Computer aided design of small axial flow hydraulic turbines

A mathematical model used in conjunction with a finite element analysis to aid in the design of small axial-flow hydraulic turbine blades is presented.

A computer program is used to create a finite element model of the blade based on performance and geometric data. Loads are calculated by using a two dimensional model of the flow by means of which the change of momentum of the fluid is determined. The load distribution is estimated using a potential flow solution.

An analysis of blades with constant thickness and varying degrees of twist was performed. The analysis entailed the calculation of the first three natural frequencies, mode shapes, and relative vibratory stresses as well as deflections and stresses due to hydrodynamic and centrifugal loading. The results were found to be compatible with experimental work in similar turbine blades.