The Radial-Equilibrium Equation of Turbomachinery

An equation is derived that describes the radial variation of circumferential-average flow properties inside of a turbomachine blade row. A physical interpretation is given for each of the several terms in the equation, and the magnitudes of the terms are demonstrated with an example. Annulus taper angle is found to be rather important. The error involved in the conventional axisymmetric (infinite-blade-number) approach is shown to be more related to the loading level, e.g., the lift-coefficient level, than the number of blades. This error is found to be small for the selected example.