Modeling of Air and Pollutant Flows in Buildings
Project Assignment 1 DUE: October26, 2017
Part a)
Numerical diffusion
The purpose of this project part is to analyze how mesh size affects the accuracy of result.
Consider the volume with the size of 1m x 1m x 0.05m. Turn offthe diffusion term in the energy equation (conductivity k=0) and calculate the temperature field for grid resolution 200x200x5 and 50x50x5 (specify only 5 cells in z direction for both cases). For both geometries inlet velocity for cold (20C) and hot (30C) air is 0.02m/s, and the flow is laminar. (Turn off the effect of the gravitation force on the fluid flow).
Repeat the calculation when the diffusion in energy equation is on.
Plot 8 figures (one for each case) and compare the results.
For each figure, comment the effect of numerical (error) and heat transfer (real) diffusion.
Part b)
Find the answer for the geometry from HW2 part 2. NOTE; Calculate the velocity so that you have turbulent flow (Re>3000) in the duct.
Partc)
Modeling of indoor environment with AIRPAK (FLUENT)
The purpose of this part of the project is to learn to use the AIRPAK CFD simulation tool.
The purpose of this project is to learn basic steps of CFD simulations.
You have a task to evaluate different ventilation strategies in a kitchen. You will need to model a stove and cooking process for 3 ventilation systems:
-Regular exhaust hood (exhaust hood above the stove),
-Downdraft exhaust hood (exhaust is part of the stove),
-Open window with a fan positioned in the window.
The restrictions for the room model:
- room should have the volume of 30 to 60 m3
- inlet is a kitchen door and outlet is hood or open window
- you should use the same exhaust airflow-rate for all 3 ventilation cases (you will need to define this flow based on manufacturer data)
- heat sources intensity is defined by electric stove power
- water vapor is evaporated from ta pot on the stove,
- position of window is arbitrary
2) The mesh size should be from 30,000 to 100,000 cells.
3) You can use zero or 2-equation turbulence model or k-e model.
4) Use steady state calculation and turn off the radiation model.
The focus of the project is on the modeling of geometry, heat sources, concentration sources, inlets and outlets, selection of important simulation parameters and mesh generation.
You should calculate flow parameters and plot the velocity (vector and scalar field), temperature, and concentration for the characteristic vertical cross-section plane of the room. You need to check mass, energy, and species balance and provide a report.