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Measurement of Ground Temperature Distribution at Various Depths
사이드(S.M. Sayeed-Bin-Asad),신용한(Young H. Shin),정한식(Hanshik Chung),정효민(Hyomin Jeong) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Knowledge on ground temperatures is essential for many construction projects. These include the calculations of heat losses of buildings to the ground and the design of thermal energy storage equipment. This study discusses the factors affecting ground temperature and the summer temperature variation with depth. Temperatures were measured in Tongyeong, Korea, with thermocouples inserted in the ground which indicate that the short-period temperature variations are prominent to a depth of approximately 0.5 m. Because of the high thermal inertia of the soil, the temperature fluctuations at the surface of the ground are diminished as the depth of the ground increases. The annual temperature variation of the ground at a depth of 2m is between 15 to 25℃ while at a depth of over 15 m is negligible and the temperature remains constant at about 22℃.
Shell and Tube형 LNG 기화기에 대한 PIV 연구
사이드(S.M. Sayeed-Bin-Asad),김영식(YS Kim),모종근(JG Mo),정한식(HM Jeong),정효민(HS Chung) 대한설비공학회 2011 대한설비공학회 학술발표대회논문집 Vol.2011 No.7
Shell-and-tube vaporizers are the most co㎜only used and dominated types of vaporizers in LNG realm. Due to efficient performance, Shell-side flow in this type of vaporizers has received considerable attention and has been investigated extensively. However, the detail flow structure in the shell needs to be determined for reliable and effective design. Therefore, the objective of this study was to clarify the flow structure in shell by particle image velocimetry (PIV). Experiments were conducted using two types of model; 15% baffle cut having inlet and outlet positions in the direction of 90ºto the cut and 30% baffle cut having inlet and outlet positions in the direction of 180ºto the cut. Each test section contains 169 ㎜ I.D. and 344.6 ㎜ length. The flow features were characterized in different baffle cuts with regards to the velocity vector field, vortex structure, stream line, turbulent intensity and Turbulent kinetic energy. The results show that the flow characteristics of the 15% baffle cut type vaporizer are comparable to the 30% baffle cut type vaporizer.
신용한(Yonghan Shin),사이드(S.M. Sayeed-Bin-Asad),전영철(YoungChul Jeon),정한식(Hanshik Chung),정효민(Hyomin Jeong) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
A numerical simulation on the flow field was carried out to improve cylindrical shell with baffle. The steady incompressible 3-D Navier-Stokes solution is obtained with the actual operational condition and geometry of the heat exchanger. The effect of the location of inlet and outlet on the cylindrical shell with baffle is investigated by varying flow rate. The present results show that the pressure drop is dependent on Reynolds number in the inlet area and position of inlet and outlet; i.e., the pressure drop increases with increasing Reynolds number and the pressure drop decreases with increasing angle between baffle cutting part and position of inlet and outlet.
정효민(Hyomin Jeong),신용한(Yonghan Shin),사이드(S.M. Sayeed Bin Asad),박진관(Chenkuan Park),정한식(Hanshik Chung) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4
LNG(Liquified Natural Gas) must be vaporized to be used as fuel in the industries, home application and soon. The cold energy generated about latent heat of 120 ㎉/㎏ and 80 kca/㎏ of sensible heat, while the vaporization process. Because air type vaporizer can't effect its vaporization performance properly due to the condensation of moisture in air outside the vaporization of moisture in air outside the vaporizer, 2~3 vaporizers are used alternately. To prevent freezing on the surface of vaporizer and solve the low performance, The heating source of gasification will use the geothermal energy. In this study, as the fundamental investigation to develop the highly efficient LNG vaporizer, When cold energy (Heat Flux : -100, -200, -300 W/m2) is connected to the ground, The soil temperature have been investigated numerically by the unsteady heat conduction equation.