A Computational study of the spray characteristics of a liquid jet atomized by cross-flowing air

交叉流空气雾化液体射流喷雾特性的计算研究

• 批准号: 0713256
• 负责人: Mark Sussman
• 金额: $ 32.24万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0713256&HistoricalAwards=false
• 关键词: Computational; study; spray; characteristics; liquid

It is proposed to develop new numerical algorithms and mathematical models predicting the breakup of liquid into droplets due to cross-flowing air and the resulting gas-liquid mixture that follows. New numerical methods are proposed which exploit large-aspect ratio computational elements. The investigator together with two graduate students, shall develop new algorithms for including the capability for large aspect ratio elements, as a part of a dynamic block-structured adaptive mesh method. The study of large aspect ratio elements as a part of an adaptive, unstructured grid framework has received significant attention recently (albeit, not in the context of two-phase flows, as we propose to study). In contrast, the study of moving mesh methods with large aspect ratio elements, as a part of a block structured adaptive framework, has received very little attention. An algorithm based on block structured adaptive mesh refinement affords one the advantage of easy scalability in regard to parallel computing, adoption of multigrid methodology and implementation of temporal sub-cycling techniques. Numerical analysis issues regarding stability and convergence of a numerical method when applied on a moving mesh, block structured adaptive grid, shall be investigated. Also, algorithms defining the motion of the moving mesh shall be investigated. It is important that the level of skewness for the moving mesh can be controlled. Research developed in this proposal can be applied to mathematical problems that exhibit moving boundary layers, shock waves, ignition fronts, or sharp interfaces. This proposal is concerned with the development of orders of magnitude faster (100 times faster) numerical tools for the simulation of multiphase flow problems as applicable to science and industry. These numerical tools shall be specifically formulated for high-density ratio, high-shear flows at an acceptable computational cost for engineering analysis of practical problems. One immediate application of the proposed research is a jet-propulsion system in which fuel injected as a liquid is atomized into spray by interaction with a gas phase. Another application is the prediction of momentum and energy transfer in the ocean due to hurricane force winds. In order to predict momentum and energy transfer at the sea surface, one must take into account the sea spray generated by the high speed winds. The ultimate benefits to society are reduced pollution, increased engine efficiency, and improved hurricane predictive capability due to a more accurate sea-spray parameterization. This proposal is motivated by interactions between the PI and industry (e.g. UTRC). Success of this proposal will not only have a direct impact on industrial applications relevant to atomization type processes, but also a direct impact on any industrial/scientific application of multiphase flow (e.g. navy ship hydrodynamics, microfluidic applications for testing human serum, biological fluid flows, nuclear reactor cooling systems, and underwater explosions). The PI has ongoing collaborations with SAIC (ship hydrodynamics), Department of Applied Chemistry at the Muroran Institute of Technology (non-newtonian multiphase flows in chemical processing applications), the Center for Bio-Imaging and Modeling at Rutgers University (CBIM, visualization and animation of multiphase flows), for which all of these collaborations benefit from the proposed research on simulating multiphase flows. The proposed research involves the participation of graduate students; graduate students shall be trained on issues which are timely and to which they have access to experts in the field.

建议开发新的数值算法和数学模型，预测由于交叉流动的空气和随后产生的气液混合物而导致的液体破碎成液滴。 新的数值方法，提出了利用大纵横比的计算元素。 研究员将与两名研究生一起开发新算法，以包括大纵横比元素的能力，作为动态块结构自适应网格方法的一部分。 作为自适应非结构化网格框架的一部分，大展弦比单元的研究最近受到了极大的关注（尽管不是在两相流的背景下，正如我们所建议的那样）。 相比之下，作为块结构自适应框架的一部分，具有大纵横比元素的移动网格方法的研究很少受到关注。 基于块结构的自适应网格加密算法在并行计算、多重网格方法和时间子循环技术的实现方面具有易扩展性的优点。 应研究在移动网格（块结构自适应网格）上应用数值方法时有关稳定性和收敛性的数值分析问题。 此外，还应研究定义移动网格运动的算法。 重要的是，可以控制移动网格的偏斜水平。 在这个建议中开发的研究可以应用到数学问题，表现出移动边界层，冲击波，点火前，或尖锐的接口。 该建议涉及的数量级更快（100倍更快）的数值工具，适用于科学和工业的多相流问题的模拟的发展。 这些数值工具应专门针对高密度比、高剪切流，以可接受的计算成本对实际问题进行工程分析。 所提出的研究的一个直接应用是喷气推进系统，其中作为液体喷射的燃料通过与气相的相互作用而雾化成喷雾。 另一个应用是由于飓风风力在海洋中的动量和能量转移的预测。 为了预测在海面的动量和能量传递，必须考虑到由高速风产生的海水喷雾。 对社会的最终好处是减少污染，提高发动机效率，并提高飓风预测能力，由于更准确的海浪参数。 该提案的动机是PI和行业（例如UTRC）之间的互动。 该提议的成功不仅将对与雾化型过程相关的工业应用产生直接影响，而且还将对多相流的任何工业/科学应用（例如，海军舰船流体动力学、用于测试人血清的微流体应用、生物流体流、核反应堆冷却系统和水下爆炸）产生直接影响。 PI与SAIC（船舶流体动力学），室兰工业大学应用化学系（化学加工应用中的非牛顿多相流），罗格斯大学生物成像和建模中心（CBIM，多相流的可视化和动画）正在进行合作，所有这些合作都受益于模拟多相流的拟议研究。 拟议的研究涉及研究生的参与;研究生应就及时的问题接受培训，他们可以接触到该领域的专家。