Coupled Transport Modelling of Evaporative Cooling

A liquid-filled ceramic vessel cooling in still-ish air is the kind of problem that looks like a heat transfer question and is not. The question I wanted a number for: how much of the cooling is evaporation, and how much is everything else?

The model

Three-dimensional, coupling turbulent airflow, heat transfer, and evaporative mass transfer. A stationary turbulent-flow field is solved first, then transient heat and moisture transport runs on top of it.

From there I swept the parameters that plausibly matter: ambient temperature, relative humidity, and latent heat of vaporisation.

The result

Neglecting latent heat shifted the predicted ten-minute liquid temperature by roughly 14 percent. Relative humidity, over the range tested, produced a substantially smaller effect.

That is the useful part of the exercise. The evaporative term is not a correction you can drop for convenience, and the sensitivity to humidity is small enough that the ambient condition you cannot control matters less than the physics you might be tempted to leave out.

Mass Transfer course project.