Reply To: Test Rigs for Exhaust Systems

[Martin Johnson]

I notice the Indian abstract refers to

a recirculation zone near the primary nozzle exit

That seems to imply major flow separation, which can only happen with uncontrolled diffusion – an inherently unstable process. When I stopped real work, the state of the CFD art had not cracked un-controlled diffusion. Has it moved on in the last 10 years or so?

Pulsations – 3 ways round that:
a storage volume in the steam exhaust – not much space “up front”
larger blast pipe orifice – may not be feasible to achieve smokebox vaccum.
Graduated exhaust opening on the valve system – may impose too much exhaust back pressure.
Take your pick.

Martin