CAREER: Non-agglomerated Nanoparticle Synthesis in Low Pressure Flames

摘要：CTS-9703357是一种低压扁平火焰中非团聚纳米颗粒生产的研究。演示了在低压火焰中生产目标材料组，包括钇稳定的氧化锆，氧化氮化硅，氧化铝，氧化锆，二氧化钛和氧化钨。参数研究评估了工艺条件对合成纳米粉末的尺寸、数量和形貌的影响。建模和诊断工作以单一纳米粉末为中心，目标是预测给定系统过程输入的颗粒大小、生产速率和团聚程度。该模型包括气相化学机理以及颗粒形成和生长机理。采用多组分激光诱导荧光法对火焰进行气相化学环境的定量分析，采用激光吸收散射法对颗粒大小场和数密度场进行定量分析。对几种基线生产条件进行了表征和建模，并对模型进行了改进以匹配实验观察结果，然后对不同的粉末种类建立了类似的模型。这项工作展示了一种高速率、固有可扩展生产一系列工业上重要的非团聚纳米粉末的技术。开发了纳米粉体生产的工艺模型。这些模型扩展了目前对气相粒子合成的理解，并允许对合成过程进行计算优化。对于放大操作，这些模型有助于确定工业反应器的适当过程诊断，并实现闭环控制算法的开发。

ABSTRACT CTS-9703357 This is an investigation of non-agglomerated nanoparticle productiol in low-pressure flat flames. Production in low-pressure flames of a target group of materials including yttrium-stabilized zirconia, silicon oxynitride, alumina, zirconia, titania, and tungsten oxide, is demonstrated. Parametric studies assess the effects of process conditions on the size, quantity, and morphology of the synthesized nanopowders. Modeling and diagnostic work centers on a single nanopowder species with the goal of predicting particle sized, production rate, and degree of agglomeration given system process inputs. A gas-phase chemical mechanism is included in the model along with mechanisms for particles formation and growth. Multispecies laser-induced fluorescence is applied to the flames to quantify the gas-phase chemical environment, while laser absorption scattering measurements are probe sampling are used to quantify the particle size- and number-density fields. Several baseline production conditions are characterized and modeled and the model is refined to match the experimental observations, Analogous models are then produced for different powder species. This work demonstrates a technique for high-rate, inherently scalable production of a series of industrially significant non-agglomerated nanopowders. Process models for nanopowder production and developed. Such models extend present understanding of gas-phase particle synthesis and allow computational optimization mf the synthesis process. For scale-up operations, the models help in identifying appropriate process diagnostics for industrial reactors and enable development of closed-loop control algorithms.