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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The KSFM Journal of Fluid Machinery
Journal Basic Information
Journal DOI :
Korean Fluid Machinery Association
Editor in Chief :
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
Selecting the target year
Experimental Study on the Performance of Screw Compressor with Various Shapes of Air End
Kim, Tae-Yoon ; Lee, Jae-Young ; Kim, Youn-Jea ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 5~10
DOI : 10.5293/kfma.2013.16.1.005
The performance of screw air compressor is affected by rotor profile, lobe number, air end wrap angle, rotor L/D ratio, suction and discharge ports, revolutions of air end and load regulation control, etc. In general, an efficient screw compressor needs a rotor profile of which has a large flow cross-section area, short sealing lines and a small blow-hole. In this study, experimental study was performed with newly designed
rotor profile and various shapes of air end. Results show that the measured specific power consumption of the newly designed screw compressor appeared to be lower than any other published data for the equivalent screw compressors manufactured.
A Study on the Design Method to Optimize an Impeller of Centrifugal Compressor
Cho, Soo-Yong ; Lee, Young-Duk ; Ahn, Kook-Young ; Kim, Young-Cheol ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 11~16
DOI : 10.5293/kfma.2013.16.1.011
A numerical study was conducted to improve the performance of an impeller of centrifugal compressor. Nine design variables were chosen with constraints. Only meridional contours and blade profile were adjusted. ANN (Artificial Neural Net) was adopted as a main optimization algorithm with PSO (Particle Swarm Optimization) in order to reduce the optimization time. At first, ANN was learned and trained with the design variable sets which were obtained using DOE (Design of Experiment). This ANN was continuously improved its accuracy for each generation of which population was one hundred. New design variable set in each generation was selected using a non-gradient based method of PSO in order to obtain the global optimized result. After
generation, the prediction difference of efficiency and pressure ratio between ANN and CFD was less than 0.6%. From more than 1,200 design variable sets, a pareto of efficiency versus pressure ratio was obtained and an optimized result was selected based on the multi-objective function. On this optimized impeller, the efficiency and pressure ratio were improved by 1% and 9.3%, respectively.
Output Optimization of Microhydro Kaplan Turbine by Double Regulating Runner and Guide Vane
Park, No-Hyun ; Rhee, Young-Woo ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 17~23
DOI : 10.5293/kfma.2013.16.1.017
Recently so much attention has been focused on renewable energy and, since its sources to exploit are already almost saturated in the country, the practical alternative to this situation could be a micro-turbine which uses the low head and low flow. From a point of view of local micro-turbine design capacity and manufacturing technology, the problems such as the accumulation of technical skills, the expansion of related industries, the national policy expansion and the turbine efficiency to improve are still vulnerable and it`s true that there are also negative views about the economic feasibility, the technicity and the operation management of the micro-turbine. However, if the improvement can be done in technology of low-head double regulation micro-turbine to generate more outputs and the operation management can be reliably realized, the micro-turbine will be re-evaluated as an appliable source of renewable energy, even the output is small, and by a paradigm shift, it could realize a power generation as an economic and rational system.
Optimization Design of Hydrofoil Shape and Flapping Motion in AUV(Autonomous Underwater Vehicle)
Kim, Il-Hwan ; Choi, Jung-Sun ; Park, Kyung-Hyun ; Lee, Do-Hyung ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 24~31
DOI : 10.5293/kfma.2013.16.1.024
The motion of living organisms such as birds, fishes, and insects, has been analyzed for the purpose of the design of MAV(Micro Air Vehicle) and NAV(Nano Air Vehicle). In this research, natural motion was considered to be applied to the determination of the geometry and motion of AUV(Autonomous Underwater Vehicle). The flapping motion of a number of hydrofoil shapes in AUV was studied, and at the same time, the optimization of the hydrofoil shape and flapping motion was executed that allow the highest thrust and efficiency. The harmonic motion of plunging and pitching of NACA 4 digit series models, was used for the numerical analysis. The meta model was made by using the kriging method in Optimization method and the experimental points of 49 were extracted for the OA(Orthogonal array) in DOE(Design of experiments). Parametric study using this experimental points was conducted and the results were applied to MGA(Micro Genetic Algorithm). The flow simulation model was validated to be an appropriate tool by comparing with experimental data and the optimized shape and motion of AUV was turned out to produce highest thrust and efficiency.
The Effect of Divergence Angle on the Control Valve Trim Characteristics
Go, Tae-Sig ; Kim, Kuisoon ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 32~39
DOI : 10.5293/kfma.2013.16.1.032
The multi-stage control valve is one of the devices which controls cavitation and high pressure drop. To attain the high pressure drop, the conventional control valves adopted the multi-stage trim to avoid the occurrence of local cavitation in valves. This work studied the effect of divergence angle on the characteristics of multi-stage trim. Pressure drop and flow characteristics was calculated for the 1 passage of multi-staged trim by using the FLUENT 6.3.26. The result showed that the pressure drop is significantly influenced by the divergence angle of multi-stage trim. In addition, the pressure drop increased consistently as the Reynolds number and divergence angle increases.
Optimization of Duct System with a Cross Flow Fan to Improve the Performance of Ventilation
Lee, Sang Hyuk ; Kwo, Oh Joon ; Hur, Nahmkeon ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 40~46
DOI : 10.5293/kfma.2013.16.1.040
Recently, the duct system with a cross flow fan was used to improve the ventilation in various industrial fields. For the efficient ventilation, it is necessary to design the duct system based on the flow characteristics around the cross flow fan. In the present study, the flow characteristics around a cross flow fan in the ventilation duct were predicted by using the moving mesh and sliding interface techniques for the rotation of blades. To design the duct system with the high performance of ventilation, the CFD simulations were repeated with the revised duct model based on the DOE. With the numerical results of flow rate through the ventilation duct with various geometric parameters, the optimized geometry of ventilation duct to maximize the flow rate was obtained by using the Kriging approximation method. From the performance curves of cross flow fan in the original and optimized models of ventilation duct, it was observed that the flow rate through the optimized model is about 16 percent larger than that through the original model.
A Numerical Analysis on Mixing Performance for Various Types of Turbine Impeller in a Stirred Vessel
Choi, Younguk ; Choi, Jongrak ; Kim, Daejoong ; Hur, Nahmkeon ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 47~55
DOI : 10.5293/kfma.2013.16.1.047
In the present study, a numerical simulation to analyze mixing performance inside an industrial mixer was investigated for various geometry of turbine impellers. Various pitching angles and various types of turbine blades were considered in the simulation. In order to model the rotation of impeller, the Multiple Reference Frames (MRF) technique was used. For evaluation of the effect of various shapes on the mixing performance, dimensionless coefficient such as flow coefficient, circulation coefficient, power coefficient, pumping effectiveness and circulation effectiveness were used. From the results, the effect of pitching angle of a pitched turbine impeller was to give best pumping effectiveness around
pitching angle, whereas best circulation effectiveness around
pitching angle. Dual pitched turbine impeller showed best performance in both pumping effectiveness and circulation effectiveness among impeller types considered in the present study.
A Feasibility Study on Shale Gas Plant Water Treatment by Direct Contact Membrane Distillation
Koo, Jae-Wuk ; Han, Jihee ; Lee, Sangho ; Hong, Seungkwan ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 56~60
DOI : 10.5293/kfma.2013.16.1.056
Non-conventional oil resources such as shale gas are becoming increasingly important and have drawn the attention of several major oil companies all over the world. Nevertheless, the market-changing growth of shale gas production in recent years has resulted in the emergence of environmental and water management challenges. This is because the water used in the hydraulic fracturing process contains large amount of pollutants including ions, organics, and particles. Accordingly, the treatment of this flowback water from shale gas plant is regarded as one of the key technologies. In this study, we examined the feasibility of membrane distillation as a treatment technology for the water from shale gas plants. Direct contact membrane distillation (DCMD) is a thermally-driven process based on a vaper pressure gradient across a hydrophobic membrane, allowing the treatment of feed waters containing high concentration of ions. Experiments were carried out put in the lab-scale under various conditions such as membrane types, temperature difference, flow rate and so on. Synthetic feed water was prepared and used based on the data from literature. The results indicated that DCMD is suitable for treating not only low-range flowback water but also high-range flowback water. Based on the theoretical calculation, DCMD could have over 80% of recovery. Nevertheless, organic pollutants such as oil and surfactant were identified as serious barriers for the application of MD. Further works will be required to develop the optimum pretreatment for this MD process.
Study on Water / Energy / Mutual-changing Technology by RO/PRO Process
Choi, Youngkwon ; Yun, Taekgeun ; Sohn, Jinsik ; Lee, Sangho ; Choi, June-Seok ;
The KSFM Journal of Fluid Machinery, volume 16, issue 1, 2013, Pages 61~65
DOI : 10.5293/kfma.2013.16.1.061
Water is an integral part of energy production because it is used directly in many power generation systems such as hydroelectric power plants and thermoelectric power plants. Water is also used extensively in energy-resource extraction, oil, natural gas, and alternative fuels refining and processing. Recently, osmotic power systems using seawater and freshwater has been also investigated to produce electricity in a sustainable way. This study focused on the use of RO and PRO for the mutual conversion of water and energy. This system allows the production of water from seawater if there is not enough water. It can also generate electricity from salinity gradient of brine water and fresh water if there is not enough energy. To demonstrate the feasibility of this technology, a set of laboratory-scale experiments were carried out using a specially-designed RO/PRO system. The efficiency of energy conversion was theoretically estimated based on the results from the experiments. The results indicated that water and energy could be easily converted using a single device. Nevertheless, a lack of optimum membrane for this purpose was identified as a major barrier for practical application.