Facility Effects on Performance Measurements of Micropropulsion Systems that Utilize Gas Expansion

Ketsdever, Andrew D.

doi:10.2514/2.6002

Cited by 15 publications

(8 citation statements)

References 8 publications

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“…The background gas may impact the mass flow measurements only for stagnation pressures larger than 1500 Pa, although the force ͑momentum flux͒ measurements are affected to some extent at all plenum pressures. A previous study 23 indicated that the force can be affected by less than 0.5% at the experimental conditions of this work. The previous study is supplemented here with the numerical modeling in order to quantify the facility effect on force measurements.…”

Section: Experimental and Numerical Uncertaintiesmentioning

confidence: 99%

“…This average velocity may generally either decrease or increase the total force on the plenum. Second, and more important, the plume molecules move background molecules away from the tube ͑front͒ side of the plenum, 23 which in turn reduces the background gas pressure on the front side compared to the back side, and acts toward decreasing the total measured momentum flux. This effect is, in fact, even more complex, since there may be also a significant flux of plume molecules coming on the front side.…”

Section: Numerical and Experimental Datamentioning

confidence: 99%

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Measurements and computations of mass flow and momentum flux through short tubes in rarefied gases

et al. 2006

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)Air Force Research Laboratory (AFMC) AFRL/PRS SPONSOR/MONITOR'S Pollux Drive NUMBER(S)Edwards AFB CA 93524-7048 AFRL-PR-ED-JA-2005-293 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited. AFRL-ERS-PAS-2005-200. SUPPLEMENTARY NOTES©2006 American Institute of Physics, published in Physics of Fluids 18, 093601 (2006) 14. ABSTRACT Gas flows through orifices and short tubes have been extensively studied from the 1960s through the 1980s for both fundamental and practical reasons. These flows are a basic and often important element of various modern gas driven instruments. Recent advances in micro-and nanoscale technologies have paved the way for a g generation of miniaturized devices in various application areas, from clinical analyses to biochemical detection to aerospace propulsion. The latter is the main area of interest of this study, where rarefied gas flow into a vacuum through short tubes with thickness-to-diameter ratios varying from 0.015 to 1.2 is investigated both experimentally and numerically with kinetic and continuum approaches. Helium and nitrogen gases are used in the range of Reynolds numbers from 0.02 to 770 (based on the tube diameter), corresponding to Knudsen numbers from 40 down to about 0.001. Propulsion properties of relatively thin and thick tubes are examined. Good agreement between experimental and numerical results is observed for mass flow rate and momentum flux, the latter being corrected for the experimental facility background pressure. For thick-to-thin tube ratios of mass flow and momentum flux versus pressure, aminimum is observed at a Knudsen number of about 0.5. A short tube propulsion efficiency is shown to be much higher than that of a thin orifice. The effect of surface specularity on a thicker tube specific impulse was found to be relatively small. Measurements and computations of mass flow and momentum flux through short tubes in rarefied gases Gas flows through orifices and short tubes have been extensively studied from the 196...

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Section: Experimental and Numerical Uncertaintiesmentioning

confidence: 99%

Section: Numerical and Experimental Datamentioning

confidence: 99%

Measurements and computations of mass flow and momentum flux through short tubes in rarefied gases

et al. 2006

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“…First, corrections to the force measurements due to the facility background gas have not been incorporated into the data analysis. However, a previous study 15 indicated that the thrust may be effected by less than 0.5% at the experimental conditions of this work. Second, the standared deviation of the stagnation pressure and mass flow measurements was found to be within approximately 1% over the range used.…”

Section: Numerical and Experimental Uncertaintiesmentioning

confidence: 75%

“…A previous study 15 has shown that at these background pressures and corresponding thrust levels there is no evidence of background pressure effects on the thrust measurements in CHAFF-IV.…”

Section: Methodsmentioning

confidence: 99%

Experimental and Numerical Determination of Micropropulsion Device Efficiencies at Low Reynolds Numbers

et al. 2005

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Abstract:The need for low thrust propulsion systems for maneuvers on micro-and nano-spacecraft is growing. Low thrust characteristics generally lead to low Reynolds number flows from propulsive devices that utilize nozzle expansions. Low Reynolds number flows of helium and nitrogen through a small conical nozzle and a thin-walled orifice have been investigated both numerically, using the Direct Simulation Monte Carlo technique, and experimentally, using a nano-Newton thrust stand. For throat Reynolds number less than 100, the nozzle to orifice thrust ratio is less than unity; however, the corresponding ratio of specific impulse remains greater than one for the Reynolds number range from 0. The need for low thrust propulsion systems for maneuvers on micro-and nano-spacecraft is growing. Low thrust characteristics generally lead to low Reynolds number flows from propulsive devices that utilize nozzle expansions. Low Reynolds number flows of helium and nitrogen through a small conical nozzle and a thin-walled orifice have been investigated both numerically, using the Direct Simulation Monte Carlo technique, and experimentally, using a nano-Newton thrust stand. For throat Reynolds number less than 100, the nozzle to orifice thrust ratio is less than unity; however, the corresponding ratio of specific impulse remains greater than one for the Reynolds number range from 0.02 to 200. Once the Direct Simulation Monte Carlo model results were verified using experimental thrust and mass flow data, the model was used to investigate the effects of geometrical variations on the conical nozzle's performance. At low Reynolds numbers, improvements to the specific impulse on the order of 4 to 8% were achieved through a combination of decreasing the nozzle length and increasing the nozzle expansion angle relative to the nominal experimental geometry.

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“…Given the experimental difficulty associated with micro-scale supersonic flow interrogation, detailed flow analyses are necessarily computational in nature. While some experimental works have also been reported (Ketsdever, 2002;Lempert et al, 2003;Ketsdever et al, 2005a) these have been generally limited to bulk thrust measurements without corresponding flow field data. Here, we summarise key findings from computational investigations of monoprellant and cold-gas propulsion schemes and discuss their consequences for efficient nozzle design.…”

Section: Supersonic Micronozzle Designmentioning

confidence: 99%

Design considerations for supersonic micronozzles

Louisos

Alexeenko²,

Hitt

et al. 2008

IJMR

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The next-generation of small satellites ('nanosats') will feature masses <10 kg and require miniaturised propulsion systems capable of providing extremely low levels of thrust. The emergence of viscous, thermal and/or rarefaction effects on the micro-scale can significantly impact the flow behaviour in supersonic micronozzles resulting in performance characteristics which differ substantially from traditional macro-scale nozzle designs. In this paper, we provide an overview of key findings obtained from computational studies of supersonic micronozzle flow and discuss the implications for future micro-scale nozzle design and optimisation.

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Facility Effects on Performance Measurements of Micropropulsion Systems that Utilize Gas Expansion

Cited by 15 publications

References 8 publications

Measurements and computations of mass flow and momentum flux through short tubes in rarefied gases

Measurements and computations of mass flow and momentum flux through short tubes in rarefied gases

Experimental and Numerical Determination of Micropropulsion Device Efficiencies at Low Reynolds Numbers

Design considerations for supersonic micronozzles

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