Lenci (2026) Thermo-viscous feedback in heat transport through fracture–matrix systems with finite thermal capacity

Identification

• Journal: Advances in Water Resources
• Year: 2026
• Date: 2026-10-26
• Authors: Alessandro Lenci
• DOI: 10.1016/j.advwatres.2026.105544

Research Groups

• Department of Civil, Chemical, Environmental, and Materials Engineering (DICAM), University of Bologna, Italy
• Department of Energy Science & Engineering, Stanford University, USA
• Univ Rennes, CNRS, Géosciences Rennes, UMR 6118, France

Short Summary

This study investigates the thermo-viscous feedback in heat transport through fracture-matrix systems with finite thermal capacity. The research reveals how viscosity contrast affects hydraulic response and breakthrough timing under fixed pressure difference.

Objective

• Investigate the effects of temperature-dependent viscosity on heat transport in fracture-matrix systems
• Analyze the impact of finite matrix thickness on breakthrough timing and front spreading

Study Configuration

• Spatial Scale: Planar fracture embedded in a finite matrix, with length L and half-aperture b
• Temporal Scale: Advection time ta = L/u0, where u0 is the reference velocity

Methodology and Data

• Models used: Reduced theory combining finite conductive memory with temperature-dependent hydraulic resistance
• Data sources: Numerical simulations using a nonlinear reference solution and perturbation expansion

Main Results

• The integrated hydraulic resistance links viscosity to discharge at fixed pressure difference
• Matrix diffusion and capacity set the timescales over which the terminal velocity is approached
• Viscosity contrast affects breakthrough timing, tails, and front spreading under strong matrix uptake
• Finite-matrix similarity collapses onto a two-variable similarity surface

Contributions

• This study provides a controlled baseline for separating mechanisms from geometrical, mechanical, buoyant, and multiphase effects in fracture-matrix heat transport
• The reduced theory offers a parsimonious semi-analytical framework for predicting thermal breakthrough in enhanced geothermal systems

Funding

• Not specified

Citation

@article{Lenci2026Thermoviscous,
  author = {Lenci, Alessandro},
  title = {Thermo-viscous feedback in heat transport through fracture–matrix systems with finite thermal capacity},
  journal = {Advances in Water Resources},
  year = {2026},
  doi = {10.1016/j.advwatres.2026.105544},
  url = {https://doi.org/10.1016/j.advwatres.2026.105544}
}