Table of Contents
1 Introduction and scope of the work 1
2 Literature Review 3
2.1 Theory on stirred vessels 3
2.2 Flow Measurements 5 2.2.1 Single point measurements 5 2.2.2 Whole flow field measurements 8
2.3 Power number 11
2.4 Flow number 13
2.5 Turbulent kinetic energy 14
2.6 Local energy dissipation rates 16 2.6.1 Energy dissipation and PIV 18
2.7 Vorticity 23
3 Material and methods 24
3.1 Vessel and impeller 24
3.2 Measure of the power number 26
3.3 Vessel configuration and PIV 26
3.4 Angle resolved measurements 28
4 Results and discussion
4.1 Comparison of power number and power
consumption for the two flow configurations 29
4.2 Power characteristics and time-averaged flow field for a PBT in up-pumping and down
pumping configurations 31 4.2.1 Time averaged flow field and instantaneous flow profiles 31
4.2.2 Comparison between time averaged flow field configurations 32 4.2.3 Turbulent kinetic energy 33
4.2.4 Vorticity 36 4.2.5 Flow number evaluation 37
4.3 Angle resolved PIV measurements for a PBT
impeller in up-pumping and down-pumping
configurations 38
4.3.1 Angle resolved flow field 38 4.3.2 Turbulent kinetic energy 41 4.3.3 Energy dissipations rates evaluated through
dimensional analysis 43
4.3.4 Direct calculation from the definition 45 4.3.5 Large eddy PIV method 47 4.3.6 Energy evaluation comparison 49
4.3.7 Vorticity 51 4.3.8 Flow number as a function of the blade angle 53
5 Conclusions 54
Appendix I: Integral length scale 57
Appendix II: MatLAB® M-Files 61
Bibliography 67
