Agitator Design Calculation Xls Repack Direct

This section calculates the hydraulic performance.

1. Tip Speed (Critical for shear sensitivity) $$ \textTip Speed = \pi \times D \times \fracN60 \quad (\textm/s) $$

2. Reynolds Number ($N_Re$) Determines if the flow is laminar or turbulent. $$ N_Re = \fracD^2 \times N \times \rho\mu $$ agitator design calculation xls repack

3. Power Number ($N_p$) This is a dimensionless number dependent on impeller geometry. You typically pull this from a lookup table in Excel (VLOOKUP).

4. Power Calculation ($P$) The most critical calculation for motor sizing. $$ P_\textshaft = N_p \times \rho \times N^3 \times D^5 $$ (Ensure units are consistent; typically Watts). This section calculates the hydraulic performance

5. Motor Power $$ P_\textmotor = \fracP_\textshaft\eta \times \textSafetyFactor $$

This is where the design engineer inputs the fluid properties and tank geometry. agitator design calculation xls repack

| Parameter | Symbol | Unit | Description | | :--- | :--- | :--- | :--- | | Fluid Density | $\rho$ | kg/m³ | Mass per unit volume of the liquid. | | Viscosity | $\mu$ | cP or Pa.s | Resistance to flow (critical for Reynolds number). | | Tank Diameter | $T$ | m | Inner diameter of the vessel. | | Liquid Level | $H$ | m | Height of the liquid content. | | Impeller Diameter | $D$ | m | Diameter of the agitator blade (usually $D = T/3$ to $T/2$). | | Rotational Speed | $N$ | rpm | Revolutions per minute. | | Number of Impellers | $n$ | - | Single or multiple stages. |

| Pitfall | Consequence | Repack Solution | | :--- | :--- | :--- | | Ignoring viscosity shear-thinning | Oversized motor | Includes power law index (n) for non-Newtonian fluids | | Wrong power number for baffled vs. unbaffled | 300% error in power draw | Separate Np tables for baffled & unbaffled conditions | | Shaft too long & slender | Whip damage, seal failure | Automatic slenderness ratio check (L/D < 15) | | Forgetting a mechanical seal cooling requirement | Seal meltdown in < 1 hour | Calculates seal face heat generation based on stuffing box pressure |

The repack’s dropdown shows 10 impellers. Select Pitched Blade Turbine (45°, 4 blades).

[ t_blend = k_t \cdot \left(\fracTD\right)^2 \cdot \frac1N ]