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Experimental investigations on transient surface water transport and ice accreting processes pertinent to aircraft icing phenomena.

机译：与飞机结冰现象有关的瞬时地表水运输和积冰过程的实验研究。

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摘要

In the present study, an multi-transducer (sparse array) ultrasonic pulse-echo (MTUPE) technique was developed to quantify the transient surface behaviors of the water film flow driven by boundary layer airflow. The instantaneous surface waves riding on the free surface of the water film flow were characterized based on the measured time series of the water film thickness. Based on the time expansions of the measured thickness profiles of the surface water film flow, a instability transition, from periodical two-dimensional waves to pebbled waves of an obviously non-periodic nature, was observed. Then, the temporally-resolved spatial wave structures in the wind-driven water film flow were reconstructed, which provide more details of the surface morphologies and evolutions of the surface waves in the wind-driven water film flow.;A strategy, based on the use of frequency dependent ultrasonic attenuation, was investigated that has the potential to characterize and differentiate between different types of ice that can form on aircraft during winter operations. The measurement methodology and system were validated using the data for acoustic attenuation in water. The data for two types of ice, rime-like and glaze-like, are in agreement with results from previous measurements. There is a significant difference seen in the ultrasonic attenuation characteristics between the two types of ice. It would appear that there is potential to add attenuation data to on-aircraft ice detection systems which could then potentially enable ice-type specific based de-icing to be implemented. Such optimized de-icing could have a potential for reducing winter weather operational costs, and ensure safety is maintained, or even improved.;A comprehensive experimental study was also conducted to quantify the transient surface water transport and dynamic ice accreting process over a wing surface at different icing conditions. The experiments were conducted in the Icing Research Tunnel available at Iowa State University (ISU-IRT). While the transient behaviors of the surface water transport over an NACA 23012 airfoil with realistic initial ice roughness at the airfoil leading edge were investigated using an innovative digital image projection-correlation (DIPC) technique, the unsteady heat transfer and phase changing processes under different icing conditions were examined in details based on the measured surface temperature maps over the ice accreting surfaces by using an infrared thermal imaging system. The objective of this study is to elucidate the underlying physics of surface water transport and ice accretion to improve our understanding of the important microphysical processes pertinent to aircraft icing phenomena to develop more effective and robust anti-/de-icing strategies to ensure safer and more efficient aircraft operations in cold weather.
机译：在本研究中，开发了一种多换能器（稀疏阵列）超声脉冲回波（MTUPE）技术来量化边界层气流驱动的水膜流动的瞬态表面行为。基于测得的水膜厚度的时间序列，表征在水膜流动的自由表面上骑行的瞬时表面波。根据所测得的地表水膜流动厚度分布的时间扩展，观察到从周期性二维波到具有明显非周期性性质的卵石波的不稳定性转变。然后，重建了风驱动水膜流中的时间分辨空间波结构，为风驱动水膜流中的表面形貌和表面波的演化提供了更多细节。对频率依赖的超声波衰减的使用进行了研究，它具有表征和区分冬季运行期间飞机上可能形成的不同类型冰的潜力。使用水声衰减数据验证了测量方法和系统。两种类型的冰（霜状和釉状）的数据与以前的测量结果一致。在两种类型的冰之间，超声衰减特性存在明显差异。似乎有可能将衰减数据添加到飞机上的冰检测系统，然后可以潜在地实现基于冰类型特定的除冰。这种优化的除冰有可能降低冬季天气的运营成本，并确保维持甚至改善安全性。；还进行了一项综合实验研究，以量化机翼表面的瞬时地表水输送和动态积冰过程在不同的结冰条件下。实验是在爱荷华州立大学（ISU-IRT）的结冰研究隧道中进行的。尽管使用创新的数字图像投影相关技术（DIPC）研究了NACA 23012机翼表面水在水面上的瞬态行为，并在机翼前沿形成了实际的初始冰粗糙度，但在不同结冰条件下进行了不稳定的传热和相变过程通过使用红外热成像系统，根据在积冰表面上测得的表面温度图，详细检查了这些条件。这项研究的目的是阐明地表水运输和积冰的基本物理原理，以增进我们对与飞机结冰现象相关的重要微物理过程的理解，从而开发出更有效，更强大的防冰/除冰策略，以确保更安全，更安全。寒冷天气下飞机的高效运行。

著录项

  • 作者

    Liu, Yang.;

  • 作者单位

    Iowa State University.;

  • 授予单位 Iowa State University.;
  • 学科 Aerospace engineering.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 198 p.
  • 总页数 198
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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