Testing Vortex Identification Methods on a Synthetic Velocity Field

ABSTRACT: The present study is devoted to the experimental investigation of the boiling process of promising dielectric refrigerants HFE 7100 and Novec 649 on silicon substrate at atmospheric pressure. The purpose of the research is to determine the key heat transfer parameters, specifically nucleation temperature, heat transfer coefficients, critical heat fluxes, as well as the growth dynamics of irreversible dry spots, using the high-speed IR thermography method. It has been found that the boiling of Novec 649 is characterized not only by higher heat transfer coefficients and a lower nucleation temperature head, but also by lower critical heat fluxes (151 kW/m²) compared to HFE 7100 (183 kW/m²). The propagation velocity of irreversible dry spots during the boiling crisis development on a silicon substrate has been measured. For Novec 649, the velocity (6.8 mm/s) turned out to be lower than for HFE 7100 (10.4 mm/s). The obtained experimental data have been generalized and methods for calculating the basic thermal characteristics based on known theoretical models for silicon–dielectric fluid systems have been proposed. The research results are also of practical importance, providing engineers with specific data for designing highly efficient direct cooling systems for silicon wafers using dielectric fluids.