Experimental Evaluation of Two-Phase Flow Parameters in the Pneumatic System of a Sowing Complex

Introduction. In modern sowing complexes, the process of transporting and distributing seeds and fertilizers is carried out using an air stream. When simulating the technological processes of these pneumatic systems using computational fluid dynamics and discrete elements, an important step is determining the parameters of the interphase interaction of two-phase air – seed and air – fertilizer flows. Both the possibility of implementing models with computational methods and the complexity of the models used depend on the intensity of interphase interaction. Aim of the Study. The aim is to estimate experimentally the parameters of two-phase flows in the pneumatic system of a sowing complex, where an air stream is used as the carrier phase and a mixture of solid particles of fertilizer granules is used as the dispersed phase. Materials and Methods. The study was conducted using experimental methods. There were used high-speed video shooting, a sail classifier and digital anemometers to analyze air flow and particle motion parameters. The study methodology included the determination of the moisture content of materials, the particle soaring velocity, the volume concentration of phases, and the calculation of hydrodynamic characteristics in various parts of the pneumatic system. Modern approaches to the analysis of two-phase flows were applied taking into account the interaction between the particles and walls of transport channels. Results. The experiments have detected significant differences in flow parameters between horizontal and vertical sections of the pneumatic system. There have been identified the dependence of the aerodynamic characteristics of the particles on their physicalmechanical properties. There was a significant change in the volume concentration of the dispersed phase along the length of the transport pneumatic pipeline of the sowing complex that indicates a transition between different flow modes. The particle drag coefficients showed a clear correlation with the similarity criteria characteristic of the interregion of the Rayleigh curve. Discussion and Conclusion. The conducted studies allowed us to develop a methodology for estimating the parameters of two-phase flows in pneumatic systems and identify key factors affecting the efficiency of transporting and distributing seeds and fertilizers. The results of the study are of practical importance for improving the designs of sowing equipment and developing digital twins of technological processes. Based on the conducted analysis, there have been proposed the topics for further studies including the development of complex CFD-DEM models, which take into account the real operating conditions of pneumatic systems. The work contributes to solving the urgent problem of increasing the seed distribution uniformity in modern tillage complexes.