Simulation of the pressure characteristics of the centrifugal compressor impeller on the basis of a “non-viscous” calculation

Abstract

Abstract

To design the impeller and to calculate gas-dynamic characteristics is necessary to follow the dependence of the pressure on the flow rate. The article uses quasi-three-dimensional approaches to study the pressure characteristics of centrifugal impellers. These approaches do not allow determining the impeller efficiency, but allow determining the effectiveness of the selected geometry based on a qualitative analysis of the velocity distribution diagrams across the blade surfaces. The second approach is a one-dimensional mathematical model that includes empirical relations linking losses in the flow path elements to their dimensions and design parameters. Therefore, the authors use PC programs of the Universal Design Method of the Peter the Great St. Petersburg Polytechnic University. The dependence “loading factor – flow rate coefficient at the impeller outlet” is linear practically. This dependence is specified by the value of the loading factor at zero flow and the angle of inclination of the pressure characteristics. The authors compare measured characteristics of the impellers of the model stages of the Peter the Great St. Petersburg Polytechnic University with the characteristics calculated for the inviscid flow. The research establishes relations between the first and second ones, approximated by algebraic equations. These equations represent the required mathematical expression of pressure characteristics.