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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 17, Issue 6 - Dec 2014
Volume 17, Issue 5 - Oct 2014
Volume 17, Issue 4 - Aug 2014
Volume 17, Issue 3 - Jun 2014
Volume 17, Issue 2 - Apr 2014
Volume 17, Issue 1 - Feb 2014
Selecting the target year
A Study of Supersonic Nozzle Design for Partial Admitted Turbine Used on Organic Rankine Cycle
Cho, Soo-Yong ; Cho, Chong-Hyun ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 5~12
DOI : 10.5293/kfma.2014.17.6.005
Organic Rankine Cycle is widely used to convert the low-grade thermal energy to the electrical energy. However, usually available thermal energy is not supplied constantly. This makes hard to use positive displacement expanders. Hence, turbo-expander has merits to apply as an expander in ORC because it can operate well off-design points even though the mass flowrate is fluctuated. The thermal energy fluctuation causes the turbo-expander to operate in partial admission. In addition, supersonic nozzles are required so that the partially admitted turbine operates efficiently. In this study, R245fa was chosen as a working fluid of ORC. A design method and an analysis technique of supersonic nozzle based on R245fa were developed. The shape of the nozzle was designed by the characteristic method. The thermal properties within the nozzle were estimated and the predicted results were agreed well with the computed results.
Performance Test and Aerodynamic Design on the High Pressure Ratio Centrifugal Compressor of a Turbocharger
Kim, Hong-Won ; Ryu, Seung-Hyup ; Lee, Geun-Sik ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 13~20
DOI : 10.5293/kfma.2014.17.6.013
It is necessary to design a compressor with high pressure ratio that satisfies the IMO(international maritime organization) NOx emission regulation for the marine diesel engine. Impeller was designed using the modified slip factor with the flow coefficient. The main purpose of this study is to investigate the sensitivity of the compressor performance by the vaned diffuser geometries. The first vaned diffuser type was based on a NACA airfoil, the second was channel diffuser, and the third was conformally transformated configuration of a NACA65(4A10)06 airfoil. The sensitivity of the performance was calculated using a commercial CFD program for three different diffuser geometries. The channel diffuser showed the wide range of operation and higher pressure characteristics, comparing with the others. This is attributed to the flow stability at diffuser. Combined with this results with impeller design, the optimized compressor was designed and verified by the test results.
Characteristics of Cavitating Flow in Turbopump Inducer/Impeller
Kim, Changhyun ; Choi, Chang-Ho ; Baek, Jehyun ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 21~28
DOI : 10.5293/kfma.2014.17.6.021
Propellent should be pressurized inside the turbopump to gain high thrust in a projectile. Turbopump is composed of an inducer, which prevents impeller performance deterioration, and an impeller. Several types of cavitation occur inside the inducer, numerous experiments and CFD simulations are conducted. Though, an inducer takes only small portion of total head of the pump and the following impeller determines whole turbopump performance. In addition, low inlet pressure makes the flow to be cavitated not only at the inducer, but also at the impeller in real cases. Therefore, flow through an inducer and an impeller should considered simultaneously. In this study, LOX pump composed of an inducer and an impeller is analyzed by using commercial CFD code ANSYS CFX 13.0. Non-cavitating flow with high inlet pressure and cavitating flow with low inlet pressure are both simulated and head, suction performances are shown. Evolution of the flow and the cavitation by reducing cavitation number and effect of cavitation on pump performance are studied.
Numerical Study of Agitation Performance in a Drilling Mud Mixing Tank to Non-Newtonian Rheological Properties
Im, Hyo-Nam ; Lee, Hee-Woong ; Lee, In-Su ; Choi, Jae-Woong ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 29~37
DOI : 10.5293/kfma.2014.17.6.029
Non-Newtonian fluid mechanics takes charge of an important role in the oil industries. Especially in the oil well drilling process, the drilling fluid such as mud keeps the drill bit cool and clean during drilling, with suspending drill cuttings and lubricating a drill bit. The purpose of this study is to examine the effect of fluid mud rheological properties to predict different characteristics of non-Newtonian fluid in the mud mixing tank on offshore drilling platforms. In this paper, ANSYS fluent package was used for the simulation to solve the hydrodynamic force and to evaluate mud mixing time. Prediction of the power consumption and the pumping effectiveness has been presented with different operating fluid models as Newtonian and non-Newtonian fluid. The comparison between Newtonain mud model and non-Newtonian mud model is confirmed by the CFD simulation method of drilling mud mixing tank. The results present useful information for the design of the drilling mud mixing tanks and provide some guidance on the use of CFD tool for such non-Newtonian fluid flow.
20kW Turbine Development for OTEC System
Han, Sangjo ; Seo, JongBeom ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 38~43
DOI : 10.5293/kfma.2014.17.6.038
In Ocean, the temperature of the deep sea water is always lower than that of the surface sea water. The temperature difference between the surface water and deep sea water is about
. Based on thermodynamics, this temperature difference can be converted into mechanical power. The mechanical power can be converted to electricity through a generator. However, the temperature difference is relatively small compared with that of traditional steam turbines. It is difficult to apply the steam turbine technology for this small temperature difference directly. Therefore, the turbine for OTEC system using low temperature difference should be designed to meet the system requirement. The present study focuses on the development of the turbine for 20 kW OTEC system using R32. The paper includes the determination of working fluids, meridional design, turbine layout and 3D CFD results. With off-design points analysis, the full performance of 20kW OTEC turbine is investigated. Through the research, one stage radial type turbine with R32 as working fluid is successfully developed and can be applied to other high temperature heat source.
A Study on CFD Methodology of the Performance Predictionfor the UV Disinfection Reactor
Kim, Hyunsoo ; Bak, Jeonggyu ; Lee, Kunghyuk ; Cho, Jinsoo ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 44~51
DOI : 10.5293/kfma.2014.17.6.044
The disinfection method using UV has emerged as photodissociation in water disinfection. In order to predict performance for UV disinfection, CFD analysis was performed due to saving cost. Most CFD studies of UV reactor have used particle tracking method. However it demands additional analysis time, computing resource and phase besides working fluid. In this paper, pathogenic microorganisms` route is assumed to streamline of fluid to save computing time. the computational results are in good agreement with experimental results. The results of streamline method are compared with the particle tracking method. In conclusion, the effectiveness of streamline method for UV disinfection are confirmed.
Design Optimization of Fan-shaped Film Cooling Hole Array on Pressure Side Surface of High Pressure Turbine Nozzle
Lee, Sanga ; Rhee, Dong-Ho ; Kang, Young-Seok ; Kim, Jinuk ; Seo, Do-Young ; Yee, Kwanjung ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 52~58
DOI : 10.5293/kfma.2014.17.6.052
In the present work, design optimization of film-cooling hole array on the pressure side of high pressure turbine nozzle was conducted. There are four rows of fan-shaped film cooling holes on the nozzle pressure side surface and each row has a straight array of holes in the spanwise direction for baseline model. For design optimization, hole distributions in streamwise and spanwise directions for three rows of holes except first row are parameterized as a 2nd-order shape function. Three-dimensional compressible RANS equations are used for flow and thermal analysis around the nozzle surface and optimization technique using Design of Experiment, Kriging surrogate model and Genetic Algorithm is used. The results shows that averaged adiabatic wall temperature at the whole nozzle surface decreases about 2.7% and averaged film cooling effectiveness at the pressure side of nozzle increased about 8.2%.
A Study on the Flow around a D-shape Bluff Body with Arc-Groove
Seo, Seong-Ho ; Nam, Chung-Do ; Lee, Hyoung-Woo ; Hong, Cheol-Hyun ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 59~63
DOI : 10.5293/kfma.2014.17.6.059
Object of this study is to see whether the arc-groove on a D-shape bluff body effects the drag reduction or not. To this end, the changes of the boundary layer on the surface of the object, the downstream flow field and wake flow were found by experiments. The experiments are conducted by changing number and depth of the groove, angle of the first groove and Reynolds number(Re). Groove did not effect on the surface in the downstream boundary layer of the object and was minimal impact on the time mean velocity recovery of the wake flow. Also the effects of Groove did not have a significant impact on the structure of the wake and the wake frequency. Therefore it is found that the arc-groove of the drag reduction effect on the D-shape bluff body was smaller.
Experimental study on the performance of urban small vertical wind turbine with different types
Kang, Deok-Hun ; Shin, Won-Sik ; Lee, Jang-Ho ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 64~68
DOI : 10.5293/kfma.2014.17.6.064
This paper is intended to provide experimental data for the design of the small VAWT(vertical axis wind turbine). Three types(lift, drag, and hybrid) of the blade of VAWT are tested with digital wind tunnel in this study. From the test, the relation of power coefficient and tip speed ratio for the blades are evaluated and compared each other depending on the blade type. Especially, the characteristics of hybrid blade which is shown to be expanded in the market without any logical data is proposed in the relation of power coefficient and tip speed ratio. It is shown that the hybrid blade can be used to make higher starting torque with trade off of degradation of power coefficient.
A Study on the Methyl Salicylate Dispersion in the Vicinity of Obstacles by Wind Tunnel Test
Hong, Chang-Ki ; Uhm, Han-Sup ; Choi, Seung-Ki ; Kim, Youn-Jea ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 69~73
DOI : 10.5293/kfma.2014.17.6.069
To predict flow fields and chemical agent dispersion in urban area, wind tunnel experiments was performed. The agent was adopted MS (methyl salicylate) because the real chemical agent is unsafe. The exact concentration of methyl salicylate was generated by the commercial gas generator (STI-2500) and three different obstacle shapes were applied (i.e., rectangular, cylinder and pyramid). The concentration was measured with the qualified ion mobility sensor and gas chromatography. The data necessary for virtual test method of the real chemical agent were obtained.
Thermal-hydraulic Design of A Printed-Circuit Steam Generator for Integral Reactor
Kang, Han-Ok ; Han, Hun Sik ; Kim, Young-In ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 77~83
DOI : 10.5293/kfma.2014.17.6.077
The vessel of integral reactor contains its major primary components such as the fuel and core, pumps, steam generators, and a pressurizer, so its size is proportional to the required space for the installation of each component. The steam generators take up the largest volume of internal space of reactor vessel and their volumes is substantial for the overall size of reactor vessel. Reduction of installation space for steam generators can lead to much smaller reactor vessel with resultant decrease of overall cost for the components and related facilities. A printed circuit heat exchanger is one of the compact types of heat exchangers available as an alternative to conventional shell and tube heat exchangers. Its name is derived from the procedure used to manufacture the flat metal plates that form the core of the heat exchanger, which is done by chemical milling. These plates are then stacked and diffusion bonded, converting the plates into a solid metal block containing precisely engineered fluid flow passages. The overall heat transfer area and pressure drops are evaluated for the steam generator based on the concept of the printed circuit heat exchanger in this study. As the printed circuit heat exchanger is known to have much larger heat transfer area density per unit volume, we can expect significantly reduced steam generator compared to former shell and tube type of steam generator. For the introduction of new steam generator, two design requirements are considered: flow area ratio between primary and secondary flow paths, and secondary side parallel channel flow oscillation. The results show that the overall volume of the steam generator can be significantly reduced with printed circuit type of steam generator.
Development of an Air-Water Combined Cooling System
Kwon, Tae-Soon ; Bae, Sung-Won ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 84~88
DOI : 10.5293/kfma.2014.17.6.084
A long term passive cooling system is considered as the most important safety feature for the nuclear design after the Fukushima Daiichi nuclear power plant accident in 2011. The conventional active pump driven safety systems are not available during a station Black Out (SBO) accident. The current design requirement on cooling time of the Passive Auxiliarly Feedwater System (PAFS) is about 8 hours only. To meet the 72 hours cooling time, the pool capacity of cooling water tank should be increased as much as 3~4 times larger than that of current water cooling tank. In order to extend the cooling time for 72 hours, a new passive air-water combined cooling system is proposed. This paper provides the feasibility of the combined passive air-water cooling system. The current pool capacity of water cooling system is preserved, and the cooling capability is extended by an additional air cooler.
Experimental Methodology Development for SFR Subchannel Analysis Code Validation with 37-Rods Bundle
Euh, Dong-Jin ; Chang, Seok-Kyu ; Bae, Hwang ; Kim, Seok ; Kim, Hyung-Mo ; Choi, Hae-Seob ; Choi, Sun-Rock ; Lee, Hyung-Yeon ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 89~94
DOI : 10.5293/kfma.2014.17.6.089
The 4th generation SFR is being designed with a milestone of construction by 2028. It is important to understand the subchannel flow characteristics in fuel assembly through the experimental investigations and to estimate the calculation uncertainties for insuring the confidence of the design code calculation results. The friction coefficient and the mixing coefficient are selected as primary parameters. The two parameters are related to the flow distribution and diffusion. To identify the flow distribution, an iso-kinetic method was developed based on the previous study. For the mixing parameters, a wire mesh system and a laser induced fluorescence methods were developed in parallel. The measuring systems were adopted on 37 rod bundle test geometry, which was developed based on the Euler number scaling. A scaling method for a design of experimental facility and the experimental identification techniques for the flow distribution and mixing parameters were developed based on the measurement requirement.
Introduction to supercritical CO
power conversion system and its development status
Lee, Jeong Ik ; Ahn, Yoonhan ; Cha, Jae Eun ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 95~103
DOI : 10.5293/kfma.2014.17.6.095
During the international effort to develop the next generation nuclear reactor technologies, many new power cycle concepts were derived to improve efficiency and reduce the capital cost. Among many innovative power cycles, it was identified that the supercritical
) Brayton cycle technology has a big potential to outperform the existing steam cycle and eventually replace it. The S-
cycle achieves high efficiency with very compact size, which is the ultimate advantage for a power cycle to have. The S-
cycle has a great potential not only for the future nuclear applications but also for general heat sources such as coal, natural gas, and concentrated solar. In this paper, a brief introduction to the S-
power cycle technologies will be first provided, and a short summary of current research and development status of the power cycle technology around the world will be followed. Especially the research works performed by KAIST, KAERI and several related research institutions in Korea will be reviewed in more detail, since they have recently developing a strong infrastructure to test these ideas by constructing a demonstration facility while producing many innovative ideas to improve and realize the concept.
Design Concept of Hybrid SIT
Kwon, Tae-Soon ; Euh, Dong-Jin ; Kim, Ki-Hwan ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 104~108
DOI : 10.5293/kfma.2014.17.6.104
The recent Fukushima nuclear power plant accidents shows that the core make up at high RCS pressure condition is very important to prevent core melting. The core make up flow at high pressure condition should be driven by gravity force or passive forces because the AC-powered safety features are not available during a Station Black Out (SBO) accident. The reactor Coolant System (RCS) mass inventory is continuously decreased by releasing steam through the pressurizer safety valves after reactor trip during a SBO accident. The core will be melted down within 2~3 hours without core make up action by active or passive mode. In the new design concept of a Hybrid Safety Injection Tank (Hybrid SIT) both for low and high RCS pressure conditions, the low pressure nitrogen gas serves as a charging pressure for a LBLOCA injection mode, while the PZR high pressure steam provides an equalizing pressure for a high pressure injection mode such as a SBO accident. After the pressure equalizing process by battery driven initiation valve at a high pressure SBO condition, the Hybrid SIT injection water will be passively injected into the reactor downcomer by gravity head. The SBO simulation by MARS code show that the core makeup injection flow through the Hybrid SIT continued up to the SIT empty condition, and the core heatup is delayed as much.
CFD Analysis of a Concept of Nuclear Hybrid Heat Pipe with Control Rod
Jeong, Yeong Shin ; Kim, Kyung Mo ; Kim, In Guk ; Bang, In Cheol ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 109~114
DOI : 10.5293/kfma.2014.17.6.109
After the Fukushima accident in 2011, it was revealed that nuclear power plant has the vulnerability to SBO accident and its extension situation without sufficient cooling of reactor core resulting core meltdown and radioactive material release even after reactor shutdown. Many safety systems had been developed like PAFS, hybrid SIT, and relocation of RPV and IRWST as a part of steps for the Fukushima accident, however, their applications have limitation in the situation that supply of feedwater into reactor is impossible due to high pressure inside reactor pressure vessel. The concept of hybrid heat pipe with control rod is introduced for breaking through the limitation. Hybrid heat pipe with control rod is the passive decay heat removal system in core, which has the abilities of reactor shutdown as control rod as well as decay heat removal as heat pipe. For evaluating the cooling performance hybrid heat pipe, a commercial CFD code, ANSYS-CFX was used. First, for validating CFD results, numerical results and experimental results with same geometry and fluid conditions were compared to a tube type heat pipe resulting in a resonable agreement between them. After that, wall temperature and thermal resistances of 2 design concepts of hybrid heat pipe were analyzed about various heat inputs. For unit length, hybrid heat pipe with a tube type of
pellet has a decreasing tendency of thermal resistance, on the other hand, hybrid heat pipe with an annular type
pellet has an increasing tendency as heat input increases.
Computational Studies on the Performance of Flow Distributor in Tank
Shin, Soo Jai ; Kim, Young In ; Ryu, Seungyeob ; Bae, Youngmin ;
The KSFM Journal of Fluid Machinery, volume 17, issue 6, 2014, Pages 115~122
DOI : 10.5293/kfma.2014.17.6.115
The optimal design of the flow distributor is very important to ensure the structural integrity of the reactor system and their safe operation during some transient or accident conditions. In the present study, we numerically investigated the performance of a flow distributor in tank with different shape factors such as the total number of the holes, the pitch-to-hole diameter ratios (p/d), the diameter of the hole and the area ratios. These data will contribute to a design of the flow distributor.