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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Energy Engineering
Journal Basic Information
Journal DOI :
The Korea Society for Energy Engineering
Editor in Chief :
Volume & Issues
Volume 19, Issue 4 - Dec 2010
Volume 19, Issue 3 - Sep 2010
Volume 19, Issue 2 - Jun 2010
Volume 19, Issue 1 - Mar 2010
Selecting the target year
A Study of the Effect of Grouting Region on the Solution of Line Source Analysis
Lee, Se-Kyoun ; Woo, Joung-Son ; Ro, Jeong-Geun ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 143~150
Line source method of borehole system assumes the entire surrounding medium is uniform. However, thermal properties of grouting region are considerably different from those of surrounding soil. In this study we investigate the effect of grouting materials on the solution of line source method with the aid of numerical analysis. This numerical model generates the temperature of borehole fluid with which line source solution can be obtained. Then this solution can be compared with input condition of numerical model. The results of this comparison show that thermal conductivity and borehole thermal resistance of line source solution are approximately 86% and 91% of the input condition of numerical model. Chart method is developed in this study to find the numerical input conditions (thermal conductivity and borehole thermal resistance) from the line source solution. Thermal response test of test borehole is conducted, the results of which are approximately consistent with the Chart method. Thermal property changes of grouting materials on the line source solution are also examined.
A Numerical Study of a Vehicle Windshield Defrosting Mechanism
Kang, Seung-Jae ; Jun, Yong-Du ; Lee, Kum-Bae ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 151~155
Adequate visibility through a vehicle windshield and frost melting period are critical aspects of major design parameters. To make progress in this area, a good understanding of the flow behavior and heat transfer characteristics produced by the HVAC module is required. The computational study was used to perform the parametric investigation into the defroster nozzle's performance with a full-scale model. The study highlights the drawbacks of current designs and points the way to improve passive defrosting mechanism. The results show that the current design of the defroster nozzles deliver the maximum airflow in the vicinity of the lower part of the windshield, which yields unsatisfactory visibility. Defrosting performance was excellent when the injection angle of the defrost nozzle was 45 degree. The numerical analysis satisfies the criteria provided by NHTSA.
Combustion Characteristics of Coal-Fired Boiler Depending on the Variations in Combustion Air Supply Method
Seo, San-Il ; Park, Ho-Young ; Kang, Dong-Soo ; Jeong, Dong-Hae ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 156~162
3-D CFD(Computational Fluid Dynamics) work were carried out to investigate the combustion characteristics in a boiler depending on the variations in air supply condition. For the gas temperature,
, NO, SOx at the outlet of economizer, the predicted values were been compared with the measured data. With the verified CFD model, the effects of air flow rates through SOFA(Separated Over Fire Air) and CCOFA(Closed Coupled Over Fire Air) on the combustion behavior in a boiler were simulated, and the distributions of NOx and gas temperature were mainly compared each other. The change in SOFA air flow rate gave the more sensitive effect on NOx than that in CCOFA. The distributions of gas temperature at convection path are differed with the changes in SOFA and CCOFA flow rate, so the combustion modification such as yaw anlge adjustment are required to get an enhanced gas temperature distribution.
Effect of Nozzle Distance and Angle in the Iron-ore Sintering Dual Burner on Flame Characteristics
Lee, Young-Jun ; Hwang, Min-Young ; Kim, Gyu-Bo ; Song, Ju-Hun ; Chang, Young-June ; Jeon, Chung-Hwan ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 163~170
The objective of this study is to investigate the combustion characteristics of dual type of sintering burner as a function of design parameters using lab-scale sintering burner through experimental and numerical approaches. Combustion characteristics were evaluated by the radical method. The numerical model was verified as a temperature using R type of thermocouple at the bed surface. The effect of nozzle distance and angle were performed through the CFD analysis, and the comparison of burner types. As a results, dual type burner has more wider and uniform flame distribution than single type burner. Asymmetry and 45 degree angle condition have been suggested as an optimal condition for the ignition of the sintering bed surface.
The Study for Idle Fuel Consumption of a Hydrogen-Blended Natural Gas Engine
Lee, Sun-Youp ; Kim, Young-Min ; Lee, Jang-Hee ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 171~176
Using a hydrogen blended compressed natural gas (HCNG) as a fuel for IC engines has a significant meaning in terms of achieving a reduction of automotive exhaust emissions as well as preparing for an upcoming hydrogen economy by constructing hydrogen infrastructure. In addition, a HCNG engine has higher thermal efficiency than a CNG engine, which is another advantage that makes HCNG fuel considered as a future alternative for natural gas. Therefore, in this study, idling operation of a 11 litre HCNG bus engine was investigated in terms of fuel consumption rate and emissions characteristics. The results show that fuel consumption rate was decreased more than 20% by use of HCNG and all the emissions were significantly reduced in idling condition.
Characteristics of Thermal Efficiency with Changing Distances Between Tubes for Heat Exchanger
Kim, Jong-Min ; Lee, Jae-Park ; Lee, Seung-Ro ; Lee, Chang-Eon ; Kum, Sung-Min ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 177~181
There are various types of heat exchanger by its purpose and usage, but the important thing is making smaller size of heat exchanger with increasing of the performance of heat exchanger. However, when a burner exists in front of a heat exchanger like boiler, the thermal efficiency of heat exchanger is not only important, but the characteristics of pollutant emission should be considered. Therefore, in this study, a circular tube type of heat exchanger in front of premixed burne, which has a shorter of flame length than that of non-premixed burner and can control
and CO emission by adjustment of equivalence ratio, was installed. Consequently, characteristics of
and CO emission and thermal efficiency of heat exchanger were studied with changing distances between tubes and equivalence ratio, experimentally.
A Study on Emission Characteristics of Inserting CO Tube
Lee, Jae-Park ; Kim, Jong-Min ; Lee, Seung-Ro ; Lee, Chang-Eon ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 182~187
This study was the effect of inserting CO tube on
and CO emission characteristics in a compact combustion chamber. In detail,
and CO emission characteristics with changing of distance due to inserting CO tube between a burner and a main heat exchanger were investigated. For this study, the commercial program, FLUENT with GRI 2.11 detail reaction mechanism, was used for the numerical study and a commercial heat exchanger was tested for the experimental study. As results, when the CO tube was inserted between a burner and a main heat exchanger, it was verified that
and CO emissions was decreased simultaneously as CO tube was closed to a burner and the distance between CO tube and a main heat exchanger was increased.
Numerical Modeling of Anodic Reaction of Carbon-Rich Fuel at Solid Oxide Fuel Cell
Lim, Ho ; Kim, Jong-Pil ; Song, Ju-Hun ; Chang, Young-June ; Jeon, Chung-Hwan ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 188~194
Direct Carbon Fuel Cell(DCFC), unlike gas turbines or engines, is a kind of fuel cell which directly generates electricity by electrochemical reaction from a carbon fuel. The advantages of DCFC are higher efficiency and lower emission in comparison with existing power generation facilities. In this study, the effects of CO and
on theoretical potential are examined using the thermodynamic equilibrium method, and the dependence of product on operating temperature is examined via two dimensional CFD method. As a result, when the reaction of CO production (Boudouard reaction) considered, theoretical potential is higher than that in only
reactions, and its value increases as temperature increases. Two dimensional results of computational fluid dynamics(CFD) confirm that the Boudouard reaction becomes more important to be considered as temperature increases and inert gas affects the equilibrium composition of the Boudouard reaction.
An Experimental Study on the Optimal Conditions of Decomposition/Synthesis of Methanol for Heat Transport from Long Distance
Yoon, Seok-Mann ; Moon, Seung-Hyun ; Lee, Seung-Jae ; Choi, Soon-Young ;
Journal of Energy Engineering, volume 19, issue 3, 2010, Pages 195~202
A third of primary energy is lost as a waste heat. To improve this inefficient use of energy, systems using chemical reaction have been suggested and studied. In this study, methanol decomposition/synthesis reaction as a chemical reaction was selected for long time heat storage and long distance heat transport system because of safe, cheap and gaseous product. The purpose of this study is to find the optimal conditions in the methanol decomposition and synthesis reactions for long distance heat transport. Several parameters such as reaction temperature, pressure,
/CO ratio, space velocity, catalyst particle size were tested to find the effects on the reaction rates for the methanol synthesis. And the reaction temperature, space velocity, catalyst particle size were tested to find the effects on the production concentration for the methanol decomposition.