STUDY THE EFFECT OF LOADING RATIO ON SECONDARY LOSS AND HEAT EXCHANGE IN TWO PHASE FLOW (GAS – SOLID )IN VARIABLE CROSS SECTIONAL PIPE.

Abstract

The flow of gas with a suspension of solid particles through venture has been analyzed theoretically. Computations of the flow parameters have been performed based on one-dimensional analysis and numerical solution of the governing equations by (physico – computational model). An investigation of pressure variation, velocity and temperature distributions across venture for air only and for gas-solid suspensions were carried out for specific air mass flow rate and solid loading ratio. Venture was used to produce a non-equilibrium two-phase flow region and the effects of solid particles on the pressure distribution have been considered. The effects of different loading ratios of (0.5 ,2 ,4) on pressure drop, gas and solid velocity and temperature distributions for the same particle diameter of 100 microns and for constant gas mass flow rate of (0.6 kg/s) are determined. Two sets of diameters of the solid particles (50, 200 microns) were used at the loading rate of (4). The most important conclusions obtained are that the increase loss of pressure due to the increased rate of loading, especially in the convergence of the Venturi, which ranges between (0.7 - 1.3) greater than the decrease of pressure in the divergence of the tube, or a decrease in the size of the particles of solid material, it range (0.7 - 1.1) for a range of particle size of (50-200 microns), where the increase in pressure loss resulting from the decrease of solid particles is greater than the loss of pressure due to increase the loading rate. Increasing the proportion of loading note a decline in the speed of the solid and the change of speed ranges between (1.1 to 2.1) and the change is evident in the spacing of the Venturi. And we get the same effect in the case of decrease in the volume of solid. And shows the amount of change in the speed of solid particles to the change of the size of the particles at a range of (1.6 to 2.7) and appears in the throat and the divergence clearly compared to the convergence of the Venturi.