Assessment of larvae killing pneumatic conveying system elbow: Screening the pressure drop and numerical simulation

Optimum design of the conveying process plays a key role in the enhancement of system performance. In this study, a critical section of a larvae killing system in wheat conveying was evaluated experimentally and numerically. Three elbow angles of 105, 120, and 135 degrees according to physical constraints were assessed to achieve the best conveying condition. Computational fluid dynamics (CFD) was used to obtain numerical results. Also, the Reynolds stress model (RSM) and discrete phase method (DPM) were applied to simulate the turbulences and interaction between solid-gas phases, respectively. The results showed that a minimum pressure drop of 131 Pa occurred in the 120 degrees configuration, and this configuration has the best development from the velocity magnitude viewpoint. Of note, the lowest vorticity magnitude (as a positive factor in safe conveying) was obtained for the 120 degrees configuration in which the vorticity magnitude 63% less than 105 degrees. Also, the contours of turbulence intensity and erosion, comprehensively investigated. Considering all aspects, the 120 degrees configuration was selected as the optimum conveying angle in the larvae killing system. Practical applications The larvae killing system is the main part of the wheat conveying processes. The optimal condition of conveying could be obtained using new numerical methods. Computational fluid dynamics is a powerful method in the simulation of process phenomena. The results achieved from this research could be utilized for energy saving through decreasing the pressure drop, besides understanding of flow field within the system.