Page 9 - Design and Operation of Heat Exchangers and their Networks

Nomenclature xiii

_ m s shell-side mass flow rate (kg/s)
Ma Mach number
M mass (kg);
number of channels
e M molar mass (kg/kmol)
number of mixing nodes
M M
n plan lifetime (yr);
mole fraction (mol/mol)
_ n molar flow rate (mol/s)
n A area exponent of nonlinear
N number of transfer units formed with heat transfer coefficient
N b number of baffles
N f number of fluid streams
N fl number of fin layers
N rc number of effective tube rows in crossflow section
N rw number of effective tube rows in window section
N s number of entropy generation units
N ss number of sealing strip pairs
N t number of tubes
N tc number of tubes in crossflow section
N tw number of tubes in one window section
number of walls
N w
N 0 number of stream entrances
N 00 number of stream exits
NTU number of transfer units
NTU* number of transfer units as counterflow heat exchanger
p pressure (Pa)
reduced pressure
p r
pressure drop due to acceleration (Pa)
Δp a
frictional pressure drop (Pa)
Δp f
static pressure drop (Pa)
Δp g
P wetted perimeter (m);
power (W)
P coefficient matrix of plate temperatures
Pe axial dispersive Peclet number
2
q heat flux (W/m )
2
q cr critical heat flux (W/m )
Q heat flow (W)
r radius (m);
rate of interest for capital appreciation
r, R eigenvalues and diagonal eigenvalue matrix of the governing equation system
r 0 rate of interest for loan
r c radius of curvature (m)
R ratio of thermal capacity rates
R specific gas constant (J/kgK)
surface roughness (m)
R a
2
fouling factor (m W/K)
R f