Questions tagged [liquid-fuel]

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

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2
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1answer
45 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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1answer
438 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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1answer
139 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 ...
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4answers
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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
466 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
119 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 ...
13
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1answer
187 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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1answer
2k 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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1answer
409 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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0answers
104 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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648 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? -...
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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 ...
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1answer
228 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 ...
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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
911 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)....
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1answer
143 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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154 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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1answer
193 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 ...
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1answer
140 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 ...
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308 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
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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 ...
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1answer
483 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-...
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1answer
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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 ...
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1answer
120 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 ...
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1answer
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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 ...
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1answer
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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 ...
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2answers
174 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?...
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1answer
466 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 ...
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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?
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3answers
886 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 ...
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1answer
165 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 ...
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1answer
207 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 ...
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2answers
236 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 ...
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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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1answer
113 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 ...
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1answer
77 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 ...
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1answer
110 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 ...
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0answers
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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 ...
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0answers
45 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 ...
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1answer
127 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 ...
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0answers
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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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2answers
197 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 ...
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3answers
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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 ...
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1answer
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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 ...
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1answer
156 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 ...
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0answers
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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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2answers
242 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 ...
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507 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, ...