Performance improvement prediction of push chain moist-mix concrete spraying machine employing orifice plate

Push chain moist-mix concrete spraying machine is widely used in shotcrete construction processes, but shotcrete surplus has always been the main problem affecting work efficiency. To improve the efficiency, the orifice plate is employed in the discharge cylinder, considering three different distributions (equal, left concentrated and both side distribution) of the holes and two hole diameters (6 mm and 8 mm). In different orifice plate, the discharge cylinder flow field is studied employing the FLUENT software by the computational fluid dynamic method. Besides, dimensionless evaluation index of the discharge cylinder flow field is defined based on the force of particles. By comparing dimensionless index and velocity vector, the best orifice plate (both side distribution and 8 mm) is presented. Compared without orifice plate, the experiment showed the shotcrete surplus ability is reduced by 26 %–87 %. This study provides guidance for the design and optimization of pneumatic conveying equipment.