JoshTheEngineer | Converging-Diverging Nozzle Pressure Delineations @JoshTheEngineer | Uploaded December 2017 | Updated October 2024, 7 hours ago.
In my converging-diverging (CD) nozzle video (link below), we saw that there were seven different flow conditions in a nozzle. If know what exit-to-reservoir pressure ratio our engine is operating at (see notes below), then we can define what condition our nozzle is operating at based on three pre-computed pressure ratios:
1) Choked Isentropic Subsonic
2) Normal Shock at Nozzle Exit
3) Choked Isentropic Supersonic
In this video, we will compute the pressure ratios needed to obtain the three states listed above for a given nozzle area ratio (Ae/At).
===== NOTES =====
→ In this video, we can say that At = A* for each case because the flow is choked, and we do have sonic flow at the throat.
→ We generally know the exit-to-reservoir pressure ratio that our engine is operating at. For instance, if we are analyzing the Space Shuttle Main Engine (RS-25) on the launchpad, then we know the exit pressure is approximately 101.325 kPa. We also know from the engine's specifications that the reservoir (or chamber) pressure is approximately 20.64 MPa. Dividing the two appropriately gives the pressure ratio we are looking for.
===== RELEVANT LINKS=====
→ Blog Post - Converging-Diverging Nozzle Pressure Delineations
joshtheengineer.com/2017/12/17/converging-diverging-nozzle-pressure-delineations
→ Solving the Area-Mach Number Relation
joshtheengineer.com/2016/11/16/solving-the-area-mach-number-relation
→ CD Nozzle MATLAB Code - GitHub
github.com/jte0419/Converging_Diverging_Nozzle
→ Compressible Flow Relations Code - GitHub
github.com/jte0419/Compressible_Flow_Relations
===== RELEVANT VIDEOS =====
→ Explained: Converging Diverging Nozzle
goo.gl/7MBSck
→ Area-Mach Number Relation [CPG]
goo.gl/t8QE9T
→ Normal Shock Relations
goo.gl/Bvv2jj
→ Stagnation Relations
goo.gl/yrT9D4
===== REFERENCES =====
► Modern Compressible Flow, Anderson
► Gas Dynamics, Volume 1, Zucrow and Hoffman
► Elements of Gasdynamics, Liepmann and Roshko
In my converging-diverging (CD) nozzle video (link below), we saw that there were seven different flow conditions in a nozzle. If know what exit-to-reservoir pressure ratio our engine is operating at (see notes below), then we can define what condition our nozzle is operating at based on three pre-computed pressure ratios:
1) Choked Isentropic Subsonic
2) Normal Shock at Nozzle Exit
3) Choked Isentropic Supersonic
In this video, we will compute the pressure ratios needed to obtain the three states listed above for a given nozzle area ratio (Ae/At).
===== NOTES =====
→ In this video, we can say that At = A* for each case because the flow is choked, and we do have sonic flow at the throat.
→ We generally know the exit-to-reservoir pressure ratio that our engine is operating at. For instance, if we are analyzing the Space Shuttle Main Engine (RS-25) on the launchpad, then we know the exit pressure is approximately 101.325 kPa. We also know from the engine's specifications that the reservoir (or chamber) pressure is approximately 20.64 MPa. Dividing the two appropriately gives the pressure ratio we are looking for.
===== RELEVANT LINKS=====
→ Blog Post - Converging-Diverging Nozzle Pressure Delineations
joshtheengineer.com/2017/12/17/converging-diverging-nozzle-pressure-delineations
→ Solving the Area-Mach Number Relation
joshtheengineer.com/2016/11/16/solving-the-area-mach-number-relation
→ CD Nozzle MATLAB Code - GitHub
github.com/jte0419/Converging_Diverging_Nozzle
→ Compressible Flow Relations Code - GitHub
github.com/jte0419/Compressible_Flow_Relations
===== RELEVANT VIDEOS =====
→ Explained: Converging Diverging Nozzle
goo.gl/7MBSck
→ Area-Mach Number Relation [CPG]
goo.gl/t8QE9T
→ Normal Shock Relations
goo.gl/Bvv2jj
→ Stagnation Relations
goo.gl/yrT9D4
===== REFERENCES =====
► Modern Compressible Flow, Anderson
► Gas Dynamics, Volume 1, Zucrow and Hoffman
► Elements of Gasdynamics, Liepmann and Roshko
![Explained: Area-Mach Number Relation [CPG]](https://i.ytimg.com/vi/bdcxN0u5hMs/hqdefault.jpg "Explained: Area-Mach Number Relation [CPG]
Can we approximate the exit Mach number of a rocket nozzle knowing only the area ratio? With a few assumptions, we certainly can! In fact, if we know how the area changes along a nozzle from the throat to the exit, we can calculate how the Mach number varies throughout the entire nozzle.
NOTES
► Ill make sure to never use my orange marker again
► If you download my Method of Characteristics MATLAB code from my GitHub (link below), you can see that the results of both match very closely!
HOW TO SOLVE AREA-MACH NUMBER RELATION
http://www.joshtheengineer.com/2016/11/16/solving-the-area-mach-number-relation/
ROCKET NOZZLE - METHOD OF CHARACTERISTICS
https://github.com/jte0419/Rocket_Nozzle_Design
RELEVANT VIDEOS
Area-Mach Number Differential Form
https://goo.gl/tDzBtM
Sonic State
https://goo.gl/j6yCxD
Stagnation-to-Static Relations
https://goo.gl/r5JZSQ
Normal Shock Relations
https://goo.gl/E5Lwac
REFERENCES
► Notes by Matt MacLean
► Modern Compressible Flow, Anderson
► Elements of Gasdynamics, Liepmann and Roshko
► Gas Dynamics, Zucrow and Hoffman
THUMBNAIL IMAGE
By NASA (http://mix.msfc.nasa.gov/abstracts.php?p=2388) [Public domain], via Wikimedia Commons")
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Explained: Pitch Stiffness [Flight Dynamics]")
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Static text fields can be used to indicate the status of your program, or simply to write text or numbers. This video describes how to set the static text field in a MATLAB GUI.")
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