A model of unmixedness for turbulent reacting flows
Abstract
Unmixedness caused by turbulent fluctuations leading to a situation in which the instantaneous value of fuel or oxidizer concentration and, therefore, the instantaneous chemical reaction rate vanish, is investigated. A simple model is developed, making possible the evaluation of the decrease in overall reaction rates, without incurring a serious penalty in computer time and memory. The model leads to a mixing length type relation connecting the local value of the r.m.s. fluctuating concentration of a given species to the local gradient of its mean concentration and to the lengthscale of the turbulent motion. Different cases are distinguished according to the possible combinations of turbulence level and mean concentration gradient.
 Publication:

Acta Astronautica
 Pub Date:
 April 1976
 DOI:
 10.1016/00945765(76)900515
 Bibcode:
 1976AcAau...3..265S
 Keywords:

 Chemical Reactions;
 Diffusion Flames;
 Mathematical Models;
 Reaction Kinetics;
 Turbulence Models;
 Turbulent Flow;
 Boundary Value Problems;
 Hydrogen;
 Jet Flow;
 Nitrogen;
 Oxygen;
 Run Time (Computers);
 Water;
 Fluid Mechanics and Heat Transfer