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Packaged units, specification of,
Packing characteristic, in cooling towers,
Packings, for cooling towers
Packings, for fixed beds:
Packinox heat exchanger,
Paints, spectral characteristics of reflectance of surfaces treated with,
Palen, J W
Panchal, C B,
Paraffins, normal and isonormal:
Paraldehyde:
Parallel channel instability, in condensers,
Partial boiling in subcooled forced convective heat transfer,
Participating media, radiation interaction in,
Particle convective component, in heat transfer from fluidized beds,
Particle emissivity,
Particle Reynolds number in fixed beds,
Particles:
Particulate fluidization,
Particulate fouling,
Pass arrangements, in plate heat exchangers,
Passes, tube side,
Passive methods, for augmentation of heat transfer, passive systems for:
PD5500 mechanical design of shell-and-tube heat exchangers to,
Peacock, D K,
Pearson number,
Peclet number
Peng-Robinson equation of state, application to hydrocarbons,
Penner's rule, in absorption of radiation by gases,
Pentachloroethane (Refrigerant 120):
Pentadecane:
Pentadecene:
Pentadiene 1, 2:
Pentadiene 1, trans 3:
Pentadiene 1, 4:
Pentadiene 2-3:
Pentafluoroethane (Refrigerant 125)
Pentamethylbenzene:
Pentane:
Pentanoic acid:
1-Pentanol:
1-Pentene:
cis-2-Pentene:
trans-2-Pentene:
Pentylacetate:
Pentylbenzene:
Pentylcyclohexane:
Pentylcyclopentane:
Pentylcyclopropane, liquid properties,
Perforated fins, in plate fin heat exchangers,
Perforated plates, loss coefficients in,
Periodic operation, of regenerator,
Periodic variations in temperature, thermal conduction in bodies with,
PFR correlation, for heat transfer in high fin tube banks,
Pharmaceutical industry, fouling of heat exchangers in,
Phase change materials, in augmentation of heat transfer,
Phase change number,
Phase equilibrium:
Phase inversion
Phase separation, as source of corrosion problems,
Phenol:
Phenols:
Phenylhydrazine:
Phonons, in thermal conductivity of solids,
Phosgene:
Physical properties:
Pi theorum, in dimensional analysis,
Pinch analysis, for heat exchanger network design,
Pioro, I L
Pioro, LS,
Pipe leads,
Piperidine:
Pipes, circular:
augmentation of heat transfer in,
boiling of binary and multicomponent mixtures in,
combined free and forced convection in,
flow boiling in: horizontal pipes,
free convective heat transfer from outside of,
heat transfer to, in fluidized beds,
heat transfer to liquid metals in,
laminar heat transfer in,
pneumatic conveyance (gas solids flow) in,
radiative heat transfer along,
roughened surface, radiative heat transfer along,
single-phase fluid flow and pressure drop in fully developed
transition between laminar and turbulent flows, heat transfer in turbulent heat transfer in,
two-phase gas-liquid flow in,
use in shell-and-tube heat exchangers for single-phase flow,
Pipes, noncircular:
Piping components:
Pitting corrosion, in stainless steels,
Planck's constant,
Planck's law, for spectral distribution of blackbody radiation,
Plane shells, steady-state thermal conduction in,
Plastic deformation
Plate fin heat exchangers
Plate fins, efficiency,
Plate heat exchangers:
Plate evaporator
Plates:
Plug flow:
Plug flow model, for furnaces,
Pneumatic conveyance,
Pneumatic conveying dryer,
P-NTU method:
Polarization, of thermal radiation,
Polyglycols, as heat transfer media,
Polymers:
Pool boiling,
Porous surfaces:
Port arrangements, in plate heat exchangers,
Portable fouling unit,
Poskas, P,
Postdryout heat transfer:
Powders:
Power law fluid (non-Newtonian),
Power plant:
Prandtl number
Precipitation (crystallization) fouling,
Precipitation hardening, of stainless steels,
Pressure coefficient:
Pressure control of condensers,
Pressure drop:
Pressure gradient:
Pressure, specification of in mechanical design to EN13445,
Pressure testing,
Pressure vessels, principle codes for,
Pressurised water reactor, fouling in,
Printed circuit heat exchanger,
Problem table algorithm, in pinch analysis,
Process heaters:
Progressive plastic deformation
Prolate spheroids, free convective heat transfer from,
Promoters, in dropwise condensation,
Propadiene:
Propane:
1-Propanol:
2-Propanol:
Propeller agitator,
Property ratio method, for temperature dependent physical property
Propionaldehyde:
Propionic acid:
Propionic anhydride:
Proprionitrile:
Propyl acetate:
Propylamine:
Propylbenzene:
Propylcyclohexane:
Propylcyclopentane:
Propylene:
1,3-Propylene glycol:
Propylene oxide:
Propyl formate:
Propyl propionate:
Pseudo-boiling in supercritical fluids,
Pseudo-film boiling in supercritical fluids,
Pseudocritical pressure,
Pseudocritical tempertaure,
Pugh, S F
Pulp and paper industry, fouling of heat exchangers in,
Pulsations, use in augmentation of heat transfer,
Pulverized fuel water-tube boiler,
Pumping, lost work in,
Pushkina and Sorokin correlation, for flooding in vertical tubes,
Pyramid, free convective heat transfer from,
Pyridine:
Index
HEDH
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Packaged units, specification of,
Packing characteristic, in cooling towers,
Packings, for cooling towers
Packings, for fixed beds:
Packinox heat exchanger,
Paints, spectral characteristics of reflectance of surfaces treated with,
Palen, J W
Panchal, C B,
Paraffins, normal and isonormal:
Paraldehyde:
Parallel channel instability, in condensers,
Partial boiling in subcooled forced convective heat transfer,
Participating media, radiation interaction in,
Particle convective component, in heat transfer from fluidized beds,
Particle emissivity,
Particle Reynolds number in fixed beds,
Particles:
Particulate fluidization,
Particulate fouling,
Pass arrangements, in plate heat exchangers,
Passes, tube side,
Passive methods, for augmentation of heat transfer, passive systems for:
PD5500 mechanical design of shell-and-tube heat exchangers to,
Peacock, D K,
Pearson number,
Peclet number
Peng-Robinson equation of state, application to hydrocarbons,
Penner's rule, in absorption of radiation by gases,
Pentachloroethane (Refrigerant 120):
Pentadecane:
Pentadecene:
Pentadiene 1, 2:
Pentadiene 1, trans 3:
Pentadiene 1, 4:
Pentadiene 2-3:
Pentafluoroethane (Refrigerant 125)
Pentamethylbenzene:
Pentane:
Pentanoic acid:
1-Pentanol:
1-Pentene:
cis-2-Pentene:
trans-2-Pentene:
Pentylacetate:
Pentylbenzene:
Pentylcyclohexane:
Pentylcyclopentane:
Pentylcyclopropane, liquid properties,
Perforated fins, in plate fin heat exchangers,
Perforated plates, loss coefficients in,
Periodic operation, of regenerator,
Periodic variations in temperature, thermal conduction in bodies with,
PFR correlation, for heat transfer in high fin tube banks,
Pharmaceutical industry, fouling of heat exchangers in,
Phase change materials, in augmentation of heat transfer,
Phase change number,
Phase equilibrium:
Phase inversion
Phase separation, as source of corrosion problems,
Phenol:
Phenols:
Phenylhydrazine:
Phonons, in thermal conductivity of solids,
Phosgene:
Physical properties:
Pi theorum, in dimensional analysis,
Pinch analysis, for heat exchanger network design,
Pioro, I L
Pioro, LS,
Pipe leads,
Piperidine:
Pipes, circular:
Q
R
S
T
U
V
W
X
Y
Z
augmentation of heat transfer in,
boiling of binary and multicomponent mixtures in,
combined free and forced convection in,
flow boiling in: horizontal pipes,
free convective heat transfer from outside of,
heat transfer to, in fluidized beds,
heat transfer to liquid metals in,
laminar heat transfer in,
pneumatic conveyance (gas solids flow) in,
radiative heat transfer along,
roughened surface, radiative heat transfer along,
single-phase fluid flow and pressure drop in fully developed
transition between laminar and turbulent flows, heat transfer in turbulent heat transfer in,
two-phase gas-liquid flow in,
use in shell-and-tube heat exchangers for single-phase flow,
Pipes, noncircular:
Piping components:
Pitting corrosion, in stainless steels,
Planck's constant,
Planck's law, for spectral distribution of blackbody radiation,
Plane shells, steady-state thermal conduction in,
Plastic deformation
Plate fin heat exchangers
Plate fins, efficiency,
Plate heat exchangers:
Plate evaporator
Plates:
Plug flow:
Plug flow model, for furnaces,
Pneumatic conveyance,
Pneumatic conveying dryer,
P-NTU method:
Polarization, of thermal radiation,
Polyglycols, as heat transfer media,
Polymers:
Pool boiling,
Porous surfaces:
Port arrangements, in plate heat exchangers,
Portable fouling unit,
Poskas, P,
Postdryout heat transfer:
Powders:
Power law fluid (non-Newtonian),
Power plant:
Prandtl number
Precipitation (crystallization) fouling,
Precipitation hardening, of stainless steels,
Pressure coefficient:
Pressure control of condensers,
Pressure drop:
Pressure gradient:
Pressure, specification of in mechanical design to EN13445,
Pressure testing,
Pressure vessels, principle codes for,
Pressurised water reactor, fouling in,
Printed circuit heat exchanger,
Problem table algorithm, in pinch analysis,
Process heaters:
Progressive plastic deformation
Prolate spheroids, free convective heat transfer from,
Promoters, in dropwise condensation,
Propadiene:
Propane:
1-Propanol:
2-Propanol:
Propeller agitator,
Property ratio method, for temperature dependent physical property
Propionaldehyde:
Propionic acid:
Propionic anhydride:
Proprionitrile:
Propyl acetate:
Propylamine:
Propylbenzene:
Propylcyclohexane:
Propylcyclopentane:
Propylene:
1,3-Propylene glycol:
Propylene oxide:
Propyl formate:
Propyl propionate:
Pseudo-boiling in supercritical fluids,
Pseudo-film boiling in supercritical fluids,
Pseudocritical pressure,
Pseudocritical tempertaure,
Pugh, S F
Pulp and paper industry, fouling of heat exchangers in,
Pulsations, use in augmentation of heat transfer,
Pulverized fuel water-tube boiler,
Pumping, lost work in,
Pushkina and Sorokin correlation, for flooding in vertical tubes,
Pyramid, free convective heat transfer from,
Pyridine:
P
Pipes, circular:
transition between laminar and turbulent flows, heat transfer in turbulent heat transfer in,
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Forced Convection in Ducts
DOI 10.1615/hedhme.a.000168
2.5.1 Forced convection in ducts
Volker Gnielinski
A. Introduction
When fluids flow at very low velocities, all the individual particles are flowing in parallel lines. This type of flow is called laminar flow. If a fluid stream enters a duct with a uniform velocity a velocity profile develops as the fluid moves down the tube, with the velocity at the duct wall being zero. At a sufficient distance downstream from the inlet, the velocity pattern becomes fixed. The shape of the velocity distribution curve is parabolic for flow in a tube or between parallel plates.
If the velocity of the fluid is gradually increased, there will be a point at which the fluid no longer flows in parallel lines, but by a series of eddies that result in a complete mixing of all parts of the flow except those immediately adjacent to the wall. This type of flow is called turbulent flow. The Reynolds number at which the flow changes from laminar to turbulent is the "critical Reynolds number" Re, where Re = u ρ d /η where u is the fluid average velocity, ρ its density, η its viscosity and d the channel equivalent diameter. The value of the critical Reynolds number in round tubes is between 2,100 and 2,300. In long rectangular ducts and annular spaces, the transition from laminar to turbulent flow also starts at a Reynolds number of 2,100 when the hydraulic diameter of the duct is used as the characteristic geometric dimension in calculating the Reynolds number.
At Reynolds numbers greater than 104, the flow is fully turbulent. Between the lower and upper limits lies the zone of transition from laminar to turbulent flow. These limits are affected by the type of entry, initial disturbances in the fluid, roughness, and so on.
If the duct wall is at a temperature different from that of the fluid, heat will be transferred and a temperature profile will develop in the fluid. At a sufficient distance from the beginning of heating or cooling, the temperature profile becomes fully developed and therefore the heat transfer coefficient is constant. The rate of heat transfer is always greater in turbulent flow.
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