Comparative analysis of the forces of resistance to the movement of coarse particles along the radial blades of turbomachines

The working media of many turbo machines (blowers, fans of pneumatic conveying systems, centrifugal impact grinders) is a mixture of gas and solid particles. Despite the progress achieved in the design, production and use of such devices many issues of their performance have not been sufficiently studied, which is due to the complexity of the frictional and aerodynamic phenomena occurring in the working area. The aim of the study is to develop a methodology to perform a comparative analysis of the resistance forces to the movement of coarse particles along the radial blades of turbo machines with its help. In the analysis, it was taken into account that when sliding along the rotor blade of turbo machines, a centrifugal force of inertia acts on the particle, causing acceleration in the radial direction, as well as the friction force and the force of aerodynamic resistance directed towards and slowing down the motion. In the perpendicular direction, the force of gravity, the Coriolis's force, as well as contact reactions from the side of the blade and the rotor disc act. The laminar, transient, and self - similar regimes of particle motion in the air flow have been analyzed. It is shown that a self - similar mode is characteristic of industrially used turbo machines. A comparative analysis of the values of the arising forces of aerodynamic resistance, as well as the forces of friction caused by the action of gravity and Coriolis's acceleration, in relation to the magnitude of the centrifugal force of inertia is carried out. It is shown that the influence of the friction force due to the gravity of the particle can be neglected over most of the blade length. The influence of aerodynamic drag is more significant and should be taken into account in accurate technical calculations.