Questions tagged [liquid-fuel]
Questions regarding rocket propellant in liquid form, the main type used for chemical rockets.
153
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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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1answer
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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 ...
4
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1answer
145 views
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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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 ...
3
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1answer
173 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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1answer
55 views
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 ...
4
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1answer
145 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. ...
2
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2answers
112 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?
3
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1answer
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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 - ...
4
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2answers
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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 ...
5
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1answer
78 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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2answers
85 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 ...
2
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3answers
201 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 ...
1
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1answer
40 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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0answers
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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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5answers
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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 ...
3
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0answers
90 views
Why didn't propylene fly? (Vector)
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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1answer
101 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/ ...
4
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1answer
86 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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4answers
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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 ...
3
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1answer
98 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 ...
3
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0answers
654 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 ...
5
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1answer
407 views
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 ...
3
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1answer
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....
10
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1answer
592 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})...
7
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1answer
193 views
Is methylsilane CH6Si ever considered as fuel in rocketary?
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, -2612KJ/mol or 56.8 MJ/kg (better ...
10
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4answers
4k 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 ...
7
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1answer
615 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-...
2
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1answer
220 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 ...
17
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1answer
547 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 ...
24
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1answer
3k 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 ...
7
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1answer
417 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 ...
3
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0answers
105 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 ...
10
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1answer
654 views
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?
-...
4
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2answers
210 views
Bio-Fuel for Rocket Science
In season 1 of the 2018 Lost In Space Series which aired on Netflix† the last Episode has the Robinson family using the by-products of living beings (faeces) as biofuel. If we were to use the same ...
2
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1answer
328 views
How did JPL detonate a liquid oxygen methane mixture with light?
This answer to Pre-mixing cryogenic fuels and using only one fuel tank quotes John D. Clark's Ignition! Chapter 11: The Hopeful Monoprops, and the quote includes the line:
How he avoided ...
11
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1answer
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What is the density of supercooled LOX at −206 °C, as SpaceX uses it
I want to calculate the size in cubic meters of Starship's propellant tanks. The only figures for LOX I can find are at −183 °C. 1141.7 kg/m³ at −183 °C. Could somebody please calculate it at −206 °C,...
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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?
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3answers
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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)....
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1answer
184 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 ...
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0answers
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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
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1answer
313 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 ...
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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
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1answer
183 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 ...
8
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2answers
476 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? ...
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1answer
319 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
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1answer
686 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
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1answer
92 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
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1answer
189 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 ...
