MIXING ENHANCEMENT USING
it is ...
Investigation of fundamental physics
Two elements must be
satisfied for the method to work:
1: Nozzle configuration
|For JSE: an annular (or
similar) convergent-divergent duct. A critical parameter is the ratio
of exit area to minimum area, Ae/Amin, of the duct.
Fig. 1(a) JSE nozzle geometry
|For MESPI: a dual-stream
nozzle with a convergent-divergent outer duct. A critical parameter is the ratio of
exit area to minimum area, Ae/Amin, of the outer duct. The shape of the inner duct
Fig. 1(b) MESPI nozzle geometry
|Element 2: Nozzle
For both JSE and MESPI,
the nozzle pressure ratio NPR (total pressure over ambient pressure) of the gas flow that
promotes mixing must satisfy: (a) occurrence of sonic flow at Amin, and (b)
generation of adverse pressure gradient in the vicinity of Ae.
The corresponding theoretical range of NPR is
shown in Fig. 2 (green area). Experiments at Ae/Amin=1.25 have
vaidated this prediction.
Fig. 2 Nozzle pressure ratio for gas
flow (green region).
Please download AIAA-2000-0093 (PDF) for more details on the operating conditions.
Also, see the 2D results for variations on the above nozzle arrangements.
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