1) GEOMETRIC SIMILARITY
Keeping the ratio of all lengths constant (constant fill ratio).
FILL RATIO: is defined as the ratio of Bed height and Diameter (H/D ratio)
H/D Ratio (Constant fill ratio) = Powder bed height (cm)/(Blender diameter (m) x 100)
Powder Bed height (cm) = (Dry mix volume (L) x 1000) / Total volume of Blender (L)
Total Volume of Blender = ¼ π D^2
Bed height (cm) = Dry mix volume (L) X 1000 / ¼ π D^2 X 10000
Bed height (cm) = 4 X Dry mix volume (L) X 1000 / π D^2 X 10000
Where,
- D = Diameter of Blender in meter
- π = 3.14
Note: Blender diameter = Available from equipment manual or qualification document.
2) DYNAMIC SIMILARITY
Maintaining constant forces.
Froude Number
Froude Number: N^2 R/g
Where,
- N - Rotation RPM
- R –Vessel Radius
- g – Gravitation Constant
3) KINEMATIC SIMILARITY
Maintaining a consistent number of revolutions (rpm × minutes).
- 50 L Blender : 15 RPM*10 minutes: 150 revolution
- 250 L Blender : 10 rpm* 15 minutes : 150 revolution
To Keep Froude Number same from Demo to Exhibit to Commercial scale, we have to change the variable i.e Rotation RPM.
