Liquid Jet and Droplet Impaction on a Moving Substrate

液体射流和液滴对移动基底的冲击

• 批准号: RGPIN-2016-03750
• 负责人: Green, Sheldon
• 金额: $ 2.4万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=652414
• 关键词: Liquid; Jet; Droplet; Impaction; Moving

In numerous industrial processes a liquid jet or liquid droplets impact on a moving solid surface. As the liquid impacts the surface a thin lamella is generated. For the case of liquid jet impaction, if the lamella adheres to the surface and all liquid remains on the surface, the impaction outcome is described as ‘deposition'. In contrast, if the liquid breaks into fine droplets, ‘splattering' or ‘splash' occurs. In most applications, for example surface coating, deposition is the desired outcome whereas splash and splattering are undesirable. Whether the jet deposits cleanly on the surface is a function of the liquid and surface properties, and surprisingly, also a function of the surrounding air.*******Several experimental methods will be used to study jet and droplet impaction. In order to determine the bulk characteristics of the jet or droplet interaction (e.g., splash versus deposition and lamella radius and width), high speed video imaging and image processing will be performed. Optical absorption, Fourier transform profilometry, or laser interferometry measurements will be used to determine the lamella thickness as a function of position. Finally, Particle Tracking Velocimetry will be used to measure the spatial variation of particulate velocity within the lamella. For Newtonian liquid jets, these measurements will be made as a function of the jet orientation, surface roughness, static contact angle of the surface, the jet Reynolds and Weber numbers, and the jet-to-surface velocity ratio. For non-Newtonian liquid jets with suspended particulates, the influence of particulate concentration and size on the spreading characteristics of the jet lamella, and possible splash, will also be determined.****In some industrial applications, the solid surface is coated with a thin film of liquid. The impaction of a liquid jet with such a moving surface will be studied in a custom apparatus. It is also known that evacuation of the surrounding air can suppress droplet splash on stationary surfaces. We plan to measure the magnitude of the splash suppression for droplet impaction on a moving surface.*******This research should provide insight into both an important industrial problem and be relevant to a problem of intense scientific interest – the moving contact line that occurs at the location where the liquid lamella on the surface interfaces with the air.*********

在许多工业过程中，液体射流或液滴撞击在移动的固体表面上。当液体冲击表面时，产生薄薄片。对于液体射流冲击的情况，如果薄片粘附到表面并且所有液体保留在表面上，则冲击结果被描述为“沉积”。相反，如果液体破碎成细小的液滴，则会发生“飞溅”或“飞溅”。在大多数应用中，例如表面涂覆，沉积是期望的结果，而飞溅和飞溅是不期望的。射流是否干净地沉积在表面上是液体和表面性质的函数，令人惊讶的是，也是周围空气的函数。几种实验方法将用于研究射流和液滴碰撞。为了确定射流或液滴相互作用的整体特性（例如，飞溅对沉积以及薄片半径和宽度），将进行高速视频成像和图像处理。将使用光学吸收、傅里叶变换轮廓测量或激光干涉测量来确定作为位置函数的薄片厚度。最后，粒子跟踪测速仪将被用来测量颗粒速度的空间变化内的薄片。对于牛顿液体射流，这些测量将作为射流方向，表面粗糙度，表面的静态接触角，射流雷诺数和韦伯数，以及射流与表面的速度比的函数。对于含有悬浮颗粒的非牛顿液体射流，还将确定颗粒浓度和尺寸对射流薄层扩散特性的影响以及可能的飞溅。*在某些工业应用中，固体表面被涂上一层液体薄膜。将在一个定制的装置中研究液体射流与这种移动表面的碰撞。还已知的是，周围空气的排空可以抑制液滴飞溅在静止表面上。我们计划测量液滴撞击在移动表面上的飞溅抑制的大小。*这项研究应该提供对一个重要的工业问题的深入了解，并与一个具有强烈科学兴趣的问题有关-在表面上的液体薄层与空气界面处发生的移动接触线。