Entropy Wave Generator for Indirect Combustion Noise Experiments in a High-Pressure Turbine
Entropy Wave Generator for Indirect Combustion Noise Experiments in a High-Pressure Turbine
复制标题
用于高压涡轮间接燃烧噪声实验的熵波发生器
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
F. Niculescu
中科院分区：
文献类型：
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作者：
P. Gaetani;G. Persico;A. Spinelli;C. Sandu;F. Niculescu
降低核心噪声是低噪声推进系统部署的一个重要目标。在此背景下，欧洲项目RECORD -核心噪音降低研究-旨在通过一组专用实验量化涡轮机对直接和间接燃烧噪音的影响，这些实验在米兰理工大学（意大利）高速试验台上安装的发动机代表性高压涡轮机上进行。将研究压力、涡量和熵波与涡轮机的气动声学相互作用。本文提出了一种新的熵波发生器（EWG）来模拟燃气涡轮机燃烧器引起的熵扰动。该设备由SMCPFA（罗马尼亚）设计和制造，通过使用双向旋转阀，在涡轮机上游交替注入热/冷空气。EWG产生的熵波在米兰理工大学的专用测试部分进行了实验表征。使用不同的绝缘系统进行测试，并调查在自由射流和浸没射流配置的熵波的传播。通过专门为该项目开发的快速热电偶（频率响应~300 Hz）和气动总压探头（频率响应~400 Hz）进行测试。结果表明，在最佳供气压力下，EWG产生的圆形热空气点具有正弦温度波动和微弱的压力振荡;温度振荡的幅度随着频率的增加而减小，但在发动机代表频率100 Hz时，温度振荡的幅度大于10 K。该值符合EWG的技术要求，使其适用于涡轮机试验台的熵噪声研究。
The reduction of core-noise represents a crucial objective for the deployment of low noise propulsion systems. In this context the European Project RECORD - REsearch on COre noise ReDuction - aims at quantifying the impact of the turbine on direct and indirect combustion noise by means of a set of dedicated experiments carried out on an engine representative high pressure turbine, installed in the high-speed test rig of Politecnico di Milano (Italy). The aeroacoustic interaction of pressure, vorticity, and entropy waves with the turbine will be studied. This paper presents a novel Entropy Wave Generator (EWG) to simulate the entropy perturbations originated by gas turbine burners. The device, designed and manufactured by SMCPFA (Romania), is based on the alternated injection of hot/cold air upstream of the turbine, by using a two-way rotary valve. The entropy waves generated by the EWG were experimentally characterized in a dedicated test section at Politecnico di Milano. Tests were performed using different insulation systems, and investigating the propagation of entropy waves in both free-jet and immersed-jet configurations. Tests were performed by means of a fast thermocouple (frequency response ~300 Hz) and a pneumatic total pressure probe (frequency response ~400 Hz), specifically developed for the project. Results indicate that for an optimal feeding pressure the EWG generates circular-shaped spots of hot air characterized by a sinusoidal temperature fluctuation and weak pressure oscillations; the amplitude of the temperature oscillation reduces as the frequency increases, however resulting higher than 10 K at the engine-representative frequency of 100 Hz. This value matches the technical requirements of the EWG, making it suitable for entropy noise studies in the turbine test rig.