Heat and mass transfer in hydrothermal systems, physical-mathematical models and experiments

Abstract

In order to investigate processes of heat and mass transfer as well as the dynamics of the formation of temperature fields of natural hydrothermal systems physico-mathematical models were developed which accounted for actual conditions of contemporary hydrothermal processes (temperature, pressure, thermo-physical properties or rocks, latent heats of transitions, etc.). The modelling of natural non-stationary processes of heat and mass transfer was realized through a physical and mathematical model complex. The mathematical model consists of a system of partial differential equations for a two-layer medium (liquid and solid) with an immobile boundary between solid and liquid phases. Models of this type were performed on an IBM computer. Physical models were carried out by means of a hydrothermal experiment at elevated temperatures (up to 200 °C) and pressures. The main problem in development and realization of models consists in the investigation of dynamics of origin and existence of temperature - moisture field or temperature and moisture distribution in time and space in the movement area of hydrothermal solutions. The quantitative result of the realization of models of the temperature and moisture fields near the fissure channels, being the movement paths of the thermal spring, is a graphical representation of temperature and moisture variation in time and space coordinates. Arising anomalies of temperature and moisture fields are interpreted as a result of the geothermal gradient action, the thermophysical features, the rock composition and pressure. The results obtained allow us to estimate the absolute formation time and the life of hydrothermal systems depending on some geological factors. The physico-mathematical modelling of heat and mass transfer in a number of actual cases can serve as a method of estimation and prediction of temperature fields arising as a result of hydrothermal activity in modern volcanic regions, and as a theoretic investigation method for various kinds of genesis of hydrothermal systems.