Abraham H. Barry (ventilation network analysis presentation)
1. University Of Liberia
College Of Engineering
Department Of Mining Engineering
Ventilation Network Analysis
Presented By: Abraham H. Barry
ID#70800
Presented To: Shri Adolphus M. G. D.
Gleekia
3. Ventilation Network Analysis
Introduction and Overview
Fundamentally the application of the principles of
Fluid dynamics and Thermodynamics
4. Ventilation Network Analysis
Introduction and Overview
Fundamental component in the design of a new
underground mine or other subsurface facility
Ventilation network analysis aids:
Quantified planning of the circulation of airflows
Identification of locations and duties of fans
Establishment of tolerable environmental
conditions
5. Ventilation Network Analysis
Introduction and Overview
Questions Ventilation Analysis answer:
What Is the behavior of airflows?
What are the resistances of the branches ?
What is the best Arrangement for desired results?
6. Ventilation Network Analysis
Kirchhoff's laws
Introduced by Gustav R. Kirchhoff
The same basic relationships that govern the
behavior of electrical current
Uses the Laws of Conservation of:
Mass
Energy
Most Basic and useful tool in the analysis of
ventilation networks
7. Ventilation Network Analysis
Kirchhoff's laws
Kirchhoff's first law states that the mass
flow entering a junction equals the mass
flow leaving that junction.
8. Ventilation Network Analysis
Kirchhoff's laws
Mathematically Kirchhoff's Law may be stated as:
Where M is the mass flow of air entering and
leaving junction i.
Where Q is the Volume flow rate and ρ is the
density.
9. Ventilation Network Analysis
Kirchhoff's laws
In subsurface ventilation system, the difference in
air density around any single junction is negligible
Valuable and useful tool in the calculation and
verification of airflow measurements taken around
a junction.
10. Ventilation Network Analysis
Kirchhoff's laws
• Kirchhoff's second law states that the algebraic
sum of all pressure drops around a closed path, or
mesh, in the network must be zero.
0
11. Ventilation Network Analysis
Kirchhoff's laws
Steady flow energy equation initially for a single
airway.
Where:
U= air velocity, Z= height above datum,
W= work input from fan, V= specific volume
P= barometric pressure, F= work done against
friction.
15. Ventilation Network Analysis
Analytical methods
Equivalent resistances:
Most elementary methods of analysis.
Limited value in the analysis of complete
networks.
Considerable simplification of the schematic of
actual subsurface ventilation systems.
17. Ventilation Network Analysis
Analytical methods
Equivalent resistances:
For a series circuit
For a parallel circuit
18. Ventilation Network Analysis
Numerical methods
A method of successive approximation.
First proposed by Atkinson in his paper of 1854.
Impractical until 1960s (Digital computer age)
Contributor to the numerical method:
• Y. J. Wang
• Professor Hardy Cross
• D. R. Scott
• F. B. Hinsley
20. Ventilation Network Analysis
Conclusion
All ventilation circuits can be rearranged into
either a series or parallel circuit.
With Kirchhoff’s equations we can determine:
Airway resistance.
Total airflow.
Ventilating pressure.
Numerical method presents better analytical tool
for the accurate estimation.
Computer programs run on the ideas introduced
by numerical analysis.
21. Ventilation Network Analysis
References
• Hartman, H. L., Mutmansky, J. M., Wang, Y. J., & Ramani, R. V.
(1997). Mine Ventilation Circuits and Networks. In H. L. hartman, J. M.
Mutmansky, Y. J. Wang, & R. V. Ramani, Mine Ventilation and Air
Conditioning (Third Edition ed., pp. 240-290). Canada: JOHN WILEY
& SONS, INC.
• MacPherson, M. J. (1993). Ventilation network analysis. In M. J.
MacPherson, Subsurface Ventilation and Environmental Engineering
(pp. 209-275). Virginia, USA: SPRINGER-SCIENCE+BUSINESS
MEDIA, B.V.
• RAMANI, R. V. (1992). MINE VENTILATION. In H. L. Hartman
(Ed.), SME Mining Engineering Handbook (2nd Edition ed., Vol.
Volume 1, pp. 1069-1109). Littleton, Colorado, USA: Society for
Mining, Metallurgy, and Exploration, Inc.