The interaction of turbulence and pressure gradients in a baffle-stabilized premixed flame

摘要: Simultaneous measurements of time-resolved velocity and temperature have been obtained by laser-Doppler anemometry numerically compensated fine-wire thermocouples in the near wake a premixed flame stabilized on disk baffle located axis, at exit, confining pipe. The diameter was 0.056 m, pipe 0.080 volumetric equivalence ratio with natural gas as fuel 0.79 Reynolds number, based upstream bulk 9 m/s, 46 800. purpose is to quantify relative magnitudes terms involving mean pressure gradient stresses balance turbulent kinetic energy heat flux strongly sheared, high-Reynolds-number, reacting flow. latter term has associated non-gradient diffusion other flows. Source are large conservation but not stress. ‘thin-flame’ model burning suggests that sign magnitude closely related conditioned velocities. axial reactants larger (by up 0.27 reference velocity) than products low-velocity side shear layer surrounds recirculation bubble reverse true high-velocity side. These observations gradient, which streamline curvature, consequent preferential acceleration low-density products. Generally, higher those and, contrast previously reported measurements, contribution unconditioned difference between reactants, so-called ‘intermittent’ contribution, small. This consequence high number our