ERI: A Novel Multiphysics Framework for Fluid Circulation and Oxygen Transport in Vocal Folds

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。发声障碍在普通人群中的流行率接近30%，在发声频率较高的职业中占60%，如教育工作者、公共演讲者和歌手。大多数发声功能障碍与发声的动态流动-结构相互作用特征一一对应，局部声带病变与组织内血流量减少和氧气水平降低有关。因此，了解声带内流体动力学对氧气流动的影响是非常有必要的，因为局部组织氧合和灌流的变化是其功能状态的关键指标。这些研究结果将使人们对发声的流体物理学及其在声带水合和氧气运输中的作用有更深入的了解。该项目还将包括教育计划，涉及YouTube频道的运营、暑期本科生研究体验，以及通过卡内基科学中心博物馆和女性参与科学小组面向当地K-12学校和公众的外联活动，通过促进低收入高中生、K-6学生和女孩参与STEM的计划。这个项目的目标是开发一个多物理计算框架，利用声带组织的双相描述来研究发声过程中声带间质液体分布和系统水化的作用。全身性水合作用在声带功能中起着关键的化学机械作用，但目前仍不完全清楚。该项目将通过将流体-孔弹性结构相互作用模型与氧气传输模型相结合来填补这一空白，具体目标有两个：(1)开发一种流体-结构相互作用建模方法，该方法集成了湍流声门气流和多孔性声带结构之间的完全耦合行为，以提供对过滤速度以及多孔性声带内氧气浓度的时空预测；(2)研究组织间流体循环与声带中氧气流动的关系，以确定声带脱水对氧气浓度的减弱程度。分别用雷诺平均的Navier-Stokes方程和Biot的孔弹性方程来模拟喉部和流体饱和的声带组织中的气流，而对于组织中的多孔流动所引起的氧气传输，则采用对流-扩散-反应方程。拟议的测量和数字将首次量化驱动质量传输和提供组织全身水化的三维组织间对流流体速度，以及不同发声条件下声带内氧气浓度的详细数据，作为组织缺氧的指标。结果将强调在发声模型中包括孔道弹性的重要性，这将促进声带疾病管理的新视野，例如在为喉切除患者开发发音假体方面。这些发现也直接适用于其他涉及流体-结构相互作用和质量传输的问题，如心血管疾病和肿瘤转移。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Voice disorders have the prevalence of almost 30% in the general population and 60% in professions with high voice usage, such as educators, public speakers, and singers. Most voice dysfunctions have a one-to-one correspondence with the dynamical flow-structure interaction feature of phonation, and localized vocal fold lesions are associated with decreased blood flow and lower oxygen levels within the tissue. There is thus a profound need for understanding the effect of fluid dynamics within the vocal fold on oxygen flow since local changes in tissue oxygenation and perfusion is a critical metric of its functional state. The research results will provide a deep understanding of the fluid physics of phonation and its contribution to hydration and oxygen transport in the vocal fold. The project will also encompass educational plans that involve the operation of a YouTube channel, summer undergraduate research experience, as well as outreach activities to local K-12 schools and the public through the Carnegie Science Center Museum and Women in Science group, through the programs that foster the participation of low-income high school students, K-6 students, and girls in STEM. The goal of this project is to develop a multi-physics computational framework to investigate the role of interstitial liquid distribution and systemic hydration of the vocal fold during phonation using a biphasic description of vocal fold tissue. Systemic hydration plays a key chemo-mechanical role in the function of vocal folds, which is still not fully understood. The project will fill this gap by combining a fluid-poroelastic structure interaction model with an oxygen transport model, in two specific aims: (1) developing a fluid-structure interaction modeling approach integrating the fully coupled behavior between turbulent glottal airflow and porous vocal fold’s structure to provide a spatiotemporal prediction of filtration velocity, as well as oxygen concentration within the porous vocal fold, and (2) investigating the relationship between interstitial fluid circulation and oxygen flow in the vocal fold, in order to identify the extent to which vocal fold dehydration attenuates oxygen concentration. The Reynolds-Averaged Navier-Stokes equations and Biot’s poroelasticity equations are going to be used to model airflow through the larynx and fluid-saturated vocal fold tissue respectively, while for oxygen transport due to the porous flow in the tissue, the convection-diffusion–reaction equation will be applied. The proposed measurements and numeric will quantify for the first time the three-dimensional interstitial convective fluid velocities that drive the mass transport and provide systemic hydration of the tissue, as well as detailed data on oxygen concentration inside the vocal fold under different phonation conditions, that acts as an indicator for tissue hypoxia. Results will highlight the importance of including poroelasticity in phonation models which promotes new visions for the management of vocal diseases, such as in the development of voice prostheses for laryngectomized patients. The findings are also directly applicable to other problems involving fluid-structure interaction and mass transport, such as cardiovascular diseases and tumor metastasis.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.