Towards Advanced in Situ Measurements of Complex Rheological Properties in Manufacturing Processes - identification of a "finger print" of a fluid

新产品开发(NPD)是一项持续的活动，涉及频繁的新产品和改进产品从实验室规模的开发转移到“吨级”的生产。传统的NPD方法关注的是实验室规模，很少或根本不关注配方的“可制造性”。这些问题通常只有在扩大规模、试验规模时才能解决，而在产品进入生产规模时往往不能完全解决。这样一种扩大规模的方法也需要妥协。这不仅导致规模扩大的时间更长、成本更高，而且还经常增加生产成本。这些关键挑战也限制了行业实现更高效和更灵活的流程的能力。用不同的方法应对这些挑战的一种方式是提高现场测量的能力。复杂的流变特性是工业上最理想的测量方法之一，它是配方产品的大部分微观和宏观结构与其流变性能密切相关。目前，市场货架上可供选择的产品有限。对于这样的测量工具，所需的细节是实时和非侵入性测量的可能性。不能将复杂流变学的表征与简单的粘度测量混淆。事实上，市场上提供的大多数在线或现场流变学测量只能描述流体在固定剪切速率(粘度计)下的粘度。众所周知，大多数复杂的流变学都表现出剪切速率与剪切应力之间的非线性关系。这就是为什么粘度计测量不能可靠地表征复杂的流体流变性。更可靠的离线测量，如锥形和板形流变仪，用于获得详细的流量斜率(剪切速率-剪切应力曲线)。然而，缺点是测量的时间尺度(~10分钟)与期望的时间尺度(~1 S)相去甚远，并且离线很远。该项目旨在填补文献中存在的空白，试图更深入地了解流体流动和复杂流变学之间的联系。挑战是根据流体在设计的障碍物中实现流动的已开发流动特征来确定流体流变学的“指纹”。第一个目标是将流变学特性与流动特性联系起来；了解从稳定的管流到由于障碍物引起的扰动流的流动发展，这将主要使用PIV(粒子图像测速)来完成。其次，了解向系统中添加蠕动流的影响，并验证其对流体流动发展的影响。该项目的另一部分是使用统计或分析方法将所有信息与模型联系起来。

New Product Developments (NPD) is an ongoing activity involving frequent new and improved products being transferred from laboratory scale development to manufacturing at "tonne scale". Traditional approaches to NPD focus the attention at laboratory scale with little or no attention to a formulation's "manufacturability". These issues are typically only addressed during scale up, at pilot scale and are often not fully resolved when the product goes to manufacturing scale. Such an approach to scale up also involves compromises. These result in not only longer and costlier scale up but also frequently increased production costs. These critical challenges also limit industry's ability to achieve more efficient and flexible processes. A way to deal with these challenges with a different approach is to improve the capabilities in terms of in situ measurements. Complex rheological characterisation is one of the most desired measurement in industry, being most of micro and macro structure of formulated products strongly related to their rheological properties. Currently, there are limited options available in the market shelf. The desired specifics, for such measurement tool, are the possibility of real time and non-intrusive measurements. The characterisation of complex rheology must not be confused with a simple viscosity measurement. In fact, most of the online or in situ rheological measurement available in the market can only describe the viscosity of a fluid at fix shear rate (viscometer). As it is well known, most of complex rheology presents a non-linear relationship between the shear rate and the shear stress. This is why viscometer measurements cannot be reliable for the characterisation of complex fluid rheology. Much more reliable, off line measurements, such cone and plate rheometer, are used to acquire a detailed flow ramp (shear Rate vs shear Stress curve). However, the drawbacks are time scale of measurement (~10 minutes) which is far from the desired one (~1 s) and being off line.The project aims to fulfil the gap that exists in the literature trying to understand more deeply the link between fluid flow and complex rheology. The challenge is to determine the "finger print" of a fluid rheology from its developed flow features achieved flowing in designed obstructions. The first objective is to link rheology properties to flow properties; understanding flow development from steady pipe flow to perturbed flow due to obstacles and this will be mainly done using PIV (Particle Image Velocimetry). Secondly, understanding the effect of adding a peristaltic flow to the system and verifying its effect on fluid flow developments. The other part of the project is to link all information to models using statistical or analytical approach.