BREAKDOWN OF A HEATED LIQUID INITIAL BREAKDOWN OF A HEATED LIQUID FILM IN COCURRENT TWO-COMPONENT ANNULAR FLOW: I. SMALL PERTURBATION MODEL

A small perturbation theory is developed for the breakdown of a thin evaporating liquid film draining down a heated tube subject to a non-negligible surface shear stress. ¹The film is always so thin that entrainment is negligible. The usual traveling wave is here not adequate, and a time-independent surface perturbation which is exponential in the flow and periodic in the cross-stream direction is assumed. The appropriate Orr-Summerfeld equation and boundary conditions are then derived. Comparison with experimental data, using a large effective contact angle, obtained from the lower bound of the eigenvalue spectrum, gives good agreement for the critical Reynolds number.