Slip coefficient by PFLEIDERER

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Slip coefficient by PFLEIDERER

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Reduced energy transmission is expressed by decreased output coefficient p:


This coefficient can be empirically calculated in dependence of experience number ψ':


  static moment from leading to trailing edge


  experience number


experience number a:


Centrifugal impeller

with guided vanes

a = 0.6

with volute

a = 0.65…0.85

with plain diffusor

a = 0.85…1.0

Mixed flow/axial impeller

a = 1.0  …1.2

(the numbers are valid for sufficiently high Re; ψ’ strongly grows with small Re)



More descriptive is the decreased output factor  kL:

  (kL=1: for flow congruent to blade)


Circumferential component of the flow, which is congruent to blade, can be calculated as follows:

Now the outflow (slip) coefficient γ according to Wiesner can be calculated: