CylinderBase

class pychemengg.heattransfer.steadystate.CylinderBase(radius=None, thermalconductivity=None)

Bases: object

Models the base of a solid circular cylinder

Parameters

radius: `int or float`

Radius of circular base of cylindrical object

thermalconductivityint or float

Thermal conductivity of cylindrical object

Examples

First import the module steadystate

Units used in this example: SI system

However, any consistent units can be used

>>> discface = ss.CylinderBase(radius=1.5e-3, thermalconductivity=0.15)
# This will create an instance of 'CylinderBase' with a name 'discface'  

Attributes

radiusint or float

Radius of circular base of cylindrical object

thermalconductivityint or float

Thermal conductivity of cylindrical object

areaint or float

Area of circular base

__init__(radius=None, thermalconductivity=None)

Methods

__init__([radius, thermalconductivity])
heatrateof_conv([heattransfercoefficient, dT])	Computes heat rate of convection for the base of a cylindrical object
heatrateof_rad([T_infinity, T_surface, …])	Computes heat rate of radiation for the base of a cylindrical object
resistanceof_conv([heattransfercoefficient])	Computes resistance of convection for the base of a cylindrical object
resistanceof_fouling([foulingfactor])	Computes resistance of fouling for the base of cylindrical object

heatrateof_conv(heattransfercoefficient=None, dT=None)

Computes heat rate of convection for the base of a cylindrical object

Parameters

heattransfercoefficientint or float

Heat transfer coefficient `h` for the cylinder base

radiusint or float

Radius of cylinder base where convective heat transfer rate is to be computed

dTint or float

Temperature difference between surface of cylinder base and surrounding fluid

Returns

heatrateint or float

Rate of heat transfer by convection

Notes

Heat rate of convection is calculated using the Newton’s Law

\[Q (heatrate) = h A \Delta T \]

where:

h = heat transfer coefficient

A = area of heat transfer (which is the base circular area)

\(\Delta T\) = temperature difference

References

[1] Yunus A. Cengel and Afshin J. Ghajar, “Heat And Mass Transfer Fundamentals and Applications”, 6th Edition. New York, McGraw Hill Education, 2020

Examples

First import the module steadystate

Units used in this example: SI system

However, any consistent units can be used

>>> from pychemengg.heattransfer import steadystate as ss
>>> disc = ss.CylinderBase(radius=0.1, thermalconductivity=401)
>>> disc.heatrateof_conv(heattransfercoefficient=132, dT=34)
140.99467829310993

heatrateof_rad(T_infinity=None, T_surface=None, emissivity=None)

Computes heat rate of radiation for the base of a cylindrical object

Parameters

radiusint or float

Radius of cylinder base where radiation heat transfer rate is to be computed

T_infinityint or float

Temperature of surroundings in absolute temperature units

T_surfaceint or float

Temperature of cylinder base surface in absolute temperature units

emissivityint or float

Emissivity of the cylinder base

Returns

heatrateint or float (returns a positive value)

Rate of heat transfer by radiation

Notes

Heat rate of radiation is calculated using the Stefan-Boltzmann law

\[Q (heatrate) = \sigma \epsilon A (T_{infinity}^4 - T_{surface}^4) \]

where:

\(\sigma\) = Stefan-Boltzmann constant

\(\epsilon\) = emissivity of object

A = area of heat transfer

\(T_{infinity}^4\) = absolute temperature of surroundings

\(T_{surface}^4\) = absolute temperature of surface

References

[1] Yunus A. Cengel and Afshin J. Ghajar, “Heat And Mass Transfer Fundamentals and Applications”, 6th Edition. New York, McGraw Hill Education, 2020

Examples

First import the module steadystate

Units used in this example: SI system

However, any consistent units can be used

>>> from pychemengg.heattransfer import steadystate as ss
>>> disc = ss.CylinderBase(radius=0.1, thermalconductivity=401)
>>> disc.heatrateof_rad(T_infinity=300, T_surface=550, emissivity=0.9)
133.72195405218372

resistanceof_conv(heattransfercoefficient=None)

Computes resistance of convection for the base of a cylindrical object

Parameters

heattransfercoefficientint or float

Heat transfer coefficient `h` for the base surface of cylindrical object

Returns

resistanceint or float

Convection resistance

Notes

The following formula is used:

\[R_{convection} = \frac{1}{hA} \]

where:

h = heat transfer coefficient

A = area of heat transfer

\(R_{convection}\) = convection resistance

References

[1] Yunus A. Cengel and Afshin J. Ghajar, “Heat And Mass Transfer Fundamentals and Applications”, 6th Edition. New York, McGraw Hill Education, 2020

Examples

First import the module steadystate

Units used in this example: SI system

However, any consistent units can be used

>>> from pychemengg.heattransfer import steadystate as ss
>>> disc = ss.CylinderBase(radius=0.1, thermalconductivity=401)
>>> disc.resistanceof_conv(heattransfercoefficient=132)
0.24114385316953837

resistanceof_fouling(foulingfactor=None)

Computes resistance of fouling for the base of cylindrical object

Parameters

foulingfactorint or float

Fouling factor \(R_f\) for the cylindrical base surface

typical units are \(m^2\) K/W

Returns

resistanceint or float

Fouling resistance

Notes

The following formula is used:

\[R_{fouling} = \frac{R_f}{A} \]

where:

\(R_f\) = fouling factor

A = fouled area of heat transfer

\(R_{fouling}\) = fouling resistance

References

[1] Yunus A. Cengel and Afshin J. Ghajar, “Heat And Mass Transfer Fundamentals and Applications”, 6th Edition. New York, McGraw Hill Education, 2020

Examples

First import the module steadystate

Units used in this example: SI system

However, any consistent units can be used

>>> from pychemengg.heattransfer import steadystate as ss
>>> disc = ss.CylinderBase(radius=0.1, thermalconductivity=401)
>>> disc.resistanceof_fouling(foulingfactor=0.0007)
0.022281692032865345