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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
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Volume & Issues
Volume 16, Issue 6 - Dec 2013
Volume 16, Issue 5 - Oct 2013
Volume 16, Issue 4 - Aug 2013
Volume 16, Issue 3 - Jun 2013
Volume 16, Issue 2 - Apr 2013
Volume 16, Issue 1 - Feb 2013
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Dynamic Response of a 2.75MW Wind Turbine Applying Torque Control Method Based on Torque-Mode
Lim, Chae-Wook ;
The KSFM Journal of Fluid Machinery, volume 16, issue 6, 2013, Pages 5~11
DOI : 10.5293/kfma.2013.16.6.005
Torque control methods of wind turbine are mainly classified into two methods: torque-mode and speed-mode methods. The traditional torque-mode method, in which generator torque proportional to square of generator speed is determined, has been chosen in many wind turbines but its response is slower as they are larger in multi-MW size. Torque control methods based on both speed-mode and torque-mode can be used to make response of wind turbine faster. In this paper, two torque control methods based on the traditional torque-mode method are applied to a 2.75 MW wind turbine. It is shown through some simulation results for real turbulence wind speeds that torque control method based on torque-mode has the merit of reducing fluctuations of generated power than PI controller based on speed-mode.
Performance Characteristics according to the Outlet Impeller Blade Shape of a Centrifugal Blower
Lee, Jong-Sung ; Jeon, Hyun-Jun ; Jang, Choon-Man ;
The KSFM Journal of Fluid Machinery, volume 16, issue 6, 2013, Pages 12~18
DOI : 10.5293/kfma.2013.16.6.012
This paper presents the performance characteristics of a centrifugal blower using the design parameters of an impeller blade. Two design variables, the bending length from the blade trailing edge and bending angles of an impeller blade, are introduced to analyze the effects on the blower performance. Three-dimensional Navier-Stokes equations with shear stress transport turbulence model are introduced to analyze the performance and internal flow of the blower. Relatively good agreement between experimental measurements and numerical simulation at the design flow condition is obtained. Throughout present study, it is known that pressure increases as the bending length from the trailing edge and bending angle increase while efficiency decreases. But efficiency is decreased. Detailed flow field inside the centrifugal blower is also analyzed and compared.
Effect of Tip Gap Height on Heat/Mass Transfer over a Cavity Squealer Tip
Kang, Dong Bum ; Moon, Hyun Suk ; Lee, Sang Woo ;
The KSFM Journal of Fluid Machinery, volume 16, issue 6, 2013, Pages 19~25
DOI : 10.5293/kfma.2013.16.6.019
The effect of tip gap height on heat/mass transfer characteristics on the floor of cavity squealer tip has been investigated in a turbine cascade for power generation by employing the naphthalene sublimation technique. The squealer rim height is chosen to be an optimal one of
= 5.51% for the tip gap height-to-chord ratios of h/c = 1.0, 2.0, 3.0 and 4.0%. The results show that heat transfer on the cavity floor is strongly dependent upon the behavior of the cavity flow falling down onto the floor. For lower h/c, the floor heat transfer is influenced by the tip leakage flow falling down along the inner face of the suction-side squealer, whereas the floor heat transfer for higher h/c is augmented mainly due to the impingement of leakage flow on the floor near the leading edge. Compared to the plane tip surface heat transfer, the cavity floor heat transfer is less influenced by h/c. For h/c = 1.0%, the average thermal load is as low as a half of the plane tip surface one, and the difference in the thermal load between the two cases tends to decrease with increasing h/c.
Methodology for Centrifugal Stress Estimation Model Development of Large Steam Turbine Blades
Lee, Byounghak ; Park, Jongho ;
The KSFM Journal of Fluid Machinery, volume 16, issue 6, 2013, Pages 26~31
DOI : 10.5293/kfma.2013.16.6.026
Last blades of low-pressure turbine in nuclear power plant are the highly damaged part and always suffered from different types of loadings leading to various stress components, stresses due to centrifugal force and steam flow loading. Especially, centrifugal stress generated by turbine rotation is one of the main problems and more significant than other stresses as they have the greatest effect on total stress. Therefore, this study was performed to obtain the important information for estimation model development of the blade centrifugal stress level and distribution.
A Study on Reliability of Kriging Based Approximation Model and Aerodynamic Optimization for Turbofan Engine High Pressure Turbine Nozzle
Lee, Sanga ; Lee, Saeil ; Kang, Young-Seok ; Rhee, Dong-Ho ; Lee, Dong-Ho ; Kim, Kyu-Hong ;
The KSFM Journal of Fluid Machinery, volume 16, issue 6, 2013, Pages 32~39
DOI : 10.5293/kfma.2013.16.6.032
In the present study, three-dimensional aerodynamic optimization of high pressure turbine nozzle for turbofan engine was performed. For this, Kriging surrogate model was built and refined iteratively by supplying additional experimental points until the surrogate model and CFX result has effective difference on objective function. When the surrogate model satisfied this reliability condition and developed enough, optimum point was investigated. Commercial program PIAnO was used for optimization process and evolutionary algorithm was used for searching optimum point. As a result, difference between estimated value from Kriging surrogate model and CFD result converges within 0.01% and the optimized nozzle shape has 0.83% improved aerodynamic efficiency.
A Numerical Study on the Effect of Fin Pitch and Fin Array on the Heat Transfer Performance of a Pre-heater
Yoo, Ji Hoon ; Kim, Kuisoon ;
The KSFM Journal of Fluid Machinery, volume 16, issue 6, 2013, Pages 40~47
DOI : 10.5293/kfma.2013.16.6.040
In this paper, a numerical study was performed to investigate the performance characteristics of a pre-heater. The effects of fin pitch and fin array type(in-line, staggered, leaned array) were reported in terms of Colburn j-factor and Fanning friction factor f, as a function of Re. Three-dimensional numerical simulation has been performed by using flow analysis program, FLUENT 13.0. The results show that Colburn j-factor decreases with the decrease of fin pitch attached in the annular tube. But the fin pitch has little effect on f-factor. The staggered array and leaned array show improved heat transfer performance compared with in-line array, so that Colburn j-factor was increased. It also shows that the f-factor of leaned array is the highest in the studied range of Reynolds number.