Simulating Heat Transfer During Transient Dropwise Condensation on a Low Thermal Conductivity Substrate

The instantaneous heat transfer performance of a surface is dictated by the number and the sizes of drops on the surface. While performance averaged over longer times is of interest from a technology standpoint, accurate simulation of the transient state is important in condenser design, because the maximum heat rejection of the surface occurs in this range. Steady-state dropwise condensation can be thought of as a collection of transient dropwise condensation cycles occurring in parallel. Traditional simulation of dropwise condensation has focused on making comparisons with experimental drop-size distributions at later times, after the process has reached statistical stationarity where the heat transfer is lower. Understanding how to model and simulate transient dropwise condensation where a maximum in heat transfer occurs, will help us design higher heat rejecting surfaces. Additionally, a constant temperature difference between the steam and the surface below the drop is assumed. While often valid, the...