OF ENGINEERING FORMULÆ.
•23
•26
•28
•33
19'
15
13
9
Compound Engines—continued.
Best Rate for Expansion under Different Pressures.
J00 lbs., excluding atmosphere, 23 times; cut off *21 stroke.
^ 80 ” '' f f'r
60 „
50 >.
40 „ „ „ a „ „ - i-i »
About 80 Jbs. Is the highest ccnveriieiit pressure for
marine engines.
Allowance for Clearance and Steam in Passages, &c.
L = Length of stroke before steam is cut off, in terms of
stroke.
C =s Clearance space 4. contents of admission port, in
terms of volume displaced by the pii-ton in Its
stroke. C varies from • 0'2 to -10.
jj.=; Ratio of expansion -
Thus, if C= -1, and L — -25, then R = 2-^— = 3-143
times. ' ' r -1 + -20
St.ftFACE <->f Tcrtfis in Square Feet per Foot Run.
Diameter Inches. 0 • i ■■■ f; i * 4
0 •0327 •0Gfl4 •0982 •1309 ■J 636 •1963
1 •2618 •21145 •3272 •58S>0 •3600 • 3927 •4254 •4581
2 •5236 •5Ä63 •6218 •6545 •6« 72 '7200
3 •7854 •8181 •8598 •8836 •9163 •9490 •9817
4 1-0472 1 -079» 1-1126 l-J434|l-178l 1-2108 1'2435
6
I
-2291
-4909
j -7527
1-0145
_______________________,____________________ _____jl-2763
1-309Ü 1'3417 1-374J, 1’4072 1’4389 l‘«26 1-5053 1-5381
Fhtctiox of Arii in Tubes.
(Unwin, ‘ Alin. Inst. £iv, Eug.,’ vol. Ixiii.)
a
lc = Coefficient of friction = - + b, a and b being constants,
and i; Velocity of air, feet per second.
Diameter of tube, feet j
Value of a.. .. ...
„ b............’.I
1-64 I 1-07 |-83 -338 '2G6 -164
001J9 -00972 -01535 -(Kjeor-OSTg -0451s
_........., 00483 -0064 -Ö0704 -00941 -00959 -01167
7^ if V— 100,-UOJ&V0065 -00719 ’00977 -00997 '01212