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Blade Information |
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Blade Information |
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The Blade angles table on the right side of the dialog shows the blade angles βB calculated in the Blade properties dialog or computed due to simple blade shapes.
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A diagram that displays the βB progression along every mean line can be accessed by the tab on the right border of the diagram. Too high local extreme values should be avoided if possible.
The progression of the cross section area within a channel built by two neighboring mean surfaces as well as hub and shroud are displayed along the mean line.
Also, the distribution of the lean angle λ is displayed. With the lean angle the quasi-orthogonal of the blade leans away from the z-direction. The quasi-orthogonal is a straight line connecting corresponding points on hub and shroud mean line. These lines are setup in the blade property dialog and are displayed in the meridional cut if just two mean lines were chosen. Otherwise the quasi-orthogonal is not displayed but internally determined by connecting corresponding points on hub and shroud mean line. ¢ see Blade lean angle |
Docking windows can be undocked or pinned when they are opened. In undocked state the transparency of the dialog can be adjusted by a track bar.
Another docking window displays the Blade information table with the resulting angles of overlapping φB and the incidence angle i for hub and shroud. Additionally the angles of the frontal view βB,xy are displayed. In case of strictly radial impellers these values are consistent with the blade angles.
[ Compressor impeller only ]
The actual Mach-number Ma1 (Act. inlet Ma-number) within the inlet cross section is given in the table Cross section. It is calculated by:
and should not be higher than the maximum Mach-number Ma1,max (Max. inlet Ma-number) within the inlet cross section to avoid sonic speed.
[ Turbine rotors only ]
With the help of the sine rule blade angles at the outlet can be evaluated. In accordance to this rule blade angles at the outlet should have almost the same size as the angle that is built by a hypotenuse being the pitch t, and a cathetus (opposite leg) being the smallest distance between two neighboring mean lines eq at a flow surface. If this is the case the outflow can be regarded as almost tangential to the trailing edge.
This is shown in a picture for a single mean line.
For every mean line the calculated angles as well as their differences to the actual blade angles are given in a table when the panel Informational value has been activated.
The actual Mach-number Ma2 (Act. outlet Ma-number) within the outlet cross section is given in the table Cross section. It is calculated by:
and should not be higher than the maximum Mach-number Mamax2 (Max. outlet Ma-number) within the outlet cross section. The maximum Mach-number Mamax2 is calculated on the basis of the sonic speed within the minimum cross section (Min. cross section) by:
This is only valid if the minimum cross section is close to the outlet cross section, because work transfer in the blade's channel between the two regarded cross sections has been neglected.
Page url: http://www.cfturbo.com/fileadmin/content/manual/en/index.html?bladeinformation.html
