Library Subscription: Guest

ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

THE BOUNDARY LAYER WITH COMBUSTION UNDER COMPLICATED CONDITIONS

Get access (open in a dialog) DOI: 10.1615/IHTC13.p26.180
10 pages

Abstract

This work deals with studying the effect of various gas-dynamic perturbations on transfer processes within a reacting boundary layer. Experiments were carried out at ethanol evaporation into an air flow with velocity of up to 70 m/s, turbulence level of 1, 8, 18% and ethanol combustion behind an obstacle with a height of h<15 mm, acceleration parameter was K<19·10−6. The burning rate was measured; data on the fields of longitudinal velocity and its pulsations were obtained using a laser Doppler anemometer. The method of Rayleigh scattering was used for temperature measurements. Distribution of OH radicals was studied using laser-induced fluorescence.
It was found out that limited areas with increased levels of velocity pulsation, OH concentration and temperature pulsation are formed in the turbulized boundary layer behind an obstacle. They correspond to surface regions with an increased burning rate and exist together with longitudinal non-uniformity of the flow structure.
Alterations of the burning rates were determined in the studied range of combustion modes; friction was estimated by analysis of integral characteristics. It is shown that the choice of streamlining conditions can change mass transfer intensity from the level, typical for a laminar boundary layer to the values, characteristic for separated flows. Friction in an accelerated flow with combustion can be higher by an order than friction in a laminar flow.