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

83
potentiometer for varing the motor voltage, and hence
speed.. The speed range vJas from 75 to 2500 RPl"I. The
motor \.Jas mounted on a se t
of bearings 1;.rhich allo'Hed it to
rotate freely. ~\Then the shaft turned the motor rotated in
the opposite direction and Hith it a 61 inch diameter pully.
A string was 'Hound around this pully and attached to a
0-25 pound scale. The torque of the rotating shaft was
counterbalanced by the pully-scale system ~nd
thus measured.
TORQUE = (Radius of pully) (Force recorded on
scale)
(in Ibs.) = (inches) x (lbs.) (4-1
Before any heat transfer data l'ITaS
taken this dynamometer
10TaS
tested 811.d it was determined that '",hen the motor l.Jas
operated under no-load conditions the dynamometer scale
read zero.
Thus there vJas negligible friction in the
bearings supporting the motor.
The motor, bearings, and scale assembly 1:mre mounted over
the 15-gallon vessel on a f1Unistrut!l~~
frame which al101.Jed
three dimensional adjustment "t..Ji th very little eff'ort.
The
motor "ras placed so that the shaft lr-ras coincident Hi th the
center line of the vessel.
The major portion of the work
was perforr!1ed lrJi th eleven diff'erent impellers of four types;
paddle, six bladed disk and v~ne
turbine, three bladed marine
propeller, and an anchor.
Hany other impellers in addition
to these eleven Here used for the ""'Tater runs.
The dimensions
~~
Trademark of Unistrut Products Co., Chicago, Illinois