Numerical Method for System Level Simulation of Long-Distance Pneumatic Conveying Pipelines

Pneumatic conveying pipelines (PCPs) provide an effective manner for long-distance transport of capsules because of their advantages in high speed, superior safety, and full automation. For better development of PCPs, a system-level simulation tool is desired, but not yet available. In this work, a new 1D model describing systemic dynamics of airflow and capsule movement in PCPs is presented, and 3D simulation is proposed to obtain the characteristic coefficients in the 1D model. The complete model accounts for those phenomena that most profoundly affect the performance of PCPs, such as the 3D layout of the pipeline, the geometry of capsules, as well as the compressibility of air in a long pipeline. A finite volume method is also presented to numerically calculate the model equations, and thereby realize the successful system-level simulation of practical PCPs for the first time. Experimental data were used for validation. For a 550 m-long and small-diameter (27.86 mm) PCP, the errors of predicted conveying times were within 4.43%. For another 30 m-long and large-diameter (125.6 mm) PCP, the errors of predicted conveying time and maximum capsule velocity were within 1%. By enabling readily and accurate prediction of the conveying process, the method provides a feasible tool for the design and application of PCP systems.