Development of Experimental Procedures for Measuring Three-Dimensional Temperature Fields in Technical Flows Using Magnetic Resonance Imaging

除了测量速度矢量场外，温度场的测量还为工程科学的许多研究领域提供了重要的关键信息。热在流体内部的对流传输以及流固界面热流密度的定量测量引起了人们极大的兴趣。拟议项目的主要目标是利用磁共振成像（MRI）定量测量流体中的三维温度分布以及三维速度分布。在静止流动中测量温度的实验程序将在弗莱堡大学医院开发。所应用的方法是基于质子共振频率和T1弛豫时间的变化，提供基本的相对温差。同时，根据流体速度和可实现的加热和冷却功率的合理平衡，将在Universität达姆施塔特技术中心开发合适的模型配置。还将进行实验，以验证使用常规温度测量技术的结果。整个系统在核磁共振机上测量的数据将在三维速度场和温度场的基础上进行后处理和分析。根据现代3D制造方法领域的快速技术进步，要开发的测量程序允许开发和验证用于传热应用的复杂和高度集成的组件。这些部件包括紧凑型热交换器、高速切削工具、内燃机和燃气轮机的冷却系统等等。

In addition to measuring velocity vector fields measuring temperature fields gives key information of main importance for numerous research fields in engineering sciences. Of great interest is the convective transport of heat inside a fluid as well as the quantitative measurement of the heat flux on interfaces of fluid and solid.The main goal of the proposed project is to quantitatively measure three-dimensional temperature distributions in a fluid in addition to the three-dimensional velocity distribution using magnetic resonance imaging (MRI). The experimental procedures for measuring temperatures in stationary flows will be developed at the University Hospital Freiburg. The applied methods are based on changes of the proton resonance frequency as well as T1 relaxation time, providing basically relative temperature differences. Simultaneously suitable model configurations will be developed at the Technische Universität Darmstadt according to a reasonable balance of fluid velocity and realizable heating and cooling power. Experiments for validating the results using conventional temperature measurement techniques will also be conducted. The data measured with the whole system inside the MRI machine will be post processed and analyzed on the basis of the three-dimensional velocity and temperature fields.The measurement procedures to be developed allow the development and validation of complex and highly integrated components for heat-transfer applications according to the fast technical progress in the field of modern 3D manufacturing methods. Such components are compact heat exchangers, high-speed cutting tools, cooling systems of combustion engines and gas turbines, to name only a few.