EXPERIMENT 4
REYNOLDS NUMBER AND POWER NUMBER
1.0 OBJECTIVE
1.1
To study the Reynolds number and power requirement based on different
concentration of solution.
1.2
To study the effect of different impeller upon power requirement.
2.0 COURSE OUTCOME
CO4: Ability to investigate and analyze geometric similarities or constant power
number to develop bioreactor scale up.
3.0 INTRODUCTION
Reynolds number is important in the mixing process as it would determine whether
the broth solution is in laminar, transition or turbulent phase. The resistance caused
by the fluid to rotation of the impeller is given by power requirement. The power
consumption is strongly depends on the diameter impeller and geometry, stirrer
speed and properties of the fluid such as density and viscosity. The power
requirement could be calculated based on Ungassed Newtonian Fluids, Ungassed
Non-Newtonian Fluids and Gassed Fluids.
4.0 MATERIALS AND EQUIPMENTS
4.1
Viscometer
4.2
Xanthan gum
4.3 Distilled water
5.0 PROCEDURES
5.1 Prepare 3 different concentration of xanthan gum (not more than 2 g/L).
5.2 Measure the diameter of impeller.
5.3 Determine the viscosity for each of the solution by using two types of impeller.
6.0 RESULTS AND CALCULATION
6.1 Record the viscosity obtained.
6.2 Calculate the power required if the power speed is 15s-1.
7.0
QUESTIONS
7.1
What is the difference between ungassed newtonian fluids and ungassed
non-newtonian fluids?
7.2
When to use the equation for gassed fluid?
7.3
How to improve mixing in the fermentation?
8.0
CONCLUSION
8.1 Draw a good conclusion regarding this experiment.