SBIR PHASE I: A New Approach to Particle Characterization - The Probability Density Function Propagation (PDFP) Model

这个小型企业创新研究(SBIR)第一阶段项目将开发一种称为概率密度函数传播(PDFP)模型的创新粒子传输和扩散模型，并将该模型应用到商业代码中。PDFP模型跟踪粒子位置的概率密度函数(PDF)作为空间和时间的函数。只需要计算每类颗粒大小或类型的一个轨迹，而当前最先进的颗粒模型需要2000到6000个轨迹。这使得PDFP模型的计算效率非常高，这对于具有大量粒子的模拟非常重要，其中粒子计算占用了大量的CPU时间。根据模型中计算的颗粒PDF，可以在模型中的任何位置计算分散相(固体或液体)的性质，从而提供颗粒行为的完整统计表示。计算速度和完全描述颗粒(固体或液体)的能力相结合，将使PDFP模型成为工程师分析两相流的宝贵工具。在第一阶段，将通过将预测与公布的数据进行比较来验证模型的可行性。概率密度函数传播(PDFP)模型将被开发并在商业代码中实现。该功能将在现有的商业代码中实现，并将提供使用当前最先进的颗粒模型轻松模拟困难或非常耗时的两相流的能力。可使用PDFP模型的应用实例包括用于点火计算、大气扩散、气动输送、喷雾冷却的非反应性喷雾的表征，以及必须对大量颗粒进行建模的任何其他应用。

This Small Business Innovation Research (SBIR) Phase I project will develop an innovative particle transport and dispersion model called the Probability Density Function Propagation (PDFP) models, and implements the model into a commercial code. The PDFP model tracks the Probability Density Function (PDF) of particle position as a function of space and time. Only one trajectory for each class of particle size or type needs to be calculated, as compared to the 2000 to 6000 trajectories needed in current state-of-the-art particulate models. This makes the PDFP model very computationally efficient, which is important for simulations with large numbers of particles where the particle calculations take a significant percentage of the CPU time. From the particle PDF's calculated in the model, the properties of the dispersed phase (solid or liquid) can be calculated anywhere in the model, providing a complete statistical representation of the particle behavior. The combination of computational speed and capability to completely describe the particles (solid or liquid) will make the PDFP model a valuable tool for engineers analyzing two-phase flows. In Phase I, the feasibility of the model will be demonstrated by comparing predictions with published data.The Probability Density Function Propagation (PDFP) model will be developed and implemented in a commercial code. The capability will be implemented in an existing commercial code and will provide the capability to easily simulate two-phase flows that are difficult or very time consuming using current state-of-the-art particle models. Examples of applications where the PDFP model can be used include characterizing nonreacting sprays for ignition calculations, atmospheric dispersion, pneumatic transport, spray cooling, and any other application where large number of particles must be modeled.