Linked Questions

0
votes
2answers
492 views

Why are exhaust nozzles in space shaped the way they are? [duplicate]

Why are nozzles in space shaped like a cone and not like a tube ensuring all the exhaust is directed strait?
1
vote
0answers
60 views

Why are rocket engines shaped like a bell rather than a gun barrel? [duplicate]

When blasting matter out of a spacecraft engine for thrust, it seems like you'd want as much velocity in one direction as possible. Why do spacecraft engines (e.g., Apollo CSM) have big bell-shaped ...
20
votes
3answers
21k views

What are the differences between a standard Merlin engine and the Merlin Vacuum engine?

I know that there's a difference between SpaceX's Falcon 9 1st stage engines and the 2nd stage engine, since that stage is specifically tuned for vacuum. Wikipedia also says that the Merlin Vacuum ...
19
votes
2answers
2k views

Where does the thrust act in a rocket engine and how is it transferred to rocket structure?

A rocket engine is basically a device that generates a high pressure inside the chamber and the pressure difference creates a force. A nozzle helps in effectively accelerating the flow and increases ...
4
votes
1answer
2k views

What is the 'Summerfield criterion' regarding rocket exhaust expansion

In this answer to Why do the shapes of these two exhaust plumes from an Atlas V 411 look different? the 'Summerfield criterion' is mentioned, saying: Historically, the Summerfield criterion was used, ...
13
votes
1answer
981 views

Why does the YF-75D nozzle have such a strong spiral pattern?

Why does the YF-75D nozzle material have such a strong spiral pattern? Is it a result/biproduct of a manufacturing process only, or does it have some specific function? edit: The last, cropped ...
-12
votes
4answers
714 views

What pushes back on rockets? [closed]

Discussion: I have removed the parts of the question regarding landing and the conic nozzle. Adding in those issues makes the question too broad. No, it makes the question meaningful. It's an ...
5
votes
1answer
2k views

How is chamber pressure and temperature determined for cold gas thrusters?

I'm trying to get some theoretical performance numbers for a cold gas thruster using quasi-one-dimensional flow, and I don't know where to start. For combustion engines you would just take a given ...
1
vote
1answer
291 views

new nozzle design, is it a fail?

So I'm an amature rocket scientist. while having a conversation with a friend on a nozzles we though of a new nozzle: Its a double nozzle where it expands a lot and then compress. I want to put this ...
6
votes
2answers
246 views

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 ...
1
vote
1answer
200 views

Why does the pressure & temperature ratio in a diverging nozzle continue decreasing once it hits supersonic flow?

From Sutton chapter 3 he uses this figure to describe the ratios of pressure//area//temperature as functions of Mach Number. I know that we are bringing the fluid to an adiabatic "stop" through ...
4
votes
1answer
59 views

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 ...
0
votes
1answer
127 views

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 ...