Heat Pipes and Through-Flows in Geothermal Reservoirs

Abstract

Previous work on steady vertical steam-liquid counterflow in a porous medium, driven by both gravity and capillary pressure, is extended to cases where there is some net mass through-flow. Visualisations of nullcline surfaces are used to analyse solution behaviour. Implications for steady-states with through-flow in geothermal reservoirs are discussed. In particular, a fixed point in the temperature-saturation phase plane is found, when net mass and energy both flow downwards. This fixed point, which dominates solution behaviour, corresponds to a steady solution with constant temperature, pressure and saturation, in free-fall (driven only by gravity).