li rong 1) , peter v. nielsen 1) , guohong tong 2) guoqiang zhang 3) , peter ravn 3)
DESCRIPTION
Computational Fluid Dynamics (CFD) Study on the Influence of Airflow Patterns on Carbon Dioxide Distribution and Emission Rate in a Scaled Livestock Building. Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3). - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/1.jpg)
Computational Fluid Dynamics (CFD) Study on the Influence of Airflow Patterns
on Carbon Dioxide Distribution and Emission Rate in a Scaled Livestock
Building
Li Rong1), Peter V. Nielsen1), GuoHong Tong2) Guoqiang Zhang3), Peter Ravn3)
1)Department of Civil Engineering, Aalborg University
2) Shenyang Agricultural University , China
3) Department of Agricultural Engineering, Research Centre Bygholm, University of Aarhus
24/06/2008
![Page 2: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/2.jpg)
Outline
• Introduction• Validation of CFD model• Results• Conclusion
![Page 3: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/3.jpg)
Introduction
• Concentration distribution inside the livestock building relating to:
ventilation system
heat condition
manure condition
etc.• Objective of this paper is to investigate the influence of the
ventilation system on concentration distribution
![Page 4: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/4.jpg)
Validation of CFD model
(a) Model in experiment 2.2m*0.62m*2.41m
(b)45 degree deflector setting model
(c) 90 degree deflector setting model
1 - inlet, 2 - outlet, 3 - deflector, 4 - slatted floor, ‘ ’﹡ - measurement points
Figure 1 models in experiment and simulations
![Page 5: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/5.jpg)
Boundary condition• Isothermal case
• Inlet: velocity in 0.2196m/s, turbulence intensity in 5% and automatic turbulence length scale, CO2 concentration in 900mg/m3
• Outlet: average pressure in 0Pa
• Floor: CO2 concentration in 2000mg/m3
• Other walls: with no CO2 emission
Turbulence model
k model
![Page 6: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/6.jpg)
Vector and CO2 concentration distribution
(a) Vector and CO2 distribution in 45 degree setting model
(b) Vector and CO2 distribution in 90 degree setting model
Figure 2 vector and CO2 concentration distribution at Z=0.31m
![Page 7: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/7.jpg)
Definition of non-dimensional CO2 concentration
* 0
0r
c cc
c c
*c
c
0c
rc
Non-dimensional CO2 concentration
CO2 concentration inside the building
Inlet CO2 concentration
Outlet CO2 concentration
![Page 8: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/8.jpg)
Definition of non-dimensional CO2 concentration
(a) 45 degree deflector setting model (b) 90 degree deflector setting model
Figure 4 comparison of non-dimensional CO2 concentration between measurements and simulations at y=0.51m, z=0.31m
![Page 9: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/9.jpg)
• Influence of airflow rate on non-dimensional CO2 concentration
• Influence of airflow rate on emission rate• Influence of an extra outlet setting below the slatted floor
on emission rate
Results
![Page 10: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/10.jpg)
Influence of airflow rate on non-dimensional CO2 concentration distribution and emission rate
Boundary conditions
• Airflow rate including 100, 150, 200m3/h• Isothermal cases• Floor: with CO2 concentration in 2000mg/m3• Other walls: with no CO2 emission • Deflector: 45 degree, 90 degree
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(a) 45 degree
(b) 90 degreeFigure 5 non-dimensional CO2 distribution along the line with y=0.51m, z=0.31m
Figure 6 influence of airflow rate on emission rate
![Page 12: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/12.jpg)
Influence of setting an extra outlet below the slatted floor on emission rate
(a) Left model, outlet 2 located at y=0.13m on the left
(b) Right model, outlet 2 located at y=0.13m on the right
(c) Top left model, outlet 2 located at y=0.235m on the left
(d) Top right model, outlet 2 located at y=0.235m on the right side
Figure 7 models in simulation with an extra outlet
1 - inlet, 2 - outlet 1, 3 - deflector, 4 - the slatted floor, 5 - manure surface, 6 -outlet 2
![Page 13: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/13.jpg)
Boundary conditions• Isothermal case
• Inlet: velocity in 0.2196m/s, turbulence intensity in 5% and automatic turbulence length scale, CO2 concentration in 900mg/m3
• Outlet 1: average pressure in 0Pa
• Outlet 2: 10%, 15%, 20%, 30% of ventilation rate
• Floor: CO2 concentration in 2000mg/m3
• Other walls: with no CO2 emission
Turbulence modelk model
![Page 14: Li Rong 1) , Peter V. Nielsen 1) , GuoHong Tong 2) Guoqiang Zhang 3) , Peter Ravn 3)](https://reader035.vdocuments.site/reader035/viewer/2022062322/5681439e550346895db01b59/html5/thumbnails/14.jpg)
(a) Total emission rate from outlet 1 and outlet 2
(b) Emission rate from outlet 1
Figure 8 Influence of setting an extra outlet below the slatted floor on emission rate in 45 degree deflector setting models
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(a) Total emission rate from outlet 1 and outlet 2
(b) Emission rate from outlet 1
Figure 9 Influence of setting an extra outlet below the slatted floor on emission rate in 90 degree deflector setting models
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Conclusion
• K-e model is an appropriate model to predict concentration distribution in this case
• Airflow patterns have an important effect on concentration distribution and the emission rate increases with increasing the airflow rate as expected
• Setting an extra outlet below the slatted floor can decrease the emission rate if the contaminants can be cleaned completely from this outlet and the emission rate will decrease when the percent of the ventilation rate from the outlet below the slatted floor increases in these cases
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Thank you very much!