Document emJr2XE4XnaGL9j3zY8xyKDDq
14
CHAPTER 2
1954 Guide
Thermal conductance per unit area, Unit conductance : heat transferred per (unit tiine) (unit area) (degree)........................................................ ...........C
C = = _L 9 = *
* A RA A(U - Q L
Thermal conductivity: heat transferred per (unit time) (unit area) (degree per unit length)...............................................................................................................k
J7
Ul --- it)
L
Surface coefficient of heat transfer, Film coefficient of heat transfer, Individual coefficient of heat transfer: heat transferred per (unit time) (unit area) (degree)...................................... .............................................................................f
9 A / = !i - t.
(In general / is not equal to k/L, where L js the actual thickness of the fluid film.) Overall coefficient of heat transfer. Thermal transmittance per unit area: heat
transferred per (unit time) (unit area) (degree overall)............................ ........ U
Thermal transmission (heat transferred per unit time)..............................................9
Q q^T
Thermal resistance (degree per unit of heat transferred per unit time)................. R
Thermal resistivity....................................................................................................... 1/k Vaporization values at constant pressure. Differences between values for satu
rated vapor and saturated liquid at the same pressure....................Subscript fg Velocity............................................................................................................................ V Viscosity, absolute...........................................................................................................m Viscosity, kinematic..................................................................................................... p/p
Volume (total)......................................................................... ...................................... 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... 9 Weight of a major item, Total weight........................................................................ Weight rate, Weight per unit of power, Weight per unit of time....... .................. Work (total)...................................................................................................................
THE GREEK ALPHABET
A a Alpha
B/S Beta r 7 Gamma a a Delta E e Epsilon
Zf Zeta H, Eta eoe Theta
I i lota K k Kappa A X Lambda M p Mu N v Nu
E Xi 0 o Omicron n ir Pi
P p Rho 2 a s Sigma T r Tau T v Upsilon 4> <p <(> Phi
Xx Chi ik & Psi U o} Omega
Abbreviations and Symbols
15
CONVERSION EQUATIONS6 Heat, Power and Work
1 ton refrigeration Latent heat of ice 1 Btu
1 Int. watthour
1 Int. kilowatthour 1 Int. kilowatt (1000 watts) 1000 I.T. calories) 1 I.T. Kilocalorie) 1 horsepower 1 boiler horsepower Weight and Volume
( 12,000 Btu per hour \ 200 Btu per minute
= 143.4 Btu per pound
778.3 ft-lb 0.2930 Int. whr 252.0 I.T. calorie
( 2656 ft-lb I 3.413 Btu | 3600 Int. joules (860 I.T. calories
( 3,413 Btu I 3.517 lb water evaporated from l and at 212 F
1.341 hp 56.88 Btu per minute
AA 00*7 ri if
3.968 Btu = 3088 ft-lb
1.1628 Int. whr
( 0.7455 Int. kw _ I 42.40 Btu per minute ~ 1 33,000 ft-lb per minute
l 550 ft-lb per second
f 33,475 Btu per hour \ 9.809 Int. kw
1 gal (U. S.)
1 British or Imperial gallon
1 cu ft
1 cu ft water at 60 F (in vacuo) 1 cu ft water at 212 F (" " ) 1 gal water at 60 F (" " ) 1 gal water at 212 F (" " )
1 lb (avdp)
1 bushel 1 short ton
Pressure
) 231 cu in. ~ \ 0.1337 cu ft
= 277.42 cu in.
/ 7.481 gal = \ 1728 cu in.
= 62.57 lb = 59.83 lb = 8.338 lb = 7.998 lb
_ f 16 oz ~ \ 7000 grains
= 1.244 cu ft = 2000 lb
1 lb per square inch 1 oz per square inch
144 lb per square foot 2.0360 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
Abbreviations Int. and I.T. refer to /nlemottonol