A Fundamental Study on Unsteady Heat Transfer and Dynamic Ice Accretion Processes Pertinent to UAV Icing Protection

无人机(UAVs)，也被称为无人机，是航空界最引人注目的发展之一，具有新兴的民用和军事应用。与在高海拔巡航的传统大型载人飞机不同，轻型无人机专门为在低空飞行而设计，因此更容易受到冰冻天气的影响，如冻雨、冰雪和雨夹雪。目前的无人机防冰策略要么是将无人机留在地面，要么改变其飞行路线，从而大大降低了无人机在寒冷气候下的作战能力。这对救生搜救行动和军用无人机应用来说尤其令人担忧，在这些应用中，结冰条件将导致任务中止和关键战术能力的丧失。该项目旨在提高我们对无人机结冰物理基础的了解，并开发新的防冰/除冰策略，以确保无人机在任何天气条件下的飞行安全。该项目还将包括重要的教育活动，包括多年研究生/本科生研究计划，开发新的教学模块，以及针对当地K-12学生的推广计划，重点是促进女性学生和代表不足的少数群体(URM)的参与。该项目的目标是进行基础研究，以表征与无人机结冰现象有关的重要微物理过程(即非稳态热传递、瞬时地表水回流和动态结冰过程)。将系统地评估表面特性(如疏水性和导热系数)对无人机机翼和旋转螺旋桨上的动态结冰过程的影响。将开展一项探索性研究，以开发一类新的低功耗和有效的无人机结冰缓解策略。还将进行一项全面的户外飞行测试活动，以在大气结冰天气(例如，雪、冻雨和雨夹雪)中飞行实验无人机，以填补理想化的实验室实验和现实的无人机飞行结冰过程之间的知识空白。这项拟议的研究将显著提高我们对无人机结冰物理基础的理解。它还将产生一种新的低功耗和有效的防/除冰战略，以确保无人机在任何天气条件下的飞行安全，这对拯救生命的搜救行动和美国国防和国家安全方面的军用无人机应用非常关键。该奖项反映了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。

Unmanned-Aerial-Vehicles (UAVs), also known as Drones, is one of the most remarkable developments in the aviation community with emerging civilian and military applications. Unlike conventional, large-sized, manned aircraft cruising at high altitudes, light-weighted UAVs are designed specifically to fly in low-altitude airspace, thus, are much more vulnerable to the impacts of icing weather such as frozen rain, snow, and sleet. Current UAV icing avoidance strategy is either keeping UAVs on the ground or modifying their flight paths, thereby, greatly reducing the UAV operation capability in cold climate. This is particularly troubling for life-saving search & rescue operations and military UAV applications, in which icing conditions would lead to aborted missions and loss of crucial tactical capabilities. This project aims to improve our understanding about the underlying UAV icing physics and to develop novel anti-/de-icing strategies for assured UAV flight safety in all weather conditions. The project will also encompass significant educational activities, including a multi-year graduate/undergraduate research program, development of new teaching modules, and an outreach program for local K-12 students with a focus of promoting the participation of female students and those from under-represented minority (URM) groups.The goal of this project is to conduct a fundamental study to characterize the important micro-physical processes (i.e., unsteady heat transfer, transient surface water runback, and dynamic ice accretion process) pertinent to UAV inflight icing phenomena. The effects of the surface properties (e.g., hydrophobicity and thermal conductivity) on the dynamic ice accretion process over UAV wings and rotating propellers will be evaluated systematically. An explorative study will be performed to develop a new class of low-power and effective strategies for UAV inflight icing mitigation. A comprehensive outdoor flight test campaign will also be conducted to fly experimental UAVs in atmospheric icing weather (e.g., snow, frozen rain, and sleet) to fill the knowledge gaps between the idealized lab experiments and realistic UAV inflight icing process. The proposed research would significantly improve our understanding about the underlying UAV icing physics. It will also lead to a new class of low-power and effective anti-/de-icing strategies for assured UAV flight safety in all weather conditions, which are very critical to life-saving search & rescue operations and military UAV applications of America’s defense and national security concerns.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.