Coupled hydrothermal flows of liquid and vapor in welded tuff: numerical modeling of proposed experiment

Pretest calculations of a proposed small-scale, heat-pipe experiment have been made using a finite element, multiphase flow, computer code. The purpose of the experiment is to characterize the response of partially saturated, welded, volcanic tuff to the two-phase countercurrent flow induced by an applied temperature gradient. The experimental measurements will be used to refine the presumed permeability and capillary pressure functions, which are used in the finite element analysis. The calculations presented in this paper, using the presumed material functions, show that saturation profiles and experimental time scales are sensitive to applied temperature gradients and initial liquid saturations. The results have been used to predict appropriate experimental parameter ranges