http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
백종훈(J . H . Baik),강병하(B . H . Kang) 한국수소및신에너지학회 1998 한국수소 및 신에너지학회논문집 Vol.9 No.3
The ortho-para H<sub>2</sub> catalytic conversion equipment has been developed to reduce the evaporation loss from stored liquid hydrogen. The ortho-para H<sub>2</sub> conversion heat is evaluated at liquid nitrogen temperature. This problem is of particular interest in the design of the ortho-para H<sub>2</sub> conversion equipment consists of a catalytic converter, a precooler, and a liquid nitrogen bath. 30-90 cc of Fe(OH)<sub>3</sub> are employed as a catalyst in the present converter. The conversion heat and conversion effectiveness are evaluated when mass flow rate of hydrogen is in the range of 0.05-1.6 g/min. It is found that the ortho-para H<sub>2</sub> conversion heat is increased while conversion effectiveness is decreased as the mass flow rate of hydrogen is increased. Both the ortho-para conversion heat and conversion effectiveness are increased with an increase in the amount of the catalyst.
김서영(S . Y . Kim),강병하(B . H . Kang),최항집(H . J . Choi) 한국수소및신에너지학회 1998 한국수소 및 신에너지학회논문집 Vol.9 No.4
An experimental study on effect of vapor-cooled heat stations in a 5.5 liter cryogenic vessel has been performed. The cryogenic vessel is made of stainless steel of thickness of 1㎜ and insulated by the combined insulation of vacuum, MLI (multi-layer insulation) and vapor-cooled radiation shield. Vapor-cooled heat stations are also constructed based on the 1-dimensional thermal analysis to reduce the heat inleak through a filling tube. Thermal analysis indicates that the vapor-cooled heat stations can substantially enhance the performance of vessel for cryogenic fluids with high C<sub>p</sub>/h<sub>fg</sub>, where C<sub>p</sub> the specific heat and h<sub>fg</sub> the heat of vaporiaation, such as LH₂ and LH₂. The experimental results for LN₂ shows that the total heat inleak into inner vessel consists of 14% radiation and 86 % conduction through the filling tube. Therefore, it is expected that the conduction heat inleak of the vessel for high C<sub>p</sub>/h<sub>fg</sub> cryogenic fluids can be significantly reduced. powders. The amount of copper coating was 20wt%. In order to examine corrosion behavior of the electrodes, the corrosion current and the current density, in 6M KOH aqueous solution after removal of oxygen in the solution, were measured by potentiodynamic and cyclic voltamo methods. The results showed that Co in the alloy increased corrosion resistance of the electrode whereas Ni decreased the stability of the electrode during the charge-discharge cycles. The exectrode used Si sealant as a binder showed a lower corrosion current density than the electrode used PTFE and the electrode used Cu-coated alloy powders showed the best corrosion resistance.
강병하(B.H.Kang),김도규(D.K.Kim),박경근(K.K.Park) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4
The heat transfer enhancement by pulsating flow in a plate heat exchanger has been experimentally investigated in this study. The effect of the pulsating flow, such as pulsating frequency and flow rate, on the heat transfer as well as pressure drop in a plate heat exchanger has been studied in detail. Reynolds number in cold side of a plate heat exchanger is varied 100~530 while that of hot side is fixed at 620. The pulsating frequency is considered in the range of 5~30 Hz. The results of the pulsating flow are also compared with those of steady flow. It is found that the average heat transfer rate as well as pressure drop is increased as flow rate is increased for both steady flow and pulsating flow cases. When pulsating flow is applied to the plate heat exchanger, heat transfer could be substantially increased in particular ranges of pulsating frequency or Strouhal number; St=0.36~0.60 and pressure drop is also increased, compared with those of steady flow.
이대영,정성훈,강병하,홍희기,Lee, D.-Y.,Jung, S.-H.,Kang, B.H.,Hong, H. 대한설비공학회 1999 설비공학 논문집 Vol.11 No.1
An experimental study on the performance enhancement of a screw-compressor-type chiller with 100kW of nominal cooling capacity has been carried out. Performance test facility was developed to investigate the effects of a partial modification from the existing chiller on the performance. By replacing the existing shell-and -tube heat exchangers with plate heat exchangers, the cooling capacity is increased by 15~18% and the COP is also increased by 19~21% depending on the operation temperature range. Charging mixed refrigerant R22/R142b(80 : 20) instead of R22 into the chiller with plate heat exchangers improves the cooling capacity by 4% and the COP very largely by 30%. Each contribution of the plate evaporator, plate condenser, and mixed refrigerant to the performance enhancement is examined by analyzing the refrigeration cycle and the heat transfer processes. It is also shown that the chiller performance can be improved by adapting 2-stage-compression cycle using an economizer.
재생기 및 냉각기가 VM열펌프의 냉방성능에 미치는 영향
이건태,강병하,유호선,이재헌,Lee, G.T.,Kang, B.H.,Yoo, H.,Lee, J.H. 대한설비공학회 1997 설비공학 논문집 Vol.9 No.3
An experimental study has been carried out to investigate the effects of the combination of the different wire mesh number in a regenerator and the tube number in a cooler on the cooling performance of a Vuilleumier cycle heat pump. Effects of operating conditions, such as charging pressure, operating speed, and heat input, on the cooling performance are also studied. The experimental results obtained indicate that the cooling performance could be improved with the proper combination of different wire meshes in a regenerator. More tubes in a cooler are desirable for better cooling performance. It is also found that the cooling capacity is enhanced, whereas COP is reduced with an increase in the heater tube temperature and the revolution speed. Both the cooling capacity and COP are incereased with a higher charging pressure.