Unformatted text preview: rs caused large
changes in performance. The Bernoulli equation seemed highly suspect as a useful tool.
Neglecting losses and gravity effects, the incompressible Bernoulli equation predicts that | e-Text Main Menu | Textbook Table of Contents | Study Guide 382 Chapter 6 Viscous Flow in Ducts 100
2θ W1 c
Jet flow 70 W2 Transitory
a 2 θ , degrees 20 L
steady stall c
b 40 b
7 Cp max 4
2θ D De a 1
1 2 4 7 Throat 10
W1 20 40 100 Exit
(c) (b) Fig. 6.26 Diffuser geometry and
typical flow regimes: (a) geometry
of a flat-walled diffuser; (b) geometry of a conical diffuser; (c) flatdiffuser stability map. (From Ref.
14, by permission of Creare, Inc.) 1
2 p V2 p0 const (6.112) where p0 is the stagnation pressure which the fluid would achieve if the fluid were
slowed to rest (V 0) without losses.
The basic output of a diffuser is the pressure-recovery coefficient Cp, defined as
p0t Cp pt
pt (6.113) where subscripts e and t mean the exit and the throat (or inlet), respectively. Higher Cp
means better performance...
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This note was uploaded on 10/27/2009 for the course MAE 101a taught by Professor Sakar during the Spring '08 term at UCSD.
- Spring '08