Particle velocity reduction in horizontal-horizontal bends of dilute phase pneumatic conveying

The significance of the acceleration zone is expressed in designing a straight pipeline that follows the feeding point or a bend of a pneumatic conveying system. Although there are various publications that suggest a mean for evaluating the primary acceleration length, no correlation has been presented for evaluating the re-acceleration length following a bend. The current paper presents a thorough experimental investigation of the particles velocity reduction due to the flow in bends and the re-acceleration velocity profile that follows various bends. The experimental results have been obtained from a 2″ dilute phase pneumatic conveying systems with a wide range of operating conditions, conveyed materials and six different bend geometries. The research resulted in a new correlation for the particle velocity reduction due to the flow in the bends, and accordingly we derived an expression for calculating the re-acceleration length following a bend, and the energy loss in the bend.