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하천수 열원이용 2단압축 열펌프시스템의 최적 중간압에 대한 실험
김종률(J. R. Kim),이영수(Y. S. Lee),나호상(H. S. Ra) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
The inter-stage pressure for two-stage vapor compression cycle is commonly taken as the geometric mean of the refrigerant evaporation and condensation pressure, which is only applicable for a perfect gas with complete inter-cooling between the stages. However, when the flash inter-cooler is incorporated, there is considerable difference between the geometric mean and the optimal pressure value. In this paper, experimental investigation for the optimum performance of HFC-134a multi-stage heat pump system was conducted to suggest optimal inter-stage pressure.
김종률(J.-R. Kim),최경민(G.-M. Choi),김덕줄(D.-J. Kim) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
Recently, development of flame control scheme has been hot issues in the combustion engineering. It has been held that flame shape can be controllable by pressure inside combustor. The influence of combustor atmospheric pressure on flame shape was investigated in the present study. The flame shape, flammable limit, flame temperature and nitric oxide emission were measured as functions of combustor atmospheric pressure and equivalence ratio. The reaction region became longer and wider with decreasing combustor atmospheric pressure by direct photography, hence reduction of blow off limit. This tendency was also observed in the mean flame temperature distribution. Nitric oxide emission decreased with decreasing combustor atmospheric pressure. Low NOx combustion is ascribed to wide-spread reaction region in the low atmospheric pressure condition. These results demonstrate that flame shape and nitric oxide emission can be controllable with combustor atmospheric pressure.
김종률(J. R. Kim),이영수(Y. S. Lee),장기창(K. C. Jang),라호상(H. S. Ra) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4
The present study has been conducted to develop a heat pump system using river water of temperature energy which not only belongs to unutilized energy but is a kind of good heat source due to maintain its temperature in a certain degree regardless of seasonal variation. The system did n01 meet the proposed performance after setup. In this paper. the system performance affected by refrigerant Oil, by pressure drop, or by other factors has been discussed, The followings were obtained : (1) Refrigerant Oil mixture rete was 2.5 in weight percentage, (2) Pressure drop through evaporator was 29.1㎪(3.1℃ in saturated tempearture) (3) Pressure drop from the end of evaporator 10 compressor inlet was 39.8㎪(4.0℃ in saturated tempearture). (4) The system performance can to be improved by modifying a pan of pipe line to compressor, and reducing pressure drop through heat exchangers.