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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 15, Issue 6 - Dec 2012
Volume 15, Issue 5 - Oct 2012
Volume 15, Issue 4 - Aug 2012
Volume 15, Issue 3 - Jun 2012
Volume 15, Issue 2 - Apr 2012
Volume 15, Issue 1 - Feb 2012
Selecting the target year
Tip Gap Flow and Aerodynamic Loss Generation over a Cavity Squealer Tip with the Variation of Pressure-Side Opening Length in a Turbine Cascade
Cheon, Joo Hong ; Lee, Sang Woo ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 5~10
DOI : 10.5293/kfma.2012.15.6.005
The effect of pressure-side opening length 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-tochord ratio of
= 5.05% and h/c = 2.0% respectively. The opening length-to-camber ratio is changed to be
= 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.7 The results show that longer OL leads not only to weaker secondary flow but also to lower aerodynamic loss in the tip leakage vortex region, while it significantly widens the area with high aerodynamic loss in the passage vortex region. The aerodynamic loss coefficient mass-averaged all over the measurement plane is kept almost constant for
, whereas it increases rapidly for
> 0.3 in proportion to
. There is little deterioration in flow turning with increasing
The Design and Analysis of Composite Advanced Propeller Blade for Next Generation Turboprop Aircraft
Choi, Won ; Kim, Kwang-Hae ; Lee, Won-Joong ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 11~17
DOI : 10.5293/kfma.2012.15.6.011
The one way fluid structure interaction analysis on advanced propeller blade for next generation turboprop aircraft. HS1 airfoil series are selected as a advanced propeller blade airfoil. Adkins method is used for aerodynamic design and performance analysis with respect to the design point. Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. propeller geometry is generated by varying chord length and pitch angle at design point. Blade sweep is designed based on the design mach number and target propulsion efficiency. The aerodynamic characteristics of the designed Advanced propeller were verified by CFD(Computational Fluid Dynamic) and showed the enhanced performance than the conventional propeller. The skin-foam sandwich structural type is adopted for blade. The high stiffness, strength carbon/epoxy composite material is used for the skin and PMI(Polymethacrylimide) is used for the foam. Aerodynamic load is calculated by computational fluid dynamics. Linear static stress analysis is performed by finite element analysis code MSC.NASTRAN in order to investigate the structural safety. The result of structural analysis showed that the design has sufficient structural safety. It was concluded that structural safety assessment should incorporate the off-design points.
Performance Analysis of a Steam Injected Gas Turbine Combined Heat and Power System Considering Turbine Blade Temperature Change
Kang, Soo Young ; Kim, Jeong Ho ; Kim, Tong Seop ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 18~24
DOI : 10.5293/kfma.2012.15.6.018
This study simulated the operation of a steam injected gas turbine combined heat and power (CHP) system. A full off-design analysis was carried out to examine the change in the turbine blade temperature caused by steam injection. The prediction of turbine blade temperature was performed for the operating modes suggested in the previous study where the limitation of compressor surge margin reduction was analyzed in the steam injected gas turbine. It was found that both the fully injected and partially injected operations suggested in the previous study would cause the blade temperature to exceed that of the pure CHP operation and the under-firing operation would provide too low blade temperature. An optimal operation was proposed where both the turbine inlet temperature and the injection amount were modulated to keep both the reference turbine blade temperature and the minimum compressor surge margin. The modulation was intended to maintain a stable compressor operation and turbine life. It was shown that the optimal operation would provide a larger power output than the under-firing operation and a higher efficiency than the original partially injected operation.
CFD Analysis on the Performance and Internal Flow of a Micro Cross-Flow Hydro Turbine in the Range of Very Low Specific Speed
Choi, Young-Do ; Son, Sung-Woo ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 25~30
DOI : 10.5293/kfma.2012.15.6.025
Renewable energy has been interested because of fluctuation of oil price, depletion of fossil fuel resources and environmental impact. Amongst renewable energy resources, hydropower is most reliable and cost effective way. In this study, to develop a new type of micro hydro turbine which can be operated in the range of very low specific speed, a cross-flow hydro turbine with simple structure is proposed. The turbine is designed to be used at the very low specific speed range of hydropower resources, such as very high-head and considerably small-flow rate water resources. CFD analysis on the performance and internal flow characteristics of the turbine is conducted to obtain a practical data for the new design method of the turbine. Results show that optimized arrangement of guide vane angle and inner guide angle can give contribution to the turbine performance improvement.
Feature Parameter Analysis for Rotor Fault Diagnosis
Jeoung, Rae-Hycuk ; Chai, Jang-Bom ; Lee, Byoung-Hak ; Lee, Do-Hwan ; Lee, Byung-Kon ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 31~38
DOI : 10.5293/kfma.2012.15.6.031
Rotor of rotating machinery is the highly damaged part. Fault of 7 different types was confirmed as the main causes of rotor damage from the pump failure history data in domestic and U.S. nuclear. For each fault types, simulation testing was performed and fault signals were collected form the sensors. To calculate the statistical parameters of time-domain & frequency-domain, measured signals were analyzed by using the discrete wavelet transform, fast fourier transform, statistical analysis. Total 84 parameters were obtained. And Effectiveness factor were used to evaluate the discrimination capacity of each parameter. From the effectiveness factor, RAW-P4/RAW-P7/WT2-NNL/WT2-EE/WT1-P1 showed high ranking. Finally, these parameters were selected as the feature parameters of intelligent fault diagnostics for rotor.
Design Parameter Sensitivity Analysis of a 200kW Class Micro Gas Turbine System
Shin, Hyun Dong ; Kang, Do Won ; Kim, Tong Seop ; Choi, Mun-Kyoung ; Park, Pil Je ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 39~45
DOI : 10.5293/kfma.2012.15.6.039
This paper describes the outcome of the design of a 200 kW class micro gas turbine and the sensitivity of its performance (efficiency and power) to the variations in major design parameters. The reference design parameters were set up based on the best available component technologies. The resulting net electricity generation efficiency of the micro gas turbine package was found to be competitive to those of other systems in the market. The sensitivities of power and efficiency to the variations in compressor and turbine efficiencies, pressure ratio, turbine inlet temperature, recuperator effectiveness, secondary air ratio, pressure loss ratios of both the cold and hot sides of the recuperator were estimated. Based on the sensitivity data, a simplified method to predict the variation in system performance responding to the combinations of small changes in all design parameters were set up and validated.
Axial Thrust Control of High-speed Centrifugal Pump with Cavity Vanes
Kim, Dae-Jin ; Choi, Chang-Ho ; Noh, Jun-Gu ; Kim, Jinhan ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 46~50
DOI : 10.5293/kfma.2012.15.6.046
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.
Performance Evaluation of Compressor to Develop 500W Class Ultra-Micro Gas Turbine
Seo, JeongMin ; Park, Jun Young ; Choi, Bum Seok ; Park, Moo Ryong ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 51~57
DOI : 10.5293/kfma.2012.15.6.051
Performance evaluation of a compressor is conducted to develop 500W class ultra-micro gas turbine (UMGT) for power generation. The performance evaluation is essential to check the performance of the components of UMGT, a radial turbine, a centrifugal compressor, an angular combustor and a shaft, which have been already designed in previous researches. The purpose of this study is to introduce the development process of the performance testing equipments of the UMGT and to present the results of compressor performance test. For the performance evaluation of the compressor, two test equipments are developed and the initial test equipment uses commercial static air bearings with long shaft. In the improved test equipment, static air bearing is improved to increase rotating speed and compressed nitrogen gas is used for utility gas of the static air bearing to supply compressed air in a stable and steady way. To increase rotating speed to 320,000 rpm, 80% speed of design speed, compressed air is provided to the turbine. The performance map of the compressor with the 50%, 60%, 70%, 80% speed of design point is presented. The results of the performance test of compressor show a good agreement with the results of 3D CFD.
A Numerical Study on the Performance Improvement of Guide Vanes in an Axial-flow Pump
Park, Hyun-Chang ; Kim, Sung ; Yoon, Joon-Yong ; Choi, Young-Seok ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 58~63
DOI : 10.5293/kfma.2012.15.6.058
This paper presents a numerical study on the performance improvement of axial-flow pump with guide vanes. Design optimization for guide vanes in an axial-flow pump has been studied through the implementation of a commercial CFD code and DOE (design of experiments). We also discussed how to improve the performance of the axial-flow pump by designing the guide vanes. Geometric design variables were defined by the meridional plane and vane plane development of guide vanes. The effect of hub tip ratio analyzed the meridional plane of guide vanes. The importance of the geometric design variables was analyzed using
factorial designs. The objective functions for guide vane geometric variables were defined as the total efficiency and the total head at the design flow rate. From the
factorial design results, the important design variables were found and the performance was increased in comparison with the base design model.
A Study on Repair Case of Journal and Bearing Damage for 25MW Industrial Gas Turbine
Kim, Byung Ok ; Sun, Kyung Ho ; Lee, An Sung ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 64~69
DOI : 10.5293/kfma.2012.15.6.064
This paper deals with the study on repair case of journal shaft and bearing damage in 25MW industrial gas turbine caused by sudden blackout, operation mistake, and logic abnormal, etc. When a serious accident such as journal and bearing damage in a gas turbine occurs, the domestic local companies having the gas turbine are dependent on manufacturer for all maintenance and repair schedule until now. This case study shows that the damaged gas turbine is normally re-operated itself in domestic by establishing repair schedule in a short period of time, repairing damage journal shaft and tilting pad bearings, and performing rotating test for a reliability check. This paper can be regarded as the important case study of emergency test run experience of the refurbished 25MW gas turbine rotor.
Waterhammer for the In-Line Intake Pumping Station with Air Chamber
Kim, Kyung-Yup ; Ahn, Cheoul-Hong ; Kim, Bum-Jun ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 70~76
DOI : 10.5293/kfma.2012.15.6.070
Recently, because people are taking a great interest in the water supply system and the related facilities are getting larger, the surge suppression is very important problem. The waterhammer occurs when the pumps are started or stoped for operation or tripped due to the power failure. As the waterhammer problems as a result of the pump power failure were very serious, these situations were carefully investigated. Accordingly, we carried out both numerical simulations and field tests to confirm the safety of Juam intake pumping station in which had the in-line pumps. In this paper, it was reviewed that the water supply system has the reliability on the pressure surge, in case the air chambers were installed at both the inlet and the oulet of the in-line pumping station. From the numerical simulations, we found that negative pressure occurred at the inlet disappeared and high pressure occurred at the outlet reduced due to the air chambers. And these results of numerical simulations verified by the field tests. The field tests carried out in case of normal start, normal stop, one and two of pumps emergency stop. By results of simulations and field tests, we are sure that Juam intake pumping station in which have the air chambers is safe for the waterhammer. In addition, we suggested the operation methods of facilities for safe maintenance of the pumping station.
Design Optimization of a Single-Stage Transonic Axial Compressor and Test Evaluation of Its Aerodynamic Performance
Park, Tae Choon ; Kang, Young-Seok ; Hwang, Oh-Sik ; Song, Ji-Han ; Lim, Byeung Jun ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 77~84
DOI : 10.5293/kfma.2012.15.6.077
The aerodynamic performance of a single-stage transonic axial compressor was experimentally evaluated by measuring pressure and temperature distribution at the inlet and outlet of the compressor. The compressor was developed by Korea Aerospace Research Institute through multidisciplinary design optimization (MDO) method, especially integrating aerodynamic performance and structural stability. The test results show that the pressure ratio is 1.65 and the efficiency is 85.8 % at design point, where the corrected speed is 22,000 rpm and the corrected mass flow rate is 15.4 kg/s, and it has a good agreement with the design target and computational results. The distribution of pressure ratio is very steep at design speed, compared with the trend of other subsonic compressors. Also the static pressure distribution on the stator casing shows that the blade loading is gradually increasing through the stage as designed.
Numerical Investigation on Internal Flow Field of a Single-Stage Transonic Axial Compressor
Song, Ji-Han ; Hwang, Oh-Sik ; Park, Tae Choon ; Lim, Byung-Jun ; Yang, Soo-Seok ; Kang, Young-Seok ;
The KSFM Journal of Fluid Machinery, volume 15, issue 6, 2012, Pages 85~91
DOI : 10.5293/kfma.2012.15.6.085
Numerical simulations on a single stage transonic compressor which is developed by Korea Aerospace Research Institute are carried out and their results are compared with experimental data for cross validations. Comparisons between experimental data and numerical simulation results show good agreements on a performance curve, static pressure and total pressure distributions. CFD results show that there is a clear interaction between tip leakage flow and normal shock in the rotor passage. Tip leakage flows are almost dissipated after the strong normal shock and it forms a strong recirculation near the blade tip. Also a large separation region grows on the suction surface just after the normal shock. As the pressure ratio and blade loading increase, the normal shock line moves upstream and it starts to deviate from the blade leading edge. Then the tip leakage flow does not overcome the strong adverse pressure gradient and flow blockage originated from the tip recirculation region. As a result, the tip leakage flow heads for the neighboring blade leading edge, which results in a compressor stall.