Valveless pulsejet-computational fluid dynamics

[ganuganu]

Hi Zono'

Thank you very much.

I am beginner in OpenFOAM, have just done flow past cylinder case . It will be very interesting to see these kind of simulations in OpenFOAM, eagerly waiting for your results. All the best.

Regards
Ganesh

[zono]

Dear Ganesh,

first I wish a happy New Year to all forum users!

Hopefully I will have a little more time next days to seek for my old simulation results images and animations done by Comsol Multiphysics

so long !

zono

[zono]

hi all,

here are two examples of my linear-acoustics Simulations (CFD for poor) elaborated with Comsol Multiphysics 4.3 : ...

afwe-eigenfrequency-helmholtz4-harmonic-pipe-end_corrected-1 :
acoustic eigenmodes of a so-called "harmonic-design" (I will report on this theory in the next weeks / months)

K-PT07X-eigenfreq :
acoustic eigenmodes of a K-PT07X (full-functional valveless designed by Marten Klein, a senior-member of this forum)

K-PT07X :
same K-PT07X engine, time-dependent Simulation of acoustic linear wave equation (en.wikipedia.org/wiki/Wave_equation)

so far,

zono

[Mike Everman]

Loving that first animation, Zono. Wish it went longer to see the pressure peak happen again in the CC. Love the way it shows the rarefaction waves colliding in the tail, where it would love to collapse if we use too thin a material!

[Mike Everman]

Hi Zono and Ganesh,
I'd like very much to know if this motor's intake and exhaust alternate. I'm about to put it to a turbine and in or out of phase is important. Any interest in running this geometry? I'm imagining test rigs to find out, but thought you guys would enjoy the idea.

Dimensions are in inches. It goes with my thought that long expansive tails have in phase inlet and exhaust, and this shorter solution alternates, and it must be one or the other.

Thanks much, Mike

[ganuganu]

Hi Mike

That's interesting. If you could share me the geometry file,it will be easy for me to proceed with simulation.

I would require the following details from your side:
1. Fuel type
2. Injector location and size
3. CAD file in x_t,x_b,step or iges format

Thank you

Regards
Ganesh

[Mike Everman]

Hi Ganesh, fuel is propane and i will post a pic of the fueling.
My motors are bent into a “u”. Do you need a straight or can you do the bent version?

[ganuganu]

Straight or bent design anything is ok for me.

[ganuganu]

Hi Zono and Ganesh,
I'd like very much to know if this motor's intake and exhaust alternate. I'm about to put it to a turbine and in or out of phase is important. Any interest in running this geometry? I'm imagining test rigs to find out, but thought you guys would enjoy the idea.
pocket jet, 3.5 lb thrust, all dimensions internal.PNG

Dimensions are in inches. It goes with my thought that long expansive tails have in phase inlet and exhaust, and this shorter solution alternates, and it must be one or the other.

Thanks much, Mike

Hi Mike
Can you tell me the position of injector, diameter of injector and mass flow rate of fuel to proceed with the simulation process.

[Mike Everman]

Hi Ganesh,
There are 6 holes of .035" diameter at the transition between intake and CC, pointing at 45 degrees from the centerline, toward a point on the centerline a bit into the CC.

I do not have a solid fuel massflow number from test, but at one time predicted it at .0011 Kg/sec

The dimensions do not show it, but each end has a quarter round flare that is approximately .3r, where r is the exit tube radius.

As you see in the photo, the transition from intake to cc is similarly rounded.

Thank you!
Mike