Definitions
This nomenclature is used at Post Mixing to describe flow patterns under turbulent conditions.
 | U = axial up flow or up-pumping or up draft. This is up the shaft
and down the walls. |
| D = axial down flow or down-pumping or down draft. This is down the
shaft and up the walls. |
| R = radial flow. This is a cylindrical jet spreading out from the
impeller. Some of it goes up the wall and some of it goes down the
walls. |
| 1 = extreme radial. The flow is perpendicular to the shaft (tank
axis) |
| 3 = extreme axial. The flow is generated by a hydrofoil of fluidfoil
and is very axial |
| 2 = mixed flow direction. The flow has components of both axial and
radial flows. |
The determination of Proximity Factors requires knowledge of the flow or
pumping direction of the impellers.
Examples
| D2: Predominately axial down flow but has radial components.
The flow pattern spreads out below the impeller. Pitched bladed
turbine:
|
| D3: Highly axial flow pattern. Hydrofoils, fluidfoils, and propellers:
 | PR-D, AP-3,
, HE-3, A100,
A110, A310,
A312,
A320, A315,
A6000 |
|
| R1: Highly radial flow pattern. Turbines with disks:
| RT, D-6,
R100, RD,
Holmes & Narver, R300,
R320, RS6,
CD-6, R130,
Smith Turbine, RDC,
BT-6, Bar
Turbine, R510, Sawtooth,
Disperser, R500 |
|
| R2: Predominately radial flow pattern but has axial
components. Turbines and paddles without a disk.
|
| U2: Predominately axial up flow but has radial components.
|
| U3: Highly axial up-flow pattern. Up-pumpers:
|
|
