Burning rate of liquid supplied through a wick

Abstract

Liquid fuel supplied through ceramic or metallic wicks is commonly used as a simulant for burning of planar liquid or solid surfaces. When the liquid flow through the wick is at least partly controlled by capillarity, the partially exposed wick matrix at the burning surface changes the concentration distribution adjacent to this surface. Here we show that when the characteristic length of the exposed matrix is not significantly smaller than the convection boundary-layer thickness, the burning rate from the wick deviates (being smaller for low thermal conductivity wicks) from that for planar liquid surfaces. The study is guided by experiments using a ceramic wick, by a one-dimensional gas-side diffusion analysis, and by a wick-side two-phase flow and heat transfer analysis.