水集群对高切割速率粘度的结构影响
Yitian Gao1, Jian Wu2, Yixuan Feng1
1State Key Laboratory of Hydro-science and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China.
The Journal of chemical physics
|March 8, 2024
概括
在液态水中切削稀释通过破坏键和改变水结构来降低粘度. 这种结构变化,用键粘度量化,与粘度变化直接相关.
科学领域:
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
- 计算物理 计算物理
背景情况:
- 液态水的独特的键网络影响其宏观性质.
- 了解剪切稀释对于流体动力学和材料科学至关重要.
研究的目的:
- 为了研究剪切稀释对液态水粘度的影响.
- 阐明键网络在剪切稀释中的结构变化的作用.
主要方法:
- 在剪切下液态水的分子动力学模拟.
- 分析键网络连接,集群大小和结构异构性.
- 键粘度的定义和计算.
主要成果:
- 强大的剪切会破坏四面体结构,减少键网络连接和平均集群大小.
- 由于剪切诱导的键形成和破坏,对水结构产生无otropic 的影响.
- 在键结构变化和粘度变化之间存在电力定律关系.
- 键粘度为总粘度贡献5%-50%,由合作分子运动驱动.
结论:
- 水的键网络结构是其剪切粘度的关键决定因素.
- 剪切稀释基本上与水的键网络的动态重组有关.
- 键粘度的概念提供了分子结构和流体特性之间的定量联系.
更多相关视频
相关概念视频
Viscosity
5.9K
When water is poured into a glass, it falls freely and quickly, whereas if honey or maple syrup is poured over a pancake, it flows slowly and sticks to the surface of the container. This difference in the flow of different kinds of liquids arises due to the fluid friction between the liquid layers and the liquid and the surrounding material. This property of fluids is called fluid viscosity. In this example, water has a lower viscosity than honey and maple syrup.
The SI unit of viscosity is...
The SI unit of viscosity is...
5.9K
Surface Tension, Capillary Action, and Viscosity
27.8K
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
27.8K
Viscosity of Fluid
402
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.
402
Newtonian Fluid: Problem Solving
222
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
222
Types of Fluids
251
Fluids can be classified into Newtonian and non-Newtonian fluids based on their response to shear stress. Newtonian fluids have a linear relationship between shear stress and the shear strain rate, following Newton's law of viscosity. Their viscosity remains constant regardless of the shear rate, making their behavior predictable and easier to analyze. Common examples include water, air, oil, and gasoline.
In contrast, non-Newtonian fluids do not follow Newton's law of viscosity, and...
In contrast, non-Newtonian fluids do not follow Newton's law of viscosity, and...
251
Characteristics of Fluids
3.9K
When a force is applied parallel to the top surface of a solid, it resists the applied force due to the internal frictional forces between the layers of the solid known as shearing resistance. However, when the force is removed, the shearing forces restore the original shape of the solid. Other deformation forces also cause temporary changes in shape if the forces are not beyond a threshold magnitude. Solids tend to retain their shape, making the study of their rest and motion easier. Beyond...
3.9K


