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274 Applied Process Design for Chemical and Petrochemical Plants

e d efficiency of driver, fraction. G d liquid loading for tubular drip type coolers,
e f finned tube efficiency; or, efficiency of fan, lb./hr(lin ft).
fraction. G e equivalent liquid mass velocity for Akers, et
2
F LMTD correction factor as read from charts; al. equation, lb./hr(ft cross-section flow
or, friction loss, (ft)(lb)/(lb). area).
2
F B-C friction loss from part B to part C in tubes, ft G e geometric mean mass velocity, lb/sec(ft ).
liquid. G g geometric mean mass velocity through shell
2
F 1 , F 2 correction factors, flooding equation. side, lb/hr(ft ).
F l total lin ft of tube, ft. G gb boiling equation mass velocity of liquid,
2
F c calorie fraction, dimensionless. lb/hr(ft ). For outside tubes, use projected
F p pressure drop factor, dimensionless. area (diameter tube length).
2
F p pressure correction factor, boiling, G s mass velocity, lb/hr(ft ); or, mass rate of flow
2
dimensionless. on shell side of exchanger, lb/(hr)(ft of
F t dimensionless tube size factor, Buthod’s flow area); also, cross-flow on shell side.
2
pressure drop method. G t mass flow rate in tubes, lb/hr(ft of cross-
2
F w tube size correction factor for water film, section flow area); or, lb/(sec)(ft ).
dimensionless. G w weighed or geometric mean mass velocity,
2
FA face area of air cooled exchanger bundle; – lb/hr(ft ).
length and width, ft 2 G mass velocity of vapor from a bottom tube
2
FV face velocity of air entering face area of air on (p-D o ) spacing, lb/(hr)(ft ), Equation
cooled exchanger, ft/min. 10-145.
–
F friction loss at inlet, ft liquid. G g arithmetic average vapor flow, inlet to out-
2
2
f friction factor, ft /in. ; or, outside film coef- let, for vapor flowing inside tubes, lb
2
2
ficient, Btu/(hr)(ft )(°F). vapor/hr(ft flow cross-section).
–
f f dimensionless friction factor. G L arithmetic average liquid flow, inlet to out-
2
2
2
f s friction factor, ft /in. , in Figure 10-140. let, inside tube, lb condensate/hr(ft of flow
f s friction factor for shell-side cross flow. cross-section).
2
2
G fluid mass velocity, lb/hr(ft tube); or, G max mass flow, lb/sec(ft of cross-section at mini-
2
lb/(sec)(ft )( cross-section flow area) for mum free area in cross-flow).
2
tube side, or lb/hr(ft ) of shell-side flow Gr Grashof number.
area for shell side; or, velocity normal to Gz Graetz number.
8
tube surface; or, superficial gas mass veloc- g or G acceleration due to gravity, 4.17 10 ,
2
2
ity, lb/(hr)(ft ); or, mass velocity, lb/(hr) ft/(hr) ; or, gravitational constant, 32.2
2
(ft ). (Used by permission: Brown Fintube ft/(sec)(sec).
2
Company.) g acceleration of gravity, 32.2 ft/(sec) .
G mass flow rate per unit tube inside circum- H heat transfer coefficient ratio, h M /h Nu .
2
ference w/( D), lb/(hr)(ft ); or, conden- H c height of segment of circle divided by
sate loading for vertical tubes, lb/(hr)(ft), diameter.
Figure 10-67A; or, mass velocity, lb/(sec) H g,d height of a gas phase mass transfer unit, ft.
2
(ft ). (Used by permission: Brown Fintube H l,d height of a liquid phase mass transfer unit,
Company.) ft.
G condensate mass flow rate inside horizontal Hp horsepower, usually as brake horsepower.
2
tubes, lb/(hr)(lin ft). h heat transfer coefficient, Btu/(hr)(ft )(°F).
G o condensate mass flow rate per unit tube h 1 nucleate boiling film coefficient,
2
outside circumference, vertical tubes, Btu/(hr)(ft )(°F).
lb/(hr)(ft). h outside film coefficient based on total out-
2
G mass velocity for tube flow, lb/sec(ft cross- side fin tube area uncorrected for fin effi-
2
section of tube); or, units as, lb/hr(ft). ciency, Btu/(hr)(ft outside surface).
G o condensate mass flow rate outside (shell h a average film coefficient entire tube,
2
side) for horizontal tubes, lb/(hr)(lin. ft). Btu/(hr)(ft )(°F); or, heat transfer film
G b mass flow rate through baffle “window,” lb coefficient between the insulated or bare
2
fluid/(hr)(net ft of flow cross- section area pipe and air; see Figure 10-171; assume
through the “window” opening in baffle). 0.90 and ambient air 70°F.
G b mass velocity through baffle opening, h a surface coefficient of heat transfer,
2
2
lb/sec(ft ). Btu/(hr)(ft )(°F/ft); or, film coefficient
2
G c mass flow, lb/hr(ft of cross-section at mini- based on arithmetic mean temperature,
2
mum free area in cross-flow). Btu/(hr)(ft )(°F).
G c maximum bundle cross-flow mass velocity, h b boiling film coefficient, corrected coeffi-
2
2
lb/sec(ft ). cient for bundle, Btu/(hr)(ft )(°F).