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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 3, Issue 4 - Dec 2000
Volume 3, Issue 3 - Sep 2000
Volume 3, Issue 2 - Jun 2000
Volume 3, Issue 1 - Mar 2000
Selecting the target year
Integrity Evaluation and Root Cause Analysis of Cracks at the Volute Tongue of Centrifugal Pump
Park, Chi-Yong ; Kim, Jin-Weon ; Kim, Yang-Seok ;
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 7~14
This paper provides integrity evaluation and root cause analysis for defects observed at volute tongue, or cutwater, of the operating centrifugal pump in power plant. The cause of the cracks are analyzed and reviewed from the viewpoint of the operation and maintenance of the pumps, and the sample obtained from the cracked volute tongue of the pump are examined. At first, in-situ hardness test and microstructure examination were performed to understand the cause of cracking at volute tongue. The evaluation of structural integrity and the possibility of the crack propagation is also evaluated. Cracks were typical intergranular cracking and propagated along with prior austenite grain boundary. At easing volute tongue, the hardness was higher than ASTM requirement and a large amount of intergranular Cr carbide was precipitated. These were due to high C content in material. P content was also higher than ASTM requirement. Therefore, Cr carbide precipitation and P segregation at grain boundary, caused by higher C and P content in material, resulted in intergranular cracking of casing volute tongue. This procedure for integrity evaluation and root cause analysis is used to guide, and support the pump designer and manufacturer's material selection and process design to avoid a costly, unplanned outage of plant.
Research on Improvement of Performance of Anemometer Using PTC Thermistor
Yoon, Joon-Yong ; Cho, Nahm-Gyoo ; Kim, Jin-Rae ; Sung, Nak-Won ; Kim, Hwang-Jin ;
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 15~21
An anemometer employing the bulk PTC thermistor as the sensing element is investigated in this study. The numerical and experimental works are carried out to improve the sensitivity problem of the element by focusing fluid dynamics point of view. The typical shape of the sensing element has been used as a rectangular type, but this shape has a sensitivity problem because of flow separations on the sharp edge when the flow direction is different from that of the sensing element. In order to reduce the reading error, the installer has to be very careful about the flow direction. The reading error fluctuation by time as well as the sensitivity problem can be improved considerably through this study. It can be concluded that the small change of the sensor shape can improve the performance of the flow sensor.
Performance Improvement of a Scroll Compressor by Heat Transfer Analysis
Hong, S. W. ; Rew, H. S. ;
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 22~29
Numerical analysis using three dimensional finite volume method for the discretization, adaptive grid method for the numerical accuracy, multiple rotating frame method for the rotating body and the standard
model for the turbulent flow was performed to understand the heat transfer phenomena and to improve the efficiency of the scroll compressor. The temperature measurement was carried out under ARI condition. It was found that the fluid temperature in the compressor was predicted accurately while the temperature of the motor coil showed large discrepancy between the calculation and experiment due to the large anisotropy of the conductivity and non homogeneity. We found that the efficiency of the compressor depends on the inlet temperature of the compressing part and the flow pattern around the inlet region of the compressing part influences the inlet temperature due to high surface temperature of the main frame. The efficiency of the compressor using Coanda effect is higher than the previous one because the smooth suction at the inlet region of the compressing part leads to low heat transfer to the refrigerant of the compressor.
Study on the Minimization of Shape Parameters by Reverse Design of an Axial Turbine Blade
Cho, Soo-Yong ; Oh, Koon-Sup ; Yoon, Eui-Soo ; Choi, Bum-Seog ;
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 30~37
Several reverse design methods are developed and applied to the suction or pressure surface for finding design values of blade geometry for a given axial turbine blade. Re-designed blade profiles using shape parameters are compared with measured blade data. Essential shape parameters for blade design are induced by the procedure of reverse design for best fitting. Characteristics of shape parameters are evaluated through the system design method and restriction conditions of structural stability or aerodynamic flow loss. Some of shape parameters i.e blade radius or exit blade angle etc., are classified to weakly adjustable shape parameters, otherwise strongly adjustable shape parameters which would be applied for controlling blade shape. Average deviation values between the measured data and re-designed blade using shape parameters are calculated for each design method. Comparing with the average deviation for a given blade geometry, minimum shape parameters required to design a blade geometry are obtained.
Application of Generalized Experimental Data Correlation in Centrifugal Compressor Design
Cho, Gyu-Sik ; Kim, Jin-Han ; Yang, Soo-Seok ; Lee, Dae-Sung ; Mileshin, Victor I. ;
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 38~43
Recently, KARI(Korea Aerospace Research Institute, Korea) and CIAM(Central Institute of Aviation Motors, Russia) have made an effort in developing a centrifugal compressor for a small gas turbine engine as part of a collaboration program. This compressor has been designed as a sub-component for an axial-centrifugal compression system for a small turbo-shaft engine aiming adiabatic efficiency higher than 0.81. The geometrical design requirement imposes restrictions to have high inlet hub-to-tip ratio and inlet swirl flow. In this study, the compressor has been designed using the generalized experimental data established from those compressors having pressure ratio of 3.7 to 5. From this generalized empirical correlation, desirable values of design parameters could be obtained. Subsequently, quasi-3D and 3D viscous flow analyses have been performed to ensure the adopted methodology. It is expected that the centrifugal compressor provides total pressure ratio of 4.89, corrected mass flow-rate of 1.64kg/sec, and adiabatic efficiency of 0.815 with inlet hub-to-tip ratio of 0.641. These relatively high total pressure ratio and inlet hub-to-tip ratio are the main distinctive features in this design. Besides, one of the main features of this centrifugal compressor is the adoption of a double-row bladed diffuser to effectively decelerate the transonic flow leaving the impeller. The compressor has been manufactured and will be tested in the near future.
Development of the Centrifugal Compressor for a R134a Turbo-Chiller Part 1 : Design of the Centrifugal Compressor
Lee, Yongduck ; Jeong, Jinhee ; Lee, Hyeonkoo ; Yoon, Pil-Hyun ; Kim, Kilyoung ;
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 44~51
The present study has been conducted to design the high efficiency centrifugal compressor for a R134a turbo-chiller. The centrifugal compressor consists of an impeller with splitters, two vaneless diffusers, a low-solidity vaned diffuser and a volute. A cycle analysis program for a turbo-chiller was developed to obtain compressor design parameters and requirements. We have designed the high efficiency centrifugal compressor by applying the repeated design procedure including a meanline design, a 3D geometry generation and fluid dynamic loading calculations.
Numerical Study on the Waterhammer of PalDang Intake Pumping Station
Kim, Kyung-Yup ; Yu, Teak-In ;
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 52~58
The numerical study on the waterhammer was carried out for the intake pumping station of the metropolitan water supply 6th stage project. Because the waterhammer problems as a result of the pump power failure were the most important, these situations were carefully investigated. The surge tank and the stand pipes effectively protected the tunnels md the downstream region of pipeline from the pressure surge. In case the moment of inertia of the pump and motor was above
, the column separation did not occur in the pipeline between the pumping station and the inlet of 1st tunnel. As the moment of inertia increased, the pressure surges decreased in the pipeline conveying raw water. The pump control valve was chosen as the main surge suppression device for the intake pumping station. After power failure, the valve disc should be rapidly closed in 2.5 seconds and controlled the final closure to 15 seconds by the oil dashpot. If the slamming happened to the pump control valve, there was some danger of this system damaging. As the reverse flow through the valve increased, the upsurge extremely increased.
유체기계 소음 해석 소프트웨어
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 59~64
PIV의 터보유체기계 적용
The KSFM Journal of Fluid Machinery, volume 3, issue 4, 2000, Pages 65~73