Paper 5: Actuator Disc Theory of the Compressible Flow in Free-Vortex Turbo-Machinery

The actuator disc method, in which each blade row of a turbo-machine is represented by a plane, axisymmetric discontinuity in the flow field, is used to produce an approximate solution of the problem of compressible, irrotational flow through an axial compressor or turbine.The flow equations are linearized and a solution for a single, isolated disc is found. The effects of mutual interference between neighbouring discs are studied for two adjacent discs. A method for extending the solution to any number of discs is outlined. Examples showing applications of the method are given and experimental measurements made near the inlet guide vanes of an axial compressor agree well with the theoretical predictions. A new exact solution for two adjacent actuator discs is also given.