Measurement and Calculation of Furnace-Flow Properties

Abstract

Measurements of the three components of mean velocity, the corresponding normal stresses, mean temperature, and wall heat flux are reported in a model furnace; they were obtained with a coaxial burner with a 20° quarl angle and swirl numbers of 0.3 and 0.5. Particular attention is devoted to the influence of the profiles in the plane of the burner exit; it is shown, for example, that combustion results in large increases in the values of maximum positive and negative velocity in the near-burner region and that the two swirl numbers result in significantly different profiles of all the measured flow properties. The variations in local furnace properties, including the wall heat flux, are quantified for the two swirl numbers and shown to agree, in general terms, with previous calculations; the location of maximum heat flux, for example, is significantly closer to the burner exit for the larger swirl number. Calculations, obtained from the numerical solution of conservation equations in differential form, are presented and compared with the measurements. Particular attention is devoted to the uncertainties associated with density fluctuation correlation and with the specification of a probability density distribution of scalar fluctuations. An attempt is made to quantify the precision with which calculations of furnace flow properties can presently be calculated.