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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 18, Issue 6 - Dec 2015
Volume 18, Issue 5 - Oct 2015
Volume 18, Issue 4 - Aug 2015
Volume 18, Issue 3 - Jun 2015
Volume 18, Issue 2 - Apr 2015
Volume 18, Issue 1 - Feb 2015
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Effect of the Dihedral Stator on the Loss in a Transonic Axial Compressor
Hwang, Dongha ; Choi, Minsuk ; Baek, Jehyun ;
The KSFM Journal of Fluid Machinery, volume 18, issue 5, 2015, Pages 5~12
DOI : 10.5293/kfma.2015.18.5.005
This paper presents a numerical investigation of the effect of the dihedral stator on the loss in a transonic axial compressor. Four stator geometries with different stacking line variables are tested in the flow simulations over the whole operating range. It is found that a large shroud loss at the rotor outlet and the subsequent shroud corner separation in the stator passage occur at low mass flow rate. The hub dihedral stator and bowed blade generate unexpected hub-corner-separation, thereby causing a large total pressure loss over the entire operating range. However, the corresponding blockage forces the high momentum flow near the hub to divert toward the upper part of the passage suppressing the negative axial velocity region. The dihedral stator increases deflection angle and secondary vorticity near the endwall where the dihedral is applied. As a result, the endwall loss which is related to the endwall relative velocity decreases.
A Study on Structural Analysis of High-Pressure Pipeline Retainer-Type Ball Valve by Pressure Testing of the Industrial Standard
Kim, Chul Kyu ; Yoon, Joon Yong ;
The KSFM Journal of Fluid Machinery, volume 18, issue 5, 2015, Pages 13~18
DOI : 10.5293/kfma.2015.18.5.013
This study has been performed to evaluate the safety of the retainer-type ball valve for a high-pressure pipeline to a district heating plant. The retainer-type ball valve is an improved design for conventional ball valves, such as the floating ball valve and the trunnion ball valve. Numerical analysis of the valve design verification has been applied to investigate the safety factor and seat leakage of the DN300 and DN400 sizes. The given condition to solve the structural analysis was based on the international standard for ISO 5208. In this study, the methods for structural analysis are described in detail. The structural analysis results present the deformations, the equivalent stresses, and the safety factors. Through these results, this study successfully demonstrates the safety and seat leakage of the retainer-type ball valve. They also streamline the process of development for valve manufacturing.
Internal Flow Characteristics of a Francis Hydro Turbine Model by Internal Flow Passage Shapes
Chen, Zhenmu ; Wei, Qingsheng ; Singh, Patrick Mark ; Choi, Young-Do ;
The KSFM Journal of Fluid Machinery, volume 18, issue 5, 2015, Pages 19~25
DOI : 10.5293/kfma.2015.18.5.019
As a core component of a hydropower station, hydro turbines play a vital role in the integration of a power station. Research on the technology of hydro turbine is continuously increasing with the development of water electricity. On the basis of one-dimensional loss analysis, for three-dimension design, there are a lot of dimension of the internal flow passage shapes that are determined by experience. Therefore, the effect of the internal flow passage shapes on the performance and internal flow characteristics of a Francis hydro turbine model is investigated in this study. In this study, the small curvature of runner blade trailing edge shape is good for improving the efficiency of Francis turbine. The straight stay vane leading edge is good for suppressing the secondary flow. Moreover, suitable tongue passage shape and stay vane number improve the performance of the turbine considerably.
Performance Evaluation on the Pipelines for an Automated Vacuum Waste Collection System
Jang, Choon-Man ; Lee, Sang-Moon ;
The KSFM Journal of Fluid Machinery, volume 18, issue 5, 2015, Pages 26~32
DOI : 10.5293/kfma.2015.18.5.026
This paper describes performance evaluation of design parameters, air velocity inside a pipeline and pressure along a pipeline, using experimental measurements in an automated vacuum waste collection system. Automatic robot having six cameras is introduced to analyze the internal pipeline conditions whether waste accumulates at the bottom of the pipeline or not. Throughout the experimental measurements of the pipeline having the various shapes, it is found that pressure and internal air velocity linearly increase along the pipeline from a waste inlet to a waste collection station while air density decreases due to the air compression effect with high pressure. Although air velocity inside the pipeline at a waste inlet keeps design velocity range between 20 m/s and 30 m/s, it is noted that air velocity near the waste collection station exceeds maximum design velocity of 30 m/s. Pressure increase per unit length is changed from 17.6 Pa/m to 18.9 Pa/m, which depends on the air velocity inside the pipeline. From the investigation inside the pipeline with CCTV loaded on an automated robot, waste accumulated at the bottom of the pipeline is mainly found at the downstream of a circular curved pipe, an inclined pipe and a bended pipe.
Cycle Analysis and Experiment for a Small-Scale Organic Rankine Cycle Using a Partially Admitted Axial Turbine
Cho, Soo-Yong ; Cho, Chong-Hyun ;
The KSFM Journal of Fluid Machinery, volume 18, issue 5, 2015, Pages 33~41
DOI : 10.5293/kfma.2015.18.5.033
Organic Rankine cycle (ORC) has been used to generate electrical or mechanical power from low-grade thermal energy. Usually, this thermal energy is not supplied continuously at the constant thermal energy level. In order to optimally utilize fluctuating thermal energy, an axial-type turbine was applied to the expander of ORC and two supersonic nozzle were used to control the mass flow rate. Experiment was conducted with various turbine inlet temperatures (TIT) with the partial admission rate of 16.7 %. The tip diameter of rotor was to be 80 mm. In the cycle analysis, the output power of ORC was predicted with considering the load dissipating the output power produced from the ORC as well as the turbine efficiency. The predicted results showed the same trend as the experimental results, and the experimental results showed that the system efficiency of 2 % was obtained at the TIT of
Development of Test Facility for Micro Gas Turbine
Lim, Hyung-Soo ; Choi, Bum-Seog ; Park, Moo-Ryong ; Hwang, Soon-Chan ; Park, Jun-Young ; Seo, Jeongmin ; Bang, Je-Sung ; Lim, Young-Chul ; Oh, In-Kyun ; Kim, Byung Ok ; Cho, Ju Hyeong ;
The KSFM Journal of Fluid Machinery, volume 18, issue 5, 2015, Pages 42~48
DOI : 10.5293/kfma.2015.18.5.042
To improve the core technology of the micro gas turbine, the performance test facility was developed. This paper is focusing on the explanation of the characteristics of micro gas turbine and its assist devices. Major part of micro gas turbine were radial type of compressor, annular type of combustor, radial type of turbine, thrust foil bearing, radial foil bearing and generator. The assist devices were consist of exhaust duct, inverter, data acquisition system, load bank and test cell. Before building up the test facility, the component test was previously conducted to confirm the component performance. After the test facility was prepared, the motoring test was conducted to investigate the rotor dynamic characteristics of the micro gas turbine. Also, the part load performance test was performed. With a developed micro gas turbine test facility, the improved core technology about the micro gas turbine can be suggested to the related industries.
A Study on Flow Characteristics with the Installed Location Change of Mechanical Deflector
Kim, Kyoung-Ryun ; Park, Jong-Ho ;
The KSFM Journal of Fluid Machinery, volume 18, issue 5, 2015, Pages 49~53
DOI : 10.5293/kfma.2015.18.5.049
Thrust vector control is the method which generates the side force and roll moment by controlling exhausted gas directly in a rocket nozzle. TVC is classified by mechanical and fluid dynamic methods. Mechanical methods can change the flow direction by several objects installed in a rocket nozzle exhaust such as tapered ramp tabs and jet vane. Fluid dynamic methods control the flight direction with the injection of secondary gaseous flows into the rocket nozzle. The tapered ramp tabs of mechanical methods are used in this paper. They installed at the rear in the rocket nozzle could be freely moved along axial and radial direction on the mounting ring to provide the mass flow rate which is injected from the rocket nozzle. TVC of the tapered ramp tabs has the potential to produce both large axial thrust and high lateral force. We have conducted the experimental research and flow analysis of ramp tabs to show the performance and the structural integrity of the TVC. The experiments are carried out with the supersonic cold flow system and the schlieren graph. This paper provides to analyze the location of normal shock wave and distribution of surface pressure on the region enclosed by the tapered ramp tabs.
A Study on Aerodynamic Characteristics with the Supersonic Nozzle Quantity
Lee, Jong-Hoon ; Kim, Kyoung-Ryun ; Park, Jong-Ho ;
The KSFM Journal of Fluid Machinery, volume 18, issue 5, 2015, Pages 54~58
DOI : 10.5293/kfma.2015.18.5.054
The objective of this paper is to investigate the flow characteristics of the multi nozzle. The configurations of the single, the 3- and the 6-nozzle were selected under Mach number of 2.5. Under-expanded pressure ratio such as 1.2, 1.6 and 2.0 were selected to elucidate interference of the free jet. The flow visualization was carried out with the Schlieren system and a supersonic cold-flow system. Also, the flow characteristics were studied computationally with the density measurements. Reasonable agreement between experimental and theoric equation has been achieved qualitatively.