Film-Boiling Heat Transfer From a Horizontal Surface

TLDR

Taylor‑Helmholtz hydrodynamic instability governs film‑boiling heat transfer from horizontal surfaces. Near the minimum film‑boiling heat flux, bubble spacing and growth are governed by Taylor instability, and a simplified geometrical model yields analytical expressions for the heat‑transfer coefficient and temperature difference at the minimum that agree with experimental data within ±10 % for n‑pentane and carbon tetrachloride.

Abstract

Taylor-Helmholtz Hydrodynamic Instability and its significance with regard to film boiling heat transfer from a horizontal surface is discussed. It is shown that near the minimum film-boiling heat flux, the bubble spacing and growth rate is determined by Taylor Instability neglecting the effect of fluid depth and viscosity. Utilizing a simplified geometrical model, an analytical expression for the heat-transfer coefficient near the minimum in film pool boiling from a horizontal surface was derived. Combining this equation with the available correlation for the minimum heat flux yields an analytical equation for the temperature difference at the minimum, which defines the location of the minimum point. The above equations agree with the available experimental measurements made on n-pentane and carbon tetrachloride within ±10 per cent.