Document NeMyR7D7Vdz3p6B4XNwvG5Ory
12
CHAPTER 2
- 1948 Guide
symbols found necessary in the individual chapters will be found in a list at the end of Chapters 3, 4, 5, .7, 15, 16, 39, and 41.
Acceleration, due to gravity...... ................................... .......................... .... ................. g Acceleration, linear___________________________________________________ ...........--o Area.,-__________________________ __________ :..... ........................ -A Change in.specific volume during vaporization--.'..... ...........J...... .'........... ......... ........ -'_rfg Density, Weight per unit volume. Specific weight..--_________________ __ --d or p (rho)
r
Distance, linear.___________ ___ .____________________________________ _______s
Dry saturated vapor, Dry saturated gas at saturation pressure and temperature, vapor in contact with liquid______________________________ ______ --Subscript g
Efficiency.................................. ............. .............................................................................. t)
Elevation above some datum ^ ____________________ ______ _____ --............. --s, Z Einissivity --- ............................................................................................................ ....;..e
Energy in general; work, total; work, molal J '! ............................ --:------ E Entropy. (The capital should be used for any weight, and the small letter for unit
weight)_______________________________________;.............. ..... ~.................... or s
Force, total load.._________________________ _______ ____ ____ ______________ ____ F
Gas Constant, in equation pV = nRT............................ .... ... ......... ........... ...............--R
Head____ ,:__-____ _:_____________________________-.'....H or h
Heat content, Total heat, Enthalpy. (The capital should be used for any weight and the small letter for unit weight)____________ ______ ;--.----------------- ----H or h
Heat content of saturated liquid, Total heat of saturated liquid, Enthalpy of saturated liquid, Sometimes called heat of the liquid-..-.:.._______________hi
Heat content of dry saturated vapor. Total heat of dry saturated vapor, Enthalpy of dry saturated vapor --:------------------------------------------------------------------------- ftg
Heat of vaporization at constant pressure___ _____ 1..... U.,,.......... ......... .. .......... L or ifg
Hydraulic radius __________________________________________ _Rn
Internal energy, Intrinsic energy. (The capital should be used for any weight and
the small letter for unit weight)
-- ----------------- .................. V or u
Length of path of heat flow, thickness............... .... .................................. ........ ...... ------ L
Load, total ________________ .................... ................ ..............---.----;..--W Mechanical efficiency-______________ ......... --.......... ....... ..... ...................... :----- --em Mechanical equivalent of heat..____________------------------------------------------- J Power, Horsepower, Work per unit time_____________________________ ___________ PPressure, Absolute pressure, Gage pressure. Force per unit area------------------------------ p
Quantity (total) of fluid, water, gas, heat; Quantity by volume; Total quantity of heat transferred____________ ________________________________________ ...--Q
Quality of steam, Pounds of dry steam per pound of mixturex
Reynolds NumberJ:---------------------------------------------------------------------------- Nut
Saturated liquid at saturation pressure and temperature. Liquid in contact with vapor._______________________________ __Subscript f
Specific heat.,------------------------------------------------------------- ----------- :............................... c
' Specific heat at constant pressure............ ..................----------- ----------- -------- ;........ --Cp
Specific heat at constant volume_______ i----------------------- ----------------------..................-Cv
Specific volume, Volume per unit weight. Volume per unit mass_______________ ____.n
Temperature (ordinary) F or C. (Theta is used preferably only when t is used for Time in the same discussion)tor 8 {theta)
Temperature (absolute) F abs .or K. (Capital theta is used preferably only when small theta is used for ordinary temperature)---------------~.-r--T or 9 {capital theta)
Abbreviations and Symbols
Thermal conductance *: heat transferred .per (unit time) (degree)____
r _L R
kA q L t, - t.
Thermal conductance per unit area, Unit conductance: heat transferred per (unit time) (unit area) (degree)--.:s_______________________________
C* =
1 RA A{ti -<,)
k
L
Thermal conductivity: heat transferred per (unit time) (unit area) (degree per unit length).____________________________________________________
g
13
fa -<>-
L
Surface coefficient of heat transfer, Film coefficient of heat transfer, Individual coefficient of heat transfer: heat transferred per (unit time) (unit area) (degree);-----------;_______ J.__________________________________________ J
A ti - t.
(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)..r.V.
/,V A h-
Thermal transmission (heat transferred per unit time)
9
Thermal resistance (degree per unit of heat transferred per unit time)
Jt
kA
Thermal resistivity:1/k Vaporization values at constant pressure. Differences between values for saturated
vapor and saturated liquid at the same pressureSubscript fg Velocity________________ J----------------------------------------------------------------------------- :_-V Viscosity, absolute.;_________________________________________ ___ ______ p Viscosity, kinematic --:------------------------------------------------------------------------------ 1--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--------- q Weight of a major item, Total weight. Weight rate. Weight per unit of power, Weight per unit of time. Work (total)
. `Terms ending ivify designate properties independent of size or shape, sometimes called specific propertres. Examples: conductivity, resistivity. Terms ending ana designate quantities dependingnot only on the material, but also upon sire and shape; sometimes called total Quantities, Examples: conductance, transmittance. Terms ending ion designate rate of heat transfer, Examples: conduction, transmission. \