Prediction of batch heat transfer coefficients for pseudoplastic fluids ...

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Calculation of Batch Heat Transfer Coefficients
If the jacket temperature was measured, the batch heat
transfer coefficients may be calculated by first calculating
the overall heat transfer coefficient using equation 1-1
and then determining the batch heat transfer coefficient
using equation 1-2 (32,49~182).
. ,
In order to use this equatlon
the fouling factor, I/hf' the medium heat transfer coefficient,
L
:b ., and the resistance of the \.Jall, 'f:!. ,
•-m.
must be determined •
KlrJ
The resistance of the wall may be calculated using the values
of wall thickness and thermal conductivity.
The fouling
factor may be estimated from a knowledge of the condition
of the heat transfer surface. The fouling factor is usually
neglected on the basis of visual observation of the inside
of the jacket. If condensing steam is the heating medium
the film coefficient of the medium is often estimated to
be about 2000, based on measurements for pipeso
The batch
heat transfer coefficient, h, is then the only unkn01tITl in
equation 1-2 and can thus be calculated. If water is the
heat transfer medium the estimation of hm becomes more difficuI
t..
Heat trans fer coefficients for liquids are much Im-Jer
than for condensing gases and depend largely upon velOCity.
Very little work has been done in the field of correlations
for the prediction of heat transfer coefficients for the
jacket side of jacketed vessels.
Many investigators use the vHlson method to determine
the s~m
of resistances to heat transfer on the heating or