Hydraulic & Energy Grade Line (HGL & EGL) Plot

If you wish to create a HGL/EGL plot, select:

 

- Tools | Composite Chart Setup. This opens a new form titled "Composite Chart Setup" as shown below.

 

 

- Select the desired Start Node and End Node & select the PLOT button. The Composite Chart for HGL/EGL will then be shown as follows:

 

 

The chart plot example above shows the HGL, EGL & Elevation plots. 

 

 

The Energy Grade Line = Static Pressure + Elevation + Velocity Pressure.

OR

The Energy Grade Line = Piezometric Pressure + Velocity Pressure.

 

Hydraulic Grade Line

The Hydraulic Grade Line = Static Pressure + Elevation

OR

The Hydraulic Grade Line = Piezometric Pressure.

Lets consider an example as shown below. 

 

ENERGY GRADE LINE:

INLET: Static Pressure + Elevation + Velocity Pressure: -1.2696 + 5 + 1.2696 = 5.0 m fluid.

OUTLET: Static Pressure + Elevation + Velocity Pressure: -1.2696 + 0 + 1.2696 = 0 m fluid.

OR

INLET: Piezometric Pressure + Velocity Pressure: 3.7304 + 1.2696 = 5.0 m fluid.

OUTLET: Piezometric Pressure + Velocity Pressure: -1.2696 + 1.2696 = 0 m fluid.

HYDRAULIC GRADE LINE:

INLET: Static Pressure + Elevation: -1.2696 + 5 = 3.7304 m fluid.

OUTLET: Static Pressure + Elevation: -1.2696 + 0 = -1.2696 m fluid.

OR SIMPLY

INLET Piezometric Pressure: 3.7304 m fluid.

OUTLET Piezometric Pressure: -1.2696 m fluid.

The HGL/EGL plot appears as follows:

The chart can be configured and you can show the node and pipe User Numbers on the chart to help relate the chart to specifics nodes in the model.

In older version of FluidFlow, the displayed HGL/EGL plot must be re-initialized after each calculation of the model by selecting: Tools | Composite Chart Setup and select the start and end nodes. In the latest release, the HGL/EGL plot will also update if we recalculate the model.