Course detail
Aerosols
FSI-IAE Acad. year: 2021/2022 Summer semester
An aerosol is defined as a suspension of liquid or solid particles in a gas. Aerosols are stable for at least a few seconds and in some cases may last a year or more. Particle size ranges from about 2 nm to more than 100 µm. Without aerosols which serve as condensation nuclei, there would be no rain. Aerosols are produced by nozzles and many other technological processes. Millions of particles enter the lungs with every breath.
The subject Aerosols deals with the description of the behaviour of aerosols, their creation and measurement. Students become familiar with the physical mechanisms acting during particle transport in the atmosphere as well as the internal environment, and the principles of filtration. Last but not least the health effect of aerosols are described.
Supervisor
Department
Learning outcomes of the course unit
Knowledge of generation and dispersion of particles for technical purposes, measurement and characterisation of aerosols. Students should be able to calculate settling velocities of various types of particles and predict their behaviour in the environment. They will know the health and environmental risks and safety regulations of aerosol handling.
Prerequisites
Maths, Physics, Thermodynamics
Planned learning activities and teaching methods
The course is taught through lectures explaining the basic principles and theory of the discipline. Exercises are organized as teacher-controlled calculation of practical problems in order to deepen the understanding of the theoretical principles explained during lectures.
Assesment methods and criteria linked to learning outcomes
The exam consists of written and oral parts, the emphasis is put on theory and solution of practical tasks.
Language of instruction
Czech
Aims
The aim of the study is to get acquainted with aerosols and the related technology, master the mathematical-physical apparatus created for aerosol description and behaviour, and comprehend the basics of the measuring techniques.
Specification of controlled education, way of implementation and compensation for absences
Attendance at seminars is required; in a case of absence (in justified cases), students will calculate special assignments. Students will have to pass a test during a semester.
The study programmes with the given course
Programme N-ETI-P: Power and Thermo-fluid Engineering, Master's
branch TEP: Environmental Engineering, 3 credits, compulsory
Type of course unit
Lecture
13 hours, optionally
Teacher / Lecturer
Syllabus
Introduction to aerosols (definition, mathematical description of aerosol characteristics), properties of gases and particles (kinetic theory of gases, mean molecular velocity, mean free path, Reynolds number, measurement of velocity, airflow and pressure).
Uniform particle motion, acceleration and curvilinear motion (Stokes Law, settling velocity, slip correction factor, non-spherical particles, aerodynamic diameter, settling in turbulent and stirred flow, relaxation time, particle stopping distance, impactors, time-of-flight instruments).
The statistical description of the particle size distribution (size distribution, moments, lognormal distribution, Hatch-Choate equations).
Adhesive forces between particles (particle detachment, resuspension, bounce), Brownian motion and diffusion (diffusion coefficient, mean free path of particles, Fick's law and diffusion flux, diffusion battery), thermophoresis.
Filtration (macroscopic properties of filters, single-fiber efficiency, deposition mechanisms, filter efficiency, pressure drop, membrane filters).
Sampling and measurement of concentration (isokinetic sampling, still air sampling, transport loss, mass concentration, direct-reading instruments, number concentration).
Coagulation (monodisperse, polydisperse and kinematic coagulation), condensation and evaporation (Kelvin effect, homogeneous and heterogeneous nucleation, condensation growth, condensation particle counters).
Atmospheric aerosols (naturally occurring aerosols, background concentration, anthropogenic aerosols, global effects).
Electrical properties of aerosols (electric field and mobility, particle charging, corona discharge, equilibrium charge distribution, precipitation, electrical measurements of aerosols).
Optical properties of aerosols (absorption and reflection of light, visibility, optical measurement of aerosols), bioaerosols and fibrous aerosols; explosivity of aerosols.
Measurement by microscopes, preparation of test aerosols (atomization of liquids, dispersion of solid particles, condensation methods).
Indoor aerosols (sources and resuspension, temporal prediction of concentration), deposition of particles in the airways (mechanisms of transport and deposition of aerosols, effects on human health).
Computer-assisted exercise
13 hours, compulsory
Teacher / Lecturer
Syllabus
Calculation of practical problems in:
Introduction to aerosols (mathematical description of aerosol characteristics), properties of gases and particles (mean molecular velocity, mean free path, Reynolds number, velocity, air flow and pressure).
Uniform particle motion, acceleration and curvilinear motion (Stokes Law, settling velocity, slip correction factor, non-spherical particles, aerodynamic diameter, settling in turbulent and stirred flow, relaxation time, particle stopping distance).
Statistical description of particle size distribution (size distribution, moments, lognormal distribution, Hatch-Choate equations).
Adhesive forces between particles (particle detachment, resuspension, bounce), Brownian motion and diffusion (diffusion coefficient, mean free path of particles, Fick's law and diffusion flux).
Filtration (single-fiber efficiency, filter efficiency, pressure drop, membrane filters).
Sampling and measurement of concentration (transport losses, mass concentration, number concentration).
Coagulation (monodisperse, polydisperse and kinematic coagulation), condensation and evaporation (Kelvin effect, condensation growth).
Atmospheric aerosols (background concentration, anthropogenic aerosols, global effects).
Electrical properties of aerosols (electric field and mobility, particle charging, corona discharge, equilibrium charge distribution, precipitation).
Optical properties of aerosols (absorption and reflection of light, visibility), bioaerosols and fibrous aerosols; explosivity of aerosols.
Measurement by microscopes, preparation of test aerosols (atomization of liquids, dispersion of solid particles, condensation methods).
Indoor aerosols (resuspension, temporal prediction of concentration), deposition of particles in the airways (mechanisms of transport and deposition of aerosols, effects on human health).