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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea Society For Power System Engineering
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Journal DOI :
The Korea Society for Power System Engineering
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Volume & Issues
Volume 20, Issue 3 - Jun 2016
Volume 20, Issue 2 - Apr 2016
Volume 20, Issue 1 - Feb 2016
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Free Vibration Analysis of Axisymmetric Conical Shell
Choi, Myung-Soo ; Yeo, Dong-Jun ; Kondou, Takahiro ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 5~16
DOI : 10.9726/kspse.2016.20.2.005
Generally, methods using transfer techniques, like the transfer matrix method and the transfer stiffness coefficient method, find natural frequencies using the sign change of frequency determinants in searching frequency region. However, these methods may omit some natural frequencies when the initial frequency interval is large. The Sylvester-transfer stiffness coefficient method ("S-TSCM") can always obtain all natural frequencies in the searching frequency region even though the initial frequency interval is large. Because the S-TSCM obtain natural frequencies using the number of natural frequencies existing under a searching frequency. In this paper, the algorithm for the free vibration analysis of axisymmetric conical shells was formulated with S-TSCM. The effectiveness of S-TSCM was verified by comparing numerical results of S-TSCM with those of other methods when analyzing free vibration in two computational models: a truncated conical shell and a complete (not truncated) conical shell.
Design and performance analysis of a gerotor expander for power generation from waste heat
Park, Keun-Tae ; Kim, Yong-Hee ; Kim, Hyun-Jin ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 17~25
DOI : 10.9726/kspse.2016.20.2.017
In this paper, the feasibility study on a gerotor type expander as a power converting device in a small scale power generation ORC system was made by performance analysis of the gerotor expander. Design of a 1kW-class gerotor expander was carried out and its performance was numerically simulated. For a R134a Rankine system with about 20 kW solar heat source, the gerotor expander efficiency was calculated to be 35~75% for the operating conditions of
. Maximum expander efficiency was obtained at an expansion ratio somewhat higher than the design expansion ratio due to pre-expansion during suction process inside the outer and inner rotor mate. If the operating expansion ratio is not far from the design expansion ratio, the gerotor expander performance can be well compared to that of a scroll type.
Development of Ventilator without Power using Air Flow
Kim, Bum-Suk ; Kwon, Taek-Joo ; Jeong, Ji-Hyun ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 26~31
DOI : 10.9726/kspse.2016.20.2.026
The studies on the efficient ventilator to reduce fire and save energy have been proceeded actively. The purpose of this paper is to design a ventilator used in residential wood stove. The ventilator consists of rotation and support part, and it is operated by natural wind without power. The shape of rotation part of the ventilator is like airfoil to reinforce pressure drop. We designed direction controller for the rotation part to track the direction of wind continuously. The rotation and support part have point-contact each other to minimize a friction. We verify the properties of the proposed ventilator though simulation and experiment. The results show the proposed ventilator can exhaust safely combustion gas of the stove more than other ventilator.
A Study on Ignition Probability and Combustion Characteristics of Low Pressure Direct Injection LPG according to a Function of Ambient Condition
Chung, Sung-Sik ; Hwang, Seong-Ill ; Yeom, Jeong-Kuk ; Jeon, Byong-Yeul ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 32~42
DOI : 10.9726/kspse.2016.20.2.032
Under part load condition of spark-ignition engine, pumping loss had great effect on engine efficiency. To reduce pumping loss, the study designed spark-ignited engines to make direct spray of gasoline to combustion chamber. In spark-ignited direct-injection engines, ignition probability is important for successful combustion and flame propagation characteristics are also different from pre-mixed combustion. This study designed a visualization testing device to study ignition probability of spark-ignited direct-injection LPG fuel and combustion flame characteristics. This visualization device consists of combustion chamber, fuel supply system, air supply system, electronic control system and data acquisition system. Ambient pressure, ambient temperature and ambient air flow velocity are important parameters on ignition probability of LPG-air mixture and flame propagation characteristics, and the study also found that sprayed LPG fuel can be directly ignited by spark-plug under proper ambient conditions. To all successful cases of ignition, the study recorded flame propagation image in digital method through ICCD camera and its flame propagation characteristics were analyzed.
A research about micro size polymer bead injecting process based on electrostatic force
Yang, Bong-Su ; Yang, Sung-Wook ; Ko, Jung-Bum ; Choi, Kyung-Hyun ; Doh, Yang-Hoi ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 43~50
DOI : 10.9726/kspse.2016.20.2.043
This research proposal is based on a novel non-contact technique of micro-sized bead injection process for fabrication of electronic paper display. This non-contact injection process is based on the principle of electrostatic force and uses micro-sized metal-coated beads dispersed in a solution. The dispersion retention times of three different solutions with viscosities of 10 cps, 100 cps, and 1000 cps were measured by optical equipment showing the retention times of 5 mins, 10 mins, and 30 mins respectively. The dispersion retention rate dropped as the time passed. The dispersion retention characteristic of 1000 cps solution was more stable as compared to those of 10 cps and 100 cps meaning that higher viscosity has better retention properties. The experimental results of bead injection at different viscosity levels of the solution were also measured and a stable injection result was achieved by using 1000 cps solution. This results show that stable injection is dependent on solution viscosity and dispersion.
A study on the application of DOE for optimization of blending oil with non-esterified biodiesel fuel at partial engine load
Kim, Hee-Jung ; Koh, Dae-Kwon ; Yang, Ju-Ho ; Koh, Sung-Wi ; Kim, Yeong-Sik ; Jeong, Tae-Young ; Jung, Suk-Ho ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 51~57
DOI : 10.9726/kspse.2016.20.2.051
Non-esterified biodiesel fuel is cheaper than esterified that because of a simple manufacturing process that only consists of filtering. Applicability of this on diesel engine with electronic control system was accomplished, then optimization adopting a fractional factorial design and response surface methodology was carried out at 25% and 50% of engine load in this study. Pressure of common rail and injection timing mainly effected on responses as specific fuel oil consumption and nitrogen oxides regardless of engine load. Estimations were 310.3 g/kWh of specific fuel oil consumption and 237 ppm of nitrogen oxides at 25% load, and 233.2 g/kWh of specific fuel oil consumption and 730 ppm of nitrogen oxides at 50% load. Tests to verify these estimations were accomplished and as the results, specific fuel oil consumption was 300.4 g/kWh and NOx was 277 ppm at 25% load and 236.8 g/kWh and 573 ppm at 50% load.
Dynamics Identification and Robust Control Performance Evaluation of Towing Rope under Rope Length Variation
Tran, Anh-Minh D. ; Kim, Young-Bok ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 58~65
DOI : 10.9726/kspse.2016.20.2.058
Lately, tugboats are widely used to maneuver vessels by pushing or towing them where tugboats use rope. In order to correctly control the motion of tugboat and towed vessel, the dynamics of the towline would be well identified. In real application environment, the towing rope length changes and the towing load is not constant due to the various sizes of towed vessel. And there are many ropes made by many types of materials. It means that it is not easy to obtain rope dynamics, such that it is too difficult to satisfy the given control purpose by designing control system. Thus real time identification or adaptive control system design method may be a solution. However it is necessary to secure sufficient information about rope dynamics to obtain desirable control performance. In this paper, the authors try to have several rope dynamic models by changing the rope length to consider real application conditions. Among them, a representative model is selected and the others are considered as uncertain models which are considered in control system design. The authors design a robust control to cope with strong uncertain and nonlinear property included in the real plant. The designed control system based on robust control framework is evaluated by simulation.
Performance Analysis on Early Detection of Fault Symptom of a Pump with Abnormal Signals
Jung, Jae-Young ; Lee, Byoung-Oh ; Kim, Hyoung-Kyun ; Kim, Dae-Woong ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 66~72
DOI : 10.9726/kspse.2016.20.2.066
As a method to improve the equipment reliability, early warning researches that can be detected fault symptom of an equipment at an early stage are being performed out among developed countries. In this paper, when abnormal signal is input to actual normal signal of a pump, early detection studies on pump's fault symptom were carried out with auto-associative kernel regression as an advanced pattern recognition algorithm. From analysis, correlations among power of motor driving pump, discharge flow of pump, power output of pump, and discharge pressure of pump are exited. When the abnormal signal is input to one of those normal signals, the other expected values are changed due to the influence of the abnormal signal. Therefore, the fault symptom of pump through the early-warning index is able to detect at an early stage.
Analysis and Verification of High Temperature Heat Pump Dryer using Waste Heat Recovery Type for R245fa Refrigerant
Bae, Kyung-Jin ; Cha, Dong-An ; Kwon, Oh-Kyung ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 73~78
DOI : 10.9726/kspse.2016.20.2.073
In this study, the performance characteristics of a high temperature heat pump dryer that is able to raise the air temperature up to
by using waste heat as heat source were investigated numerically. The main components of the heat pump dryer were modeling as a compressor, condenser, evaporator and expansion device, and R245fa was selected as refrigerant. Experiments were also conducted to validate the numerical data. As a result, when the evaporator air inlet temperature increased from
, the numerical results of the hot air temperature at outlet and heat pump COP were about 8~11% and 5~8% higher than that of experimental ones, respectively.
Performance Analysis of Ocean Thermal Energy Conversion on Working Fluid Classification
Lee, Ho-Saeng ; Moon, Jung-Hyun ; Kim, Hyeon-Ju ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 79~84
DOI : 10.9726/kspse.2016.20.2.079
The thermodynamic performance of ocean thermal energy conversion with 1 kg/s geothermal water flow rate as a heat source was evaluated to obtain the basic data for the optimal design of cycle with respect to the classification of the working fluid. The basic thermodynamic model for cycle is rankine cycle and the geothermal water and deep seawater were adapted for the heat source of evaporator and condenser, respectively. R245fa, R134a are better to use as a working fluid than others in view of the use of geothermal water. It is important to select the proper working fluid to operate the ocean thermal energy conversion. So, this paper can be used as the basic data for the design of ocean thermal energy conversion with geothermal water and deep seawater.
Performance Analysis of a Seawater Ice Machine Applied Two-stage vapor compression refrigeration system for Various Refrigerants
Yoon, Jeong-In ; Son, Chang-Hyo ; Heo, Seong-Kwan ; Jeon, Min-Joo ; Jeon, Tae-Young ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 85~90
DOI : 10.9726/kspse.2016.20.2.085
Coefficient of performance (COP) for two-stage compression system is investigated in this paper to develop seawater ice machine. The system performance is analyzed with respect to degrees of superheating and subcooling, condensing and evaporating temperatures, compression and mechanical efficiencies and mass flow ratio in an inter-cooler. The main results are summarized as follows : The COP of the system grows when the mass flow ratio, subcooling degree and evaporating temperature edge up. Contrariwise, the system performance descends in case that superheating degree and condensing temperature increase. The most effective factor for the COP is the mass flow rate ratio. Each refrigerant has different limitation for a value of the mass flow ratio in the inter-cooler because of difference in material property.
Performance Comparison of Flooded Seawater Cooling System with respect to Heat Sink Temperature
Yoon, Jung-In ; Choi, Kwang-Hwan ; Son, Chang-Hyo ; Kang, In-Ho ; Kim, Chung-Lae ; Seol, Sung-Hoon ;
Journal of the Korea Society For Power System Engineering, volume 20, issue 2, 2016, Pages 91~96
DOI : 10.9726/kspse.2016.20.2.091
A fleet consists of a main vessel, light vessels and carrying vessels for purse seine fishery. Carrying vessels contains fish storages to maintain freshness of catches. Currently most carrying vessels applies the cooling system using plain ice though accompanied various shortcomings. Seawater cooling system directly chilling seawater are now in use on carrying vessels in some developed countries to make up for these shortcomings and maximize advantages. This research deals with necessity of seawater cooling systems and establishes system criteria using Aspentech HYSYS program, prior to an experiment of compact-scale seawater cooling system which now in progress of manufacture. Performance comparison on condensation capacity, mass flow rate of working fluid, compressor power input, pump power input and others of the seawater cooling system applying a flooded evaporator is conducted with respect to the temperature of surface seawater varying according to seasons. The result presents that mass flow rate circulating the system is increased about 16.7% as the temperature of surface seawater increases. At the same condition, condensation capacity and compressor input work also increase about 9.8% and 91.2%, respectively.