Download Free An Investigation Of Ducted Two Stream Variable Density Turbulent Jet Mixing With Recirculation Book in PDF and EPUB Free Download. You can read online An Investigation Of Ducted Two Stream Variable Density Turbulent Jet Mixing With Recirculation and write the review.

An investigation was conducted of two-stream, variable-density, turbulent jet mixing with recirculation confined within an axisymmetric duct that simulated a combustor configuration. The recirculating flow fields in the combustor simulator were the result of coaxial jet mixing between a central, primary air stream with a velocity of about 650 ft/sec and an annular secondary stream of hydrogen with velocities of 13, 23, or 48 ft/sec, depending on the desired test conditions. Experimental measurements are presented of radial distributions of time-averaged axial velocity and hydrogen mass fraction, axial distributions of time-averaged static pressure on the duct wall, axial velocity on the duct centerline, and hydrogen mass fraction on the duct wall and on the duct centerline. A theoretical study of the experimental flows was also conducted using a finite difference numerical solution technique for the calculation of viscous, recirculating flows. Comparison of theory and experiment shows that the predictive technique and the turbulence transport model require further development before accurate prediction of recirculating turbulent flows can be realized.
An experimental investigation of ducted, two stream, subsonic, reactive, turbulent jet mixing with recirculation was conducted. A primary jet of air at a mass flow rate of 0.075 lb/sec and velocity of 700 ft/sec was surrounded by an outer, low velocity, hydrogen stream. Data were obtained with hydrogen-air ratios of 0.143 and 0.107. The duct-to-inner nozzle diameter ratio was ten. Radial distributions of hydrogen mass fraction, mean axial velocity, turbulence intensity, and total pressure as well as axial distributions of wall hydrogen mass fraction and wall static pressure are presented for axial stations from one-half to five duct diameters from the nozzle exit plane. Comparison of the experimental data with calculations assuming frozen or equilibrium chemistry indicate that he measured velocity, pressure, and composition data are, in general, self-consistent. The maximum turbulent intensities which occurred in the center of the mixing layer and within the recirculation eddy were very high having values of 20 percent of the jet exit velocity. The velocity and composition field indicate that, while and mixing in the reactive flow field is slower than for the nonreactive case, the reaction had little effect on the size and location of the recirculation zone within the mixing duct.
Mixing: Theory and Practice, Volume III is a five-chapter text that covers the significant improvements in the theoretical aspects and knowledge in mixing related to industrial-scale operations. The introductory chapters deal with the agitation of particulate solid-liquid mixtures and the turbulent radial mixing in pipes, with particular emphasis on the effects of jets and baffles on such mixing. The following chapter presents the theoretical analysis and experimental confirmation for predicting hydrodynamic characteristics and some process results in mechanically agitated vessels. Another chapter provides a comprehensive development of approaches and recommended practices for scale-up of agitated liquid equipment. The methods considered serve as a useful guide for reducing the risk of scale-up and scale-down catastrophes. The last chapter discusses the fundamental concepts and measures of the quality of mixing and the mechanisms of mixing and segregation. This chapter also introduces the process of continuous mixing of solids.
A numerical solution procedure for ducted, recirculating flows has been developed and applied to predict both turbulent pipe flow and ducted, coaxial jet mixing with recirculation. The solution procedure is based on a decay-function, finite-difference formulation applied to a system of governing equations based on stream functions and vorticity. The vorticity governing equation is complete in that no source terms have been deleted or neglected in its derivation from the Navier-Stokes equations. Boundary values for all dependent variables are defined by physically realistic conditions. Solutions obtained indicate that the accuracy of the solution procedure depends on having an accurate turbulent viscosity model. (Author).