Project ForgeThe velocity triangles at the inlet and exit of the rotor of a turbomachine are shown, with V denoting the absolute velocity of the fluid, W the relative velocity, and U the blade velocity (subscripts 1 and 2 refer to inlet and outlet respectively). If V2=W1 and V1=W2, then the degree of reaction is
- A0
- B1
- 0.5
- D0.25
Explanation
V2=W1 and V1=W2 means the inlet and outlet velocity triangles are exact mirror images of each other about the blade-speed line — this symmetry is precisely the defining geometric signature of a 50% reaction stage (rotor and stator blade passages shaped identically), so the degree of reaction R=0.5.
Source: GATE ME 2012 (Booklet Code A) (2012)
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