Aerodynamic Equilibrium and Stability in Ventilation and Air Quality Control of Complex Urban Tunnels

Modern urban vehicular tunnels generally have a branched structure and complex nonlinear aerodynamics. The authors established and analyzed the 1-D aerodynamic equations and pollutant dispersion model in such bifurcate hydraulic networks. To design a tractable model that captures system complexity, the authors proposed a novel piecewise-affine (PWA) approximation for the flow-dependent local pressure-loss coefficients at tunnel junctions. This enables them to model the flow system via first-order ordinary differential equations (ODEs) with piecewise-quadratic polynomials. The authors proved a fundamental and easily verifiable sufficient condition for the uniqueness and stability of the steady-state solution of each ODE piece. The authors also demonstrated via a numerical study that for the entire system (across different ODE pieces) there may exist multiple stable steady-state solutions, which can lead to different CO concentration distributions in the system. This study provides a systematic modeling tool and a theoretical foundation for air quality management in complex tunnels.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; References; Tables;
  • Pagination: 17p

Subject/Index Terms

Filing Info

  • Accession Number: 01716090
  • Record Type: Publication
  • Contract Numbers: 69A3551747119
  • Files: UTC, NTL, TRIS, ATRI, USDOT
  • Created Date: Aug 30 2019 1:55PM