| Experimental and Computational Observation of Radiometric Forces on a Plate (Postprint) |
12 JUN 2007 |
13 pages |
| Authors:
N. Selden; C. Ngalande; S. Gimelshein; A. Ketsdever; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
 | The radiometric force on several configurations of heated plates placed in a stagnant gas is examined experimentally on a high resolution thrust stand and numerically using the direct simulation Monte Carlo method. A wide range of pressures from 0.006Pa to 6Pa corresponding to Knudsen numbers from 20 to 0.02 is examined for nitrogen, argon, xenon, and helium test gases. It is shown that the force is maximum in the transition ... |
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| Experimental and Computational Observation of Radiometric Forces on a Plate (Preprint) |
12 JUN 2007 |
13 pages |
| Authors:
N. Selden; C. Ngalande; S. Gimelshein; A. Ketsdever; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| The radiometric force on several configurations of heated plates placed in a stagnant gas is examined experimentally on a high resolution thrust stand and numerically using the direct simulation Monte Carlo method. A wide range of pressures from 0.006Pa to 6Pa corresponding to Knudsen numbers from 20 to 0.02 is examined for nitrogen, argon, xenon, and helium test gases. It is shown that the force is maximum in the transition ... |
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| Surface Roughness Effects in Low Reynolds Number Channel Flows (POSTPRINT) |
JUL 2006 |
9 pages |
| Authors:
N. Gimelshein; J. Duncan; T. Lilly; S. Gimelshein; A. Ketsdever; I. Wysong; ENGINEERING RESEARCH AND CONSULTING INC (ERC INC) EDWARDS AFB CA
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| Rarefied helium and nitrogen flow expanding into vacuum through 150 micron high and 1.5 cm long channels is studied experimentally and numerically with the DSMC method. Different types of channel walls are examined, both polished and rough with well characterized roughness shaped as triangles and rectangles. The pressure varies from 200 to 13,000 Pa, with the gas mean free path being both much larger and much smaller than the roughness ... |
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| Surface Roughness Effects in Low Reynolds Number Channel Flows |
12 JUN 2006 |
9 pages |
| Authors:
N. Gimelsheim; J. Duncan; T. Lilly; S. Gimelshein; A. Ketsdever; I. Wysong; ERC INTERNATIONAL INC SAN DIEGO CA
|
| Rarefied helium and nitrogen flow expanding into vacuum through 150 micrometers high and 1.5 cm long channels is studied experimentally and numerically with the DSMC method. Different types of channel walls are examined, both polished and rough with well characterized roughness shaped as triangles and rectangles. The pressure varies from 200 to 13,000 Pa, with the gas mean free path being both much larger and much smaller than the roughness ... |
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| Nozzle Plume Impingement on Spacecraft Surfaces: Effects of Surface Roughness (POSTPRINT) |
JUN 2005 |
15 pages |
| Authors:
C. Ngalande; M. Killingsworth; T. Lilly; S. Gimelshein; A. Ketsdever; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES
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| An experimental and numerical effort was undertaken to assess the effects of a cold gas (T0-300 K) nozzle plume impinging on simulated spacecraft surfaces. The nozzle flow impingement is investigated experimentally using a nano-Newton resolution force balance and numerically using the Direct Simulation Monte Carlo (DSMC) numerical technique. The Reynolds number range investigated in this study is from approximately 2 to 350 using nitrogen propellant. The thrust produced by the ... |
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