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Turbomachinery: Impulse Turbine

1) The steam from the nozzles of a single wheel impulse turbine discharges with a velocity of 600 m/s at an angle of 20 degrees. The blade wheel rotates at 3000 rev/min and the mean blade radius is 590 mm. The axial velocity of the stream at the exit from the blades is 164 m/s and the blades are symmetrical.

Sketch the annotated velocity triangles and calculate:
a) the blade inlet angle
b) the diagram specific work
c) the diagram efficiency
d) the blade velocity coefficient
e) Show that for symmetrical blading and no friction n_rot = 4(U/V_1)(cos(alpha_1) - (U/V_1)) and determine the optimum blade speed ratio and efficiency. Make a sketch of your results.

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Solution Preview

Notations and assumptions:
[ ]* = total features (like p*, T*)
cp = specific heat at constant pressure (for superheated steam we will take cp ...

Solution Summary

This complete solution provides details and formated step-by-step calculations and answers in the attached Word document. The student will be able to clearly see how formulas are derived and answers are calculated for each part (a) through (e). The solution provides an illustration of the geometry of the velocities pattern. (e) also includes an illustration of the velocities pattern for maximum rotor efficiency.