THE APPLICATION OF A STRAIN-GAUGE TECHNIQUE TO THE MEASUREMENT OF THEPOWER CHARACTERISTICS OF 5 IMPELLERS

The work described in this paper establishes the accuracy with which t he power number can be measured within a mixing vessel and presents me asurements for five impellers (Rushton, ''bucket'', 45 degrees-pitched blade, 60 degrees-pitched blade and hyperboloid) as a function of rot ational speed. The technique uses strain gauges and the telemetric tra nsmission of the strain and is, therefore, more accurate than methods which involve mechanical determination of torque and that allows power measurements to be carried out in relatively small and more cost-effe ctive models of mixing vessels. In the cases where previous data exist s the results of this study compare well. This work provides new data for the ''bucket'', 45 degrees-pitched blade and hyperboloid (low Reyn olds numbers) impellers and represented a systematic study for all fiv e impellers with one measurement system.