1. Buildings Course: Modeling of Air and Pollutant Flows in
The University of Texas at Austin Fall 2017
CAEE Department
Course: Modeling of Air and Pollutant Flows in
Buildings
Instructor: Dr. Atila Novoselac
Office: ECJ, 5.430
Phone: (512)
Office Hours:
Tuesday and Thursday 11:00 a.m.–12:00 p.m.
Contacting me
Web site not operational yet
Office – come see me, come see me, come see me,
Call me. Fax me.
me if youmust. Fine for quick answers, to let me know that you are going to miss a class

2. Today’s Lecture Objectives:
Discuss the Syllabus
Describe scope of the course
Introduce the course themes
Answer your question
Fluid dynamics review

3. Introduce Yourself Name Background Professional interests
- academic program and status
Professional interests

4. Motivation for Modeling of Indoor Air Distribution using CFD:
Major exposure to contaminant is in indoor environment
Ventilation system provides contaminant dilution
Controlled airflow (ventilation) can considerably improve
the IAQ and reduce the ventilation air requirement
Air-flow transports pollutants – gaseous and particulate
Contaminant concentration in the space is more or less non-uniform
– It affects: emission, filtration, reactions, exposure

5. Why to Care About Indoor Airflow Distribution ?
Pollutant concentration is very often non-uniform
- Exposure depends on dispersion
We can control exposure by controlling the flow field
Perfect mixing

6. Examples of Exposure Control by Ventilation Systems
1) Control Exhaust
2) Control Supply
Supply
diffusers

7. Example of Buoyancy Driven Flow: Airflow in a Stairwell
Heater (radiator)

8. Example of Force Convection Contaminant Concentration in a Kitchen

9. Example Particle Dispersion

10. What CFD Does
Real flow
Modeling

11. Fluid Dynamics
Continuity:
Momentum:

12. Numerical Methods

13. Simulation Software (CFD)
Input
Output If
Garbage IN
Then
Garbage OUT

14. Course Objectives
Recognize the physics behind various numerical tools used for solving airflow problems.
Employ basic numerical methods for solving Navier-Stokes Equations.
Apply CFD for airflow simulations in buildings and use these tools in design and research.
Evaluate the thermal comfort and indoor air quality (IAQ) with different ventilation systems.
Assess human exposure to different pollutant types.
Critically analyze and evaluate CFD results.
First is overall theme – relevant to everyone
2nd also relevant to everyone
example of mechanical engineer resisting your change
Project manager- knowledge of planning for BES stages
4 main areas – HVAC, electrical, lighting, plumbing
Noise control and acoustics – if we have time

15. Topics: 1. Course Introduction and Background 1 wk
2. Fundamentals of fluid dynamics wks
3. Turbulence models wks
4. Numerical methods and parameters 2 wks
5. CFD modeling parameters wks
6. Introduction to CFD software wk
7. Application of CFD for building airflows 1 wk
8. Simulation of IAQ parameters wk
9. Simulation of thermal comfort parameters 1 wk
10. Modeling of aerosols wk
11. Air and pollutant flows in the vicinity of occupants 1 wk
12. Accuracy and validation of building airflow simulations wk
30%
30%
40%

16. Prerequisites - Fluid Dynamics
Knowledge of the following is useful but
not necessary:
Numerical analysis
Programming

17. Textbook References: An Introduction to Computational Fluid Dynamics,
Versteeg, H.K. and Malalasekera, W.
References:
2) Computational Fluid Dynamics –The Basics With Applications
Anderson
3) Turbulence Modeling for CFD
Wilcox

18. Handouts Copies of appropriate book sections
An Introduction to Computational Fluid Dynamics
I will mark important sections
Disadvantage - different nomenclature
I will point-out terms nomenclature and terminology differences
Journal papers and CFD software manual
Related to application of airflow simulation programs

19. Energy simulation software
Fluent
Airpark

20. Star CD Software – Supply airflow patern

21. There is a large availability of CFD software !
Star CD , Fluent (ANSYS and Airpak)
We have it and you will use it
- Phoenics
CFX
Flow Vent

22. TENTATIVE COURSE SCHEDULE
In the syllabus and on the website
Note funny ordering of chapters
Air systems – ventilation and IAQ
controls
Additional review before midterm
Project assignment
Lighting

23. Grading Test 30% Homework Assignments 25% Midterm Project 10%
Final Project & Presentation 30%
Classroom Participation 5%
100%
Quizzes – 9 of them – every Wednesday (unless otherwise noted)
Midterm October 16th, Wednsday
Project
Homework (every week or two) – if you do the homework and come to class –
Participation – 5% internet resources, completing homework assignment, participating in class discussions, coming to see me, fieldtrips and guest speakers
Final Exam – sorry about the time

24. Participation 5%
Based on my assessment of your participation in the class
How to get participation points
Come to class
Submit all assignments/projects on time
Participate in class discussions
Come to see me in my office

25. Homework 25% Targeted number: 3 HW1 HW2 HW3
Problems related to fluid dynamic
HW2
Problem related to turbulence modeling
HW3
Problem related numeric

26. Midterm Project 10% Individual project
Use of CFD program for air and pollutant flow analysis
Primary goal is to get familiar with the CFD software

27. Midterm Exam 30% In-class exam (90 minutes)
After 2/3 of the course (sometime in October )
we will arrange the exact time
Problems based on topics cover in the first two parts of the course

28. Final Project 30%
Use of CFD for detail airflow, thermal and IAQ analyses
Different projects topics
Real engineering an/or research problems
Final presentation (~15 minutes)

29. Previous Course projects -Human Exposure to Indoor Pollutants
Previous Course projects -Human Exposure to Indoor Pollutants - dispersion of pollutant with DV

30. Previous Course projects - Surface Boundary Layer

31. Previous Course Projects - Hydro-Jet Screen

32. Previous Course projects - Natural Ventilation

33. Modeling of Smoke in Stairwell

34. More CFD Final Project:
Design of ventilation system
Smoke management
Natural ventilation
Human exposure to various pollutants
Your suggestion

35. Grading
> 93 A
90-93 A-
86-90 B+
83-86 B
80-83 B-
< 80 C-, C, C+

36. Course Website All course information:
Except your grades and HW solutions
Grades and progress on the Canvas
On the course website
Look at Assignments sections
Review class material ahead of time
use posted class notes

37. My Issues
Please try to use office hours for questions problems and other reasons for visit
Tuesday and Thursday morning reserved - Class preparation
Please don’t use to ask me questions which require long explanations
Come to see me or call me
Suggestions are welcome
The more specific the better

38. Fluid Dynamics
Review

39. Conservation equations

40. Important operations
Total derivative for fluid particle which is moving: V z
any scalar y
Vector and scalar operators: x
scalar
vector

41. Shear and Normal stress
τyx

42. Continuity equation -conservation of mass
Mass flow in and out of fluid element
Infinitely small volume
Volume V = δxδyδz
Volume sides:
Ax = δyδz
Ay = δxδz
Az = δxδy
Change of density in volume =
= Σ(Mass in) - Σ(Mass out)
……………….

43. Momentum equation –Newton’s second law
dimensions of
fluid particle
Stress components in x direction
forces
per unit of volume
in direction x
………………..
………………
…………….
total
derivative

44. Momentum equation Sum of all forces in x direction Internal source
y direction
z direction

45. Newtonian fluids
Viscous stress are proportional to the rate of deformation (e)
Elongation:
Shearing deformation:
For incompressible flow
Viscous stress:
viscosity

46. Momentum equations for Newtonian fluids
After substitution:
x direction:
y direction:
z direction: