Physics of Critical Heat Flux
Evaporation momentum theory Vs Hydrodynamic instability theory
Project Overview
Our research investigates the underlying physics of critical heat flux (CHF), a fundamental limit in heat transfer from a heated surface to a surrounding boiling liquid. This phenomenon has been extensively studied since Nukiyama’s discovery in 1934, leading to various hypotheses and predictive models by Kutateladze, Steinchen, Sefiane, Zuber, and Kandlikar.
Key Findings and Contributions
We conducted experimental and analytical studies on liquids with diverse thermophysical properties on planar heater surfaces of varying sizes. Our results reveal that the evaporation momentum limit (CHFEM) can reach approximately four times the value of Zuber’s limit (CHFZuber). We demonstrated that CHFEM is observed when the hydrodynamics of the liquid and vapor above the surface are stabilized, representing an ultimate limit governed by a force balance at the surface-fluid interface.
Our findings show that CHF progressively increases beyond the Zuber limit with decreasing heater length-to-capillary length ratio (lh/lc). Specifically, CHFEM is observed for lh/lc < 1, while the hydrodynamic limit is observed for lh/lc > 1. This research advances our understanding of CHF and its limits, providing valuable insights for the design of high-performance cooling systems.
For more details, please refer to our publication: Critical Heat Flux Study.