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Mixing of Cryogenic Fluids in Rocket Injectors
Investigators: Vivek Gautam, Ahmed Abdelhafez, Jakub Gmurczyk


The objective of this research is to work with NASA engineers and researchers to examine the mixing behavior of various cryogenic, non-cryogenic propellants and their simulants from a realistic rocket engine injector. Our goal is to provide detailed information on shear layer and other modes of mixing and its subsequent effect on ignition, stability and performance in a single element of the rocket injector under atmospheric pressure and simulated in-space conditions. The detailed database will be used for model validation and model development. The approach used is both experimental and theoretical.

Sample Images from High Speed Cameras

High speed image of unconfined LN2/GN2 flow with no recess

High speed image of unconfined 
2/GN2 flow with 0.2 inch recess
Shlieren movie of LN2/GN2 flow

High speed image of unconfined LN2/CO2 flow (MR = 12)

High speed image of unconfined 
2/He flow (MR = 40)

Distribution of centerline temperature for the IR 
thermal images

Sample Images from IR Thermal 

IR thermal image of unconfined LN2/GN2 flow with 
no recess

IR thermal image of unconfined LN2/GN2 flow with 
0.2 inch recess

Temperature distribution (C) for unconfined
2/CO2 flow with no recess (MR = 12)

Temperature distribution (C) for unconfined LN2/He 
flow with no recess (MR = 40)

Sample Schlieren Images

LN2/CO2 (MR = 5.6)

LN2/He (MR = 5.6)

LN2/He (Swirl Number = 5 , MR = 5.6)

Sample Results on Ignition Behavior of H
2/O2 and CH4/O2 Mixtures

PIV Results

Flowfield distribution with He (inner pipe) / O
(outer annulus) case

Flowfield distribution with He (inner pipe) / CO2
(outer annulus) case

Axial velocity distribution at a distance of Y = 0.16 D 
from the injector exit

Shear strain distribution at a distance of Y = 0.16 D
from the injector exit


Last Edited: May 13, 2006