Purpose

The purpose of this paper is to numerically and experimentally evaluate the effect of the protection net icing on the inlet performance of helicopter engines.

Design/methodology/approach

The ice shapes of the protection net at different times are first simulated by a two-dimensional (2D) icing calculation, then the porous media parameters are calculated based on the 2D ice shapes. Afterward, three-dimensional flow fields of the engine inlet with the iced net are simulated using the porous media model instead of the real protection net. The transient pressure losses of the iced protection net are calculated and tested through an icing wind tunnel test rig under different icing conditions.

Findings

Overall, the numerical results and experimental data show a good agreement. The effects of several control parameters, such as liquid water contents (LWC), water droplet diameters and airflow velocities on the pressure loss of the protection net during the icing process are analyzed in a systematic manner. The results indicate that the pressure loss increases with the increase of the LWC at the same icing time. The same trend occurs when the water droplet diameter and the airflow velocity increase.

Originality/value

A new method to predict the pressure loss of the iced protection net is proposed. A series of tests in an icing wind tunnel are performed to obtain the ice shapes and pressure loss of protection net during the icing process.

中文翻译：

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直升机发动机进气道防护网结冰数值与实验研究

目的

本文的目的是通过数值和实验评估防护网结冰对直升机发动机进气道性能的影响。

设计/方法/方法

首先通过二维（2D）结冰计算模拟不同时间防护网的冰形，然后根据二维冰形计算多孔介质参数。然后，使用多孔介质模型代替真实的防护网，对带有冰网的发动机进气口的三维流场进行了模拟。通过结冰风洞试验台在不同结冰条件下计算和测试结冰保护网的瞬态压力损失。

发现

总体而言，数值结果和实验数据显示出良好的一致性。系统地分析了几个控制参数，如液态水含量（LWC）、水滴直径和气流速度对结冰过程中防护网压力损失的影响。结果表明，在相同的结冰时间，压力损失随着LWC的增加而增加。当水滴直径和气流速度增加时，也会出现同样的趋势。

原创性/价值

提出了一种预测结冰防护网压力损失的新方法。在结冰风洞中进行了一系列试验，获得了结冰过程中防护网的冰形和压力损失。