chemical Archives - Castle Point Rocketry

News

Testing: Days 0 – 2

July 12, 2019June 5, 2020
by Dakota

These last three days were dominated by the minutiae associated with launching a rocket. Sure, we did as much setup as possible beforehand. But there’s much more to do once the rocket actually gets here.

Day Zero: Packing Up

Tuesday, July 9, was particularly chaotic. Myriad administrative snafus demanded quick action from the whole team. Dakota grabbed a truck so we could transport our rocket. And, most pressingly, we needed to move everything out of our Griffith work space and go mobile.

Monica, Nathan, Ben, Dan, Will, and Dakota (behind camera) take a breather after lifting our rocket onto the dolly. More straps and plastic wrap were added to further reduce movement.

Due to everything else going on, we didn’t even get around to packing until 6:00pm. By that point, we knew we would be leaving late, but we hoped 1:00am would be the limit. Yet 1:00am came and went.

At 2:30am, we gently loaded the rocket into the truck. (Lift gates are a blessing.) It took all of the remaining six of us, but it happened without a snag. Come 4:00am, we were practically finished.

Our lab and rocket, all crammed into one 26′ box truck.

The lab looked lived in, but at least it was devoid of much our mess. And what better time than 4:00am to start 2.5 hours of highway truck driving?

Day One: Tying It All Together

Dakota scrambled into the driver’s seat. Ben and Rodrigo piled in and kept him company to Salem County. (And kept him awake.) After all, there’s that old saying: “Six eyes are better than two with a $500,000 rocket and boxed-up laboratory in tow.”

They arrived okay — and just in time to volley off the first round of calls to gas/cryogenic companies to confirm our delivery schedule. Starting at 8:00am on the dot, Dakota, Will, and Nathan were on the phone until noon. Then, it was just a matter of waiting for the team to assemble.

The shed at left will store our chemicals. Ground control is barely off-screen to the right. The test site is 2,000 feet behind the camera.

A brief team meeting preceded driving to the test site and setting up ground control. The remaining daylight hours were swallowed up by running 2,000 feet of fiber optic cable and cleaning out the on-site shed for our chemical deliveries.

Day Two: Finishing Touches

It took a little under 14 months, but it’s finally happened — Castle Point Rocketry has received a shipment of rocket propellant. (The oxidizing half, at least.) Shortly after a late start to the day, the first cryogen delivery came through: liquid nitrogen and liquid oxygen. It’s a good thing we got that shed cleaned out!

For the rest of the day, we split up into small project teams. The test stand was bent and needed a quick weld — Rodrigo made short work of it. Over the weekend, the gantry hoist slipped on the muddy ground. We righted and reinforced it. Ben and Nathan focused on getting the avionics and valves attached and laid out.

CP Rocketry Test Site, featuring the Mayor’s Soy Beans

Though all parts of plumbing were screwed together, Will and Monica still had some tightening to do. They spent most of the day in the truck-lab working on the rocket. Dakota manned the ground control station, where there is WiFi and a view of the road, to finish up some remaining purchases and administrative duties.

The inside of our truck-turned-lab. (There are no chemicals stored inside.)

When interrupted by a small storm, we broke for lunch. Then, after three more hours in the sun, a massive thunderstorm rumbled in from Delaware. We took it as our cue to leave before it got dark out — but not without first getting absolutely drenched.

What’s Left

We’re zooming in on the first day of true testing. It’s highly likely that, after a delivery Friday morning, we will be testing Friday afternoon. In the meantime, the team still has a short laundry list of tasks to accomplish. First and foremost, we need to reestablish ground control. It kinda tipped over in the rain, and we had to rescue it.

Stay tuned to our Facebook page for a live feed of testing. (Or the live feed itself.)

News

Ready to Test

July 9, 2019June 5, 2020
by Dakota

Here we go. The last fourteen months of work have all come down to this: testing. Over the last two weeks, we have traveled back and forth from South Jersey to inspect the site, set up infrastructure, and clear the area.

In the next 6 days, Castle Point Rocketry will be pursuing a rigorous testing schedule. The testing procedure is 65 pages… But what all will we be doing?

You’ll be able to follow along on live streams that we post to our social media pages. In case you’re still curious what we’re doing along the way, here’s a short explanation.

Phase One: Tank Testing

The first set of tests caters specifically to our experimental liquid oxygen (LOX) tank from Infinite Composites Technologies. Though the composite overwrapped pressure vessel (COPV) is theoretically capable of handing pure oxygen at such cold temperatures and high pressure, we want to test it to be absolutely positive. That way, if we notice any problems, we can stop everything before we have it inside our rocket.

Our Tank Testing series consists of three tests. TT.01: COPV Cryogen Validation proves the tank can withstand cryogens at high pressure. (A gas is “cryogenic” if it can be turned into a liquid below -240°F .) Then, TT.02: COPV LOX Compatibility Validation and TT.03: COPV Cryogenic Pressure Validation step into chemical compatibility with LOX and a system at full pressure.

Phase Two: Full Stack Testing

The second set of tests is more complicated and involves more subsystems. Rather than just the LOX tank and its assorted plumbing, the next five tests incorporate the whole rocket — but don’t let it leave the ground. Computer, mechanical, and chemical systems all interact with one another to give the team an idea of the rocket’s performance.

Similar to the Tank Testing procedures, FST.01: Full Stack Pressurization Test and FST.02: Cold Flow Test simply ensure that everything can withstand operational temperature and pressure. Then, we introduce fire.

FST.03: Ignition Sequence Test is expected to be the longest test Castle Point Rocketry will perform. It is a critical juncture of the project, for limiting the time between when chemicals flow and when the engine ignites will conserve precious fuel and help us make it to the Karman Line. FST.04: Hot Abort Sequence Test then double-checks that, once turned on, we can turn it off as necessary.

Finally, the grand finale. FST.05: Full Stack Hot Fire Test. This test will be the most exciting, the most relieving, and the most Instagram-able. (So we’ve left room for it to happen twice.) Picture a rocket — without its nose or tail — strapped to the ground, straining upwards under full thrust. This test is essential not only to prove we can launch, but also to fully grasp the efficiency of our engine.

What Then?

And then, well, we pack up and go home. We’ll have a truck to return, a rocket to clean, and some data to send off to interested parties. Not to mention, we’ll be so ecstatic we probably won’t sleep for three days. (Or, alternatively, so ecstatic we will sleep for three days.) We have the future of this project to look forward to — including a launch looming in the near future.

News

“Always Open”

June 24, 2019June 5, 2020
by Dakota

Those of you who follow us on Facebook may have noticed a quirk. Under the “About” section, just under the map of Hoboken, it says “Always Open.” This is no mistake.

Here’s a little peek into what we’ve been up to this weekend — at all hours of the day.

Tank Cleaning

As you may recall from a few weeks back, the vast majority of our propulsion system needs to be “Clean for Oxygen Use.” We have finished pipes, fittings, and adapters and are onto the bigger pieces: our tanks.

The helium and oxygen tanks we use were made special for us by Infinite Composites Technologies. We are rigorously cleaning both with isopropyl alcohol baths to dislodge any remaining construction materials from the inside.

Since the alcohol coming out is dirty, we also needed to clean it for reuse — about 34 liters (9 gallons) worth. Monica and Dakota spent much of Saturday vacuum filtering all 34 liters.

The process of vacuum filtration. Dirty isopropyl in the top, clean out the bottom.
We changed filters once every 2 liters — about when they started to look like this.

Load Cell Calibration

A by-product of last weekend’s Dry Run Mechanical Test, we are confirming all of our load cells work. In order to accurately measure the thrust of the rocket, we will attach it to the ground with cables. These cables will pull on our load cells, which tell us how much thrust the rocket has.

Ben was hard at work making sure the code was solid while Will used the engine hoist to test a few known loads.

Will’s load cell testing apparatus.
Ben working on code — as seen through the clean room walls.

Now that it’s Monday, Will, Tom, and Abe are out on Walker Lawn with the load cells and duck bill anchors. The anchors are being used to test the load cells, and vice versa. We want to make sure our duck bill anchors are rated properly. After all, the last thing we would want is for an anchor to come out of the ground during a test.

Fitting Tightening

Last but not least, we have our piping. As mentioned above, all of the propulsion subassemblies have been cleaned for oxygen use. Now, it’s just a matter of preparing them for testing and launch.

Our propulsion system has threaded joints from two rival piping standards: JIC (Joint Industry Council) and NPT (National Pipe Tapered). Each of these two standards comes in multiple sizes — and each size requires a unique tightening force. Larger threads require greater tightening force — as much as 100 foot-pounds.

Nathan and Will using two wrenches and a vise to tighten a JIC-12 fitting to specification.

In order to accurately tighten each joint, we use both a torque wrench and a crescent wrench. (One to twist, one to hold the rest of the subassembly.) For some subassemblies, more advanced methods are needed, though. In the case of particularly wiggly or oddly-shaped pieces, a vise is necessary to get a good grip. Thus the above picture outside the clean room — as long as the interior is not compromised, the outside of the subassembly can always be cleaned again.

A Little Fun

We also manage to have a little fun after a long day’s work. (And usually right before another long night’s work.) Friday night, we all stepped outside to enjoy a barbecue dinner. Because how else would we ring in the first day of summer?

News

Successful First Igniter Test

April 26, 2019June 5, 2020
by Dakota

As those of you who follow our Facebook and Instagram (@cprocketry) pages might know, we had an exciting night this past Monday.

After several weeks of deliberation on how to ignite, we settled upon a cocurrent jumpstart from a solid rocket motor. Imagine our large engine housing a smaller engine. The heat of combustion of the small engine ignites the rush of fuel traveling through our bigger engine and — POOF. We have lift-off.

Capturing footage of a solid rocket motor — plain, and without our igniter design.

The Theory

Combustion theory is hard. A good assumption to make, one that doesn’t need a Ph.D., is that our oxidizer and fuel will both need to be vaporized before burning. That is: They need to be a gas. This, at least, is handled by the injector.

The second part is the orientation of the starter flame. To summarize many, many studies and papers in one quick sentence: “The igniter should be oriented the same direction as fluid flow.” (Downwards.) Doing so reduces turbulence inside the engine, reducing the chances of the engine exploding. It also orients the igniter flame away from the shower-head face of the injector, which could cause some orifices to close up.

The big question, then, is how to take a solid, put it inside a liquid shower, turn it all into a gas, and light the whole thing on fire.

The Model

A few ideas came to mind. Do we hang it from a shepherd’s crook? Adhere it to the bottom of a plate? Stick it to the side of a wood pole? The problem with each of these ideas was two-fold. One: With the relatively small size of our engine, how do we ensure that these bulky geometries don’t increase the turbulence? Two: How do we take the straight flame from a solid motor and fan it out in all directions to ignite as much fuel as possible?

Luckily, a little bit of CAD helped solve all of these problems. We settled on a cylindrical igniter plug. This design allows for a variety of motors to be installed and incorporates a diverter to spread flames in all directions. (You can see the outline of our model in the video below.)

The Test

After a watching our first prototype plug print for a few hours, we couldn’t wait to test it out. Even though it was printed from polylactic acid (a plastic which melts at 220°C) and solid motors burn MUCH hotter than that, we figured we could get a few seconds of slow-motion burn time on camera.

And boy, did we get a show.

Proof of concept: The igniter plug design works!

After slowing five seconds of burn time down to several minutes, we had 10 seconds worth of good footage. You can see in the video that each of the radial flame outlets has even distribution and steady flow. Which is just what we want!

You can also tell when the melting plastic starts to disrupt the flame dispersion — about 7 seconds in. The result of that were the smoking, charred remains of our plastic igniter plug. It gave renewed meaning to the word “pungent.”

The Future

Though the test was a success, we began optimizing our design immediately. We inverted the design to allow for ease of access during testing and launch. Loading the motor from the bottom required the flame to shoot upwards, though. This, in turn, required us to reorient the flame outlets.

The team also bought several cylindrical bars of aluminum. After a successful test of our new design, we plan to machine a couple out of aluminum — which hopefully won’t be reduced to a smoky pile of ooze.

Currently, the greatest design hurdle is how to remove the igniter from the engine during testing. Since the rocket is attached to the ground and the current igniter design doesn’t move, we’re back to square one — disrupted Mach flow in the engine. (A result of turbulence.) Luckily, we’ve got a crack team of young rocket scientists working on it.

So that’s where we stand! Proof of concept confirmed, future planned out, and a moveable design in the works. Just in time for our rapidly-approaching testing timeline.

Uncategorized

Full Circle

February 12, 2019June 5, 2020
by Dakota

One of the most competitive facets of our rocket is the engine assembly. Rather than the hundreds (and sometimes thousands!) of parts used to create a traditional rocket engine, our team has streamlined the process into just two: an injector and a nozzle.

Since they’re so integral — and so specialized — we’ve spent hours upon hours designing, modeling, and simulating these parts. And we’ve come full circle.

Phase One: Solidworks

The CAD starter kit for any Stevens engineering student, Solidworks helped us make our first few rounds of injectors. It was pretty cool. Tom spent a lot of time on it.

Injector, Mk. 1. It was bulky, but it got the job done.

Phase Two: COMSOL

Once happy with the geometry, we needed to simulate fluid flow through the manifold. What better software to use than a COMSOL, taught to grad students and marketed as a multi-physics program with a hefty computational fluid dynamics (CFD) engine. Dakota’s self-taught COMSOL regimen came to a standstill when, no matter how finely we meshed the part, physics kept saying, “Nope.”

COMSOL needed the injector flipped inside out. Crazy, right? This part seemed okay…

… But this one obviously had some problems.

They ended up both not working out. One kept growing gnarly spikes, the other had faces that wouldn’t meet up. In the end, no amount of curve smoothing could fix it.

Phase Three: Ansys Fluent

So, what now? Let’s try another CFD! Stevens also offers Ansys to its students, which comes with the handy Fluent plug-in. Abe and Dakota worked on modeling the part in early January, only realizing after returning to campus why it wouldn’t work: Even when simplifying the models by excluding symmetrical pieces, the parts were MUCH, MUCH too big for our Ansys versions to handle. (If years of math has taught me one thing, it’s that 1.1 million “cells” is larger than 512 thousand “cells.”)

Phase Four: Back to Solidworks

The most recent iteration of the injector. We’ve come quite a long way!

We were lost. What do we do? Our school’s CFD programs weren’t working. We had tried simplifying the parts to no avail. Were we just going to hope our applications of what we read in NASA journals would work? Would our rocket engine be held together by dreams and back-of-the-napkin calculations?

Of course not. In the words of Professor Aziz, who teaches courses in Modeling and Simulation at Stevens, “You started
in Solidworks. Why did you leave?”

This simulation tracks individual particles traveling through the injector manifolds. Red means high speed, blue means low speed. Good news: They don’t stop!

So we’ve come full circle. We’re back where we started. We’ve been running fluid flow simulations fairly smoothly, these last couple of weeks. Sure, we keep iterating and optimizing. But at least it’s all built-in, now.

And boy, are the simulations colorful.

News

“Will It Fly?”

December 18, 2018June 5, 2020
by Dakota

It may be the the question we ask ourselves the most. (Behind, of course, “What’s for lunch” and “How’d your exam go?”) The answer: “Ask NASA.” (To them all, obviously.)

Most recently, it’s fallen to the ChemE team to answer this question. Initial assumptions of the chemical reactions out of the way, it’s time to buckle down and do some hardcore engineering.

And when you need to engineer something, who better to turn to than NASA?

Using a little-known software called CEA (made available online as CEARUN), we’ve been iteratively testing hundreds of fuel combinations and engine conditions over the last few days to comb through and find The One.

It’s not every program that can crank out 23,000-some lines of code in under five seconds. That’s just the NASA difference, I guess.