Optoelectronic visualization and study of heat transfer from metal wires to water by a compact Schlieren system

摘要

The aim of this paper is to present some results in the experimental study of heat transfer in fluids by optoelectronic methods. The thermal source was a thin metal wire (TMW) heated by electrical impulses and the propagation medium was the distilled water. We studied the following configurations for the thermal wave propagation and heat transfer. (1) Horizontal TMW far from the water tank walls; (2) Horizontal TMW in the proximity of a vertical metal wall and at a discontinuity introduced by another metal wire; (3) Horizontal TMW with a controlled air bubble flow. The phase perturbations in the transparent medium were visualized by a compact schlieren system with laser diode illumination and were digitally processed in a PC. These results offer a better understanding of some progressively complex thermohydrodynamic phenomena. Some possible applications are in visualization of the route to turbulence in these flows and in designing calibrated phase objects.