APPLICATION OF A SCHLIEREN TECHNIQUE TO HEAT-TRANSFER MEASUREMENTS INFREE-CONVECTION

The application of a quantitative schlieren technique to the study of two-dimensional free convection heat transfer is presented. As it is w ell known, the schlieren technique utilizes the refraction of light ra ys to display a pattern related to the temperature field. The schliere n system employed here makes use of an opaque filament to identify reg ions of fluid that deflect light rays by the same amount. The schliere n images recorded enable the temperature field and local heat transfer coefficients to be reconstructed. After a description of the experime ntal technique, results concerning standard geometrical configurations (a single, vertical plate and parallel vertical channels) are present ed and compared with theoretical predictions and numerical computation s.