Do liquid propellant rocket engines experience thrust oscillation?Limiting factors of liquid rocket engine thrustProblems with the “How to Design, Build and Test Small Liquid-Fuel Rocket Engines” textHow do they know how much liquid propellant is in a rocket just before launch?Liquid propellant stored as solidCould a “nuclear turbo-jet” be built?
Why 401k contribution as % of salary vs. fixed amount per pay check?
Why are the norm symbols || not aligned in this situation?
Can I call the airport to see if my boyfriend made it through customs?
What are the maximum hit points of an NPC?
How does "unlimited holidays" work in practice?
60's or earlier fantasy about two children pranksters who turn out to be persian deities
Collision detection when falling: two identical cases?
How does Wall of Roots interact with +1/+1 counters?
How do you technically represent a procedurally-generated map in the scene?
Employer wants me to do something explicitly illegal
Is there any theory why (for Bitcoin) the discrete logarithm problem is so hard to solve?
Is it possible to safely mine bitcoin at 13.5 TH/s with hardware with 10.5 TH/s?
Lewis Structure of OF+
Universal example of Lie algebra
Do Klingons have escape pods?
What is this nut?
Exactly what color was the text on monochrome terminals with green-on-black and amber-on-black screens?
How do you call a note, that stays through the whole song?
Are trigonometry functions Ratios or Distance?
What happens if a crew comply but do not repeat ATC instructions?
Convention for inverted signal
Is it good to take a fianchettoed Bishop?
I peer reviewed a paper and found it to be sound - technically and language-wise. How should I write the review report?
Tiling on Drywall in Shower
Do liquid propellant rocket engines experience thrust oscillation?
Limiting factors of liquid rocket engine thrustProblems with the “How to Design, Build and Test Small Liquid-Fuel Rocket Engines” textHow do they know how much liquid propellant is in a rocket just before launch?Liquid propellant stored as solidCould a “nuclear turbo-jet” be built?
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty
margin-bottom:0;
.everyonelovesstackoverflowposition:absolute;height:1px;width:1px;opacity:0;top:0;left:0;pointer-events:none;
$begingroup$
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 magnitude? If so what is the main cause of this constant small variation in thrust level? Is it because of the combustion process inside the bell? In Falcon 9 launches you often see photos like this 
The streak patterns of the exhaust plume indicate there is at least some non-uniformity of the pressure and temperature field inside. I assume every liquid engine actually behaves like this, but it's only apparent on LOX/RP-1 engine because of soot acting like temperature indicator through the intensity of the glow for the pattern.
rockets liquid-fuel exhaust
edited Sep 18 at 12:13
Machavity
3,9051 gold badge11 silver badges42 bronze badges
asked Sep 17 at 20:40
Meatball PrincessMeatball Princess
1,1681 silver badge13 bronze badges
$endgroup$
add a comment
|
$begingroup$
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 magnitude? If so what is the main cause of this constant small variation in thrust level? Is it because of the combustion process inside the bell? In Falcon 9 launches you often see photos like this
The streak patterns of the exhaust plume indicate there is at least some non-uniformity of the pressure and temperature field inside. I assume every liquid engine actually behaves like this, but it's only apparent on LOX/RP-1 engine because of soot acting like temperature indicator through the intensity of the glow for the pattern.
rockets liquid-fuel exhaust
edited Sep 18 at 12:13
Machavity
3,9051 gold badge11 silver badges42 bronze badges
asked Sep 17 at 20:40
Meatball PrincessMeatball Princess
1,1681 silver badge13 bronze badges
$endgroup$
2
$begingroup$
I think the vertical streaking is closely related to the physical arrangement of the fuel/oxidizer injectors and resulting flow patterns, but I'm not sure why I think that.
$endgroup$
– Russell Borogove
Sep 17 at 22:15
2
$begingroup$
Agreed, and if it was perfectly mixed, you likely wouldn't see the streaking.
$endgroup$
– Organic Marble
Sep 18 at 0:01
$begingroup$
If I find out that KSP streak patterns have changed in KSP2, I'm coming back to this question...
$endgroup$
– Erin B
Sep 19 at 13:18
add a comment
|
$begingroup$
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 magnitude? If so what is the main cause of this constant small variation in thrust level? Is it because of the combustion process inside the bell? In Falcon 9 launches you often see photos like this
The streak patterns of the exhaust plume indicate there is at least some non-uniformity of the pressure and temperature field inside. I assume every liquid engine actually behaves like this, but it's only apparent on LOX/RP-1 engine because of soot acting like temperature indicator through the intensity of the glow for the pattern.
rockets liquid-fuel exhaust
edited Sep 18 at 12:13
Machavity
3,9051 gold badge11 silver badges42 bronze badges
asked Sep 17 at 20:40
Meatball PrincessMeatball Princess
1,1681 silver badge13 bronze badges
$endgroup$
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 magnitude? If so what is the main cause of this constant small variation in thrust level? Is it because of the combustion process inside the bell? In Falcon 9 launches you often see photos like this
The streak patterns of the exhaust plume indicate there is at least some non-uniformity of the pressure and temperature field inside. I assume every liquid engine actually behaves like this, but it's only apparent on LOX/RP-1 engine because of soot acting like temperature indicator through the intensity of the glow for the pattern.
rockets liquid-fuel exhaust
rockets liquid-fuel exhaust
edited Sep 18 at 12:13
Machavity
3,9051 gold badge11 silver badges42 bronze badges
asked Sep 17 at 20:40
Meatball PrincessMeatball Princess
1,1681 silver badge13 bronze badges
edited Sep 18 at 12:13
Machavity
3,9051 gold badge11 silver badges42 bronze badges
asked Sep 17 at 20:40
Meatball PrincessMeatball Princess
1,1681 silver badge13 bronze badges
edited Sep 18 at 12:13
Machavity
3,9051 gold badge11 silver badges42 bronze badges
edited Sep 18 at 12:13
Machavity
3,9051 gold badge11 silver badges42 bronze badges
edited Sep 18 at 12:13
Machavity
3,9051 gold badge11 silver badges42 bronze badges
3,9051 gold badge11 silver badges42 bronze badges
asked Sep 17 at 20:40
Meatball PrincessMeatball Princess
1,1681 silver badge13 bronze badges
asked Sep 17 at 20:40
Meatball PrincessMeatball Princess
1,1681 silver badge13 bronze badges
asked Sep 17 at 20:40
Meatball PrincessMeatball Princess
1,1681 silver badge13 bronze badges
1,1681 silver badge13 bronze badges
2
$begingroup$
I think the vertical streaking is closely related to the physical arrangement of the fuel/oxidizer injectors and resulting flow patterns, but I'm not sure why I think that.
$endgroup$
– Russell Borogove
Sep 17 at 22:15
2
$begingroup$
Agreed, and if it was perfectly mixed, you likely wouldn't see the streaking.
$endgroup$
– Organic Marble
Sep 18 at 0:01
$begingroup$
If I find out that KSP streak patterns have changed in KSP2, I'm coming back to this question...
$endgroup$
– Erin B
Sep 19 at 13:18
add a comment
|
2
$begingroup$
I think the vertical streaking is closely related to the physical arrangement of the fuel/oxidizer injectors and resulting flow patterns, but I'm not sure why I think that.
$endgroup$
– Russell Borogove
Sep 17 at 22:15
2
$begingroup$
Agreed, and if it was perfectly mixed, you likely wouldn't see the streaking.
$endgroup$
– Organic Marble
Sep 18 at 0:01
$begingroup$
If I find out that KSP streak patterns have changed in KSP2, I'm coming back to this question...
$endgroup$
– Erin B
Sep 19 at 13:18
2
2
$begingroup$
I think the vertical streaking is closely related to the physical arrangement of the fuel/oxidizer injectors and resulting flow patterns, but I'm not sure why I think that.
$endgroup$
– Russell Borogove
Sep 17 at 22:15
$begingroup$
I think the vertical streaking is closely related to the physical arrangement of the fuel/oxidizer injectors and resulting flow patterns, but I'm not sure why I think that.
$endgroup$
– Russell Borogove
Sep 17 at 22:15
2
2
$begingroup$
Agreed, and if it was perfectly mixed, you likely wouldn't see the streaking.
$endgroup$
– Organic Marble
Sep 18 at 0:01
$begingroup$
Agreed, and if it was perfectly mixed, you likely wouldn't see the streaking.
$endgroup$
– Organic Marble
Sep 18 at 0:01
$begingroup$
If I find out that KSP streak patterns have changed in KSP2, I'm coming back to this question...
$endgroup$
– Erin B
Sep 19 at 13:18
$begingroup$
If I find out that KSP streak patterns have changed in KSP2, I'm coming back to this question...
$endgroup$
– Erin B
Sep 19 at 13:18
add a comment
|
2 Answers
2
active
oldest
votes
$begingroup$
Yes, in liquid engines this phenomenon is called "rough combustion".
Sutton (4th edition) says
Combustion that gives pressure fluctuations greater than about +/- 5%
of the mean pressure at a chamber wall location and which occur at
completely random intervals is called rough combustion.
It's different from "combustion instability" defined as activity which
displays organized oscillations ocurring at well-defined intervals
with a pressure peak that may be maintained, may increase, or may die
out.
pp. 257 - 259
The streak patterns you mention are more likely due to non-uniform mixing resulting in slight variations in local mixture ratio, than due to rough combustion, IMHO.
answered Sep 17 at 21:16
Organic MarbleOrganic Marble
88.6k4 gold badges272 silver badges378 bronze badges
$endgroup$
$begingroup$
F1s had problems with non-uniform mixing (combustion instability) behind the single injector plate, so not technically in the bell. Source: Apollo's Daring Mission (~14 min. in). Solved by adding baffles before the plate so that it was more like the individual nozzles found on V2s.
$endgroup$
– Mazura
Sep 19 at 4:45
add a comment
|
$begingroup$
In addition to the "rough combustion" that Organic Marble mentions, liquid engines also characteristically suffer from pogo oscillation. This is the phenomenon in which the thrust causes acceleration of the rocket, which changes the flow of propellant in the lines fuel and oxidizer lines, which then causes a change in the thrust, which is now a loop.
Pogo oscillation was a major problem in the development of the Saturn rockets, and I believe the Jupiters before them.
edited Sep 18 at 17:39
Russell Borogove
110k6 gold badges383 silver badges465 bronze badges
answered Sep 18 at 14:39
dotancohendotancohen
5,2272 gold badges16 silver badges44 bronze badges
$endgroup$
3
$begingroup$
I see figures of up to 34g oscillation at 16Hz (zero-to-peak, at the engine's mount point). This would make for a VERY uncomfortable ride.
$endgroup$
– jeffB
Sep 18 at 17:13
1
$begingroup$
The Titan (ICBM) boosters used in the Gemini program had some serious (i.e., destructive) pogo oscillations in their initial flight tests. Fortunately the were largely resolved before the rockets were carrying human passengers.
$endgroup$
– FKEinternet
Sep 18 at 21:57
$begingroup$
What methods can be used to prevent it?
$endgroup$
– DrMcCleod
Sep 19 at 11:17
$begingroup$
@DrMcCleod: I know that the Saturns were fixed by making the thrust plate more rigid. I'm not sure about general solutions to the problem, though. There are some rocket scientists who frequent this site, I hope they chime in.
$endgroup$
– dotancohen
Sep 19 at 13:15
1
$begingroup$
Space Shuttle Main Engine had a "pogo accumulator" built in, a pressurized volume connected to the LOX feedline which helped to damp out oscillations.
$endgroup$
– Organic Marble
Sep 29 at 23:04
add a comment
|
Your Answer
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "508"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/4.0/"u003ecc by-sa 4.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fspace.stackexchange.com%2fquestions%2f38867%2fdo-liquid-propellant-rocket-engines-experience-thrust-oscillation%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Yes, in liquid engines this phenomenon is called "rough combustion".
Sutton (4th edition) says
Combustion that gives pressure fluctuations greater than about +/- 5%
of the mean pressure at a chamber wall location and which occur at
completely random intervals is called rough combustion.
It's different from "combustion instability" defined as activity which
displays organized oscillations ocurring at well-defined intervals
with a pressure peak that may be maintained, may increase, or may die
out.
pp. 257 - 259
The streak patterns you mention are more likely due to non-uniform mixing resulting in slight variations in local mixture ratio, than due to rough combustion, IMHO.
answered Sep 17 at 21:16
Organic MarbleOrganic Marble
88.6k4 gold badges272 silver badges378 bronze badges
$endgroup$
$begingroup$
F1s had problems with non-uniform mixing (combustion instability) behind the single injector plate, so not technically in the bell. Source: Apollo's Daring Mission (~14 min. in). Solved by adding baffles before the plate so that it was more like the individual nozzles found on V2s.
$endgroup$
– Mazura
Sep 19 at 4:45
add a comment
|
$begingroup$
Yes, in liquid engines this phenomenon is called "rough combustion".
Sutton (4th edition) says
Combustion that gives pressure fluctuations greater than about +/- 5%
of the mean pressure at a chamber wall location and which occur at
completely random intervals is called rough combustion.
It's different from "combustion instability" defined as activity which
displays organized oscillations ocurring at well-defined intervals
with a pressure peak that may be maintained, may increase, or may die
out.
pp. 257 - 259
The streak patterns you mention are more likely due to non-uniform mixing resulting in slight variations in local mixture ratio, than due to rough combustion, IMHO.
answered Sep 17 at 21:16
Organic MarbleOrganic Marble
88.6k4 gold badges272 silver badges378 bronze badges
$endgroup$
$begingroup$
F1s had problems with non-uniform mixing (combustion instability) behind the single injector plate, so not technically in the bell. Source: Apollo's Daring Mission (~14 min. in). Solved by adding baffles before the plate so that it was more like the individual nozzles found on V2s.
$endgroup$
– Mazura
Sep 19 at 4:45
add a comment
|
$begingroup$
Yes, in liquid engines this phenomenon is called "rough combustion".
Sutton (4th edition) says
Combustion that gives pressure fluctuations greater than about +/- 5%
of the mean pressure at a chamber wall location and which occur at
completely random intervals is called rough combustion.
It's different from "combustion instability" defined as activity which
displays organized oscillations ocurring at well-defined intervals
with a pressure peak that may be maintained, may increase, or may die
out.
pp. 257 - 259
The streak patterns you mention are more likely due to non-uniform mixing resulting in slight variations in local mixture ratio, than due to rough combustion, IMHO.
answered Sep 17 at 21:16
Organic MarbleOrganic Marble
88.6k4 gold badges272 silver badges378 bronze badges
$endgroup$
Yes, in liquid engines this phenomenon is called "rough combustion".
Sutton (4th edition) says
Combustion that gives pressure fluctuations greater than about +/- 5%
of the mean pressure at a chamber wall location and which occur at
completely random intervals is called rough combustion.
It's different from "combustion instability" defined as activity which
displays organized oscillations ocurring at well-defined intervals
with a pressure peak that may be maintained, may increase, or may die
out.
pp. 257 - 259
The streak patterns you mention are more likely due to non-uniform mixing resulting in slight variations in local mixture ratio, than due to rough combustion, IMHO.
answered Sep 17 at 21:16
Organic MarbleOrganic Marble
88.6k4 gold badges272 silver badges378 bronze badges
edited Sep 17 at 21:21
answered Sep 17 at 21:16
Organic MarbleOrganic Marble
88.6k4 gold badges272 silver badges378 bronze badges
answered Sep 17 at 21:16
Organic MarbleOrganic Marble
88.6k4 gold badges272 silver badges378 bronze badges
answered Sep 17 at 21:16
Organic MarbleOrganic Marble
88.6k4 gold badges272 silver badges378 bronze badges
88.6k4 gold badges272 silver badges378 bronze badges
$begingroup$
F1s had problems with non-uniform mixing (combustion instability) behind the single injector plate, so not technically in the bell. Source: Apollo's Daring Mission (~14 min. in). Solved by adding baffles before the plate so that it was more like the individual nozzles found on V2s.
$endgroup$
– Mazura
Sep 19 at 4:45
add a comment
|
$begingroup$
F1s had problems with non-uniform mixing (combustion instability) behind the single injector plate, so not technically in the bell. Source: Apollo's Daring Mission (~14 min. in). Solved by adding baffles before the plate so that it was more like the individual nozzles found on V2s.
$endgroup$
– Mazura
Sep 19 at 4:45
$begingroup$
F1s had problems with non-uniform mixing (combustion instability) behind the single injector plate, so not technically in the bell. Source: Apollo's Daring Mission (~14 min. in). Solved by adding baffles before the plate so that it was more like the individual nozzles found on V2s.
$endgroup$
– Mazura
Sep 19 at 4:45
$begingroup$
F1s had problems with non-uniform mixing (combustion instability) behind the single injector plate, so not technically in the bell. Source: Apollo's Daring Mission (~14 min. in). Solved by adding baffles before the plate so that it was more like the individual nozzles found on V2s.
$endgroup$
– Mazura
Sep 19 at 4:45
add a comment
|
$begingroup$
In addition to the "rough combustion" that Organic Marble mentions, liquid engines also characteristically suffer from pogo oscillation. This is the phenomenon in which the thrust causes acceleration of the rocket, which changes the flow of propellant in the lines fuel and oxidizer lines, which then causes a change in the thrust, which is now a loop.
Pogo oscillation was a major problem in the development of the Saturn rockets, and I believe the Jupiters before them.
edited Sep 18 at 17:39
Russell Borogove
110k6 gold badges383 silver badges465 bronze badges
answered Sep 18 at 14:39
dotancohendotancohen
5,2272 gold badges16 silver badges44 bronze badges
$endgroup$
3
$begingroup$
I see figures of up to 34g oscillation at 16Hz (zero-to-peak, at the engine's mount point). This would make for a VERY uncomfortable ride.
$endgroup$
– jeffB
Sep 18 at 17:13
1
$begingroup$
The Titan (ICBM) boosters used in the Gemini program had some serious (i.e., destructive) pogo oscillations in their initial flight tests. Fortunately the were largely resolved before the rockets were carrying human passengers.
$endgroup$
– FKEinternet
Sep 18 at 21:57
$begingroup$
What methods can be used to prevent it?
$endgroup$
– DrMcCleod
Sep 19 at 11:17
$begingroup$
@DrMcCleod: I know that the Saturns were fixed by making the thrust plate more rigid. I'm not sure about general solutions to the problem, though. There are some rocket scientists who frequent this site, I hope they chime in.
$endgroup$
– dotancohen
Sep 19 at 13:15
1
$begingroup$
Space Shuttle Main Engine had a "pogo accumulator" built in, a pressurized volume connected to the LOX feedline which helped to damp out oscillations.
$endgroup$
– Organic Marble
Sep 29 at 23:04
add a comment
|
$begingroup$
In addition to the "rough combustion" that Organic Marble mentions, liquid engines also characteristically suffer from pogo oscillation. This is the phenomenon in which the thrust causes acceleration of the rocket, which changes the flow of propellant in the lines fuel and oxidizer lines, which then causes a change in the thrust, which is now a loop.
Pogo oscillation was a major problem in the development of the Saturn rockets, and I believe the Jupiters before them.
edited Sep 18 at 17:39
Russell Borogove
110k6 gold badges383 silver badges465 bronze badges
answered Sep 18 at 14:39
dotancohendotancohen
5,2272 gold badges16 silver badges44 bronze badges
$endgroup$
3
$begingroup$
I see figures of up to 34g oscillation at 16Hz (zero-to-peak, at the engine's mount point). This would make for a VERY uncomfortable ride.
$endgroup$
– jeffB
Sep 18 at 17:13
1
$begingroup$
The Titan (ICBM) boosters used in the Gemini program had some serious (i.e., destructive) pogo oscillations in their initial flight tests. Fortunately the were largely resolved before the rockets were carrying human passengers.
$endgroup$
– FKEinternet
Sep 18 at 21:57
$begingroup$
What methods can be used to prevent it?
$endgroup$
– DrMcCleod
Sep 19 at 11:17
$begingroup$
@DrMcCleod: I know that the Saturns were fixed by making the thrust plate more rigid. I'm not sure about general solutions to the problem, though. There are some rocket scientists who frequent this site, I hope they chime in.
$endgroup$
– dotancohen
Sep 19 at 13:15
1
$begingroup$
Space Shuttle Main Engine had a "pogo accumulator" built in, a pressurized volume connected to the LOX feedline which helped to damp out oscillations.
$endgroup$
– Organic Marble
Sep 29 at 23:04
add a comment
|
$begingroup$
In addition to the "rough combustion" that Organic Marble mentions, liquid engines also characteristically suffer from pogo oscillation. This is the phenomenon in which the thrust causes acceleration of the rocket, which changes the flow of propellant in the lines fuel and oxidizer lines, which then causes a change in the thrust, which is now a loop.
Pogo oscillation was a major problem in the development of the Saturn rockets, and I believe the Jupiters before them.
edited Sep 18 at 17:39
Russell Borogove
110k6 gold badges383 silver badges465 bronze badges
answered Sep 18 at 14:39
dotancohendotancohen
5,2272 gold badges16 silver badges44 bronze badges
$endgroup$
In addition to the "rough combustion" that Organic Marble mentions, liquid engines also characteristically suffer from pogo oscillation. This is the phenomenon in which the thrust causes acceleration of the rocket, which changes the flow of propellant in the lines fuel and oxidizer lines, which then causes a change in the thrust, which is now a loop.
Pogo oscillation was a major problem in the development of the Saturn rockets, and I believe the Jupiters before them.
edited Sep 18 at 17:39
Russell Borogove
110k6 gold badges383 silver badges465 bronze badges
answered Sep 18 at 14:39
dotancohendotancohen
5,2272 gold badges16 silver badges44 bronze badges
edited Sep 18 at 17:39
Russell Borogove
110k6 gold badges383 silver badges465 bronze badges
edited Sep 18 at 17:39
Russell Borogove
110k6 gold badges383 silver badges465 bronze badges
edited Sep 18 at 17:39
Russell Borogove
110k6 gold badges383 silver badges465 bronze badges
110k6 gold badges383 silver badges465 bronze badges
answered Sep 18 at 14:39
dotancohendotancohen
5,2272 gold badges16 silver badges44 bronze badges
answered Sep 18 at 14:39
dotancohendotancohen
5,2272 gold badges16 silver badges44 bronze badges
answered Sep 18 at 14:39
dotancohendotancohen
5,2272 gold badges16 silver badges44 bronze badges
5,2272 gold badges16 silver badges44 bronze badges
3
$begingroup$
I see figures of up to 34g oscillation at 16Hz (zero-to-peak, at the engine's mount point). This would make for a VERY uncomfortable ride.
$endgroup$
– jeffB
Sep 18 at 17:13
1
$begingroup$
The Titan (ICBM) boosters used in the Gemini program had some serious (i.e., destructive) pogo oscillations in their initial flight tests. Fortunately the were largely resolved before the rockets were carrying human passengers.
$endgroup$
– FKEinternet
Sep 18 at 21:57
$begingroup$
What methods can be used to prevent it?
$endgroup$
– DrMcCleod
Sep 19 at 11:17
$begingroup$
@DrMcCleod: I know that the Saturns were fixed by making the thrust plate more rigid. I'm not sure about general solutions to the problem, though. There are some rocket scientists who frequent this site, I hope they chime in.
$endgroup$
– dotancohen
Sep 19 at 13:15
1
$begingroup$
Space Shuttle Main Engine had a "pogo accumulator" built in, a pressurized volume connected to the LOX feedline which helped to damp out oscillations.
$endgroup$
– Organic Marble
Sep 29 at 23:04
add a comment
|
3
$begingroup$
I see figures of up to 34g oscillation at 16Hz (zero-to-peak, at the engine's mount point). This would make for a VERY uncomfortable ride.
$endgroup$
– jeffB
Sep 18 at 17:13
1
$begingroup$
The Titan (ICBM) boosters used in the Gemini program had some serious (i.e., destructive) pogo oscillations in their initial flight tests. Fortunately the were largely resolved before the rockets were carrying human passengers.
$endgroup$
– FKEinternet
Sep 18 at 21:57
$begingroup$
What methods can be used to prevent it?
$endgroup$
– DrMcCleod
Sep 19 at 11:17
$begingroup$
@DrMcCleod: I know that the Saturns were fixed by making the thrust plate more rigid. I'm not sure about general solutions to the problem, though. There are some rocket scientists who frequent this site, I hope they chime in.
$endgroup$
– dotancohen
Sep 19 at 13:15
1
$begingroup$
Space Shuttle Main Engine had a "pogo accumulator" built in, a pressurized volume connected to the LOX feedline which helped to damp out oscillations.
$endgroup$
– Organic Marble
Sep 29 at 23:04
3
3
$begingroup$
I see figures of up to 34g oscillation at 16Hz (zero-to-peak, at the engine's mount point). This would make for a VERY uncomfortable ride.
$endgroup$
– jeffB
Sep 18 at 17:13
$begingroup$
I see figures of up to 34g oscillation at 16Hz (zero-to-peak, at the engine's mount point). This would make for a VERY uncomfortable ride.
$endgroup$
– jeffB
Sep 18 at 17:13
1
1
$begingroup$
The Titan (ICBM) boosters used in the Gemini program had some serious (i.e., destructive) pogo oscillations in their initial flight tests. Fortunately the were largely resolved before the rockets were carrying human passengers.
$endgroup$
– FKEinternet
Sep 18 at 21:57
$begingroup$
The Titan (ICBM) boosters used in the Gemini program had some serious (i.e., destructive) pogo oscillations in their initial flight tests. Fortunately the were largely resolved before the rockets were carrying human passengers.
$endgroup$
– FKEinternet
Sep 18 at 21:57
$begingroup$
What methods can be used to prevent it?
$endgroup$
– DrMcCleod
Sep 19 at 11:17
$begingroup$
What methods can be used to prevent it?
$endgroup$
– DrMcCleod
Sep 19 at 11:17
$begingroup$
@DrMcCleod: I know that the Saturns were fixed by making the thrust plate more rigid. I'm not sure about general solutions to the problem, though. There are some rocket scientists who frequent this site, I hope they chime in.
$endgroup$
– dotancohen
Sep 19 at 13:15
$begingroup$
@DrMcCleod: I know that the Saturns were fixed by making the thrust plate more rigid. I'm not sure about general solutions to the problem, though. There are some rocket scientists who frequent this site, I hope they chime in.
$endgroup$
– dotancohen
Sep 19 at 13:15
1
1
$begingroup$
Space Shuttle Main Engine had a "pogo accumulator" built in, a pressurized volume connected to the LOX feedline which helped to damp out oscillations.
$endgroup$
– Organic Marble
Sep 29 at 23:04
$begingroup$
Space Shuttle Main Engine had a "pogo accumulator" built in, a pressurized volume connected to the LOX feedline which helped to damp out oscillations.
$endgroup$
– Organic Marble
Sep 29 at 23:04
add a comment
|
Thanks for contributing an answer to Space Exploration Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fspace.stackexchange.com%2fquestions%2f38867%2fdo-liquid-propellant-rocket-engines-experience-thrust-oscillation%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
2
$begingroup$
I think the vertical streaking is closely related to the physical arrangement of the fuel/oxidizer injectors and resulting flow patterns, but I'm not sure why I think that.
$endgroup$
– Russell Borogove
Sep 17 at 22:15
2
$begingroup$
Agreed, and if it was perfectly mixed, you likely wouldn't see the streaking.
$endgroup$
– Organic Marble
Sep 18 at 0:01
$begingroup$
If I find out that KSP streak patterns have changed in KSP2, I'm coming back to this question...
$endgroup$
– Erin B
Sep 19 at 13:18