Questions tagged [liquid-fuel]
Questions regarding rocket propellant in liquid form, the main type used for chemical rockets.
115
questions
10
votes
6answers
4k views
Is it possible to use gases instead of liquids as fuel in a rocket engine?
Im reading about rocket engines and I have a question about is it possible to use fuels in the form of gases than a liquid in a rocket engine?
6
votes
1answer
628 views
Rocket explosion compared to kT of TNT; has one ever knocked something over at a distance?
The energy equivalent of 1 gram of TNT is about 1 kcal or large Calorie. For reference, 1 gram of carbohydrates gives us almost 4 Calories of energy (if we are lucky enough to use it and not store it)....
2
votes
1answer
114 views
Why did Virgin Galactic decide to use a hybrid engine vs liquid on their space ship?
To me, it seems like their business case is very dependent on rapid reuse. With this in mind, using a hybrid engine that would need to be replaced every flight seems very counter intuitive vs a liquid ...
4
votes
0answers
145 views
Are there examples of a spacecraft designed for transitions from supercritical to liquid+gas mixtures?
The question What happens when supercritical fuel tanks deplete below critical point? suggests some possible scenarios when the pressure of a tank is in danger of dropping below the supercritical ...
3
votes
1answer
119 views
What's the viscosity of chilled RP-1?
I would like to compare the viscosity of "chilled" RP-1 as it is used for Falcon 9 launches to that of some everyday fluids. However, I am unable to find this information elsewhere. Would you please ...
20
votes
2answers
2k views
Do liquid propellant rocket engines experience thrust oscillation?
I know SRBs have a quite bit of thrust oscillation, and it's pretty much part and parcel of burning solid propellant. Do liquid-propellant engines experience something similar albeit at a much smaller ...
3
votes
1answer
117 views
Are these sliding ullage bulkheads in the OTRAG rocket? How do they seal?
This answer to Were there any non-state organizations to organize space flight and colonizations in the second half of the 20th century? mentions OTRAG and links to Astronautix's OTRAG page.
The ...
7
votes
2answers
191 views
Do any rocket engines besides the F1 need/require baffles?
The F1 engine required baffles on the injector plate to control combustion instabilities so that it wouldn't blow itself up. Was that unique? Or do other engines also have baffles for the same reason? ...
1
vote
1answer
222 views
Does this Soyuz vehicle burn coal or oil? What is its official name?
This tweet shows the image below and says:
Soyuz rocket on its way to the launch pad (on a train of course).
Question: Does this Soyuz vehicle (a train engine) burn coal or oil? Does it have an ...
4
votes
1answer
244 views
Why can't an expander-cycle engine be built to use RP-1 or other non-cryogenic fuels?
The expander cycle family of rocket-engine power cycles involve using waste heat from the engine's combustion chamber and/or nozzle to vapourise some or all of the engine's fuel, and using the now-...
0
votes
1answer
65 views
Could LNG fuel be used to pressure feed itself into combustion chamber?
In pressure fed cycle a high pressure gas tank contents are exhausted into the fuel and oxidizer tanks to essentially push them into the combustion chamber.
Could a portion of the fuel from an LNG ...
2
votes
1answer
67 views
Chamber pressure of a gas pressure fed liquid rocket motor
I am studying rocketry and am currently learning about pump fed vs gas pressure fed propulsion systems.
Upon reading about gas pressure systems, I googled the formula to find the chamber pressure for ...
24
votes
1answer
4k views
How did sloshing prevent the Apollo Service Module from moving safely away from the Command Module and how was this fixed?
The Insider.com article 'We could have lost the Apollo 11 crew:' A once-classified anomaly nearly killed NASA's first moon astronauts, a new book reveals describes a problem during reentry of several ...
5
votes
1answer
149 views
Are rocket fuels and LOX pure or are there additives?
I wonder whether there are any small amounts of additives in rocket fuels such as hydrogen and kerosene, or to the liquid oxygen, or if they are absolutely pure (barring any unintentional ...
2
votes
2answers
97 views
Oxidizer Line Pressure of DIY Hybrid Rocket Engine Limits Thrust?
So I’ve seen engines like these which use gaseous oxygen as an oxidizer and then a solid tube as a fuel. But do these types of hybrid engines have any possibility of creating a useful amount of thrust?...
5
votes
0answers
205 views
Why can’t cryogenic propellants be storable, at least on the ground, via refrigeration?
Cryogenic fuels (liquid hydrogen, liquid methane)1 and oxidisers (liquid oxygen)2 are the rocket propellants of choice where raw performance is the overriding concern, due to the very high performance ...
1
vote
0answers
44 views
How much more hardware is needed in a cross-fed CBC rocket than a non-cross-fed one?
Is it just a matter of adding a multi-in fuel manifold?
7
votes
3answers
811 views
Why doesn't Rocket Lab use a solid stage?
I was just reading about the Scout, an all-solid rocket, and thought of Rocket Lab's Electron, which seems to have a similar mission of deploying small payloads to orbit. I understand the engines to ...
2
votes
1answer
142 views
What kind of methane-fueled rocket engines exist?
I have heard of methane being a strong contender for Mars and beyond. Methane is a cryogenic fuel and is said to have a high specific impulse, and work with closed- and open-expander cycles. I have ...
3
votes
1answer
161 views
How much fuel/oxidizer was held in the piping of the Shuttle orbiter?
The space shuttle main engines were in the orbiter portion of the vehicle, but fed fuel (LH2) and oxidizer (LOX) from the external tank. Suppose the external tank is ejected before the LH2 and LOX ...
5
votes
1answer
167 views
Can Amateur Rocketeers use Liquid Nitrogen Dioxide as oxidizer?
I was reading similar question as mine here. But no one talked about Nitrogen Dioxide (NO2). Its boiling point is 21C. So easy to store. But how easy it is to handle compared to Hydrogen Peroxide or ...
2
votes
0answers
62 views
LOX as annular heat sink
I'm thinking of my time spent working with cryostats. Liquid helium pot on the inside, and surrounded by a liquid nitrogen jacket. And the whole thing insulated with vacuum and superinsulation. (...
4
votes
1answer
86 views
How do pressure fed and pump fed systems compare at different scale of rockets
Rocket Design is all about optimising mass, within cost constraints while accepting a certain amount of risk. Both pressure fed and pump fed systems have their pros and cons, but how do they compare ...
1
vote
1answer
66 views
What differences exist between the pressurants and their associated systems between a pressure fed and pump fed liquid rocket engine
There is an apparent need to have pressurants in both pressure fed and pump fed systems. However, since pump fed systems can create the necessary pressure, they can work with less pressurants and ...
2
votes
1answer
91 views
What happens when LOX and H2 are injected into the combustion chamber of a rocket?
I can't seem to find an answer on this.
I thought that when oxygen and hydrogen get injected they collide and break bonds etc. to form water vapour which because of the pressure in the combustion ...
3
votes
0answers
95 views
What fuels would make refueling in space more dangerous/complicated?
I saw the question:
Has in-space refueling been done?
And was actually beginning to wonder, is refueling and transferring propellant dangerous in space? I understand that this would most likely be ...
2
votes
0answers
42 views
What are some common exit pressures for liquid propellant engines?
Most engines are overexpanded at launch so that they reach peak efficiency at altitude. It’s easy to find values for thrust, specific impulse, expansion ratio, chamber pressure, etc, but I’m trying to ...
1
vote
1answer
113 views
Can I able to use RP 1 and LOX in metal tin small size rockets? Is that possible? [closed]
I love rockets. Planning to build a tin rocket but not with water and air pressure. I would like to build a small metal tin rocket using fuel as RP 1 and oxidizer as LOX. I know this is too hazardous ...
2
votes
0answers
55 views
Would a liquid propellant fire in Mars' atmosphere cause charring?
If a ship carrying liquid propellant crashed on the surface of Mars, rupturing all tanks, I assume the propellant could ignite.
If the propellant did ignite might it leave indications of charring on ...
2
votes
2answers
163 views
Solid hydrogen hybrid motor engine for launch?
Would hydrogen unlike water in a solid state take less space or be more stable? How would a rocket work using a block of melting solid hydrogen instead of liquid hydrogen? Has and could any kind of ...
15
votes
3answers
4k views
Is it bad if hydrazine freezes on a spacecraft? Is it always kept as liquid, or can it be safely allowed to freeze and then thawed when needed?
After having read this answer I wondered what happens if hydrazine freezes.
It looks like it is "normal" and not like water, in the sense that it contracts when freezing, unlike water which expands ...
5
votes
1answer
239 views
How will Robotic Refueling Mission-3's liquid methane tank remain full for six months without any boil off?
Space.com's Lasers, Crystals and 36,000 Worms Will Ride a SpaceX Dragon to Space Station says:
To fly on those journeys, astronauts might have to someday harvest fuel from the surface of the moon ...
2
votes
1answer
147 views
What liquids last the longest in space?
I am trying to find something that is somewhat stable as a liquid in space. What happens to various liquid elements and compounds in a vacuum? Is there a list or table of the effects of local space ...
4
votes
0answers
62 views
Why doesn't a regeneratively cooled engine crack due to differential expansion induced by thermal gradients?
A liquid rocket engine with regeneratively cooled chamber walls and nozzles would definitely be one among those components experiencing the steepest thermal gradients (Chamber wall inner - $3000 K$ ...
2
votes
2answers
199 views
Why are LOx plumbing not insulated?(ref: Huzel and Huang)
In the book Modern Engineering for Design of Liquid Propellant Rocket Engines, the following excerpt appear in chapter 9 - Interconnecting Components and Mounts:
The liquid-oxygen lines were not ...
6
votes
2answers
390 views
Other than He and N as pressurizing gases
To pressurize the liquid propellant tanks Helium is most widely used and after that Nitrogen. Helium is quite costly and Nitrogen is economic but it messes with the O/F ratio of the engine (ref). So, ...
1
vote
0answers
121 views
How are the liquid propellant umbilical cord protected from the exhaust?
The launch pad umbilical cords supply propellant to the rocket, and will definitely have some remaining at the time of liftoff.
I remember the Saturn V footage wherein a heavy protection door slams ...
9
votes
1answer
1k views
Why is a purging process necessary for static firing test of liquid rocket engines?
In Chapter 7 of Modern Engineering for Design of Liquid propellant Rocket Engines by Huzel and Huang, mentions the following engine cut off procedure.
The cutoff sequence usually consists of
...
2
votes
0answers
39 views
Effect of the location of igniter in starting liquid rocket engine
What will be the effect of off axis igniter, say a Spark igniter has to be used along with a pintle? Will the igniter being off axis have any effect on engine start?
Also, will an off-center igniter ...
6
votes
1answer
403 views
Why are 22N and 440N liquid engines quite common?
One can often spot that liquid apogee engines are 440 N and attitude control systems are 22 N.
Is there a reason why the thrusts are proportional? If the engines are scaled for reducing development ...
0
votes
2answers
295 views
Challenges of using propyne (aka methylacetylene) as rocket fuel
Propyne is a light hydrocarbon which packs quite a lot of energy in a triple carbon bound. It poses no significant health or explosion hazard by itself, and some European studies have found it to be a ...
4
votes
2answers
153 views
Liquid propellant stored as solid
Some propellants have wildly different melting points. The most extreme case is the theoretically fantastic (and nightmarish in practice) Fluorine-Lithium-Hydrogen tripropellant, with liquid hydrogen ...
12
votes
2answers
565 views
How does SpaceX plan to deal with boiloff on the trip to Mars?
Both BFR booster and BFS are to run on Raptor engines, fueled with liquid methane and liquid oxygen - cryofuels.
The trip to Mars will take at least a couple months, and BFS requires fuel for powered ...
14
votes
1answer
1k views
What is the advantage of using Helium over Nitrogen when used for pressurising LOx?
In this Twitter post of the plumbing line diagram(left half) by LauncherSpace, one can notice that Helium is used for pressurising LOx while Nitrogen is used for pressurising Kerosene.
Why the ...
3
votes
0answers
132 views
Do rocket labs store propellants at higher pressure than the other rockets?
It is known that the Rutherford engines run on an electric pump-fed cycle. There must be a trade-off between the tank pressure of the electron rocket and battery capacity, for batteries are dead ...
2
votes
0answers
88 views
How to overcome the challenge of igniting kerosene using spark plugs?
Discussions in this question and its answer, concerning the use of spark plug ignition for Kero/GOx system outlines the energy limitations of spark plugs to ignite the mixture.
But Ignition Transient ...
1
vote
1answer
221 views
Does kerosene get ignited by a spark plug? [duplicate]
Are spark plugs used in kero-LOx engine(say J1 engines)? If so, then there are two major issues when using spark plug to ignite kerosene.
Wetting of the spark plug causes spark to be smaller and the ...
5
votes
1answer
266 views
How do they know how much liquid propellant is in a rocket just before launch?
In this answer I wrote:
In other words, a few tons here or there could depend on something as simple as the weather, or trying to squeeze a little extra propellant in for a given mission with a ...
7
votes
1answer
102 views
What parameters of an rocket engine determines whether it is fit for any more static hot fire test?
Typically engines built are repeatedly hot fired to analyses their performance.
In between tests, what are the review that the engine undergoes? How is an engine gauged suitable for a hot fire ...
8
votes
3answers
1k views
Impact of tidal forces to a liquid in a half-full tank
The german Wikipedia article about tidal forces contains a sentence which mentions, that tidal forces have an impact to an half-full fuel tank:
Wo keine mechanisch feste Verbindung besteht, können ...
