The modified method from the drift flux model is proposed to correlate the in-situ volume fraction of the solid phase in liquid·solid two-phase flow and in gas-liquid-solid three-phase flow. Though the settling velocity of particles in a stationary liquid has been usually related to the intercept with the axis of the mean solid velocity, Vs, the suspension velocity of particles in a flowing fluid is now related to the intercept with the axis of the total volumetric flux, jγ, in the linear functional relation between Vs and jγ. The applicability of this proposed method is verified well by the comparison of the calculated values with the experimental results of the in-situ volume fraction obtained in an aluminium particles-water two-phase flow and an aluminium particles-air-water three-phase flow in a vertical pipe 20.6 mm in I. D. and 6.4 m in length.
