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.
Questions tagged [nozzle]
118 questions
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Convergent-Divergent / De Laval Nozzle Dimensions
I'm creating a super sonic ping pong ball cannon like the one recently shown on Mythbusters. I plan on using pressure rated steel pipe so it's as safe as realistically possible and showing it off at science and technology exhibits for kids. I think…
Michael
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What happens if the mass flow rate is increased continuously in a converging nozzle?
I recently studied about nozzles where I came to know that the maximum velocity one could attain using a converging nozzle is the sonic velocity at the exit of the converging nozzle. An further decrease in the exit area would only decrease the mass…
Prasanna B
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Are there rocket nozzles that use non-elliptical shapes?
I was reading this question: Why the non-symmetric design of rocket nozzles?
Which got me thinking, have there been any nozzles that don't end in an ellipse? Even the one in that question ends in a conic section, which is an ellipse. Perhaps maybe a…
Magic Octopus Urn
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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) thrust if I decrease the nozzle exit area?
So I…
Lucas
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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 optimised for maximum specific impulse over the…
Paul Price
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Difference between Optimum Expansion Ratio and Maximum Thrust
when I look at the equation for thrust of a rocket:
$$
F=\dot{m}*v_{exit}+(p_{exit}-p_{amb})*A_{exit}
$$
In the book "Rocket Propulsion" from Sutton it says on page 33:
In the vacuum of space $p_{exit}=0$ and the pressure thrust becomes a…
Lucas
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How complex is the science of a fixed nozzle shape?
Obviously in the simplest variant it's not complex at all. I've seen amateur rocket engine nozzles shaped through applying a nail to packed clay layer.
How complex is the science behind the shape of fixed nozzles used professionally - in…
SF.
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Calculate Thrust of Rocket Nozzle - Off Design
I have designed a nozzle for the following input parameters
$p_{combustion}=p_c=200*10e5 Pa$
$T_{combustion}=T_c=2800 K$
$F=70 kN$
$\kappa=1,2$
$R = 330 J/kgK$
I assume that all my gas properties stay constant for this calculation.
The nozzle…
Kevin
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How to avoid big nozzle lengths in high altitude?
I am currently designing a serial staged rocket with 3 stages. The first stage brings me up to 10 km. When I do my calculations for the required expansion ratio and nozzle length (Rao Nozzle) for the second nozzle I get a length of nearly 350 mm.…
Lucas
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Choked Flow: Throat Radius should not change any more below critical pressure ratio?
I am trying to understand some calculations of a student colleague:
The pressure inside the combustion chamber is 200 bar. This means, the critical pressure ratio should be p*/p0 with p0=101325 Pascal and k=1.18 -- >
p*/(200*10^5 Pa) =…
Lucas
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