Search found 613 matches

by pezman
Tue Oct 19, 2004 10:13 pm
Forum: Off topic forum
Topic: UFLOW guide for the FAQ?
Replies: 5
Views: 1673

Re: UFLOW guide for the FAQ?

Actually, on a more serious note, pulse-jet modeling seems to be a special case of modeling, and one simple change to UFLOW would rule -- a COM interface so that you could shove model parameters in using, e.g. Excel, run the model a bit, take calculated values out and feed them back in for a 2nd pas...
by pezman
Tue Oct 19, 2004 9:58 pm
Forum: Off topic forum
Topic: UFLOW guide for the FAQ?
Replies: 5
Views: 1673

Re: UFLOW guide for the FAQ?

Hmm, too bad there is no karma button in this forum. Anyone willing to just say FAQ-it deserves karma.
by pezman
Sun Oct 17, 2004 6:24 am
Forum: Valveless pulsejet forum
Topic: UFlow
Replies: 13
Views: 4091

Re: UFlow

Two processes would moderate the pressure rise. One is the fact that a certain amount of gas is diverted to generate thrust. The other is that the pressure rise would at some point start limiting the amount of fresh charge the engine would be able to ingest. UFlow agrees! The "Plumbing" design (jus...
by pezman
Sun Oct 17, 2004 5:51 am
Forum: Tools and Construction
Topic: tapering tubes?
Replies: 11
Views: 4571

Re: tapering tubes?

The table thing is sheer genius. The dimensions just need to be close enough for govt. work -- if the design is too sensitive to geometry, then it probably won't throttle, won't operate when its too hot or cold etc., etc. I'll grab a table for long sections and maybe a chair for some shorter section...
by pezman
Sun Oct 17, 2004 2:59 am
Forum: Tools and Construction
Topic: tapering tubes?
Replies: 11
Views: 4571

tapering tubes?

I want to start fiddling with the creation of a "Bruno-O" high compression pulsejet. The only uflow models that show promise consists tapered tubes end to end. Anyone got ideas on how to make a tapered tube (1" id -> 0.5" id) about a half meter long? I think that the engine will take some fiddling t...
by pezman
Fri Oct 15, 2004 1:10 am
Forum: Valveless pulsejet forum
Topic: Lockwood model -- nice,simple UFLOW1D example
Replies: 7
Views: 4254

Re: Lockwood model -- nice,simple UFLOW1D example

That worked -- apparently it's all in the wrist ;). I tried successive runs with ambient temps and pressures and it looks like the compression tops out at about 7:1. The pulses in the combustion zone are horrific though -- 50 bar! (using 2200K/300k * 1 bar * 7). I also had to shorten the arms to alm...
by pezman
Thu Oct 14, 2004 9:32 pm
Forum: Valveless pulsejet forum
Topic: Lockwood model -- nice,simple UFLOW1D example
Replies: 7
Views: 4254

Re: Lockwood model -- nice,simple UFLOW1D example

Not quite what was requested, but here's a "Bruno" engine that actually breathes a little. I dubbed it the "Bruno O'Lockwood" since it's derived from the Lockwood design. The attached model just does one pulse from ambient initial conditions. The combustion occurs at the left end of the engine. Some...
by pezman
Wed Oct 13, 2004 2:05 pm
Forum: Valveless pulsejet forum
Topic: Lockwood model -- nice,simple UFLOW1D example
Replies: 7
Views: 4254

Re: Lockwood model -- nice,simple UFLOW1D example

Actually, it looks like the model is reasonably close to this, except that the pressures are a little high, the temperatures are a little low and the all portions of tube that are not part of the combustion zone are at ambient conditions. The model is just one pulse from a cold-start and intended to...
by pezman
Wed Oct 13, 2004 3:50 am
Forum: Valved pulsejet forum
Topic: Q's: Brauner Design
Replies: 22
Views: 9226

Re: Q's: Brauner Design

Tony,

Awesome workmanship!

I stumbled across this guide on making valves, in case it's of any use:
http://www.aardvark.co.nz/pjet/makevalves1.pdf

The etching technique looks cool.
by pezman
Wed Oct 13, 2004 3:33 am
Forum: Valveless pulsejet forum
Topic: Lockwood model -- nice,simple UFLOW1D example
Replies: 7
Views: 4254

Lockwood model -- nice,simple UFLOW1D example

I threw together a model of a Lockwood engine that Andreas Sunnhordvik posted . The basic idea was to test uflow1d against a well-known design to see if my technique for modeling the combustion ICs was sound. It seems like a decent model. You can actually see the short arm of the Lockwood "breathe"....
by pezman
Tue Oct 12, 2004 4:29 pm
Forum: Valveless pulsejet forum
Topic: UFlow
Replies: 13
Views: 4091

Re: UFlow

Hey, sorry about misspelling your name <:o ! I guess that I still have two questions: * Is the thrust just the mass flow rate at the nozzle? * Is it reasonable to simulate combustion with propane as: having a temperature of about 2200k, with presure scaled accordingly (i.e. 730000 PA at 1:1 compresi...
by pezman
Tue Oct 12, 2004 2:59 am
Forum: Valveless pulsejet forum
Topic: UFlow
Replies: 13
Views: 4091

Re: UFlow

I have a similar question. I was working on a valveless model -- basically the "ping-pong" design the Bruno Olgerec proposed for high-compression valveless pulse jets-- and simulated the initial conditions by splitting the "ignition zone" into two sections that had the same initial temperature (e.g....
by pezman
Fri Oct 08, 2004 4:16 am
Forum: Ramjet forum
Topic: Rocket/Ramjet?
Replies: 3
Views: 3044

Re: Rocket/Ramjet?

I think that the old Bomarc missile worked exactly as you describe.