Novel multi-phase transport processes using yield stress fluids

粘塑性流体(具有屈服应力)广泛存在于工业和自然界中，例如牙膏、湿面食、水泥和泥浆、发胶、油漆悬浮液。具有屈服应力的流体即使在施加剪切应力的情况下也可能保持不变。作为例子，考虑一下墙上的一层油漆，杯形蛋糕上的新鲜糖霜，被困在加工机械中的酸奶，或者在固井过程中卡在井筒里的钻井液。尽管有时会产生负面影响，但屈服压力也可能被以新的方式利用，从而导致新的流动。这个项目的第一部分旨在开发2个这样的新流程应用程序。该项目的第二部分涉及如何以更有效的方式计算屈服应力流体中的悬浮物。 第一个新的应用领域涉及液滴的封装和运输(大规模)。第二个新应用涉及沿管道高效输送粘性流体。这两种应用都依赖于UBC开发的一项技术，该技术通过在流体之间的界面(VPL流)使用屈服应力流体来消除界面不稳定性(即波和最终的混合)。这些流量的目标应用可能在石油和天然气行业，尽管泥浆管道和食品加工也有可能。第一个项目将改善井筒完整性，以加强碳酸盐岩油藏酸压裂等井下化学品的输送。第二个项目的目标是使用减少的电力长距离运输重油。 关于该项目的第二部分，非牛顿悬浮流在加拿大的资源和能源行业中的应用非常广泛，例如清孔(油井)、开采尾矿的运输和沉积、稠密的纸浆纤维流、一些粘性支撑剂的运输。然而，缺少关键的理解、模型，特别是计算工具，本项目旨在纠正这一点。最近的进展使我们相信这是可能的。这在很大程度上将是方法论上的影响，使其他国家能够解决以前无法解决的问题。 该项目还为2名博士生和1名博士后提供培训，我们希望他们能带着新技能进入加拿大劳动力大军。

Visco-plastic fluids (with a yield stress) occur widely in industry & nature, e.g. toothpaste, wet pasta, cement and mud slurries, hair gel, paint suspensions. Fluids with yield stress may remain stationary even under an applied shear stress. As examples, consider a paint layer on a wall, fresh icing on a cupcake, yoghurt trapped in processing machinery or drilling fluid stuck in a wellbore during cementing. Although sometimes having a negative effect, the yield stress may also be exploited in novel ways leading to new flows. The first part of this project aims to develop 2 such new flow applications. The second part of the project concerns how to compute suspensions held in yield stress fluids in more efficient ways. The first new application concerns droplet encapsulation and transport (on a large scale). The second new application concerns efficient transport of viscous fluids along pipelines. Both applications rely on a technique developed at UBC for eliminating interfacial instabilities (i.e. waves and eventual mixing) by using a yield stress fluid at the interface between fluids (VPL flows). Target applications for these flows would likely be within the oil & gas industry, although possibilities exist in slurry pipelining and food processing. The first project would improve wellbore integrity in enhancing delivery of downhole chemicals in e.g. acid fracturing of carbonate reservoirs. The second project is targeted at transport of heavy oil over long distances using reduced power. Regarding the second part of the project, applications of non-Newtonian suspension flows are very widespread in Canada’s resource and energy industries, e.g. hole-cleaning (oil wells), mined tailings transport and deposition, dense pulp fiber flows, some viscous proppant transport. Key understanding, models and particularly computational tools are however missing and this project aims to correct this. Recent advances lead us to believe that this is possible. The impact of this would be mostly methodological, allowing others to tackle previously unreachable problems. The project also provides training for 2 PhD students and 1 postdoc, whom we hope will enter the Canadian workforce with their new skills.