The relationship between root-mean-square deviation of fluctuating differential pressure and void fraction of gas-liquid two-phase flow in Venturi tube was investigated.The effect of mass flow rate

pressure

differential pressure and density ratio on the relationship was taken into consideration.With void fraction increasing

the fluctuation of differential pressure signal became stronger firstly and weaker subsequently after it reached a maximum.The experiments were carried out for air-water and oil-air two-phase flow with 40 mm and 50 mm diameter pipes respectively

static pressure less than 0.4 MPa

oil flow rate ranging from 0.97 kg8226;s-1 to 1.81 kg8226;s-1

water flow rate ranging from 1.58 kg8226;s-1 to 2.54 kg8226;s-1.Based on the experimental data and theoretical analysis

a dimensionless correlation between differential pressure and void fraction was proposed. Furthermore

void fraction could be determined with the correlation.The results showed that the void fraction determination error of air-water flow was 10.9% and that of oil-air flow was 11.3%

respectively.