HYDROGEN COMBUSTION DESCRIBED WITH INCOMPRESSIBLE-FLUID APPROXIMATION

Burning of small hydrogen concentration in air is a slow process with spatially uniform pressure. Thus it can be modelled with methods adopt ed from incompressible flow. Burning in a cylindrical vessel is descri bed by the full Navier-Stokes (N - S) system of differential equations , where the pressure field is decomposed into a steady part, equalized throughout the vessel, and the dynamic part, which is only taken into account in the equation of motion. Chemical kinetics of the reaction is described by a single activation term. Turbulence is introduced in the Prandtl mixing-length approximation. Numerical algorithm basis on the standard MAC (Marker and Cell, [2]) method: staggered grid is used , the Poisson equation for the dynamic pressure is solved and the full y explicit scheme is adopted for the other variables. Results of the t wo-dimensional model are compared with the results of an explicit sche me for the compressible fluid flow and with the experimental data.