Calculation of Inlet Throat Area

2 Calculation of Inlet Throat Area For a Vane-Type Inlet Device 

We use the following notation Dov, Dm for the outer and inner diameter of the vane assembly, respectively Dmid for the geometric mean diameter of vane equals (DovDiv) / I for the horizontal separation between two adjacent vane elements / for the horizontal width of a vane element Ny for the number of vane elements (also equals number of vane openings) t for the vane thickness (3 for the vane angle relative to the horizontal and ay,hy for the length and 

The circumference at diameter Dmid is very closely approximated by the 

The height and width of each of the Ny trapezoidally shaped flow areas normal to the flow direction is  

since Ath = UybyNy, the total vane throat area normal to the flow 

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