Questions tagged [liquid-fuel]

Questions regarding rocket propellant in liquid form, the main type used for chemical rockets.

21 questions with no upvoted or accepted answers
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7 votes
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Why aren't injector pumps used in rockets?

Is there something that makes injectors unsuitable as oxidizer pumps? Seems to me that rockets would benefit significantly from a pump with no moving parts that runs off its own exhaust.
5 votes
0 answers
121 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 ...
4 votes
0 answers
98 views

Is Lucy fueled with hydrazine and liquid oxygen?

On Sept. 18, propulsion engineers finished filling Lucy’s fuel tanks with approximately 1,600 pounds (725 kilograms) of liquid hydrazine and liquid oxygen, which make up 40% of the mass of the ...
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4 votes
0 answers
221 views

Why didn't propylene fly? (Vector—yes, Vector—is back)?

Ars Technicha's Rocket Report: SLS has technical problems, Vector—yes, Vector—is back links to Vector restarting operations under new ownership which says: One thing they did wrong was the technology ...
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4 votes
0 answers
2k views

How do Falcon-9's cold gas thruster maneuvers account for the center of mass changes due to "floating fuel shifts"?

The Art of Engineering video How SpaceX Lands Rockets with Astonishing Accuracy after 07:19 explains: Cold Gas Thrusters The falcon 9 is equipped with a total of ...
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4 votes
0 answers
179 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 ...
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4 votes
0 answers
85 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 - $3000 K$ ...
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4 votes
1 answer
116 views

How to experimentally determine the degree of atomization of the propellants mixing in a fuel injector?

When validating a fuel injector design on a test stand using liquid water to simulate a liquid-liquid fuel injector(the one i'm working with currently is a pintle design but I suppose one could ...
3 votes
0 answers
168 views

Injector design - LOX vs nitrous oxide

What will be the main design differences between using liquid oxygen and liquid nitrous oxide as oxidizer in a bi-propellant rocket engine? What liquid/gas properties (vapor pressure etc.) play the ...
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3 votes
0 answers
107 views

How are cryogenic fuels and oxidizers generated and procured?

I understand hydrogen can be generated from steam-methane reforming or from electrolysis of water and then cooled to liquid through a series of cryogenic coolers. For steam reforming, the hydrogen ...
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3 votes
0 answers
299 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 ...
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3 votes
0 answers
284 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 ...
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2 votes
0 answers
104 views

What does "pogo bleed" entail?

At around T-3:00 on every Falcon 9 countdown, we hear the following: Stage 1 pogo bleed verification I assume they are referring to pogo oscillation, but what exactly does "pogo bleed" ...
2 votes
0 answers
88 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. (...
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2 votes
0 answers
51 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 ...
2 votes
0 answers
61 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 ...
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2 votes
0 answers
69 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 ...
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2 votes
0 answers
171 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 ...
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1 vote
0 answers
51 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?
0 votes
0 answers
120 views

Has combustion chamber water injection been used in RP1 rocket engine design?

Goddard’s rocket, the V2 rocket and Redstone all used water in their Alcohol fuel for combustion temperature control. To the best of my knowledge, water has not been used in RP1 fueled rockets for ...
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0 votes
0 answers
113 views

Liquid fueled suborbital rockets?

Which suborbital (sounding, balistic, amateur or else) rockets use or used liquid fuel? I could find (with help from A. Rumlin) New Shepard - Blue Origin - RP-1 Spica - Copenhagen Suborbitals - ...
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