Gas-phase velocity field measurements in dense sprays by laser-based flow tagging

2000 ◽  
Vol 70 (3) ◽  
pp. 463-466 ◽  
Author(s):  
S. Krüger ◽  
G. Grünefeld
Keyword(s):  
Velocity Field ◽  
Phase Velocity ◽  
Gas Phase ◽  
Field Measurements

Gas-phase velocity field measurements in sprays without particle seeding

2000 ◽  
Vol 29 (3) ◽  
pp. 238-246 ◽  
Author(s):  
G. Grünefeld ◽  
J. Bartelheimer ◽  
H. Finke ◽  
S. Krüger
Keyword(s):  
Velocity Field ◽  
Phase Velocity ◽  
Gas Phase ◽  
Field Measurements

CONSIDERATIONS ON THE GAS-PHASE VELOCITY FIELD IN A NONEVAPORATING DIESEL SPRAY

2000 ◽  
Vol 10 (6) ◽  
pp. 15 ◽  
Author(s):  
M. L. Sanchez ◽  
F. Castro ◽  
F. V. Tinaut ◽  
A. Melgar
Keyword(s):  
Velocity Field ◽  
Phase Velocity ◽  
Gas Phase ◽  
Diesel Spray

scholarly journals Modeling organic aerosols in a megacity: comparison of simple and complex representations of the volatility basis set approach

2010 ◽  
Vol 10 (12) ◽  
pp. 30205-30277 ◽  
Author(s):  
M. Shrivastava ◽  
J. Fast ◽  
R. Easter ◽  
W. I. Gustafson ◽  
R. A. Zaveri ◽  
...  
Keyword(s):  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Computational Cost ◽  
Organic Aerosols ◽  
Field Measurements ◽  
Organic Aerosol ◽  
Basis Set ◽  
Aerosol Formation ◽  
Secondary Organic Aerosol Formation ◽  
The City

Abstract. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is modified to include a volatility basis set (VBS) treatment of secondary organic aerosol formation. The VBS approach, coupled with SAPRC-99 gas-phase chemistry mechanism, is used to model gas-particle partitioning and multiple generations of gas-phase oxidation of organic vapors. In addition to the detailed 9-species VBS, a simplified mechanism using 2 volatility species (2-species VBS) is developed and tested for similarity to the 9-species VBS in terms of both mass and oxygen-to-carbon ratios of organic aerosols in the atmosphere. WRF-Chem results are evaluated against field measurements of organic aerosols collected during the MILAGRO 2006 campaign in the vicinity of Mexico City. The simplified 2-species mechanism reduces the computational cost by a factor of 2 as compared to 9-species VBS. Both ground site and aircraft measurements suggest that the 9-species and 2-species VBS predictions of total organic aerosol mass as well as individual organic aerosol components including primary, secondary, and biomass burning are comparable in magnitude. In addition, oxygen-to-carbon ratio predictions from both approaches agree within 25%, providing evidence that the 2-species VBS is well suited to represent the complex evolution of organic aerosols. Model sensitivity to amount of anthropogenic semi-volatile and intermediate volatility (S/IVOC) precursor emissions is also examined by doubling the default emissions. Both the emission cases significantly under-predict primary organic aerosols in the city center and along aircraft flight transects. Secondary organic aerosols are predicted reasonably well along flight tracks surrounding the city, but are consistently over-predicted downwind of the city. Also, oxygen-to-carbon ratio predictions are significantly improved compared to prior studies by adding 15% oxygen mass per generation of oxidation; however, all modeling cases still under-predict these ratios downwind as compared to measurements, suggesting a need to further improve chemistry parameterizations of secondary organic aerosol formation.

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