The investigation of absolute flow non-uniform velocity distributions influence at the centrifugal compressor axial radial impeller inlet using numerical calculation methods in ANSYS CFX

Abstract

Currently, methods of numerical modelling are widely used. They are especially widely used in the design of turbo compressors. For the specific task of designing new flowing parts of a centrifugal compressor, it is not recommended to deviate from the canonical design techniques, but it is preferable to supplement them with numerical methods. This article is devoted to the end two-element stage investigation of a centrifugal compressor with an axial radial impeller; the stage main dimensions were obtained using the method of V.F. Rice. In order to obtain the necessary pressure characteristics and determine the dependence for the absolute velocity non-uniform distribution at the inlet to the axial radial impeller, the flow path main dimensions were optimized using numerical calculation methods. The calculation was performed using the SST turbulence model using computational gas dynamics methods in the ANSYS CFX software environment. Based on the optimization results, five compressor designs and corresponding characteristics were obtained. The absolute velocity distribution nature at the inlet to the centrifugal compressor axial radial impeller for five flow path variants is investigated. Empirical dependences are obtained for the deviation of the absolute velocity at the inlet in the hub section axial radial impeller and the absolute velocity deviation at the shroud from the absolute velocity at the average diameter based on the results of a numerical experiment. Recommendations are made for further absolute velocity distributions investigating at the inlet to the compressor impeller.

Results of the Experimental Studies of Grain Cleaning with an Air-Spiral Separator

“…To study and set the main parameters: the process of pre-cleaning of the grain heap from weed impurities; the air-spiral separator with a horizontal screw aspiration channel, and its operating mode, we developed a laboratory setup to simulate the real processes of grain cleaning from weed impurities. To simulate the processes of grain cleaning in air separators, it is most effective to use the modern ANSYS CFX software product [11][12][13][14][15]. Based on the analytical description of the process of grain cleaning from weed impurities in the air-spiral separator, we determined that the separation process is ensured at an air flow rate V = 7.1...7.9 m/s and the diameter of the working element D = 0.3 m/ To ensure a pressure of 120.7...133.4 Pa in the working element of the separator, the fan should provide the initial air flow pressure P = 158.7…175.4 Pa.…”