Questions tagged [liquid-fuel]

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

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Is adiabatic flame temperature the same as nozzle stagnation temperature?

I am trying to understand whether these two concepts are in fact, the same parameter. The way I see it, the adiabatic flame temperature is the highest temperature achieved by stoichiometric combustion ...
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6 votes
2 answers
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What are the advantages and disadvantages of using either liquid hydrogen or liquid methane based rocket fuels?

I am working on a near-hard scifi story that mainly involves travel across a single widely populated solar system. I imagine that realistically there will probably be a wide variety of ship designs, ...
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8 votes
1 answer
983 views

What is the purpose of the shrouds surrounding these rocket engines?

While researching the purpose of some rocket engine components, I came across several images of perforated shrouds surrounding the combustion chambers of rocket engines. I was highly curious about ...
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1 vote
0 answers
26 views

Relative location of RP1 and LOX tanks in Saturn V [duplicate]

In Saturn V, the 2nd and 3rd stages had their fuel tank located above the LOX tank, but in the first stage, the LOX tank was located above the fuel tank. Is it because the individual stages had their ...
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4 votes
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Is N2O a practical monopropellant?

N2O has been worked with very early on in the 40s and now again is seeing a resurgence. Is this interest merited, disregarding its apparent non-toxicity, and how well does it perform in an engine/...
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7 votes
2 answers
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Is it more expensive to send a chemical rocket from surface of Earth to an orbit or from this orbit to Mars?

I was trying to understand how cost-effective it would be to use an ion engine to power a mission. But since these propulsion systems cannot be used to leave Earth's gravitational field due to their ...
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4 votes
2 answers
663 views

Starship: Methane and Oxygen can't both be liquid, except in a narrow temperature range. Is this a problem for interplanetary voyages?

On an extended spaceflight in Starship, the liquid propellant and oxidizer will tend towards the same temperature. The tanks can be refrigerated by boiling off contents, but your mileage may vary ...
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4 votes
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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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Can the cryogenic expansion of liquid oxygen and liquid hydrogen be used to pump a rocket engine?

A common fuel amongst rockets is that of the combination of cryogenic liquid hydrogen and liquid oxygen. I looked at the design of a simple rocket using this cocktail that is the propellant and found ...
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6 votes
1 answer
268 views

Does anyone know the stay time, or what characteristic length should be used, for a LOX/LCH4-fuelled rocket engine?

Just what it says on the tin. I need to know either the "stay time" (Ts) or characteristic length (L*) that would be used to figure combustion chamber dimensions used with a LOX/LCH4-...
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Why can solid rockets be both the skinniest and most spherical launch vehicles while liquid fuel rockets have a more limited range of aspect ratios?

Question: Why can solid rockets be both the skinniest and most spherical launch vehicles while liquid fuel rockets have a more limited range of aspect ratios? Are there fundamental engineering ...
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Comparison of rocket engines using LH2 & LOX as propellants

I am a bit confused - If it is correct that RL 10 and LR 87-LH2 both were developed in 1950 by Aerojet, and both used LOX and LH2 as the propellants, if so, then why was there a huge difference in ...
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2 votes
1 answer
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What expansion ratio is the best for mars surface level engines?

What expansion ratio is the best for mars surface level engines? For launches from Earth, first stage nozzles are much shorter than second stage nozzles because of Earth's high sea-level pressure. For ...
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4 votes
1 answer
166 views

Can rocket engines which use hypergolic propellants be augmented with LOX for increased efficiency?

Hypergolic rocket engines typically use NTO and hydrazine based propellants. Wikipedia page on Liquid Rocket Propellants shows N2O4 and N2H4 at 1.36 ratio to have 286s Isp at sea level. My question is ...
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1 answer
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Was liquid ozone + fluorine ever tested as an oxidizer? Ever with jet fuel?

Searching for ozone layer circa 1957 I got Theoretical Rocket Performance of JP-4 Fuel with Mixtures of Liquid Ozone and Fluorine, NACA RM E56K14, Issue 58, Volume 63, Vearl N. Huff, Sanford Gordon. ...
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4 votes
1 answer
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Can kerolox or SRB soot particles grow too large too quickly; not accelerated in expanding exhaust leading to a loss of mass-specific impulse?

In this answer to Is methyl silane CH6Si ever considered as fuel in rocketry? I argue that there's no huge loss in mass-specific impulse (Isp) when producing sand (and by extension soot) in the ...
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12 votes
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Why is an inflatable balloon inside a fuel tank not used to prevent fuel from "sloshing around"?

After seeing all the Starship failures, having something with a membrane keep things in place seems like an obvious solution. Has it been considered or tested - or do we simply lack a material that is ...
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4 votes
1 answer
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Why are propellant tanks filled from the bottom?

It seems that the norm is to (fast-) fill fuel and oxidiser tanks from the bottom. For example, on this drawing of the Saturn S-IC stage you can see the LOX and RP-1 fill valves at the bottom of the ...
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3 votes
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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
1 answer
914 views

Open source liquid rocket engine

Is there an open source bi-propelant liquid rocket engine that would have all the documentation, computations, test results and 3D design files (CAD) freely accessible?
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0 votes
1 answer
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Highest Isp achieved with nitrous oxide as oxidizer

What is the highest Isp achieved on orbital rocket for an engine that used nitrous oxide as oxidizer? Both hybrid and liquid engines can be considered. Not considering nitrous oxide monopropellant ...
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4 votes
1 answer
535 views

If high-test peroxide is most stable when pure, why are most uses of it in rocketry at lower concentrations?

Per the Wikipedia article for High-test peroxide: Hydrogen peroxide becomes more stable with higher peroxide content. For example, 98% hydrogen peroxide is more stable than 70% hydrogen peroxide. ...
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2 votes
2 answers
272 views

Is there a "green" hypergolic propellant?

Is there any such thing as a non-cryogenic, liquid, "green" hypergolic bipropellant, where green means environment friendly and non-toxic?
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3 votes
1 answer
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What is the products of a catalyzed reaction between Hydrogen Peroxide and Ethanolamine with Copper(II) Chloride?

I found this article about Hypergols, specifically H2O2. It mentions in table 3 and in the body of the paper that they found that Ethanolamine with Copper Chloride reacted vigorously. In my search for ...
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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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  • 2,502
4 votes
2 answers
6k views

Rocket fuel cost to launch 1 kg to orbit

I have 2 questions about the cost of liquid rocket fuel to launch (anything) to LEO orbit. Let's assume we use fuels used in commercial spaceflight today (probably LOX+LH2 or LOX+RP-1 etc.). What is ...
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5 votes
1 answer
136 views

Is there a distinct flame-front in a liquid-fuelled rocket combustion chamber?

Liquid fuel and liquid oxidizer are injected at high pressure through small orifices into the 'top' of a rocket's combustion chamber. The intention is that these mix quickly and then burn completely ...
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1 vote
2 answers
109 views

How many times is a single rocket engine tested?

When a rocket engine is loaded into a test stand is it tested once before removal or is it allowed to cool and then tested again. Is every liquid-fueled rocket motor that flies to space first tested ...
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3 votes
3 answers
426 views

Can liquid rocket engines have the same thrust as solid rocket engines?

Take the Vega rocket launcher for example. Its first three stages are solid rocket engines and burn at a relatively short time. If I were to change its first stage into a liquid rocket engine, can ...
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1 vote
1 answer
129 views

What is the effect of calorific value of fuel on the specific impulse of a rocket engine?

What is the effect of calorific value of a fuel on the specific impulse of a rocket engine? Other things remaining the same, and if it is possible to use both, will the same fuel provide the same ...
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3 votes
1 answer
199 views

Dinitrogen tetroxide decomposes to nitrogen dioxide at room temperature, but rockets that use it are usually said to use N₂O₄ and not NO₂ - why?

To the best of my understanding, both dinitrogen tetroxide and nitrogen dioxide are usable and perform quite similarly as oxidizers, but rockets that use either are almost always said to use ...
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6 votes
5 answers
2k views

Using of the rocket propellant for engine cooling

Why does liquid space propellant make a good engine coolant? I was researching the regeneratively cooled nozzle and combustion chamber on the Merlin 1D when I found this out. I do know that the pipes ...
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4 votes
0 answers
206 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
1 answer
183 views

Concerns/challenges with LOX as a regenerative coolant

What are the fundamental issues that make LOX as a regenerative coolant difficult to work with or less ideal than using fuels as a coolant instead in small scale engines (<7000lbs of thrust/ ...
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4 votes
1 answer
102 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 ...
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14 votes
4 answers
3k views

Do the SpaceX Falcon-9 rockets use foam insulation similar to the Space Shuttle? Is it still a potential problem?

The Space Shuttle used polyurethane and polyisocyanurate foams for insulation. A chunk of foam breaking off during launch resulted in the Space Shuttle Columbia disaster. Do all chemically-fueled ...
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3 votes
1 answer
111 views

At which pressure does a liquid fueled rocket start producing supersonic flow?

In a compressed-tank LOX+ethanol (or similar liquid fuel) rocket: How much should the tank or combustion chamber pressure (which should be the same) be to have a significant exhaust velocity increase ...
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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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5 votes
1 answer
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How much does launch costs have to come down to make chemical fuel deep space probes feasible?

Considering that NASA have been running short of plutonium for their RTGs, it makes sense to consider alternatives. For the inner solar system up to Jupiter, solar cells have been demonstrated on ...
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3 votes
1 answer
55 views

How to predict reaction of propellants at chamber temperature and pressure? [duplicate]

I would like to understand how to calculate the complete reaction of propellants at chamber temperature and pressure. For instance taking ethyl alcohol (75%) and LOX combustion with mixture ratio of 1....
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10 votes
1 answer
854 views

why do under-expanded engines have less than ideal thrust?

I've been looking into rocket propulsion a bit and got stumped on something. I read that the thrust generated by an engine can be determined by the following: $$ F = \frac{w}{g}v_{e}+A_{e}(P_{e}-P_{a})...
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8 votes
1 answer
299 views

Has methylsilane (CH₆Si) ever been considered as fuel in rocketry?

Methylsilane CH6Si seems to have some useful properties for rocket fuel: high hydrogen content, 6 atoms per molecule, 13% of overall mass; high combustion energy, -2612 KJ/mol or 56.8 MJ/kg (better ...
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10 votes
4 answers
5k views

Why can't cryogenic oxygen and cryogenic kerosene be "stored" together?

This question, to my knowledge, is only applicable to Rocket Lab's Electron, pressure-fed engines that use non-hypergolic fuels, and other engine cycles that don't use a fuel/oxygen-rich preburner. My ...
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7 votes
1 answer
849 views

Why is RP-1 dyed red?

I was interested to learn that RP-1 is at least sometimes dyed to a red color. What is the reason for doing this / what benefit does it give compared to leaving it the usual hydrocarbon clear-to-...
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2 votes
1 answer
382 views

Fat as hydrocarbon rocket fuel?

Have fat/grease or fatty acids ever been studied as a liquid rocket fuel? (I don't expect it to be a good rocket fuel, but I wonder if anybody has ever burned it in an engine or made a serious study ...
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20 votes
1 answer
796 views

What is the MXP-351 storable bipropellant?

Masten Space Systems has a proprietary hypergolic bipropellant called MXP-351 intended for use in the XL-1 lunar lander. We seem to know the following information: Non-cryogenic, with storage life of ...
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24 votes
1 answer
4k views

What actually is RP-1, and how is it different from any other hydrocarbon liquid fuel?

Related: Russian "kerosene" versus American "RP-1", however that's more about the details of specific rocket kerosene specs than rocket kerosene in the context of hydrocarbon and ...
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7 votes
1 answer
442 views

Do mixture ratio always need to be constant throughout the flight?

What factors can change the mixture ratio of propellant? I think they can be changed to control the thrust of a rocket.Stay safe. EDIT:What about considering only one stage? Do they change or can they ...
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3 votes
0 answers
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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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10 votes
1 answer
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How are fuel/hydraulics pipes coupled in spacecraft?

How are pipes coupled in spacecraft? I found Shape memory alloy pipe couplings (SCoup, see image taken from link) are sometimes used. -Is this still the case and in what quantity are they used? -...
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