Questions tagged [nozzle]
Questions regarding the rocket engine nozzles, semi-open compartments of various shapes and sizes into which propellant components are injected by their own pressure or with a help of a turbine, often preheated and ignited to start a thermochemical reaction in the nozzle's combustion chamber, producing thrust with expansion into gases and ejecting them through the nozzle's exhaust as plumes, accelerating the rocket to high-mach velocities.
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Specific impulse of a rocket engine
Keeping other things (fuel, oxidizer, their ratio, mass flow rates, throat diameter, other hardware like pump, injector nozzles & impinging pattern etc.) same, if I changed only the geometry (...
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Using a laval nozzle as supersonic inlet - what happens at throat? [closed]
I am wondering what will happen, if I use the laval-nozzle , which normaly accelerates a fluid the other way round:
So what happens if I fly with my aircraft at Mach 2 and I collect all the air in my ...
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Designing of CD nozzle with respect to Mass flow rate of propellants
How do I calculate the flow rate of exhaust gases required at the throat of a CD nozzle, with given throat diameter of "D", so as to achieve a "Choked flow condition" (velocity of ...
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Can Vacuum nozzles be used as cooling radiators in LEO?
Radiators are used for thermoregulation of spacecraft. https://www.academia.edu/934756/Thermal_Control_Handbook . Their effectiveness requires their surface be exposed to deep space, not an IR ...
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276 views
Calculating rocket nozzle throat area
I'm trying to calculate a rocket nozzle throat area, $A_t$. My propellant is KNDX. I am trying to do this according to the following equations, taken from this reference:
where $P_t$ is
and $T_t$ ...
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What happens with thrust if I decrease the convergent divergent nozzle exit area?
I am new to rocket design and I have a couple of questions.
If I have a convergent - divergent nozzle and I have a choked flow condition for the throat, what will happen a) with my exit pressure b) ...
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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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1answer
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Conversion of heat into electricity in rocket nozzles
Can we use advanced thermoelectric materials to reduce the temperature of nozzles by converting heat energy to electric energy and reducing the strain on the nozzle material and the coolant while ...
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1answer
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Sea-level nozzles
I understand that there are sea level-optimised and vacuum-optimised nozzles, but why optimise for sea level when the rocket doesn't spend much time there? I would expect the first stage nozzles to be ...
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Aerospike calculator software doesn't seem to altitude-compensate - am I misunderstanding aerospikes?
I'm using mvernacc's Aerospike Nozzle Design GUI, which is supposed to be able to design and predict the performance of aerospike rocket engines. The workings of the software are apparently based on ...
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What were/are the stingiest and most generous vacuum nozzle? (records for the smallest and largest expansion ratios)
Vacuum nozzles are huge compared to their sea-level or atmospheric counterparts, as can be seen by comparing the first stage engines on an Electron or Falcon-9 to their second stages, where a big ...
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nozzle throat area calculation for choked flow
I am quite confused for my sugar propellant rocket nozzle. I have designed a CD nozzle by hit and trial method. It worked but produced so less amount of thrust .I have used 2.3 kg propellant which ...
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How can firing a Space Shuttle OMS engine below 21 km cause its nozzle to "collapse"?
This answer to Can the space shuttle use OMS engines during landing? says:
No
and quotes Section 3.7 of the Orbital Maneuvering System Workbook; OMS 21002 October 10, 2006, Final version, USA006500 ...
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Is it always one nozzle per combustion chamber and one combustion chamber per nozzle?
When I read about engines like the RD-170 they might have a single turbopump feeding multiple combustion chambers, and each combustion chamber has its own nozzle. Is there, or would it be reasonable ...
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Design a cold gas ACS nozzle
I have the total thrust required to be F=16.9 KN. I am using nitrogen gas, and the stored temperature in the nitrogen gas cylinder is 155 bars with a temperature of 325k. How would I design the nozzle ...
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Aerospike with solid fuel
I was scrolling in youtube and I saw this awesome video
and I think, if we put an aerospike nozzle in a sounding rocket,or even a small orbital rocket, as a first stage solid booster, this type of ...
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Do pulse detonation rocket engines require any type of nozzle?
Rocket nozzles are used to convert slow moving gas under high pressure and temperature into hypersonic gas under approximately ambient pressure. From many videos of experimental Pulse Detonation ...
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Which engine has the highest nozzle wall temperature? [closed]
From all the rocket engines that were used in flight, which one has the highest nozzle wall temperature?
The nozzle wall is not heated uniformly. But there are regions where they reach max temperature....
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How hot do rocket engine nozzles get?
What temperatures are encountered by the nozzles of rocket engines like those in SpaceX's Merlin series? Radiative or regenerative cooling, atmosphere or vacuum.
There's plenty of info about exhaust ...
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What if we have a DC nozzle instead of a CD nozzle?
My understanding is that the exhaust gas gains velocity as its heat converts to kinetic energy, regardless of the geometry of the nozzle, and the reason we have a convergent-divergent (CD) nozzle is ...
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I'm having a problem with the Throat Area formula derivation
I came upon this when reading "Introduction to Rocket Science and Engineering, he said "by differentiating" , my question is: differentiate with respect to what? and how do you get such ...
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439 views
Contracting rocket engine nozzles
The efficiency of rocket engine nozzles depends greatly on their expansion ratio an how well the ambient pressure matches the rocket nozzles exit pressure. An optimal expansion ratio means that there ...
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1answer
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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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Can exit pressure of nozzle be less than atmospheric pressure?
This is kinda dumb question .I got 5psi pressure at outlet of the nozzle from open motor software. Is that possible because its less than atmospheric pressure 14.7 psi?
Am i missing out something?
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Why nozzle extensions for ULA's Vulcan; why not make them this long in the first place?
This answer to What is the difference between the Vulcan 562 configuration and the Vulcan 5H2 ("Heavy") configuration? explains that the 2nd stage nozzles were modified by extending them, ...
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Need help finding a clean expression for exit velocity [duplicate]
I'm trying to calculate a engine burning LOX and ethanol (96%) and for that I am using both
CEAgui, a GUI for NASA's CEA (Chemical Equilibrium with Applications) code
Sutton's Rocket Propulsion ...
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1answer
101 views
Efficiency of rocket stages and converging/diverging nozzle
It is a fact (to the best of my knowledge) that for optimum thrust from a rocket engine, one of the most important factor is the design of its converging/diverging Nozzle - the diverging cone to be ...
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Do converging-diverging engine nozzles need to be bell-shaped?
Many rockets designed after the V2 but prior to Saturn V, do not show the typical "Bell" shaped diverging nozzle. Why is it so? Do they achieve supersonic speeds for the exhaust gases in any other way?...
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Supersonic flow of non-compressible fluids
Will the non-compressible fluids, travelling at Mach 1, at the throat of a CD nozzle, accelerate after they leave the throat?
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Nozzle throat velocity
I have the following question regarding nozzles; It is known that in a CD nozzle there can be only one of the following outcomes;
a flow fully subsonic in the convergent, subsonic at the throat and ...
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1answer
397 views
Nozzle Exit Pressure Too High?
I've been doing some simple rocket science for fun, and I wanted to calculate the specifications of the Lunar Module Descent Engine (LMDE). The LMDE uses Aerozine-50 (UDMH) and Dinitrogen Tetroxide($...
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1answer
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What is the thickness of a rocket nozzle?
For a university project, I'm working on optimisation of a Falcon-9-like launch vehicle, and one element of that is varying expansion ratios of the engines. This will impact on the engine mass, but to ...
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What was the first rocket with de Laval (convergent-divergent) nozzle to fly?
Rocket engine Wikipedia article states that
Goddard was the first to use a De Laval nozzle on a solid-propellant (gunpowder) rocket engine, doubling the thrust and increasing the efficiency by a ...
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Why do many ablative nozzles use phenolic resin and not some other resin?
I am currently looking into ablatively cooled nozzles. Most of the nozzles made out of composite material that I have found use phenol as resin (Space Shuttle Solid Rocket Booster, ARCA Excecutor).
...
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535 views
What is a typical sea-level engine nozzle/expansion ratio? What about vacuum engines?
On a sea-Level engine, what is the average nozzle ratio? What about an upper-stage vacuum engine?
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Deep throttling in sea level engines
In this excellent answer, asked for merlin engines deep throttling in first stage and produced here.
To help you understand where the cross over point is, here is some math for understanding the ...
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1answer
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Grossly overexpanded nozzle?
How do we classify a nozzle to be grossly overexpanded in the design phase? For example, looking at the dimensions and operating at sea level, can we determine if it will be overexpanded or grossly ...
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Why should the velocity through the nozzle throat be sonic?
I have read (even on this site), that exhaust gas velocity is (normally?) sonic (exactly Mach 1) through the choke point of a De Laval, or convergent-divergent, nozzle:
At the "throat", where the ...
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What factors determine the altitude at which rocket exhaust plumes start blooming hugely?
The images below are from a much larger set of photos in Spaceflight Now's August 8, 2019 article Photos: Atlas 5 paints the sky with spectacular sunrise launch.
They show several effects related to ...
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Do the pipes used for RS-25 nozzle cooling channel have a constant section?
If I understand correctly from this question, The SSME's nozzle is made of pipes into which cool propellant circulate.
The nozzle is larger at the end than near the combustion chamber. Thus, it must ...
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648 views
Sea level static test of an upper stage possible?
As we know that for the upper stages of the rocket, we need high propulsion efficiency thereby high specific impulse. For that we employ a nozzle with higher expansion ratios.
Now, if we conduct the ...
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Does adding a nozzle increase peak pressure in a rocket?
If I had two charges of the same solid propellant both in the same geometry and casing, and added a de laval nozzle to one, while the other would have just a simple hole for an exhaust, upon firing, ...
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1answer
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Under-expanded nozzle at sea level - is it a problem?
I'm designing a solid rocket motor with a fixed pressure in the combustion chamber $p_{cc} = 70~bar$. When it comes to the choice of the right nozzle, I have to consider the proper expansion ratio, in ...
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Why does the Superdraco exhaust seem so under-expanded in this photo?
The Ars Technica articles
From zero to 100mph in 1.2 seconds, the SuperDraco thruster delivers
Dragon was destroyed just before the firing of its SuperDraco thrusters
both include this "file photo" ...
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What are these big shiny metallic "lumps" on the bottom edge of each Falcon Heavy nozzle?
What are these big shiny metallic "lumps" on the bottom edge of each nozzle of each core of this Falcon Heavy image from the Teslarati article SpaceX reveals Falcon Heavy Block 5 in first official ...
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1answer
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What is the white spray-pattern residue inside these Falcon Heavy nozzles?
What is the white residue in a spray pattern seen on the inside of each nozzle of each side core of this Falcon Heavy image from the Teslarati article SpaceX reveals Falcon Heavy Block 5 in first ...
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Issue with units for a rocket nozzle throat area problem
I'm working through How to Design, Build, and Test Small Liquid-Fuel Rocket Engines. The guide explains calculating a rocket nozzle throat area using Eq. (7):
$$A_t = \frac{w_t}{P_t} \sqrt{\frac{R ...
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550 views
Weight Flow Rate
I read in the book INTRODUCTION TO ROCKET SCIENCE AND ENGINEERING by T.S.T that Rocket Engineers design how big the throat of the nozzle should be based on the Weight Flow Rate.
So my question is HOW?
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Rao contour nozzle: Calculate throat and exit angle?
The Rao nozzle formula is an empiric formula for a parabolic nozzle used in pretty much all nozzles today.
The problem is it depends on the throat and exit-angle of the nozzle, which varies with ...
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1answer
291 views
How is the exit velocity of the flow in a sounding rocket nozzle?
How is the exit velocity of the flow in a sounding rocket nozzle?
Is it subsonic or supersonic?
Is a de Laval nozzle required for sounding rockets?
Bonus Question: What about Model Rockets?