Purpose

The purpose of this paper is to identify freezing in pitot tubes at real-time, by means of the estimated heat transfer coefficient (HTC) at the tip of the probe. The prompt identification of such freezing is paramount to activate and control mechanisms for ice removal, which in turn are essential for the safety of the aircraft and its passengers.

Design/methodology/approach

The proposed problem is solved by means of an inverse analysis, performed within the Bayesian approach of inverse problems, with temperature measurements assumed available along the pitot probe over time. A heat conduction model is used for describing the average temperature of the pitot tube, which is then rewritten in the form of a state estimation problem. The model is linear and time invariant, so that the inverse problem can be solved using the steady-state Kalman filter (SSKF), a computationally efficient algorithm.

Findings

The results show that the SSKF is fully capable of recovering the HTC information from the temperature measurements. Any variation of the HTC – either smooth or discontinuous – is promptly detected with high accuracy. Computational effort is significantly lower than the physical time, so that the proposed methodology is fully capable of estimating the HTC at real-time.

Originality/value

The methodology herein solves the proposed problem not only by estimating the HTC accurately but also doing so with a very small computational effort, so that real-time estimation and freezing control become possible. To the best of the authors’ knowledge, no likewise publications have been found so far.

中文翻译：

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冷冻皮托管传热系数的实时估算

目的

本文的目的是通过探头尖端的估计传热系数 (HTC) 实时识别皮托管中的冻结。及时识别这种冻结对于激活和控制除冰机制至关重要，而这反过来又对飞机及其乘客的安全至关重要。

设计/方法/途径

所提出的问题是通过逆向分析解决的，在逆向问题的贝叶斯方法中执行，假设随着时间的推移沿着皮托管探头可以进行温度测量。热传导模型用于描述皮托管的平均温度，然后将其改写为状态估计问题的形式。该模型是线性且时不变的，因此可以使用计算效率高的算法稳态卡尔曼滤波器 (SSKF) 求解逆问题。

发现

结果表明，SSKF 完全能够从温度测量中恢复 HTC 信息。HTC 的任何变化——无论是平滑的还是不连续的——都会被迅速、高精度地检测到。计算量明显低于物理时间，因此所提出的方法完全能够实时估算 HTC。

原创性/价值

本文的方法不仅通过准确估计 HTC，而且以非常小的计算量来解决所提出的问题，从而使实时估计和冻结控制成为可能。据作者所知，到目前为止还没有发现类似的出版物。