Hello, world! It’s been awhile since I’ve posted, but in that time I have completed a 141-page junior monstrosity of a thesis, which will shortly be published, stuck up on a shelf, and gather lots of dust. I’m not really being cynical; this is just what happens.
It’s nice to have a chance to catch my breath. Last week, my defense was on Wednesday, and the “Exam Only” (meaning that I only had to defend this semester) deposit deadline was that Friday, so the 48 hours in between the two were rather hectic. This was partly due to changes/corrections requested by my committee, and also to the formatting regulations imposed by the graduate school.
I went hiking with a few friends on Saturday, and will post those pictures when I have time. For now, I’ve been enjoying the chance to sleep and read books that have absolutely nothing to do with hydrazine!
However, I’ve not been entirely a bum. I have an interview with Aerojet next week, hopefully a phone conversation with GE Global Research at some point, and am preparing some materials that SpaceX has requested a look at. Hopefully some of these opportunities will come to fruition, so please keep them in your prayers.
More to come!
I haven’t posted in awhile, so here’s a lit review.
The decomposition and oxidation of hydrazine has been a topic of scientific interest for at least eighty years. Early studies, such as those by Askey or Bamford, focused on the vapor phase. Bamford noted that the chemical exploded when sparked or heated.
Audrieth noted much interest in low-concentration (~30%) hydrazine as a fuel in the years after World War II, writing that, “The hydrogen peroxide-hydrazine combination was first utilized by the Germans as a rocket fuel and represents one of the most promising bi-fuels for long-range high-altitude missiles.” He also documented that this combination appeared to be “self-starting”. In the same year, 1951, a paper by Murray and Hall recorded the observation of a 93% hydrazine flame. They described “possibly two inner cones, separated from one another by a very small distance.” This is extremely interesting to note in light of the dual-flame phenomena for droplets, although the authors attributed the second cone to “radiation from reaction products”. Continue reading
Monomethyl hydrazine is based on hydrazine, which has the chemical formula N2H4. Hydrazine is also used as a propellant and is both unstable and toxic. It may be used as monopropellant (usually after being run through an appropriate catalyst bed), or more commonly as a bipropellant, being hypergolic with nitrogen tetroxide (NTO). Applications of hydrazine have included propelling the Me163B (the first rocket-powered fighter, WWII), on the Viking and Phoenix lander descent engines, and powering F-16 emergency power units. Notably, the thrusters on the spy satellite USA 193 were fueled with hydrazine; an interesting article on the role of hydrazine in the satellite shootdown is here: http://spectrum.ieee.org/aerospace/satellites/us-satellite-shootdown-the-inside-story
Monomethyl hydrazine (MMH) is the result of replacing one of the hydrogens in hydrazine with a methyl group, CH3. It is more stable than hydrazine (can be used in regeneratively cooled engines), and is thus favored as a storable propellant. Because it is still toxic, as well as a suspected carcinogen, great care is taken in handling it. It is most commonly used in hypergolic combination with NTO, such as in the Space Shuttle’s Reaction Control System (thrusters). MMH decomposes into mainly H2, with some CH4, N2, and trace amounts of NH3 and C (soot).
“First of all,” my sister writes, “you should post on what your project is/is trying to accomplish.” … All right, my objective: Characterize the behavior of dual flame fronts in gelled MMH/gaseous NTO as NTO diluent partial pressure and type vary.
This is the simplest way to summarize my project while still preserving the technical aspect. It does, however, lead to a slew of questions: What is involved in “characterizing”? What is a dual flame front? What do MMH and NTO stand for and what are they? Why would you gel them? Why is diluent involved and what am I using? And how does this help babies in Africa?
My math prof on algorithms: “… switch off the thinking part of your brain … [because] … you see an algorithm – you start thinking about it – [and] you become emotionally involved.” (He emphasized the part in italics.)
Professor: “How is your semester going?”
Me: “It’s going all right – I’m looking for a research advisor.”
Professor: “What are you interested in?”
Me: *goes into semi-exhaustive detail*
Professor: “Aggghhhh funding!”
Me: “But I don’t have to be paid this year because I have a TAship.”
Professor: *fails to take the hint* “Ah … well … good luck!”
Me: “So … I’m looking for a thesis topic and advisor.”
Professors: “It’s okay, you have a TAship this year – you don’t have to worry.”
Grad Students: “Get one ASAP or you’ll be here forever!!!!!! Like me!”
Girl walking past me talking on phone: “I’m a science major in an engineering class for engineers, and I don’t know how to do the first problem set even though it’s been explained to me three times, and I WANT TO SHOOT MYSELF.” (Sheesh, chill out. It’s only the second week of class.)
Me: “In my rocket propulsion class, the grad students get to earn their keep by coordinating the rocket launch project.”
Peter: “How is that punishment?”
Me: *smirks slightly* “Exactly.”