Model Validation for Photosynthetically Active Radiation Transport and Multiphase Flow in Algal Photobioreactors

CBET-1236676 Vigil最近对algebra的兴趣主要是由于希望获得石油产品的可再生替代品。然而，商业上可行的藻类生物精炼厂的发展不仅需要在调整以生产高价值产品的稳健的、快速生长的微生物的生物工程方面取得重大进展，而且还需要在工艺工程方面进行实质性改进以更快速和有效地生产藻类产品。藻类光生物反应器的设计和优化的突破可以通过实施辐射传输和复杂的多相流体现象，表征这些反应器的高精度和计算效率的数值模型来实现。该研究项目直接解决了开发能够用于藻类光生物反应器的设计和放大的可靠计算模型的需求。特别地，将通过使用折射率匹配方法来验证光生物反应器中常见的浮力驱动的泡状流的最先进的两相计算流体动力学模拟，以进行具有足够的时间和空间分辨率的粒子图像测速实验，以严格测试模拟预测，并确定包括阻力、升力、虚拟质量、旋转、和应变。藻类光生物反应器中的光的三维分布将模拟开发一种新的光谱辐射传输模型（基于离散坐标的方法），也占气泡的存在和透明的反应器壁的光学效应。光谱辐射传输模型的验证将通过在圆柱形藻类生物反应器中进行一系列光测量来实现，所述圆柱形藻类生物反应器由过滤光源照射，所述过滤光源在光合作用活跃的制度中通过具有窄带波长的辐射。 计算流体动力学和辐射传输模拟已经验证后，在反应器中的流体动力学和辐射传输之间的相互作用将进行拉格朗日粒子跟踪模拟，以计算单个藻类细胞所经历的光吸收的历史，这是至关重要的，在确定这些微生物量的生产率进行探索。藻类是一种越来越有吸引力的替代生产燃料和化学品来自石油，但经济上可行的藻类生物精炼厂的发展需要显着改善工程的精英微生物和在设计和放大的光生物反应器。该项目将采用实验方法和计算机模拟，以更好地了解藻类光生物反应器中的流体运动和光分布如何影响生物量的生产，其结果将成为构建模拟工具的基础，以改进藻类生物反应器中使用的生产规模设备的设计。该研究还将为研究生和本科生提供教育机会，研究具有战略意义的国家重要性的研究领域。

CBET-1236676VigilRecent interest in algaculture is largely driven by the desire to acquire renewable alternatives for petroleum-based products. However, the development of commercially-viable algal biorefineries requires significant advancements not only in the bioengineering of robust, fast-growing microorganisms tuned to produce high-value products, but also substantial improvements in process engineering for more rapid and efficient production of algal products. Breakthroughs in the design and optimization of algal photobioreactors can be achieved through the implementation of highly accurate and computationally efficient numerical models of radiation transport and complex multiphase fluid phenomena that characterize these reactors. This research project directly addresses the need to develop reliable computational models capable of being used for the design and scale-up of algal photobioreactors. In particular, state-of-the-art two-phase computational fluid dynamics simulations of buoyancy-driven bubbly flows commonly found in photobioreactors will be validated by using index-of-refraction matching methods to carry out particle image velocimetry experiments with sufficient temporal and spatial resolution to rigorously test simulation predictions and to determine the importance of including various interface force models for drag, lift, virtual mass, rotation, and strain. The three-dimensional distribution of light in algal photobioreactors will be simulated by developing a novel spectral radiation transport model (based upon the method of discrete ordinates) that also accounts for the presence of bubbles and the optical effects of transparent reactor walls. Validation of the spectral radiation transport model will be achieved by carrying out a series of light measurements in a cylindrical algal bioreactor illuminated by filtered light sources that pass radiation with narrow bands of wavelengths in the photosynthetically active regime. After the computational fluid dynamics and radiation transport simulations have been validated, the interplay between the fluid dynamics and the radiation transport in the reactor will be explored by carrying out Lagrangian particle tracking simulations to compute light absorption histories experienced by individual algal cells, which is of paramount importance in determining the rate of production of biomass by these microorganisms. Algaculture is an increasingly attractive alternative for producing fuels and chemicals derived from petroleum, but the development of economically viable algal biorefineries requires significant improvements in both the engineering of elite microorganisms and in the design and scaleup of photobioreactors. This project will employ experimental methods and computer simulations to improve the understanding of how fluid motion and light distribution in algal photobioreactors impacts the production of biomass, and the results will form the basis for constructing a simulation tool for improving the design of production-scale equipment used in algaculture. The research will also provide educational opportunities for graduate and undergraduate students in a research area of strategic national importance.