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Experimental investigation of pre-evacuation effect on the high altitude test of a parabolic nozzle with second throat exhaust diffuser

Experimental investigation of pre-evacuation effect on the high altitude test of a parabolic nozzle with second throat exhaust diffuser pRJy0

The present study is carried out to investigate the influences of pre-evacuation of high altitude test facility on startup performance of second throat diffuser during the experimental test of a thrust optimized parabolic (TOP) nozzle. These types of nozzles are of great importance in space applications, including satellite launch vehicles. In this study, an experimental sub-scale set-up is used called high-altitude testing equipment with compressed air as working fluid. Due to the importance of the dimensionless parameter of the area ratio of the cross-section of the diffuser inlet to the cross-section of its second throat, the effect of changes in this parameter has been investigated on the start-up performance of the nozzle and diffuser. to evaluate the instantaneous performance, the pressure was instantly applied to the nozzle chamber in two accompanying modes with and without pre-evacuation of the system, In each of the fixed diffuser geometries. And vacuum chamber pressure and static pressure distribution are measured along the diffuser length. Results show that starting the diffuser with pre-evacuation takes 50 to 60 percent less time than without pre-evacuation. Furthermore, pre-evacuation of the test chamber can eliminate separation pattern transition pattern during start-up of the nozzle and diffuser. It has also been observed that minimum diffuser starting pressure increases as the second throat cross-section is decreased down to a certain value in which flow is choked.

The present study is carried
 out to investigate the influences of Possible spelling mistake found.reevaluation
pre-evacuation
 of high altitude This phrase/word (depending on the context) can be potentially replaced with :evaluate
test
 facility on startup performance of second throat diffuser during the experimental This phrase/word (depending on the context) can be potentially replaced with :evaluate
test
 of a thrust optimized parabolic (TOP) nozzle.

These types of You use this word too often, consider replacing it withfaucetspigot
nozzles
 are of great importance in space applications, including satellite launch vehicles.

In this study, an experimental sub-scale set-up is This phrase/word (depending on the context) can be potentially replaced with :exploited
used
 called high-altitude testing equipment with compressed air as working fluid.

Due to the importance of the dimensionless parameter of the area ratio of the cross-section of the diffuser inlet to the cross-section of its second throat, the effect of This phrase/word (depending on the context) can be potentially replaced with :altersadjusts
changes
 in this parameter has been investigated
 on the This phrase/word (depending on the context) can be potentially replaced with :initiate
start
-up performance of the You use this word too often, consider replacing it withfaucetspigot
nozzle
 and diffuser.

This sentence does not start with an uppercase letterTo
to
 evaluate the instantaneous performance, the You use this word too often, consider replacing it withtensionstressstrengthstrainburdensqueeze
pressure
 was instantly
 applied to the You use this word too often, consider replacing it withfaucetspigot
nozzle
 chamber in two accompanying modes with and without Possible spelling mistake found.reevaluation
pre-evacuation
 of the system, In each of the This phrase/word (depending on the context) can be potentially replaced with :rectified
fixed
 diffuser geometries.

And vacuum chamber You use this word too often, consider replacing it withtensionstressstrengthstrainburdensqueeze
pressure
 and static You use this word too often, consider replacing it withtensionstressstrengthstrainburdensqueeze
pressure
 distribution are measured
 along the diffuser length.

Results This phrase/word (depending on the context) can be potentially replaced with :demonstrateportrayindicatedisplay
show
 that starting the diffuser with Possible spelling mistake found.reevaluation
pre-evacuation
 takes 50 to 60 percent less time than without Possible spelling mistake found.reevaluation
pre-evacuation
.

Furthermore
, Possible spelling mistake found.reevaluation
pre-evacuation
 of the This phrase/word (depending on the context) can be potentially replaced with :evaluate
test
 chamber can eliminate separation pattern transition pattern during This phrase/word (depending on the context) can be potentially replaced with :initiate
start
-up of the You use this word too often, consider replacing it withfaucetspigot
nozzle
 and diffuser.

It has also
been observed
 that minimum diffuser starting You use this word too often, consider replacing it withtensionstressstrengthstrainburdensqueeze
pressure
 increases as the second throat cross-section is decreased
 down to a certain value in which flow is choked
. 