Распространение осесимметричной турбулентной струи метана в спутном потоке воздуха при горении с конечной скоростью

Abstract

The paper introduces a numerical method for solving the problem of the axisymmetric methane jet propagation in an infinite co-current air flow. For modeling, we used the dimensionless equations of the turbulent boundary layer of reacting gases in the Mises coordinates. To close the Reynolds equation, a modified k - ε turbulence model was used. The k - ε model is considered a low Rhine turbulence model. Assuming that the intensities of convective and turbulent transfers of components are the same and using the stoichiometric ratios of the concentrations of components during combustion, we reduced five equations for the transfer and conservation of the mass of components to two equations for the relative excess concentration of the combustible gas. The concentrations of the components were determined from the solutions of these equations. By using relatively excessive velocities and total enthalpy, we reduced the boundary conditions for the three equations to a general form. To solve the problem in the Mises coordinates, we used a two-layer, six-point implicit finite-difference scheme, which provides the second order of accuracy of approximation in coordinates. The equations for the conservation and transfer of substances being non-linear, an iterative process was implemented. The influence of the radius of the fuel nozzle on the indices of the turbulent jet and flame was investigated. Findings of research show that in an endless co-current flow of fuel with a decrease in the radius of the nozzle, the rate of the chemical reaction and the maximum temperature in the calculation area decrease, and the amount of unburned part of the combustible gas increases