last modified: 24-JUN-1991 | catalog | categories | new | search |

NESC1006 MAEROS.

MAEROS, Multicomponent Aerosol Time Evolution

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1. NAME OR DESIGNATION OF PROGRAM:  MAEROS.
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2. COMPUTERS
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Program name Package id Status Status date
MAEROS NESC1006/01 Tested 24-JUN-1991

Machines used:

Package ID Orig. computer Test computer
NESC1006/01 CDC 7600 CDC CYBER 830
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3. DESCRIPTION OF PROGRAM OR FUNCTION

MAEROS calculates aerosol composition and mass concentration as a function of particle size and time. The processes that may be considered are coagulation due to Brownian motion, gravity, and turbulence; particle deposition due to gravitational settling, diffusion, and thermophoresis; particle growth due to condensation of a gas, typically water vapor, and time-varying sources of particles of different sizes and chemical compositions.
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4. METHOD OF SOLUTION

The numerical technique used is based upon dividing the particle size domain into m sections and imposing the condition of mass conservation for each chemical component for the processes considered. Aerosol mass concentrations are grouped into sections (i.e., size classes) for which an average composition is determined. For m sections, a set of 2m(m+2) sectional coefficients  must be calculated before integrating in time. These coefficients are determined from the basic coagulation, condensation, and deposition coefficients. Since the sectional coefficients depend on  the physical properties of the containment chamber (e.g., temperature, pressure, chamber volume, and deposition surface area), they will generally need to be recalculated for a particular application. However, for a given containment chamber, the sectional coefficients will probably vary only with temperature and pressure.  Consequently, the code has been developed so that sectional coefficients are stored at a user-specified upper and lower bound for both termperature and pressure, and linear interpolation is used to determine the appropriate sectional coefficients for a given temperature and pressure. A Runge-Kutta-Fehlberg method is used to integrate in time.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of:
   20 sections
    8 components
   50 rows for plotting
  101 columns for plotting.
MAEROS is limited to geometrically spaced sections in particle mass (i.e., v(m+1).GE.2v(m) is the largest particle mass in section  m).
The code is also restricted in coagulation, deposition, and condensation mechanisms which are dependent only on particle mass, not on chemical composition. The source mechanisms may be both particle size and composition dependent.
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6. TYPICAL RUNNING TIME

NESC ran the sample problem on a CDC CYBER 175 in approximately 12 CP seconds.
NESC1006/01
The program ran at NEADB on a CDC CYBER 830 in 125 sec. of CPU time.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS:
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9. STATUS
Package ID Status date Status
NESC1006/01 24-JUN-1991 Tested at NEADB
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10. REFERENCES:
NESC1006/01, included references:
- F. Gelbard :
  MAEROS User Manual
  NUREG/CR-1391 SAND80-0822 (December 1982)
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11. MACHINE REQUIREMENTS:
NESC1006/01
The program requires on CDC CYBER830 60,600 (octal) words of main storage.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC1006/01 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:
NESC1006/01
The program ran at NEADB under NOS2.5.1 (CDC CYBER830).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHORS:
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16. MATERIAL AVAILABLE
NESC1006/01
File name File description Records
NESC1006_01.001 Information file 42
NESC1006_01.002 JCL and control information 9
NESC1006_01.003 MAEROS FORTRAN source 2365
NESC1006_01.004 Sample problem output 737
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17. CATEGORIES
  • R. Environmental and Earth Sciences

Keywords: aerosols, air pollution, particle size, particles.