calc_overallheattransfercoefficient

pychemengg.heattransfer.heatcommonmethods.calc_overallheattransfercoefficient(inner_heattransfercoefficient=None, outer_heattransfercoefficient=None, inner_foulingfactor=None, outer_foulingfactor=None, resistanceof_wall=None, inner_area=None, outer_area=None, is_basedon_outerarea=False, is_basedon_innerarea=False)

To compute overall heat transfer coefficient (U) from resistance values

Parameters

inner_heattransfercoefficientint or float

Heat transfer coefficient on inside/oneside of object.

outer_heattransfercoefficientint or float

Heat transfer coefficient on outside/otherside of object.

inner_foulingfactor: `int or float`

Fouling factor on inside/oneside of object.

outer_foulingfactor: `int or float`

Fouling factor on outside/otherside of object.

resistanceof_wall: `int or float`,

Resistance of conduction of object material (based on shape).

inner_area: `int or float`

Surface area of inside/oneside of object.

outer_area: `int or float`

Surface area of outside/otherside of object.

is_basedon_outerareabool, default = False

Specification whether overall heat transfer coefficient (U) is based on outside/oneside surface area.

is_basedon_innerareabool, default = False

Specification whether overall heat transfer coefficient (U) is based on inside/oneside surface area.

Returns

Overall heat transfer coefficient (U)int or float

If ‘is_basedon_innerarea == True’ ‘U’ based on inner/oneside area is returned

If ‘is_basedon_outerarea == True’ ‘U’ based on inner/oneside area is returned

See also

pychemengg.heattransfer.steadystate.Slab.resistanceof_cond

pychemengg.heattransfer.steadystate.Slab.resistanceof_conv

pychemengg.heattransfer.steadystate.Slab.resistanceof_fouling

pychemengg.heattransfer.steadystate.Cylinder.resistanceof_cond

pychemengg.heattransfer.steadystate.Cylinder.resistanceof_conv

pychemengg.heattransfer.steadystate.Cylinder.resistanceof_fouling

pychemengg.heattransfer.steadystate.Sphere.resistanceof_cond

pychemengg.heattransfer.steadystate.Sphere.resistanceof_conv

pychemengg.heattransfer.steadystate.Sphere.resistanceof_fouling

Notes

The following formula is used.

\[\frac{1}{U_iA_i} = \frac{1}{U_oA_o} = R_{convection, in} + R_{fouling, in} + R_{conduction} + R_{fouling, out} + R_{convection, out}\]

where:

\(U_i\) = overall heat transfer coefficient based on inner area

\(U_o\) = overall heat transfer coefficient based on outer area

\(A_i\) = inner surface area of heat transfer

\(A_o\) = outer area of heat transfer

\(R_{*}\) = resistance of conduction, convection or fouling

What if some resistances are zero

Simply leave their respective keywords at default value of ‘None’.

References

[1] G. F. Nellis and S. A. Klein, “Introduction to Engineering Heat Transfer”, 1st Edition. Cambridge University Press, 2021.

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

[3] T.L. Bergman, A. S. Lavine, F. P. Incropera, D. P. Dewitt, “Fundamentals of Heat and Mass Transfer”, 7th Edition, John Wiley, 2011.

Examples

First import the module heatcommonmethods.

>>> from pychemengg.heattransfer import heatcommonmethods as hcm 
>>> hcm.calc_overallheattransfercoefficient(inner_heattransfercoefficient=800,
                          outer_heattransfercoefficient=1200,
                          inner_foulingfactor=0.0004,
                          outer_foulingfactor=0.0001,
                          resistanceof_wall=0.0025,
                          inner_area=0.0471,
                          outer_area=0.0597,
                          is_basedon_outerarea=True)
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