Heat transfer analysis in artificial ground freezing under high seepage: Validation and heatlines visualization

Abstract

The primary goal of artificial ground freezing (AGF) system is to create a hydraulic barrier encircling working areas and stall groundwater seepage. This goal is achieved once a consolidated frozen wall is developed between the freeze pipes. Groundwater flow, however, has an undesirable effect on the formation and the growth rate of the frozen body - high water flow could hamper, totally, the establishment of a merged frozen wall between two freeze pipes. Therefore, it is of great interest to evolve a reliable prediction of the transient response of the ground structure toward the AGF process under high seepage flow conditions. This work interprets the multiphase heat transfer that accompanying the development of a frozen body between two freeze pipes with and without the presence of the groundwater seepage. A mathematical model has been derived, validated, and implemented to simulate the effect of the coolant's temperature, the spacing between two freeze pipes, and the seepage temperature on the closure time and the shape of the frozen body. The results are presented in terms of temperature fields, phase-change interface, velocity-streamlines, and heatlines. The results indicate that spacing between two pipes and seepage velocity have the highest impact on the closure time and the frozen body width.