### 5.2.1. Aerodynamics Tab

Figure 5.6: Aerodynamics Input Tab

Operating Conditions:

Rotational speed, Mass flow rate, Inlet total pressure, Inlet total temperature, Total head rise and Efficiency estimate .

The total head rise used here is the net head rise after any downstream pressure loss (see Downstream mixing losses parameter below). This also neglects any downstream swirl component of dynamic pressure.

While the efficiency estimate will be used as the specified value in the meanline calculation, this will differ from the efficiency reported by the design calculation as the throughflow method uses empirical correlations to derive the efficiency.

Stator exit angles:

IGV exit angle and OGV exit angle.

Should the IGV and/or OGV be omitted in the machine configuration, then these options will be disabled accordingly.

Additional parameters:

Downstream mixing losses , Hub velocity deficit factor and Hub loading parameter .

The downstream mixing losses parameter specifies the proportion of axial dynamic pressure at rotor exit that is assumed to be lost due to the aerodynamic mixing process. The default value of 0.25 is reasonable for most industrial fan designs and should not require significant adjustment.

The hub velocity deficit factor is used to adjust the meanline calculation to take into account the influence of the boundary layer at the hub. Reducing this value can be useful to make the meanline calculation for the hub gas exit angle correlate more closely with that of the design calculation.

Typically an initial fan design will be more highly loaded at the hub of the machine and more lightly loaded at the tip. Reducing the hub loading parameter redistributes the workload to reduce the loading at the hub of the machine whilst maintaining the overall pressure rise.

Machine configuration:

Check boxes indicating whether an IGV and/or OGV will be included in the calculation.

Units:

Option buttons to select either SI or Imperial units. This impacts both input data and results and may be switched at any time with immediate effect.

Release 18.2 - © ANSYS, Inc. All rights reserved.