Experimental Study on Two-Phase Flow and Heat Transfer through Narrow Rectangular Channel under Middle-Low Pressure Condition

Two-phase boiling experiments have been performed in narrow rectangular channel at middle-low pressure.Based on the measured pressure drop and temperature across the test section,the effect of pressure and mass flow rate has been analyzed.Saturated boiling heat transfer was studied.And a new correlation has been developed for saturated boiling heat transfer under middle-low pressure condition.Additionally,based on the predigested one-dimensioned model of two-phase boiling flow,a new correlation has been developed for two-phase flow pressure drop under middle-low pressure condition.Furthermore,F parameter has been defined to expresses proportion of moistening perimeter between steam-phase and wall in this new correlation.The calculation results of new correlation predict well the experimental results.The average saturated boiling heat transfer coefficient is great impacted by system pressure,mass flow and heat flux.