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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Energy Engineering
Journal Basic Information
Journal DOI :
The Korea Society for Energy Engineering
Editor in Chief :
Volume & Issues
Volume 15, Issue 4 - Dec 2006
Volume 15, Issue 3 - Sep 2006
Volume 15, Issue 2 - Jun 2006
Volume 15, Issue 1 - Feb 2006
Selecting the target year
Assessment of MARS Multi-dimensional Two-phase Turbulent Flow Models for the Nuclear System Analysis
Lee S.M. ; Lee U.C. ; Bae S.W. ; Chung B.D. ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 1~7
The multi-dimensional two-phase flow models were developed for analyze the multi-dimensional behaviors or nuclear systems. To verify the simple turbulence model, The single phase mixing problem in a rectangular slab was calculated and compared with the commercial CFD code results. That result shows a good agreement with the CFD result. And the RPI Air-water experiments were simulated to assess the two-phase turbulence model in the multi-dimensional component. The first calculated distribution or void-fraction is highly dispersed and diffusive. It was revealed that the main reason is undesirable stratification force in a horizontal stratified flow regimes. Therefore the horizontally stratified flow regime is deleted because the stratified flow regime is not expected in multi-dimensional flow. With the modification of the flow regime, the predicted flow patterns and void fraction profiles are in good agreement with the measured data.
Oxidation Behavior of
Kang Kweon-Ho ; Moon Heung-Soo ; Na Sang-Ho ; Oh Se-Yong ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 8~13
The oxidation behavior of
, pellet was studied using an XRD and a thermogravimetric analyzer in the temperature range from 573 to 873 K and in the density range from 94.64 to 99.10% of theoretical density in air. It was found from the XRD study that
was completely converted to
in this experimental temperature range. The formation of
displays sigmoidal reaction kinetics. The oxidation rate was reduced with density. Induction time for the oxidation of
was delayed with density because of open pore formed in surface of
pellet. The activation energy for oxidation of
was determined to be 89.54 kJ/mol and 34.40 kJ/mol in the temperature range from 573 to 723 K and from 723 to 873 K, respectively.
Electricity Cost Variations subject to Nuclear and Renewable Power Portions
Ko Sang-Hyuk ; Chung Bum-Jin ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 14~22
Various pros and cons are raised as to the nuclear and renewable power portions. In order to generate scientific, objective, and comparative data, this study reviewed energy policies of some countries and derived 34 possible energy mix scenarios depending on the nuclear portion, the renewable portion and the make-up power sources. For each scenario, the unit electricity cost was calculated using the BLMP (Base Load Marginal Price) and SMP (System Marginal Price) methodology, which is currently adopted in Korean electricity market. The unit electricity cost for the current energy mix was 22.18 Won/kWh and those fir other scenarios spreaded from 19.74 to 164.07 Won/kWh excluding the transmission costs and profits of the electric utility companies. Generally, the increased nuclear power portion leads reduction in the unit electricity cost while the trend is reversed in the renewable power portion. Notable observation is that when the renewable power portion exceeds 20%, as the scenario cannot enjoy the benefit of cheap base load, the unit electricity cost at low demand time zone is increased.
Evaluation of Performance and Service Life of Low Pressure LPG Regulators for Home Use
Kim Young-Gyu ; Cho Seok-Beom ; Kim Pil-Jong ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 23~27
This paper presents the evaluation of LPG (Liquefied petroleum gas) regulators for home use. For the evaluation, several properties of the regulators were experimentally analyzed, such as the operation of safety device, the adjusting and lock-up pressure, the adjusting spring and the diaphragm, with respect to the used time of the regulators. Experimental results showed that the initial operation performance of regulators were degraded with increase of the service time and also showed that the degradation of the performance and material property could become serious after six-year-use of the regulator.
A Study on the Performance of a Cross-Flow Beat Exchanger by Tube Array Change
Jeon Yong-Han ; Kim Nam-Jin ; Kim Chong-Bo ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 28~34
The convective heat transfer on the outer surface of tube arrays perpendicular to the flow direction was experimentally investigated. The test sections which include the aligned and staggered arrangements were made and the local heat transfer coefficients on the outer surface of the tube were measured after the Hour has been fully developed. The results showed that the local heat transfer coefficients of the staggered arrangement, which has transverse pitch of 0.075 m and longitudinal pitch of 0.08 m, were about 15% greater than that of the aligned arrangement. Also, the overall mom Nusselt number of the former was greater thu that of the latter.
Experimental Study on Effect of Boiling Heat Transfer by Ultrasonic Vibration
Na Gee-Dae ; Oh Yool-Kwon ; Yang Ho-Dong ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 35~44
This study experimentally investigates effect of boiling heat transfer when ultrasonic vibration was applied. Under the wall temperature condition, temperature distribution in a cavity was measured during the boiling process and heat transfer coefficient of convection, sub-tooled boiling and saturated boiling states were measured with and without ultrasonic vibration, respectively. Also, the profiles of the pressure distribution in acoustic field measured by a hydrophone were compared with the augmentation ratios of heat transfer calculated by local heat transfer coefficient. Result of this study, heat transfer coefficient and augmentation ratio of heat transfer is higher with ultrasonic waves than without one. Especially, augmentation ratio of heat transfer is more increased the convection state than sub-cooled boiling and saturated boiling states. Acoustic pressure is relatively higher near ultrasonic transducer than other points where is no installed it and affects the augmentation ratio of heat transfer.
Heat Transfer Characteristics of Tube Bundle Type Beat Exchanger for LFG and LNG Mixed Fuel
Jeon Yong-Han ; Kim Yong ; Seo Tae-Beom ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 45~51
The purpose of this study is to investigate experimentally the heat transfer characteristics of combustion gas or a mixture fuel of LFG and LNG as compared LFG, LNG A Pilot combustion system is constructed. Tube bundle type heat exchangers with vertical and horizontal baffles are used, and the experiment is carried out for different operating conditions, the heating value, the concentration of methane (44.5%, 54.5%). The results show that the Nusselt number of LNG is higher than that of LFG at the same Reynolds number, and in case LFG, the Nusselt number of the mixture of LFG and LNG is larger than that of LFG alone. Therefore, heat transfer is improved by using LFG that is added to LNG pertinently, if and instability of LFG supply will be relaxed.
The Conversion of Methane with Oxygenated Gases using Atmospheric Dielectric Barrier Discharge
Lee Kwang-Sik ; Yeo Yeong-Koo ; Choi Jae-Wook ; Lee Hwa-Ung ; Song Hyung-Keun ; Na Byung-Ki ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 52~59
This paper examined the conversion of methane to hydrogen and other higher hydrocarbons using dielectric barrier discharge with AC pulse power. Two metal electrodes of a coaxial-type plasma reactor were separated by gas gap and an alumina tube. The inner electrode was located inside the alumina tube. The alumina tube was located inside the stainless steel tube, which was used as the outer electrode. Effect of feed gas composition (methane, oxygen, argon, water and helium), flow rate, applied frequency, input volt-age on methane conversion and product distribution were studied. The major products of plasma chemical reactions were ethylene, ethane, propane, buthane, hydrogen, carbon monoxide and carbon dioxide. The increment of applied voltage and the usage of inert gas as the background (helium and argon) enhanced the selectivity of hydrocarbons and methane conversion. The addition of water in the feed stream enhanced the conversion of methane and yield of hydrogen. Higher voltage leads to higher yield of
and yield or
appeared highly in lower voltage.
Heat Transfer and Flow Characteristics in an Annulus Filled with Aluminum Foam
Noh Joo-Suk ; Han Young-Hee ; Lee Kye-Bock ; Lee Chung-Gu ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 60~66
An experimental investigation on the flow and convective heat transfer characteristics has been carried out far aluminum foam heat sink inserted into the annulus to examine the feasibility as a heat sink. Two aluminum foams or different permeability were selected to provide the friction factor and heat transfer correlations as function of Darcy, Reynolds and Prandtl number. Experimental results show that the friction factor is higher than clear annulus without aluminum foam, while
times augmentation in Nusselt number is obtained. This technique can be used for the compactness of the heat exchanger.
A Real-time Calculation Method on Performance Impact of Controllable Operation Parameters for Combined Cycle rower Plant
Joo Yong-Jin ; Park Jong-Ho ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 67~73
A calculation method on performance impact of the controllable operations parameter such as GT inlet filter
, compressor efficiency, and condenser pressure was devised to achieve best performance of combined cycle power plant with the on-line performance monitoring system. This method calculates the performance impact on the deviation between 'Expected' values and 'Actual' values. Controllable parameter targets are determined based on achievable performance given existing equipments and control conditions.
Assessment Framework for Multicriteria Comparison Indicators in Various Electricity Supply Systems
Kim Seong-Ho ; Kim Tae-Woon ;
Journal of Energy Engineering, volume 15, issue 1, 2006, Pages 74~81
In this study, on the basis of an analytic hierarchy process (AHP) method and through a questionnaire on subjective preference and importance, various power supply systems were comprehensively compared with multiple decision criteria such as environmental, social, healthy, and economic viewpoints and then overall priority was assessed. When a decision-making problem is modelled by a hierarchy structure, the AHP method is regarded as a useful tool for extracting subjective opinions via the aforementioned questionnaire. Here, the overall preferences were obtained by linearly aggregating weighting vector and preference matrix. The energy systems such as nuclear, coal, and LNG power plants were selected because they took share over 90% of domestic electricity supply in Korea. Furthermore, wind power and photovoltaic solar systems were included as representative renewable energy systems in Korea. According to the results of this demonstration study, the following comprehensive comparison indicators were yielded: 1) weighting factors for 4 types of main criteria as well as for 11 types of sub-criteria; 2) preference valuation for 7 types of energy systems under consideration; 3) overall score for each energy systems.