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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
Measurement of Dynamic Coefficients of Air Foil Bearing for High Speed Rotor by Using Impact Test
Park, Cheol-Hoon ; Choi, Sang-Kyu ; Ham, Sang-Yong ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 5~10
DOI : 10.5293/KFMA.2011.14.1.005
MTG(Micro turbine generator) operating at 400,000 rpm is under development and the impact test rig to measure the dynamic stiffness and damping coefficient of air foil bearing for high speed rotor is presented in this study. The stiffness and damping coefficient of air foil bearing depending on the rotational speed can be measured easily and effectively by using the simple configuration of impact test rig which is composed of air gun, gap sensors and high speed motor. The estimation results of stiffness and dampling coefficient using least square estimation method is presented as well.
Performance Evaluation on Impeller Related Parameters Change in Centrifugal Pump of very Low Specific Speed
Choung, Young-Dae ; Lee, Kye-Bock ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 11~17
DOI : 10.5293/KFMA.2011.14.1.011
The numerical study was conducted to investigate the pump performance due to impeller related parameters change in centrifugal pump of very low specific speed by using CFD code. A small centrifugal pump whose specific speed is
was used, and the performance characteristics were discussed for different number of vanes, rotational speed, and the length and height of vane. The numerical results at a very low specific speed show that the increase of the number of vanes has little effect on improvement of output pressure but results in the reduction of pressure fluctuation, and that the head increases with the increase in the rotational speed. The decreasing the length of vane has a considerable reduction of the capacity coefficient in comparison with decreasing the height of vane.
Hydraulic Design of Reactor Coolant Pump Considering Head Curve Slope at Design Point
Yoo, Il-Su ; Park, Mu-Ryong ; Yoon, Eui-Soo ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 18~23
DOI : 10.5293/KFMA.2011.14.1.018
The hydraulic part in reactor coolant pump consists of suction nozzle, impeller, diffuser, and discharge nozzle. Among them, impeller is required to be designed to satisfy performance requirements such as head, NPSHR, and head curve slope at design point. Present study is intended to suggest the preliminary design method sizing the impeller size to satisfy the design requirement particularly including head curve slope at design point. On a basis of preliminary design result, hydraulic components have been designed in detail by CFD and then manufactured in a reduced scale. Experiment in parallel with computational analysis has been executed in order to confirm the hydraulic performance. Comparison results show good agreement with design result, confirming the validity of design method suggested in this study.
A Study on Development of a Circulating Pump with Space Constraintst
Yoon, Eui-Soo ; Yoo, Il-Su ; Hwang, Soon-Chan ; Oh, Hyoung-Woo ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 24~33
DOI : 10.5293/KFMA.2011.14.1.024
A circulating pump with installation space constraints was developed satisfying performance requirements such as flowrate, head and NPSHAv. The development procedures are composed of conceptual design, configuration design, performance analysis by CFD and performance test which were established in KIMM. The developed pump is OH4 type centrifugal pump which has a mixed-flow type impeller, a double volute and a rigid coupling. As a result of tests, the pump proved to meet all the requirements including space constraints and performance.
Estimation of the Properties for a Charring Material Using the RPSO Algorithm
Chang, Hee-Chul ; Park, Won-Hee ; Yoon, Kyung-Beom ; Kim, Tae-Kuk ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 34~41
DOI : 10.5293/KFMA.2011.14.1.034
Fire characteristics can be analyzed more realistically by using more accurate properties related to the fire dynamics and one way to acquire these fire properties is to use one of the inverse property estimation techniques. In this study two optimization algorithms which are frequently applied for the inverse heat transfer problems are selected to demonstrate the procedure of obtaining pyrolysis properties of charring material with relatively simple thermal decomposition. Thermal decomposition is occurred at the surface of the charring material heated by receiving the radiative energy from external heat sources and in this process the heat transfer through the charring material is simplified by an unsteady 1-dimensional problem. The basic genetic algorithm(GA) and repulsive particle swarm optimization(RPSO) algorithm are used to find the eight properties of a charring material; thermal conductivity(virgin, char), specific heat(virgin, char), char density, heat of pyrolysis, pre-exponential factor and activation energy by using the surface temperature and mass loss rate history data which are obtained from the calculated experiments. Results show that the RPSO algorithm has better performance in estimating the eight pyrolysis properties than the basic GA for problems considered in this study.
Measurement Uncertainty Analysis of a Turbine Flowmeter for Fuel Flow Measurement in Altitude Engine Test
Yang, In-Young ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 42~47
DOI : 10.5293/KFMA.2011.14.1.042
Measurement uncertainty analysis of fuel flow using turbine flowmeter was performed for the case of altitude engine test. SAE ARP4990 was used as the fuel flow calculation procedure, as well as the mathematical model for the measurement uncertainty assessment. The assessment was performed using Sensitivity Coefficient Method. 11 parameters involved in the calculation of the flow rate were considered. For the given equipment setup, the measurement uncertainty of fuel flow was assessed in the range of 1.19~1.86 % for high flow rate case, and 1.47~3.31 % for low flow rate case. Fluctuation in frequency signal from the flowmeter had the largest influence on the fuel flow measurement uncertainty for most cases. Fuel temperature measurement had the largest for the case of low temperature and low flow rate. Calibration of K-factor and the interpolation of the calibration data also had large influence, especially for the case of very low temperature. Reference temperature, at which the reference viscosity of the sample fuel was measured, had relatively small contribution, but it became larger when the operating fuel temperature was far from reference temperature. Measurement of reference density had small contribution on the flow rate uncertainty. Fuel pressure and atmospheric pressure measurement had virtually no contribution on the flow rate uncertainty.
Three-Dimensional Flow and Aerodynamic Loss Downstream of Turbine Rotor Blade with a Cutback Cavity Squealer Tip
Kim, Seon-Ung ; Lee, Sang-Woo ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 48~54
DOI : 10.5293/KFMA.2011.14.1.048
The effect of channel cutback on three-dimensional flow fields and aerodynamic losses downstream of a cavity squealer tip has been investigated in a turbine rotor cascade for the squealer rim height-to-chord ratio and tip gap height-to-chord ratio of
= 5.51% and h/c = 2.0% respectively. The cutback length-to-camber ratio is changed to be
= 0.0, 0.1, 0.2 and 0.3. The results show that longer cutback delivers not only stronger secondary flow but also higher aerodynamic loss in the tip leakage vortex region, meanwhile it leads to lower aerodynamic loss in the passage vortex region. The discharge of cavity fluid through the cutback opening provides a beneficial effect in the reduction of aerodynamic loss, whereas there also exists a side effect of aerodynamic loss increase due to local wider tip gap near the trailing edge. With increasing
from 0.0 to 0.3, the aerodynamic loss coefficient mass-averaged all over the measurement plane tends to increase slightly.
Numerical Analysis for a Supersonic Turbine having Square Section Nozzles
Park, Pyun-Goo ; Jeong, Eun-Hwan ; Kim, Jin-Han ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 55~60
DOI : 10.5293/KFMA.2011.14.1.055
Numerical analyses of a turbine redesigned to achieving the weight reduction by equipping square nozzles and the original turbine have been conducted and the results have been compared. The results show that the turbine with square section nozzles has more even flow distribution at the first row rotor inlet and less inactive areas but the loss induced by wake is increased. Despite the wake loss, the newly designed turbine shows better performance than the original one. It has also been found that the turbine performance can be improved by reshaping its stator and second row rotor.
Water Tests of Fuel Pump for 75-ton Class Liquid Rocket Engine
Kim, Dae-Jin ; Choi, Chang-Ho ; Hong, Soon-Sam ; Kwak, Hyun-D. ; Kim, Jin-Han ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 61~65
DOI : 10.5293/KFMA.2011.14.1.061
A series of water tests of a fuel pump for liquid rocket engines are performed at a room temperature. According to the test results, the head coefficient of the pump follows the conventional similarity rule - unlike this, the pump shows better efficiency with higher rotational speed. Also, it is found that the pressure at the rear bearing outlet is higher than expected because the inlet of bypass pipe line is narrow. Furthermore, the cavitation performance of the fuel pump is found to be sufficient for the engine operation and is better at the lower flow ratio and higher rotational speed.
Shape Optimization of a Rotating Two-Pass Duct with a Guide Vane in the Turning Region
Moon, Mi-Ae ; Kim, Kwang-Yong ;
The KSFM Journal of Fluid Machinery, volume 14, issue 1, 2011, Pages 66~76
DOI : 10.5293/KFMA.2011.14.1.066
The heat transfer and pressure loss characteristics of a rotating two-pass channel with a guide vane in the turning region have been studied using three-dimensional Reynolds-averaged Navier-Stokes (RANS) analysis, and the shape of the guide vane has been optimized using surrogate modeling optimization technique. For the optimization, thickness, location and angle of the guide vanes have been selected as design variables. The objective function has been defined as a linear combination of the heat transfer and the friction loss related terms with a weighting factor. Latin hypercube sampling has been applied to determine the design points as design of experiments. A weighted-average surrogate model, PBA has been used as the surrogate model. The guide vane in the turning region does not influence the heat transfer in the first passage upstream of the turning region, but enhances largely the heat transfer in the turning region and the second passage. In an example of the optimization, the objective function has been increased by 13.6%.