Thermo-liquid crystal (TLC) thermography for the 3D temperature characterization of liquid microflows

微流体领域正呈指数级增长，因为它在现代工业应用中的影响，从制药/医疗部门到消费电子，一直到航空航天和大型机械。大量的此类微流体应用涉及采用具有复杂几何形状和流动结构的精密微流体装置的传热解决方案。然而，所有这些创新都是在缺乏实验时间分辨方法的情况下发展起来的，这种方法可以同时表征流过微流控芯片的流体的三维速度和温度场。这种精确理解流程的能力将使科学家和工程师能够在错误和设备故障发生之前纠正错误，并在复杂设计的开发中节省大量成本。本研究项目的目的是进一步发展热液晶（TLC）热成像测量技术，以实现期待已久的液体流动温度和速度场的同时三维重建。在过去的几年中，该方法的基础已经奠定，但在TLC颗粒的制造，采集硬件和软件，颜色评估算法和校准程序方面的进一步改进是必要的，以使该技术能够在实际工业和科学应用中可靠地测量流量。此外，关于TLC材料的性质和颜色响应的关键问题，这些问题多年来一直没有得到回答，也将被评估，而且他们的颜色信号的时间响应和强剪切力对他们的颜色的影响也将被检查。

The field of microfluidics is growing exponentially as is its impact in modern industrial applications ranging from the pharmaceutical/medical sector, to consumer electronics, reaching all the way to aerospace and large scale machinery. A great amount of such microfluidics applications, involve heat transfer solutions which employ sophisticated microfluidic devices with complex geometries and flow structures. However, all these innovations have been developed in the absence of an experimental time-resolved means of simultaneously characterizing the 3D velocity and temperature fields of the flow that runs through the microfluidic chips. The ability to understand the flow with this degree of precision will empower scientist and engineers to correct mistakes and device failures before they happen and save substantial costs in development of complex designs.The aim of this research project is to further develop the thermo-liquid crystal (TLC) thermography measurement technique in order to materialize the long awaited simultaneous 3D reconstruction of temperature and velocity fields in liquid flows. Over the last few years, the foundation of the method has been laid out, but further improvements in the fabrication of the TLC particles, acquisition hardware and software, color evaluation algorithms and calibration procedures are necessary to bring the technique to the point where flows in real industrial and scientific applications can be measured reliably. Furthermore, critical questions regarding the nature and color response of the TLC materials, which have remained unanswered for many years, will also be assessed but also the time response of their color signal and the effect of strong shear forces on their color will be examined.