수평관내 이산화탄소의 증발 압력강하
Evaporation pressure drop of CO2 in a horizontal tube
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Abstract
The evaporation pressure drop of CO2 (R-744) in a horizontal tube was investigated experimentally. The experiments were conducted without oil in a closed refrigerant loop which was driven by a magnetic gear pump. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and evaporator (test section). The test section consists of a smooth, horizontal stainless steel tube of 7.75 mm inner diameter. The experiments were conducted at mass flux of 200 to 500 kg/m2s, saturation temperature of -5 to 5 , and heat flux of 10 to 40 kW/m2. The test results showed the evaporation pressure drop of CO2 are highly dependent on the vapor quality, heat flux and saturation temperature. Theevaporation pressure drop of CO2 is very lower than that of R-22. In comparison with test results and existing correlations, the best fit of the present experimental data is obtained with the correlation of Choi et al. But existing correlations failed to predict the evaporation pressure drop of CO2. Therefore, it is necessary to develop reliable and accurate predictions determining the evaporation pressure drop of CO2 in a horizontal tube.
참고문헌 (14)
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