SubjectsSubjects(version: 855)
Course, academic year 2019/2020
  
Aerosol engineering - AP409008
Title: Aerosol engineering
Guaranteed by: Department of Chemical Engineering (409)
Actual: from 2019
Semester: summer
Points: summer s.:0
E-Credits: summer s.:0
Examination process: summer s.:
Hours per week, examination: summer s.:3/0 other [hours/week]
Capacity: unlimited / unknown (unknown)
Min. number of students: unlimited
Language: English
Teaching methods: full-time
Level:  
For type: doctoral
Note: course is intended for doctoral students only
can be fulfilled in the future
Guarantor: Ždímal Vladimír Ing. Dr.
Interchangeability : D409020, P409008
Examination dates   Schedule   
Annotation -
Last update: Pátková Vlasta (16.11.2018)
Introduction to the field of aerosols. The course is designed for doctoral students - non-specialists in the field. The course will give students a basic overview of the aerosol domain, the methods of their investigation, as well as the modeling of aerosol processes.
Literature -
Last update: Pátková Vlasta (16.11.2018)

Hinds W.C.: Aerosol Technology, John Wiley&Sons, New York, 2.edit., 1998.

Syllabus -
Last update: Pátková Vlasta (16.11.2018)

1. Introduction, motivation. What is an aerosol? Why are we studying aerosols? Quiz from the history of aerosol science. The formation, transformation and extinction of aerosol particles. Aerosol ZOO. Sizes and shape of aerosol particles. Concentration of aerosols and units used.

2. Properties of gases. Gas pressure and temperature, distribution of molecular velocities, mean free path in gas, viscosity, diffusivity and thermal conductivity. Reynolds number. Methods of measuring gas velocity, volumetric flow, transported volume, pressure drop and associated quantities.

3. Uniform motion of aerosol particles. Newton and Stokes' law and range of their use. Dependency of drag coefficient on Re. Settling velocity. Correction of the Stokes law in the free molecular regime, slip (Cunningham) correction factor. Nonspherical particles. Aerodynamic diameter. Methods of measurement of settling velocity.

4. Particle size distributions and their transformations. Probability density function and cummulative distribution function. Means, medians and modes. Moment averages. Moment distributions. Particle size distribution weighted by number, surface, mass. Normal and lognormal distribution. Comparison of various characteristic diameters.

5. Straight-line acceleration. Mechanical mobility. Relaxation time. Accelerated motion in 1-d and 2-d. Particle stopping distance. Curvilinear particle motion. Stokes number. Experimental methods: inertial impactor, virtual Impactor, time-of-flight instruments.

6. Brownian motion and diffusion. Diffusion coefficient. Stokes-Einstein relation. Particle mean free path. Brownian displacement. Diffusional deposition. Deposition during flow in the tube. Experimental methods based on diffusion: diffusion batteries, denuders, strippers.

7. Adhesion of particles. Types of adhesive forces. London-van der Waals's force. Electrostatic force. Adhesive force due to surface tension. Experimental methods of measuring adhesion forces and their comparison. Resuspension of particles. Particle bounce.

8. Phoretic phenomena. Thermophoresis, diffusiophoresis and photophoresis. Thermophoretic velocity in the free molecule and continuum region. Comparison of the importance of thermophoresis with other particle transport processes. Experimental methods: thermophoretic precipitator.

9. Filtration of aerosol particles. Filter types: fibrous, porous membrane, capillary pore membranes. Characterization of filters. Single-fiber efficiency. Deposition mechanisms: interception, inertial impaction, diffusion, gravitational settling, electrostatics. Total filter efficiency and its particle size dependence. Pressure drop on the filter. Experimental methods for determining aerosol filter efficiency.

10. Sampling. Isokinetic sampling. Still air sampling. Transport losses of aerosol particles and how to correct them. Measurement of the particles' mass concentration. Experimental methods: direct-reading instruments. Measurement of particle number concentrations. Types and characteristics of pumps.

11. Respiratory deposition. Aerosols and health. Parameters of the human respiratory system. Deposition mechanisms of aerosol particles in the respiratory system. Total and regional deposition. Mathematical models of deposition. Inhalable, thoracic and respirable fractions, PM10, PM2.5. Experimental methods of measuring personal exposure.

12. Coagulation. Monodisperse coagulation, Smoluchowski model. Coagulation coefficient. Dependence on initial concentration. Polydisperse coagulation. Changes in particle size distribution with time. Kinematic coagulation.

13. Condensation. Saturated vapor pressure. Kelvin effect. Supersaturation and how to achieve it. Homogenous nucleation. Experimental methods of nucleation rate measurement. Growth by condensation. Heterogeneous condensation. Experimental methods: condensation particle counters. Evaporation and droplet lifetime.

14. Electrical properties of aerosols. Coulomb's law. Electric field. Millikan's experiment. Electrical mobility. Charging mechanisms for aerosol particles. Limit charge, equilibrium charge distribution. Experimental methods: differential mobility particle sizer.

15. Optical properties of aerosols. Extinction, absorption and light scattering. Mie theory. Visual range in the atmosphere. Apparent and threshold contrast. Experimental methods: Photometer, integrating nephelometer, optical particle counter, optical spectrometer.

16. Atmospheric aerosols. Sources and global emissions. Natural background. Stratospheric aerosol. Tropospheric aerosol. Urban aerosol. Typical concentrations and modes of atmospheric aerosol. Typical aerosol composition. Global effects.

17. Aerosol generators. Liquid atomization. Nebulization. Atomization of particles in liquid suspensions. Dispersion of powders. Generators based on evaporation and subsequent condensation. Practical examples of aerosol generators.

 
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