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) 475-8175 e-mail: atila@mail.utexas.edu http://www.ce.utexas.edu/prof/Novoselac 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. E-mail me if youmust. Fine for quick answers, to let me know that you are going to miss a class

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

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

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

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

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

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

Example of Force Convection Contaminant Concentration in a Kitchen

Example Particle Dispersion

What CFD Does Real flow Modeling

Fluid Dynamics Continuity: Momentum:

Numerical Methods

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

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

Topics: 1. Course Introduction and Background 1 wk 2. Fundamentals of fluid dynamics 2 wks 3. Turbulence models 1.5 wks 4. Numerical methods and parameters 2 wks 5. CFD modeling parameters 1.5 wks 6. Introduction to CFD software 1 wk 7. Application of CFD for building airflows 1 wk 8. Simulation of IAQ parameters 1 wk 9. Simulation of thermal comfort parameters 1 wk 10. Modeling of aerosols 1 wk 11. Air and pollutant flows in the vicinity of occupants 1 wk 12. Accuracy and validation of building airflow simulations 1 wk 30% 30% 40%

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

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

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

Energy simulation software Fluent Airpark

Star CD Software – Supply airflow patern

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

TENTATIVE COURSE SCHEDULE In the syllabus and on the website http://www.ce.utexas.edu/prof/Novoselac/classes/ARE372/Notes.html Note funny ordering of chapters Air systems – ventilation and IAQ controls Additional review before midterm Project assignment Lighting

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

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

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

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

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

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)

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

Previous Course projects - Surface Boundary Layer

Previous Course Projects - Hydro-Jet Screen

Previous Course projects - Natural Ventilation

Modeling of Smoke in Stairwell

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

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

Course Website All course information: http://www.ce.utexas.edu/prof/Novoselac/Classes/ARE372/ 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

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 e-mail to ask me questions which require long explanations Come to see me or call me Suggestions are welcome The more specific the better

Fluid Dynamics Review

Conservation equations

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

Shear and Normal stress τyx

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) ……………….

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

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

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

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