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CHAPTER 2
1949 Guide
Thermal conductance per unit area, Unit conductance: heat transferred per' (unit time) (unit area) (degree)...............................................................................C
c = = --
9 -k
* A RA = A(h - tO " L
Thermal conductivity: heat transferred per (unit time) (unit area) (degree per unit length).............................................. ..................................................................k
Jfc =-~A-(h tz) L
Surface coefficient of heat transfer, Film coefficient of heat transfer. Individual. coefficient of heat transfer: heat transferred per (unit time) (unit area) (degree).......................................................................................................................... /
jf A ti -- li
(In general / is not equal to k/L, where L is the actual thickness of the fluid film.) Over-all coefficient of heat transfer, Thermal transmittance per unit area: heat
transferred per (unit time) (unit area) (degree over-all).................................. XJ
1
Thermal transmission (heat transferred per unit time)..........................
Q ?=7
Thermal resistance (degree per unit of heat transferred per unit time)
? R
L_ R=
kA
Thermal resistivity....'..................................... ...............................................Ilk
Vaporization values at constant pressure. Differences between values for satu-
,
rated vapor and saturated liquid at the same pressure......... ....... . .Subscript r
Velocity................... .................................................................................. ...........................V ^
Viscosity, absolute...................................................................................................... -' M .
Viscosity, kinematic............................................................................ ' ...................... m/p
Volume (total)...................... 1...................-................................... ....................................V-
Volume per unit time. Rate at which quantity of material passes through a
machine, Quantity of heat per unit time, Quantity of heat per unit weight... q
Weight of a major item. Total weight..............................
.................... .......... ,.. W
Weight rate, Weight per unit of power, Weight per unit of time.............. '.............. w
Work (total).................................................................................,. ........................... /.... W
THE GREEK ALPHABET
-A a Alpha B (3 Beta T y Gamma A 5 Delta E Epsilon
Z f . Zeta ,Ht| Eta
0 d 0 Theta
11 Iota ' K k Kappa ' A X Lamdba
Mm Mu N v Nu
si xi
0 o Omicron Ur Pi
P p Rho 2<rr Sigma Tt Tau T u Upsilon
Phi
Xx Chi rj/ Psi
flu Omega
Abbreviations and Symbols
CONVERSION EQUATIONS5 Heat, Power and Work
1 ton refrigeration Latent heat of ice 1 Btu
1 Int. watthour
1 Int. kilowatthour
{ 12,000 Btu per hour Btu per minute
143.4 Btu per pound
( 778.3 ft-ib { 0.2930 Int. whr l 252.0 I.T. calorie
2656 ft-lb 3.413 Btu 3600 Int. joules 360 I.T. calories
1 Int. kilowatt (1000 watts)
1000 I.T. calories \ 1 I.T. Kilocalorie j
1 horsepower
1 boiler horsepower
Weight and Volume 1 gal (U. S.)
1 British or Imperial gallon I cu ft
1
1 1
cu ft water at 60 F
cu ft water at 212 F gal water at 60 F
(in f"
vacuo "
) )
1 gal water at 212 F ( " " )
I lb .(avdp)
1 bushel 1 short ton
Pressure
f 1.341 hp > ! 56.88 Btu per minute
l 44,267 ft-lb per minute-
f 3.968 Btu ( 3088 ft-lb
{ 1.1628 Int. whr
{0.7455 Int. kw 42.40 Btu per minute 33,000 ft-lb per minute 650 ft-lb per second
-{ 33,475 Btu per hour 9.809 Int. kw
/ 231 cu in. 1 0.1337 cu ft
277.42 cu in.
/ 7.481 gal \ 172? cu in.
62.37 lb 59.83 lb 8.338 lb 7.998 lb
/ 16 oz \ 7000 grains
1.244 cu ft 2000 lb
1 lb per square inch 1 oz per square inch
"8
is.iaiou in. mercury at 32 F 2.0422 in. mercury at 62 F 2.309 ft water at 62 F 27.71 in. water at 62 F
{ 0.1276 in. mercury at 62 F . .1.732 in. water at 62 F
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