scope:

ABSTRACT

The present numerical investigation was carried out using ANSYS FLUENT CFD (Computational Fluid Dynamics) package to investigate how to attain the required thermal comfort for the travelers in metro cabins. Full three dimensional governing equations of mass, three momentum, energy and species concentrations were solved. The turbulence characteristics of the flow were represented through the application of the RNG k-epsilon model equations as turbulence closure assumptions. Tetrahedral mesh grids of different sizes were used in the present study and typically about 7,000,000 mesh volumes and 1,000 iterations for each case yielded grid independent and converged solutions. CFD simulations are incorporated to indicate the effects the location of air inlets at the ceiling and the variation of the locations of air outlets inside the metro cabin on attaining thermal comfort conditions. The main objective of the research conducted is to examine the airflow regimes and thermal comfort in metro cabin using computational fluid dynamics (CFD) software. The designed air velocities, typically used in Cairo Metro Cabins , were in the range from 0 to 0.12 m/s(24 fpm) and this provides thermal comfort; the range of temperature was from 19 to24^oC(66 to75 ^oF) considering the expected rise in the temperature at locations between the passenger's bodies due to crowdness.