In a constant volume chamber, we did 6 hole nozzle injector to simulate gas (methane) injection simulation. As part of the inlet boundary condition, we used velocity inlet boundary condition (i.e. 25m/s) for all the nozzles.
The results obtained are so confusing
1. The mass flow rate of each nozzle is different from the other.
2. With the increase in injection velocity, the simulation fails stating "Recycling requested by state variable update" and fails finally saying timestep driven is too small.
Why this phenomenon occurs.
The constant volume chamber is closed from every side, and nitrogen is filled in the chamber.
If there was a heat transfer in your computation domain, maybe the density of the fluid in each of the nozzles were different. So, the mass flow rates were not the same...
Thank you Nazaruddin Sinaga, I defined total pressure at the inlet. I got lucky, now getting same profile for all the nozzle.
I want to increase the mass flow rate, what can I do keeping same nozzle area:
1. increasing pressure, thereby increasing density.
2. increasing inlet velocity..
I do not know which one will be good, keeping choke condition in mind.
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