Characterization of a toroidal well stirred reactor

Abstract

A stirred combustion reactor has been deveoped to provide substantially better mixing characteristics than in the classis spherical desig. Mixing is achieved in a toroidal design with a high velocity swirling flow. The premixed fuel and air enter the reactor at sonic velocity through 32 jets located on the outside circumference of the toroid. The jets are angled so that they can penetrate and be rapidly dispersed, into the swirling flow. The reactor exhausts through ports on the inside circumference of the toroid. For fuel lean conditions, time average temperature, is evenly distributed in the reactor; however, under fuel rich conditions the temperature is lower than average at the centerline and at the walls. Time resolved measurements, of ion concentration, in an ethylene flame, show no evidence of unburned eddies. A theoretical study of the reactor behavior for CO+H 2 combustion with heat losses based on a comprehensive reaction scheme is compared with experimental data for temperature and blowout, with good agreement. Soot free toluene and ethylene combustion was possible in the reactor with substantially less oxygen than reported in the literature for hemispherical reactors. A coalescence-dispersion model of CO/H 2 combustion gave time average radical concentrations that deviate a maximum of 12% from the completely mixed case for mixing frequencies in the range estimated from jet entrainment estimates and from an isotropic turbulence model. While fluctuations in the concentration of the most reactive flame intermediates are indicated and require futher study, the reactor is judged to be useful for study of reactions such as nitric oxide formation, polycyclic aromatic hydrocarbon synthesis, soot formation, and combustion of near limit fuel-lean mixtures.