FLOW CHARACTERISTICS IN HORIZONTAL PNEUMATIC CONVEYANCE AT LOW FLUID VELOCITIES .3. ADDITIONAL PRESSURE-DROP AND THE FRICTION FACTOR

In this paper, a fundamental equation for the friction factor of an ad ditional pressure drop due to solid particles is first derived based o n the observed dow pattern of solid particles reported in part 1 on a fully developed dow at low fluid velocities in horizontal pipes. Next, an empirical equation for the friction factor is obtained by the subs titution of the parameter of the gravitational force and the velocity ratio of particles to fluid determined in part 2 into the foregoing eq uation. More than 95% of the values calculated by the equation fall wi thin +/-20% of the present experimental values.