Interaction between seepage and temperature fields in different groundwater flow systems

Abstract

In the regions with rich geothermal resources, it is necessary to study the interaction between the seepage and temperature fields under different groundwater flow systems.Based on numerical simulation and sandbox experiments in a two-dimensional unconfined groundwater basin with multi-sources and sinks, we changed the rainfall infiltration intensity and studied the changes of seepage and temperature fields under different temperature difference between surface and bottom by heating the sandbox bottom.The results showed that with the increasing of the rainfall infiltration intensity, the groundwater velocity increased, groundwater flow systems presented changes from single regional system to a complex local-regional nested system and local-intermediate-regional nested systems, and the groundwater flow had a greater impact on the temperature redistribution.The isotherm in the recharge area moved down under the influence of downward groundwater flow, while the isotherm in the discharge area was lifted up under the influence of upward groundwater flow.And the temperature change in the regional recharge and discharge areas were the most obvious.After heating the sandbox bottom, the water table of the unconfined aquifer decreased and the groundwater velocity increased.Overall penetration depth of streamline became larger, and the scope of stagnant zones decreased.The geothermal energy becomes a nonnegligible driving power in the study of groundwater flow systems in rich geothermal areas.

Keywords

• groundwater flow systems
• numerical simulation
• sandbox experiment
• seepage field
• temperature field