Diffuser

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Ü Volute | Diffuser Diffuser

 

The geometry of the outlet diffuser can be designed and calculated in this dialog box.

 

diff_dlg

 

 

In general, 3 basic shapes are differentiated (Direction):

 

diff_tang

 

Tangential diffuser

diff_rad

 

Radial diffuser

diff_spline

 

Spline-diffuser

 

The tangential diffuser is easier to manufacture, the radial diffuser has the advantage of minimizing tangential forces. The spline diffuser is similar to the radial but with extended flexibility.

 

In the case of a radial diffuser, the angle ε between the outlet branch and the line connecting impeller-center and outlet branch center can be selected.

 

For the Spline-diffuser the angle φ6 between connecting line impeller-center ↔ outlet branch center and diffuser start section has to be defined. Points 0 and 4 are start and endpoint of the middle line on the inlet and outlet cross section, point 2 is fixed by the intersection of appropriate perpendiculars of these sections. Position of points 1 and 3 influence the curve shape of the middle line.

 

 

The extension of the diffuser can be defined in panel Dimensions. Parameters in the x,y-plane can be specified, as well as a rake of the diffuser in z-direction.

 

diff_H6C6

For all diffuser shapes the extension is defined by the diffuser height h6, which is the distance from the diffuser outlet to a parallel line through the center point.

 

The distance C6 from the h6-line to the center point is displayed for information, both in the diagram and numerical in the Information panel.

 

 

Additionally the starting position of the diffuser is defined by the angle φ0, whereas 0° is horizontal right. The whole volute can be rotated by this value. By using the button Vertical outflow direction the volute can be rotated for vertical direction of the pressure joint.

 

The diffuser bending in z-direction is described by the parameters shown in the sketch.

There exist 2 straight segments 1, 3 and a circular segment 2. The lengths L1, L2 and L3 are specified percental.

The curvature is defined by the radius R, the direction by the angle α.

The z-bend is illustrated in the diagram by a green center line.

diff_z-benddiff_z-bend

 

 

The end cross-section of the diffuser can be either round or rectangular. The diameter D6 can be directly defined or selected from standard tables. In the case of a rectangular end cross-section the height H6 and width B6 can be chosen.

Furthermore the percental position can be specified, where the shape of the end cross section is reached (default = 100%). Afterwards the shape is constant and the cross section area is changing only.

 

 

The following values are shown for information purposes:

 

DIN

Diameter of the equivalent circle at the diffuser inlet

Equivalent diameter DOUT

Diameter of the equivalent circle at the diffuser outlet

Area IN AIN

Area at diffuser inlet

Area OUT AOUT

Area at diffuser outlet

Deceleration ratio AR

Length L

Length of the diffuser

Angle to middle φ

Angle between connecting line impeller-centre ↔ outlet branch centre and diffuser start section

Center distance C

Distance from the h6-line to the center point

Cone angle ϑ

Cone angle from D5 to D6 over the length L

Diffusor radius R

Radius of middle line (for radial diffuser only)

 

 

By clicking on Default, you can return to the standard values for the diffuser geometry.

 

Under Display options, changes can be made which affect only the graphics.

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