稲葉 英男

非共沸混合冷媒R114/R113の水平二重管環状部における凝縮 : 圧力降下と物質伝達の整理

Frictional pressure gradient and vapor phase mass transfer correlations were developed for condensation of nonazeotropic refrigerant mixture R114/R113 in the annuli of horizontal double tubes with an enhanced inner tube. The frictional pressure gradient data were correlated fairly well by a previously developed empirical equation for condensation of pure refrigerants. The vapor phase mass transfer correlation was based on the previous results for turbulent flow in smooth and rough tubes with and without surface suction. For given conditions of vapor and tube wall, the heat transfer coefficient can be calculated by using the correlations for the vapor phase mass transfer coefficient and the heat transfer coefficient for the condensate film. The calculated values agree with the measured data to a mean absolute deviation of 14.3%.

曲り円管の凍結破壊 : 第1報,180°曲り円管の凍結挙動

The formation of the ice growth that occurs in 180° curved pipes containing water flow was investigated. The experiments were carried out under various experimental conditions in a range of pipe with an inside diameter of d=16.5mm21mm, Reynolds numbers (based on pipe i.d.) Re=2906653, and temperature ratios of the freezing parameter, T*(=Tf-Tw)/(T∞-Tf), Tf=0°C, Tf=cooling pipe temperature, T∞=temperature of flowing water)=1.5211. From visual observations of ice formation and measurements of the pressure drop between the inlet and outlet of a curved pipe, it was understood that the flow condition and temperature ratio T* played an important role in the formation of ice in the curved pipe. The transient behaviors of ice formation, according to time proceeding, were expressed in the relationship between nondimensional friction resistance f and Reynolds number for various temperature ratios T*. Moreover, the critical condition of perfect ice blockage in the curved pipe was obtained with experimental correlation equations in terms of T* and Re.