Ellipse Law

It was originally developed experimentally by Professor Stodola and published in English in 1927. The paper shows that constant flow coefficient method is really a special case of the more generalized law of the Ellipse.

Graphic interpretation of the law of Ellipse for controlled and uncontrolled extraction and variation for sonic choking and reduce number of stage (including single stage) are presented.

(hopely this theory can make a better calculation for Turbine Blade Design as http://idpowerstation.blogspot.com/2011/04/turbine-blade-design.html.)




Pressure - flow relations in cascading multistage turbine, where the intermediate expansion pressure may vary with nozzle flow coefficients and blade flow angles as the reaction changes at off design loads, are very complex phenomena.

Usually, they turbine manufacturer provides curves of key pressures vs flow for normal operating load changes, and heat balances which establish pressure and flow at all significant points based on detailed row by row calculations which take account of such complex phenomena.

These heat balances are usually provided at maximum calculated, 100, 75, 50 and 25 percent of normal design or guaranteed output and are generally regarded as the closest thing to true operating conditions unless or until modification to conform to actual test measurements takes place.