Questions tagged [liquid-fuel]

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

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4answers
840 views

Modern ambient temperature rocket fuel?

This question is in regard to rocket propellants that are liquid at room temperature & pressure (not solid fuel, and not liquid hydrogen liquid oxygen, both of which would be gasses at STP). It'...
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1answer
125 views

An program that automatically generates a rocket guidance system?

This is for a liquid propelled rocket that launches from earth. It could also perhaps be used for orbital maneuvers and landing on the Moon (not mars or earth). The inputs for such a program would ...
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0answers
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How do current reusable boosters create fuel pressure for retro-burn? [duplicate]

For the SpaceX launches of the Falcon9 and Falcon Heavy, and also Blue Origin launch vehicles, the booster stage lands with a controlled decent and firing of main engines for retro-thrust. During ...
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0answers
180 views

Does LOx stay as liquid when entering combustion chamber?

Given the heat from combustion and increased temperature, would the LOx still be in liquid form after emanating from the injector? Or will it instantly transform into gas? Are injectors cooled using ...
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2answers
3k views

How do rockets keep their fuel in a liquid state?

What are some of the measures engineers would take to ensure that the LOX and other similar fuels are kept below their boiling point during flight?
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1answer
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Don't Preburner exhaust fumes disturb the combustion in a Full-flow Staged Engine?

Since Full-Flow Staged Engine uses preburned fuel/OX-rich gases in combustion chamber, don't those exhaust fumes produced by the preburner somehow unbalance or 'pollute' the pure combustion of fuel ...
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214 views

Challenges in Development of small scale liquid propellant engines [closed]

Being aeronautical engineering graduate, I have gone through huge literature regarding design of Liquid propellant engines(LPRs). But as I am planning to develop small LPR based on gasoline and oxygen....
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2answers
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What is producing the orange-brown smoke in the exhaust of some North Korean missiles?

Accompanying a newsreader's report of North Korea's launch of a new long-range (claimed up to 10,000km) missile is footage of a launch in which the rocket produces clouds of orange/brown smoke. ...
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5answers
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Reasons why liquid anhydrous ammonia fuel chosen for the X-15? Has it been used in other rocket engines?

Both Flight 90 and Flight 91 of the North American X-15 crossed the Kármán line, reaching altitudes of 106.01 and 107.96 km respectively. Both flights were piloted by Joseph A. Walker, who became in ...
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1answer
161 views

The structures in regenerative cooling method and structural strength?

Does the jacket of tubes used to cool the nozzle and combustion chamber in a rocket engine also give it some structural strength? Does it have any function relating to withstanding the pressure of ...
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2answers
302 views

How is gas put back into the tanks once liquid has begun being pumped out?

I am trying to build a rocket with liquid fuel and oxidizer that is being pumped to the injectors/combustion chamber using electric motors/pumps. Assuming that the oxidizer and fuel are liquid, wouldn'...
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1answer
906 views

How does a gas generator engine begin ignition?

I am designing a liquid fueled amateur rocket with my brother, and settled on a gas generator engine. We understand the concept and process, however we are still confused on how the engine is ...
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3answers
369 views

Is there a demand for large liquid engines (> 5 MN)?

In other words, why was the F1 rocket engine programme stopped? Is there a sense that solid motors can take care of high thrust cases in a better way? Or is it an unfortunate fallout of the end of the ...
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2answers
1k views

What are these thirteen purple grape-like things inside this tank?

I am not sure this is a view of the inside of a liquid propellant tank, and even if was, not sure if it belongs to a Falcon 9 per se. But there are places for fourteen round objects at the far end, ...
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1answer
625 views

Falcon 9 - relief valves closing times

From what I understand, prior to the launch, the relief valves are open to allow some of the boiling LOX to evaporate and be replaced with fresh, cold one (we can see oxygen evaporating - and "...
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1answer
2k views

The principle behind regenerative cooling?

In regenerative cooling the fuel is passed around the nozzle before being pumped into the combustion chamber right? I don't really see how this affects cooling itself, since the heat captured around ...
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3answers
716 views

Is nitrous oxide hypergolic with anything reasonably safe and obtainable?

Can I start an amateur rocket using nitrous oxide as either oxidizer or monopropellant, using a hypergolic slug of something reasonable for use by an amateur rocketeer? What substance could it be?
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1answer
491 views

Could super-cold LOX be used in every rocket engine?

Super-cold LOX gives advantages in performance for a rocket. But it isn't used in all rockets. SpaceX's Merlin 1D rocket engine uses super-cold LOX. Also NK-33 use sub-cooled LOX. Could super-cold LOX ...
4
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1answer
165 views

Why were hypergolics tanks vented manually?

As I'm reading "Ignition!" I'm finding one point baffling: vapor pressure being such a big deal. Outgassing of both fuels and oxidizers would cause dangerous pressure build-up. The book describes the ...
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1answer
442 views

Liquid Helium (4.2K) sealed, then raised to sub-LOX temperature (~70K) - what is the new pressure?

In this question there is discussion of the large differences in temperature between liquid helium-4, subcooled liquid oxygen (sub-LOX) and cold kerosene (RP-1). Approximate temperatures are 4.2K, ~...
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1answer
1k views

Is it correct to say that a LH2/LOX rocket uses water as propellant?

The title more or less sums it up. A rocket engine works pretty much by combining fuel and oxidizer, and expelling some propellant resulting in foward motion as described by Newton's third law of ...
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3answers
880 views

Is HAN-water propellant “green” enough to ever be used in a cubesat?

I just read about the "green" propellant Hydroxylammonium nitrate writing this answer. It will be tested in the Green Propellant Infusion Mission (also see GPIM AF-M315E Propulsion System). Catalytic ...
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2answers
865 views

Why does the BE-3 use hydrogen as fuel?

We've covered why the BE-4 uses methane as fuel; what I want to know is, why did Blue Origin go with hydrogen for the BE-3? Liquid hydrogen is notoriously hard to work with; it seems like an odd ...
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1answer
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What is the spherical tank in this drawing of the BFS?

The big news in this article is the extremely large carbon-fiber fuel tank. However, the drawing in the article does not show it well. Instead what stands out like a sore thumb in the drawing is the ...
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3answers
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How was fuel crossfeed achieved, between the main tank and the Shuttle?

Whenever a fan of Kerbal Space Program mentions the super-efficient 'asparagus staging' in any professional context, the automatic response is 'That won't work. KSP fuel pipes are pure magic.' The ...
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Why does the BE-4 use methane as fuel?

I understand the Mars ISRU reasoning for SpaceX's Raptor which is also going to be methalox based. But why would ULA, who is the prime customer for BE-4 besides Blue Origin itself, chose to support a ...
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1answer
8k views

Rocket Engine Plumbing: Still don't understand the Full Flow Staged Combustion Cycle

I just found this incredible video KSP Doesn't Teach: Rocket Engine Plumbing and ran through it a few times. It's very helpful in the way it outlines the various issues first, and then designs the ...
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2answers
958 views

Platinum Colloid in Liquid Hydrogen fuel to increase fuel efficiency

In certain chemical reactions, catalysts can be used to decrease the activation energy of those reactions. For example, platinum is a catalyst for hydrogen/oxygen reactions, so, therefore, the ...
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4answers
6k views

Autogenous pressurization with sub-cooled propellant

In his IAC 2016 talk, Elon Musk said (at 28m 4s in the video) that the ITS booster tanks would use autogenous pressurization. This means there is gaseous oxygen resp. methane in the tank. To stay ...
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Is the pressurization of propellant tanks necessary for structural integrity?

Propellant tank pressurization is a critical aspect of liquid propellant rocket design. Many designs use high pressure helium, heated and recirculated, however the propellant gases themselves can be ...
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3answers
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Limiting factors of liquid rocket engine thrust

What are the limitations for the 1st stage liquid fueled rocket engines that are currently in widespread use, what are the factors that limit their total thrust? Why can't you just inject more and ...
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1answer
867 views

Why is the Deep Space Industries Prospector 1 using water propellant instead of hydrazine?

A lot of satellites use hydrazine propellant but the Prospector 1 is using water. What are the benefits and drawbacks of that decision?
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1answer
305 views

Liquids Plumbing on board

When a cargo mission is flown toward the ISS, there are at least four different kinds of liquids that may need to be moved into/out of the station: Propellant for Zvezda's thrusters Water Wastewater ...
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2answers
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Pros and Cons of LH2/LOX vs Other Fuels

As I stated in the answer to another question, LH2 suffers some serious drawbacks compared to other fuels. Off the top of my head, they are Extremely low density, resulting in: Lower mass-fraction ...
12
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1answer
962 views

What is the ortho/para issue with LH2 as a fuel?

I remember reading somewhere that a catalyst was used to change the ratio of ortho- vs para-hydrogen before it is loaded as LH2 propellant on a rocket. What is this exactly, and why is it necessary? ...
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1answer
280 views

Density impulse of monopropellant hydrazine?

I only found sources (like this ) giving impulse density of hydrazine used as a bipropellant in conjunction with various oxidizers, but I was unable to find any that would give me density impulse of ...
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2answers
797 views

How long can a vehicle stay fueled before the liquid oxygen gets too warm?

On February 28 2016, Falcon 9 attempted a second launch for its 22nd flight. However, it was put on hold for about 20 minutes at T-01:33 and had its countdown reset to T-11:44, giving a total of about ...
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1answer
309 views

How often can liquid hydrogen engines be restarted?

A proposal for lunar development, LunarCOTS, relies on a reusable shuttle running on LH2 and LOX to work. It lands, is refueled on the lunar surface, and then takes off again. Presumably it could sit ...
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2answers
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Why were the Titan II's Flames Clear?

I've seen multiple sources attribute the clear flames to the use of hypergolic fuels for propulsion, but I have been unable to find any explanation for why hypergolic fuels burn clearly. (Image ...
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3answers
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Alternator/generator on launcher engines?

In Kerbal Space Program, most liquid fueled engines include a generator which provides electricity to systems on the rocket, keeping the batteries topped up while on ascent. Do any real rockets (...
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3answers
2k views

What are the phases of ignition (and flameout) of a liquid fuel engine?

As I observed ignition of several rocket engines (Shuttle, AMDE, Lynx Suborbital, Saturn V) they all come through a couple phases - emitting various vapors, unfocused flame, etc, before the proper "...
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4answers
14k views

Why don't rockets drive the turbopump from the combustion chamber?

As I understand it, liquid-fueled rockets typically burn some amount of their fuel in a separate low-pressure combustion chamber, and then use the combustion products produced to drive the turbopump. ...
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2answers
600 views

What challenges are there for more, smaller liquid fuel engines instead of one large?

Some questions popped up about difficulties of creating throttleable liquid fuel engines. I wonder why the obvious alternative isn't more common: multiple engines, from which only some will be lit; ...
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2answers
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What's so hard about creating hydrazine?

I've read an article about EU lifting sanctions against Russia related to rocket fuel components. As far as I understand (correct me, if I'm wrong), Russia can now continue to export rocket fuel ...
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1answer
487 views

Is a fluorine/hydrogen engine feasible for use in space? [duplicate]

Fluorine is a bit more efficient chemically than oxygen. It has never been used as a launcher oxidizer because it and its exhaust products are so toxic. That's as much I've heard about it anyway. But, ...
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3answers
1k views

Are ICBMs and orbital launchers similar enough to be co-developed today?

Russia has two types of hypergolic liquid fuel ICBMs deployed, UR-100N and R-36M2 Vojewoda and they are working on the big Sarmat. There's in this category also the Chinese DF-A5. (A list of ICBMs ...
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2answers
2k views

What is the market for small liquid rocket motors (0.5 to 10 kN thrust)? [closed]

I was wondering if anyone had information on the availability of small liquid fuelled rocket motors in the US (or elsewhere)
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1answer
2k views

How to seal the connection between the combustion chamber and outer shell in this rocket engine model?

Here is rocket engine drawing. The combustion chamber made from copper and the outer shell from stainless steel. The coolant, either water or gasoline will be between (source: wonderhowto.com) With ...
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2answers
3k views

Structural composition of shuttle liquid fuel tank wall

Somewhere I read the shuttle fuel tank kept structural integrity only thanks to internal pressure of the fuel, a'la inflated balloon; empty it would collapse under own weight; and the walls were ...
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5answers
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Can a solid first stage compete with a liquid fueled first stage?

The thing about solids is that they can have awe inspiring amounts of thrust compared to liquid engines, as you can see in this collection of boosters and thrust levels: Shuttle SRB - 2.8 Mlbs Ariane ...

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