STUDY OF FLOW AND HEAT TRANSFER CHARACTERISTICS IN A SWIRLING IMPINGING JET / ESTUDO DO ESCOAMENTO E TRANSFERÊNCIA DE CALOR EM UM JATO ESPIRALADO INCIDENTE

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The present work is an experimental study of the characteristics of a swirling impinging air jet. The goals of the study are: to evaluate the influence of the presence of a circumferential velocity component in the distribution of the local heat transfer coefficients, to obtain instantaneous velocity fields in the axisymmetric plane, as well as information about the turbulence characteristics in the flow. During the experiments, the influence of the impingement distance and swirl intensity were investigated. As a preliminary validation of the velocity measurement tecniques, an experimental investigation of an axisymmetric free jet was conducted. The results were compared with literature showing good agreement. The spatial distribution of heat transfer coefficients was evaluated by imposing a constant heat flux condition to the plate and measuring temperature of several points along the radial distance of the plate with thermocouples. Local coefficients could then be estimated. Instantaneous axial and radial velocity fields were obtained with Particle Image Velocimetry (PIV) and tangential velocity profiles (mean and fluctuations) obtained by using Laser Doppler Velocimetry (LDV). The results showed that the flow patterns change significantly when the tangential component is added. For the highest value of Swirl number, strong recirculation zones were observed in the stagnation region.

ASSUNTO(S)

velocimetria por imagens de particulas nusselt number numero de nusselt turbulencia turbulence velocimetria laser-doppler laser-doppler velocimetry jato espiralado particle image velocimetry swirling jet

ACESSO AO ARTIGO

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