Page 8 - Design and Operation of Heat Exchangers and their Networks

xii Nomenclature

f Fanning friction factor;
frequency (Hz)
Darcy friction factor
f D
F correction factor for the logarithmic mean temperature difference;
flexibility factor
fraction of tubes in crossflow section
F c
Fr Froude number
fraction of tubes in baffle window
F w
g ij element of interconnection matrix
0 element of entrance matching matrix
g ik
00 element of exit matching matrix
g ki
000 element of bypass matrix
g lk
2
G mass velocity (kg/m s)
G interconnection matrix
G 0 entrance matching matrix
G 00 exit matching matrix
G 000 bypass matrix
2
G w mass velocity in window section (kg/m s)
h specific enthalpy (J/kg)
h, H height (m)
h f fin height (m)
fin free spacing in height (m)
h fs
louver height (m)
h l
specific enthalpy of vaporization (J/kg)
Δh v
H matrix of eigenvectors of the governing equation system
Hg Hagen number
j mixture volumetric flux (m/s);
Colburn j factor
superficial gas velocity (m/s)
j g
superficial liquid velocity (m/s)
j l
dimensionless superficial gas velocity
J g
2
k overall heat transfer coefficient (W/m K)
K dimensionless thermal conductivity
K c loss coefficients for abrupt contraction
K e loss coefficients for abrupt expansion
l characteristic length (m)
l bc central baffle spacing (m)
l bi inlet baffle spacing (m)
l bo outlet baffle spacing (m)
l c baffle cut (m)
l f actual fin height along the fin surface (m)
l s strip length of offset strip fins, wavy fins, or louver fins (m)
l w wavelength of wavy fins or herringbone-type plates (m)
L length of the heat exchanger (m)
L Laplace transform operator
m fin performance factor (1/m)
_ m mass flow rate (kg/s)