. The steam-engine and other heat-motors . Figs. 241 and 242. (From Thomas Steam-turbines.) SUPERHEATED STEAM AND STEAM-TURBINES. 463 absolute velocity of departure, as DE = CB. For a series of buckets,as in the Curtis turbine, where AB represents the initial velocityand NP the final velocity a diagram similar to Fig. 179 may bedrawiic In this theoretical diagram AC = CD, EK = KL, etc. Ifthe frictionis to be considered then CD = (l-f)AC, KL= {l-j)EKyetc., where /, / are the coefficients of has the following (Fig. 243):. Fig. 243- The friction in a nozzle has the effect of decr
. The steam-engine and other heat-motors . Figs. 241 and 242. (From Thomas Steam-turbines.) SUPERHEATED STEAM AND STEAM-TURBINES. 463 absolute velocity of departure, as DE = CB. For a series of buckets,as in the Curtis turbine, where AB represents the initial velocityand NP the final velocity a diagram similar to Fig. 179 may bedrawiic In this theoretical diagram AC = CD, EK = KL, etc. Ifthe frictionis to be considered then CD = (l-f)AC, KL= {l-j)EKyetc., where /, / are the coefficients of has the following (Fig. 243):. Fig. 243- The friction in a nozzle has the effect of decreasing the exitvelocity to the value C\= fao, where c0 denotes the theoretical value C0 = V2gLo778 = V2£(#! - ff 2)778. - The coefficient can be taken in long nozzles with condensation at .95 to .90; in short nozzles with free exhaust at .95 to .975. Combinirg cx with — u again gives (relative velocity) wlf but this is decreased by friction and eddy currents during exhaust to the smaller value w2 = (Pwu 464 THE STEAM-ENGINE AND OTHER HEAT-MOTORS. in which <p depends upon the velocity wXj on the form of theblades and other factors. It appears that the smallest value of?(p is .7; with smaller values of w1} <p would increase, and = 820 feet might approximately be estimated at from .85 to . w2 and +u give the velocity of exit c2. These losses by friction expressed as loss of work are, in thenozzle, co2~ci2 n ,2^ the blade-channel, The indicated work per pound of steam is t _^2? Cp2 -cx2 ^wx2
Size: 1704px × 1467px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisheretcetc, booksubject
