Page:Model steam turbines; how to design and build them (IA modelsteamturbin00harrrich).pdf/20

16 one-third of that of the jet, or $1/x$=$1/3$, $V/x$=$300/3$=100 feet per second.

Work done on the vanes is from (3).


 * $2/32⋅2$×(300-100)×100=1240 foot pounds,

Fig. 5 -- Variations of Efficiency with Different Speeds.

and the efficiency which is equal to the ratio $Work got out/work put in$ is by (4) and the preceding calculations $1240/2790$=44.5 per cent.

Taking the same figures as to velocity of jet and weight of fluid discharges, but varying the vane velocities, the curve, fig. 5, is obtained, showing