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

!4ETHODS OF STuDY OF B..4.TCH HEAT TRANSFER
USED BY PREVIOUS AUTHORS
Experimental Work
The ex.perimental portion of the work in developing a
correlation is the measurement of data needed to calculate
the batch heat transfer coefficients for a variety of conditions.
The basic equipment used is a jacketed vessel
equipped with a variable speed motor or drive and provisions
for measuring the jacket and batch temperatures (and possibly
the wall temperature) ..
The tank is sometimes equipped
-v.ri th baffles, usually four "\,,)"i th a width equal to 1/10 to
1/12 the vessel diameter. The vessel is often constrllcted
of stainless steel to enable corrosive materials to be
tested and also to help prevent fouling.
The diameter of
the vessels used to date has varied from one to five feet"
The most frequently tested impellers are paddles, disk and
vane (straight blade turbines) and retreating blade turbines,
marine propellers (dOl,ffi thrusting), and anchors.
There is
usually a relatively close clearance (an inch or less) beh.reen
the vessel floor and v.ralls and the anchor type impeller
although sometimes there is more clearance.
The
standard position for the other impellers is about one third
the liquid height.
The temperature of the batch is usually measured in
about three different locations to ensure complete mix.ing.