Mixing at transcritical conditions

两种流体化合物的混合过程是跨临界的，当两种流体的初始状态（混合前）不允许明确预测混合是否会发生在单相或两相中。虽然在跨临界条件下的混合被广泛用于推进系统和柴油发动机，在新的CryoPower回热分置循环发动机（RSCE）和高压过程中的颗粒生成，我们没有一个清晰的理解不同的机制（两相与单相混合）的相关性，涉及到混合物的形成。因此，目前还没有共识，如何跨临界混合可以最好地模拟，以可靠地反映相关的机制。关于跨临界混合过程的定量实验见解的数据是罕见的。因此，本建议的主要目的是实验提供定量的混合物成分和温度对沿着真实的的跨临界混合路径轨迹（工作包2和3），这在未来可以作为定量的参考建模方法。比较真实的与理论混合路径轨迹（工作包4和5），将揭示在何种程度上（i）偏离热力学平衡，（ii）相界面的退化和（iii）由于额外的热和质量扩散，不同的能量和质量传输速率，必须考虑在跨临界混合过程的描述模型。将通过各种互补光学测量技术的组合提供定量组成/温度数据（空间分辨）。在很大程度上，该项目基于利用现有的成分或温度数据，通过本提案，这些数据将补充到相关成分和温度数据的高价值对中。

Mixing processes of two fluid compounds are transcritical, when the initial states of the two fluids (before mixing) do not allow a definite prediction on whether the mixing will take place in a single- or in two-phases. Though mixing at transcritical conditions is widely used in propulsion systems and diesel motors, in the novel CryoPower recuperated split cycle engine (RSCE) and high pressure processes for particle generation, we do not have a clear understanding about the relevance of the different mechanisms (two-phase vs single-phase mixing) involved into mixture formation. As a consequence, there is currently no consensus about how transcritical mixing can be modelled best in order to reliably reflect the relevant mechanisms. The data-availability on quantitative experimental insights into transcritical mixing processes is rare. Therefore, the main aim of this proposal is the experimental provision of quantitative mixture compositions and temperature couples along real transcritical mixing path trajectories (work packages 2 & 3), which in the future can serve as quantitative reference for modelling approaches. The comparison of real vs theoretical mixing path trajectories (work packages 4 & 5), will reveal to which extent (i) the departure from thermodynamic equilibrium, (ii) the degradation of a phase interface and (iii) the different rates of energy and mass transport due to the additional thermal and mass diffusion, have to be regarded in the models for the description of transcritical mixing processes. The quantitative composition/temperature-data (spatially resolved) will be provided via the combination of various complementary optical measurement techniques. To a large extend the project is based on the utilization of already existing either composition or temperature data, which through this proposal will be supplemented to high-value couples of correlated compositional and temperature data.