Experimental and CFD analysis of nozzle position of subsonic ejector

Abstract

The influence of nozzle position on the performance of an ejector was analyzed qualitatively with free jet flow model. Experimental investigations and computational fluid dynamics (CFD) analysis of the nozzle position of the subsonic ejector were also conducted. The results show that there is an optimum nozzle position for the ejector. The ejecting coefficient reaches its maximum when the nozzle is positioned at the optimum and decreases when deviating. Moreover, the nozzle position of an ejector is not a fixed value, but is influenced greatly by the flow parameters. Considering the complexity of the ejector, CFD is reckoned as a useful tool in the design of ejectors.

Keywords

ejector / nozzle position / ejecting coefficient / CFD

References

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Acknowledgements

This work was supported by the National Basic Research Program of China (No. 2007CB206901) and WISDRI Engineering & Research Incorporation Limited.

Notation

p—gauge pressure/kPa

Q—volume flow rate/m³·s^-1

D—diameter/mm

R—radius/mm

n—ejecting coefficient

L—length/mm

α—turbulence number

θ—jet spread angle

Subscripts:

p—primary flow

s—secondary flow

m—mixture flow

pn—primary nozzle

jn—jet nozzle

js—jet cross section

mc—mixing chamber

im—inlet of mixing chamber

om—outlet of mixing chamber

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg