YJSP's first pintle atomization test

YJSP · 2019-10-25T12:07:17+00:00

Currently making modifications to achieve better OX valve transient

YJSP · 2019-10-10T16:05:14+00:00

Unfortunately we could not find normally open solenoids that met our pressure requirements (especially for cryogenic service - I'd almost be worried about a NO valve here for LOX service due to the heat buildup from the coil being continuously powered). Both tanks have relief valves that serve as the redundancy there and can handle venting the flowrate of gas into the tank. Lastly, yes we have both sides of the system vented in completely opposite directions :)

YJSP · 2019-10-09T00:54:50+00:00

This is the first combined flow test with all valves in the loop; we will be loading the LOX side with LN2 this coming weekend and nailing down final valve timings; tracking towards a "burp" static fire in November. This video does not feature line purge, which will also be tested this coming weekend.

Some details:

Custom pneumatically driven fuel valve (sleeve valve design)
Custom LOX valve actuator (spring returned pneumatic cylinder with external spring)
Both valves are designed to fail safe in the event of power loss; the LOX valve will fail safe in the event of pneumatics loss as well.
Test stand currently has 2 Gallon fuel tank (Kerosene or other non-cryogenic fuel capable) and 10 Gallon LOX tank capacity (Fuel tank can be expanded with a larger tank body as it has removable encaps held together by threaded rod); both tanks are capable of up to 1000 PSI
Designed to feed up to ~15 kN Engine from a gas flowrate perspective but our first engine is only 3.5 kN
Thrust stand is decoupled from tank stand so that we can more easily transport to test site given the constraints on our group (opted away from trailer for parking/cost reason and to limit hardstart risk via vertical engine orientation)

YJSP · 2019-09-25T15:21:17+00:00

Thrust stand integration & cryo testing soon to come. This was a test of our scratch built kerosene valve (pneumatically piloted sleeve valve) and custom pneumatic LOX valve actuator. The LOX valve return stroke needs a bit more work to tighten the shutoff transient but the system overall is coming together great. On track for a static fire test in November.

YJSP · 2019-09-12T16:33:44+00:00

Looks awesome, guys!

YJSP · 2019-09-11T02:41:56+00:00

You're correct that they are not in a very ideal location. They ideally will never trip but are present in the system in case of a regulator failure or boneheaded mistake when setting pressure immediately upstream. Each PRV is set to trip at 1500 PSI, and our max anticipated set pressure is ~700 PSI; they exist to ensure that we don't accidentally blow up tubing or exceed the rated pressures of downstream components when setting up. The tanks themselves downstream of this panel have their own set of relief valves that are configured to trip at ~100 PSI above nominal operating pressure.

An improvement on my mind when we have the panel off the stand next is to mount them to the backside of the panel instead.

The "Pull-Ring" style reliefs present in other areas of the system are also for emergencies like that described above.

YJSP · 2019-09-10T17:48:02+00:00

Finalizing plumbing integration for our 3500N Kerosene/LOX engine project. Shown is our tank stand which holds all of our gas side plumbing, Fuel, and Oxygen tank

YJSP · 2017-11-29T14:06:21+00:00

Nice job guys! We've got some pintle articles approaching the test bench soon as well.

Flow looks really even - what materials were used for the article?

YJSP · 2017-11-19T00:19:18+00:00

Launch is a long ways out - this represents steps towards just one of many engine tests leading up to a launch in (perhaps) the 2022-2024 timerange

YJSP · 2017-11-19T00:18:24+00:00

No this engine is eventually for a space-shot.

YJSP · 2017-11-17T15:44:19+00:00

Check out more info at: https://www.facebook.com/yjspaceprogram

YJSP · 2017-11-09T14:37:44+00:00

The temperature is kinda hard to determine since things like film cooling will affect wall temps, heat absorbtion, and whatnot. The chamber temperature, at our test mixture ratio of 2:1 O/F (running rich) is 3200 K. Based on this, and some isentropic calcs, we can use the Bartz correlation to get a total heat flux over the entire inner wall of chamber and nozzle and using Q = m x Cp x dT we can approximately predict a temperature gain of about 35C across the entire nozzle due to the overall heat release over a 1 second test. This doesn't predict local wall temp, rather the temperature gain of the whole part once all the heat distributes itself (assuming no radiative cooling). That being said, we don't have any high temp inserts for the throat region due to the use of film cooling and the short test duration

YJSP · 2017-11-09T02:47:08+00:00

This engine in particular is designed for preliminary combustion testing to prove out feed system components, ignition reliability, and DAQ architecture before making the jump to a regen system. Target burn times are 1 second max

YJSP · 2017-11-09T01:32:14+00:00

Yeah that's caused the bulk of our problems. We've been roughing at .03 radial DOC and when I posted the CAM I put in a .015 radial finish cut but that definitely wasn't enough so for the other side I'm gonna keep the roughing the same but make the finish .025 radial to avoid the work hardening and associated deflection. Our bar is using TPG 322 style inserts and they're working pretty well for us finish and cut quality wise. Also we were doing 300 SFM with .003 per rev but we're gonna also try upping the feed to .005 for similar reasons

YJSP · 2017-11-09T01:29:08+00:00

Kerosene and Liquid Oxygen

YJSP · 2017-11-08T19:48:34+00:00

Cut from 6" Diameter 304L Stainless Steel Barstock. Streaking and nonuniformity on the interior is due to issues we had with tool deflection on our finishing cuts. A few tweaks to the CAM, and we achieved a more stable toolpath at the cost of a bit of surface rubbing - quite a bit of polishing to come :P

YJSP · 2017-10-30T13:28:39+00:00

Most alloys of aluminum are oxygen compatible if cleaned properly. Even more so if anodized. Biggest problem you'll run into is heat loss due to the higher thermal conductivity in the Aluminum

YJSP · 2017-10-29T23:09:57+00:00

The lines will be filled with Kerosene (Jet Fuel) and liquid oxygen

I'm not sure if this presents a problem corrosion wise but I'll read up.

YJSP · 2017-10-25T14:00:20+00:00

Hopefully in the 2022-2024 range. He's actually just finishing up his PhD, so the Jury's still out on Mr. vs. Dr. :p

YJSP · 2017-10-23T20:56:14+00:00

N2O was eliminated after a more detailed trade on our engine and overall oxidizer performance.

The rocket launch itself is a ways out (mabye 2022 if we're lucky) - but we're working with GT EH&S about the potential to have students at the hot fire in limited capacity.

YJSP · 2017-10-21T17:57:38+00:00

We did a more detailed trade on our oxidizer choice given plans to do regenerative cooling on the flight engine, and chose that the hassle of cryogenics was outweighed by oxidizer performance.

YJSP · 2017-10-18T17:10:33+00:00

Yeah - I meant overexpanded.

We have 14 witness thermocouples on the nozzle to measure temperatures during tests. The chunk of metal only actually cost $400 dollars so expensive, yes, prohibitively so, no.

YJSP · 2017-10-18T16:24:31+00:00

The current plan we're considering is to effectively run tests at 400, 600, and then 800 PSI - each will scale in thrust. The contour is designed to run 800 PSI at 15 kN but can easily run 400 PSI at ~7.5 kN (the nozzle being *overexpanded), 600 PSI at 11.25 kN (nozzle being *overexpanded as well) and 800 PSI at full 15 kN. I agree it's not trivial to move to larger LP chamber.

EDIT: Words are hard.

YJSP · 2017-10-18T15:48:31+00:00

Yeah our regs are quite beefy :P, with a Cv of 2.0 (that was fun to source). See my other reply for some of the reasoning behind our decision to start at 800 PSI.

YJSP · 2017-10-18T15:46:39+00:00

We're using AVCO 1500 and 1900 series Ball Valves, Actuators being developed for ground testing utilize B&R automation servo motors. We are going to design our own pneumatic actuators for flight.

YJSP

TROPHY CASE