The Mach disc in underexpanded exhaust plumes

1970 ◽  
Author(s):  
M. ABBETT
Keyword(s):  
Mach Disc ◽  
Exhaust Plumes

EFFECT OF FLIGHT AND MOTOR OPERATING CONDITIONS ON INFRARED SIGNATURE PREDICTIONS OF ROCKET EXHAUST PLUMES

2015 ◽  
Vol 14 (1) ◽  
pp. 29-56 ◽  
Author(s):  
Robert Stowe ◽  
Sophie Ringuette ◽  
Pierre Fournier ◽  
Tracy Smithson ◽  
Rogerio Pimentel ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Exhaust Plumes ◽  
Infrared Signature ◽  
Rocket Exhaust

The effect of spacecraft descent engine plumes on spore transfer to planetary surfaces: Phoenix as a test case

2011 ◽  
Vol 10 (4) ◽  
pp. 335-340 ◽  
Author(s):  
J.R. Marshall ◽  
R.L. Mancinelli
Keyword(s):  
Atmospheric Pressure ◽  
Laboratory Experiments ◽  
Particle Impact ◽  
Test Case ◽  
Surrounding Area ◽  
Planetary Protection ◽  
Engine Thrust ◽  
Exhaust Plumes ◽  
Microbial Contaminants ◽  
Different Parts

AbstractLaboratory experiments were conducted to determine the effect of descent-engine plumes on the scouring of surface (microbial) contaminants from a spacecraft. A simulated touchdown of a half-scale lander engine and deck configuration was conducted at Mars atmospheric pressure in the NASA Ames Planetary Aeolian Laboratory. Low-density particles were used for the soil simulant to emulate the lower Martian gravity. The underside of the model had small witness plates with controlled microbial surface populations and particle impact detectors. For both steady-state engine thrust (Viking) and pulsed engine thrust (Phoenix), the exhaust plumes from the engines violently excavated the soil and produced particle-laden eddies beneath the lander that sandblasted the lander underside. The result was nearly complete erosion of microbial contaminants from the spacecraft model with their subsequent deposition in the surrounding area. It is concluded that different planetary protection cleanliness levels for different parts of a spacecraft do not necessarily prevent soil contamination because these cleaning strategies evolved without consideration of the effects of the descent engine plumes.

Exhaust plumes from nozzles with wall boundary layers.

1968 ◽  
Vol 5 (10) ◽  
pp. 1143-1147 ◽  
Author(s):  
FREDERICK P. BOYNTON
Keyword(s):  
Boundary Layers ◽  
Wall Boundary ◽  
Exhaust Plumes

A New Method of Modeling Underexpanded Exhaust Plumes for Wind Tunnel Aerodynamic Testing

1989 ◽  
Vol 111 (4) ◽  
pp. 748-754
Author(s):  
V. Salemann ◽  
J. M. Williams
Keyword(s):  
Wind Tunnel ◽  
Free Stream ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Area Ratio ◽  
Full Scale ◽  
New Method ◽  
Thrust Coefficient ◽  
Model Scale ◽  
Exhaust Plumes

A new method for modeling hot underexpanded exhaust plumes with cold model scale plumes in aerodynamic wind tunnel testing has been developed. The method is applicable to aeropropulsion testing where significant interaction between the exhaust and the free stream and aftbody may be present. The technique scales the model and nozzle external geometry, including the nozzle exit area, matches the model jet to free-stream dynamic pressure ratio to full-scale jet to free-stream dynamic pressure ratio, and matches the model thrust coefficient to full-scale thrust coefficient. The technique does not require scaling of the internal nozzle geometry. A generalized method of characteristic computer code was used to predict the plume shapes of a hot (γ = 1.2) half-scale nozzle of area ratio 3.2 and of a cold (γ = 1.4) model scale nozzle of area ratio 1.3, whose pressure ratio and area ratio were selected to satisfy the above criteria and other testing requirements. The plume shapes showed good agreement. Code validity was checked by comparing code results for cold air exhausting into a quiescent atmosphere to pilot surveys and shadowgraphs of model nozzle plumes taken in a static facility.

Aerosol formation in aircraft exhaust plumes

1995 ◽  
Vol 26 ◽  
pp. S155-S156
Author(s):  
I.J Ford ◽  
P.D Whitefield ◽  
D.E Hagen
Keyword(s):  
Aerosol Formation ◽  
Exhaust Plumes

Commuter Exposure to Vehicle Exhaust Plumes in New Delhi, India

Epidemiology ◽  
2011 ◽  
Vol 22 ◽  
pp. S146
Author(s):  
Joshua S. Apte ◽  
Thomas W. Kirchstetter ◽  
Julian D. Marshall ◽  
William W. Nazaroff
Keyword(s):  
New Delhi ◽  
Vehicle Exhaust ◽  
Exhaust Plumes ◽  
Commuter Exposure

scholarly journals Intrusion, retention, and snowpack chemical effects from exhaust emissions at Concordia Station, Antarctica

2018 ◽  
Author(s):  
Detlev Helmig ◽  
Daniel Liptzin ◽  
Jacques Hueber ◽  
Joel Savarino
Keyword(s):  
Nitrogen Oxides ◽  
Atmospheric Chemistry ◽  
Power Grid ◽  
Photochemical Reactions ◽  
Particulate Emissions ◽  
Surface Sampling ◽  
Surface Exchange ◽  
Exhaust Plumes ◽  
Clean Air ◽  
Main Station

Abstract. Continuous measurements of reactive gases in the snowpack and above the snowpack surface were conducted at Concordia Station (Dome C), Antarctica, from December 2012–January 2014. Measured species included ozone, nitrogen oxides, gaseous elemental mercury, and formaldehyde, for study of photochemical reactions, surface exchange, and the seasonal cycles and atmospheric chemistry of these gases. The experiment was installed ~ 1 km from the main station infrastructure inside the station clean air sector and within the station electrical power grid boundary. Air was sampled continuously from three inlets on a 10 m meteorological tower, as well as from two above and four below the surface sampling inlets from within the snowpack. Despite being in the clean air sector, over the course of the 1.2-year study, we observed on the order of 15 occasions when exhaust plumes from the camp, most notably from the power generation system, were transported to the study site. Highly elevated levels of nitrogen oxides (up to 1000 x background) and lowered ozone (down to ~ 50 %), most likely from titration with nitric oxide, were measured in the exhaust plumes. Within 5–15 minutes from observing elevated pollutant levels above the snow, rapidly increasing and long-lasting concentration enhancements were measured in snowpack air. While pollution events typically lasted only a few minutes to an hour above the snow surface, elevated nitrogen oxides levels were observed in the snowpack lasting from a few days to one week. These observations add important new insight to the discussion of if and how snow-photochemical experiments within reach of the power grid of polar research sites are possibly compromised by the snowpack being chemically influenced (contaminated) by gaseous and particulate emissions from the research camp activities. This question is critical for evaluating if snowpack trace chemical measurements from within the camp boundaries are representative for the vast polar ice sheets.

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