Dynamic behavior of gas-solid flow in horizontal pipes

الملخص EN

The dynamic behavior of a two phase (gas-solid) flow in a horizontal pipe is studied in this work.

The experimental and theoretical methods are set to examine the effects of inlet velocity, loading ratio for different sizes of solid particles on the pressure, velocity and the volume phase fraction along the pipe.

The range of velocities used in this work are between (12-42 m / s) and the loading ratios are between (2-12) as mass of solid to mass of air.

The solid is the sand at four groups of particle size (150-300 µ m), (300-425 µ m), (425-600 µ m ) and (600-850µ m).

The experimental rig is constructed to measure the inlet velocity and pressure along (3.175cm) diameter (6m) long horizontal pipe.

The results show that the loading ratio (LR) and Reynolds number (Re) are the main parameters that control the pressure drop along the pipe.

The pressure drop increases as both Reynolds number and loading ratio increase whereas the effect of particle size is opposite to that effect.

The pressure drop for a small particle is less than for the larger one.

The empirical correlation that relates the friction coefficient (Cf) through the pipe is represented by the dimensionless groups (Re), (volume fraction, α) and (Froude number, Fr).

Cf exp = 9.737.

α -1.356 Re-0.681 Fr 0.125 The theoretical analysis consists of the solution of the steady state and the unsteady state of the differential equations using the boundary conditions that govern the two phase (gas-solid) flow GSVF is the computer program that was build to simulate the dynamic behavior of the flow involved in the semi-empirical correlation for (gas–solid) interaction (Sa).

The dimensionless number (SR) suggested in this work indicates that the volume fraction is the most effective parameter than Re and Fr.

SR = 5.3 *10 -3 α0.848 Re-0.004Fr 0.008 The volume fraction, velocity and pressure profiles are evaluated as the output of the computer program, only the pressure profiles are compared with the experimental values.

The pressure drop and the friction coefficients produced from the theoretical analysis show that the theoretical values are (24 %) higher than the experimental one.

C f theo.

= 7.207α-1.368 Re -0.681 Fr 0.077