the corresponding return-channel on the overall hydrodynamic performance of the first stage pump has also been demonstrated over the normal operating conditions. The predicted hydrodynamics for the diffusing components herein could provide useful information to match the inlet blade angle of the next stage impeller for improving the multistage pump performances.
Thermal Flow Analysis of Operating Parameters in Autothermal Reformer
Park, Seung-Hwan ; Kim, Jin-Wook ; Park, Dal-Yung ; Kim, Jae-Dong ; Lee, Do-Hyung ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 61~67
DOI : 10.5293/kfma..2011.14.6.061
The study is to analyze the chemical and heat-flow reactions in the hydrogen generation unit(autothermal reformer), using computational numerical tools. Autothermal reformer(ATR) is involved in complex chemical reaction, mass and heat transfer due to exothermic and endothermic reactions. Therefore it is necessary to reveal the effects of various operation parameters and geometries on the ATR performance by using numerical analysis. Numerical analysis needs to dominant chemical reactions that includes Full Combustion(FC) reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction and Direct Steam Reforming(DSR) reaction. The objective of the study is to improve theoretically the reformer design capability for the goal of high hydrogen production in the autothermal reformer using methane. Hydrogen production reached maximum in a certain value of Oxygen to Carbon Ratio(OCR) or Steam to Carbon Ratio(SCR). When the longitudinal distance to dimeter ratio(L/D) is increased, hydrogen production increases.
Changes in Performance and Operating Condition of a Gas Turbine Combined Heat and Power System by Steam Injection - A Focus on Compressor Operation
Kang, Soo-Young ; Kim, Tong-Seop ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 68~75
DOI : 10.5293/kfma..2011.14.6.068
This study simulated the effect of steam injection on the performance and operation of a gas turbine combined heat and power (CHP) system. A commercial simple cycle gas turbine was analyzed. A full off-design analysis was carried out to investigate the variations in not only engine performance but also the operating characteristics of the compressor caused by steam injection. Variation in engine performance and operation characteristics according to various operation modes were examined. First, the impact of full steam injection was investigated. Then, operations aiming to guarantee a minimum compressor surge margin, such as under-firing and partial steam injection, were investigated. The former and latter were turned out to be relatively superior to each other in terms of power and efficiency, respectively.
Effect of Inlet Velocity Distribution on the Heat Transfer Coefficient in a Rotating Smooth Channel
Choi, Eun-Yeong ; Lee, Yong-Jin ; Jeon, Chang-Soo ; Kwak, Jae-Su ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 76~84
DOI : 10.5293/kfma..2011.14.6.076
The effect of inlet velocity profile on the heat transfer coefficient in a rotating smooth channel was investigated experimentally. Three simulated inlet flow conditions of fully developed, uniform, and distorted inlet conditions were tested. The Reynolds number based on the channel hydraulic diameter was ranged from 10,000 to 30,000 and the transient liquid crystal technique was used to measure the distribution of the heat transfer coefficient in the rotating channel. Results showed that the overall heat transfer coefficient increased as the Reynolds number increased. Also, the distribution of the heat transfer coefficient was strongly affected by the inlet flow condition. Generally, the fully developed flow simulated condition showed the highest heat transfer coefficient.
A Study on the Kinematic Characteristics of the Ocean High Elevation Fountain
Lee, Choon-Tae ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 85~90
DOI : 10.5293/kfma..2011.14.6.085
Recently, many high elevation fountain are constructed for the beauty of beach landscape. Typically, a fountain has several nozzles that shoots water upwards or at an angle into the air. But unfortunately, the weather and wind can cause the water soak nearby walkways and pedestrians. Therefore, in this study, a mathematical model of high elevation fountain is suggested to predict the actual travelling distance of water droplet by the wind. To simplify our treatment of the water flow and to avoid issues such as fluid dynamics and surface tension, we have adopted a particle model for the fountain water. The particles are assumed not to interact with each other, and do not deform during their flight through air.
Rotordynamic Characteristics Analysis of Turbocharger Turbine for Spin Test
Kim, Byung-Ok ; Yang, Sung-Jin ; Lee, Myung-Ho ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 91~95
DOI : 10.5293/kfma..2011.14.6.091
This paper deals with the detail rotordynamic analysis for the assembly rotor composed of turbine wheel, turbine shaft, connecting arbor, and flange & spindle in order to perform the spin test of turbocharger turbine. Prior to rotordynamic analysis, the 1st spin test was performed but the test was failed by excess vibration in the neighborhood rated speed. It is the reason for this fail that the separation margin between the rated speed and critical speed is not enough, confirmed by rotordynamic analysis results. Since then, the dimension of turbine shaft was modified and the critical speeds were again reviewed for modified assmebly rotor. In results, the separation margin between the rated speed and critical speed is over 20% and then the 2nd spin test was performed successfully. In preparing spin test for turbine, compressor wheels and etc., the geometry design of connecting arbor and dimension of rough machining should be reviewed by considering rotordynamic results, and the separation margin should be enough for successful spin test.
Experimental Research on Multi Stage Transonic Axial Compressor Performance Evaluation
Kang, Young-Seok ; Park, Tae-Choon ; Hwang, Oh-Sik ; Yang, Soo-Seok ;
The KSFM Journal of Fluid Machinery, volume 14, issue 6, 2011, Pages 96~101
DOI : 10.5293/kfma..2011.14.6.096
Korea Aerospace Research Institute is performing 3 stage transonic axial compressor development program. This paper introduces design step of the compressor, the performance test results and its analysis. In the fore part of the paper, aerodynamic process of the 3 stage axial compressor is presented. To satisfy both of the mass flow and pressure rise, the compressor should rotate at a high rotational speed. Therefore the transonic flow field forms in the rotor stages and it is designed with a relatively high pressure rise per stage to satisfy its design target. The compressor stage consists of 3 stages, and the bulk pressure ratio is 2.5. The first stage is burdened with the highest pressure ratio and less pressure rises occur in the following stages. Also it is designed that tip Mach number of the first rotor row does not exceed 1.3, while the maximum relative Mach number in the rotor stage is between 1.3~1.4 to increase the compressor flow coefficient. The final design has been confirmed by iterating three dimensional CFD calculations to verify design target and some design intentions. In the latter part of the paper, its performance test processes and results are presented. The performance test result shows that the overall compressor performance targets; pressure ratio and efficiency are well achieved. The stator static pressure distributions show that the blade loading is gradually increasing from the downstream of the compressor.