Flow and heat transfer characteristics of seepage-channel wall to injected suspended particles in a groundwater heat pump system

• Published in: Geothermics Vol. 103; p. 102411
• Main Authors: Song, Wei, Wang, Zihan, Liu, Xiaoxiu, Wang, Hao, Zhang, Qian
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2022; Elsevier Science Ltd
• Subjects: Aquifers; Artificial injection; Capillary flow; Clogging; Deposition; Design optimization; Fluid flow; Geothermal power; Groundwater; Groundwater heat pump; Heat exchangers; Heat pumps; Heat transfer; Injection; Particle migration; Particle size; Pipe flow; Porous media; Pressure; Pressure drop; Roughness; Seepage; Temperature gradients; Artificial injection; Clogging; Particle migration; Heat transfer; Groundwater heat pump
• ISSN: 0375-6505; 1879-3576
• DOI: 10.1016/j.geothermics.2022.102411

•Particles flowing in a finite channel are described using two-phase flow theory.•Suspended particle size affected the temperature gradient of rough pipe boundary.•Factors affecting particle flow and deposition were judged via orthogonal analysis.•Injection fluid influences particle deposition and energy loss in finite pipes. Well and aquifer clogging caused by deposition of particles is a serious problem that restricts the application and heat transfer efficiency of groundwater heat-pump systems. Mixed flow of particles and fluid in a porous medium was simplified to pipe flow based on a capillary model. A migration test bench for suspended particles was set up to explore the flow and heat transfer response of the seepage channel to the injecting suspension by varying suspended particle size (Dp), roughness of pipe wall (K), and injection pressure (Pin). The results show that the pressure drop of the suspension was influenced by the factors in the order Pin > Dp > K. Suspended particles were deposited at the entrance of the seepage channel, and deposition increased with increasing particle size. The temperature variation of the channel wall was sensitive to particle size. The temperature gradient of the suspension with a particle median size of 17.62 μm was 0.049 °C/min when the injection pressure was 1.8 kPa and wall roughness was 1.65 mm, which was lower than at 0.148 °C/min, when the particle median size was 25.12 μm. This research provides insights into the design and optimization of injection projects to prevent particle clogging.