This project uses time-dependent liquid crystal thermography to capture images of the incipient pool phenomenon in dielectric fluids. The results focus on two issues: the distribution of temperature across the heated surface, and the inherently transient nature of the incipient boiling phenomenon. The technique produces a temporal sequence of images of the surface temperature distribution. These images show the surface temperature patterns as the system approaches, passes through, and sustains nucleate pool boiling. Of particular interest is the transient process by which the nucleation sites activate and grow in number to displace the single-phase convection. The effects of surface preparations, fluid subcooling, and content of dissolved gases will be investigated. The results include real-time color images, and measurements of the spatial-averaged surface temperature and surface temperature spectra for selected configurations.
