Jet Engine Noise Generation, Prediction, and Control
Jet Engine Noise Generation, Prediction, and Control
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喷气发动机噪声的产生、预测和控制
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
E. Envia
中科院分区：
文献类型：
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作者：
D. Huff;E. Envia
飞机噪音多年来一直是机场附近的一个问题。这是一个影响世界各地数百万人的生活质量问题。解决这个问题一直是降噪研究的主要目标，该研究始于商用喷气式飞机旅行成为现实。虽然在降低机体和发动机噪音方面取得了进展，但历史上，大多数飞机噪音降低工作都集中在发动机上。这一点在20世纪50年代和60年代涡轮喷气发动机得到广泛应用时表现得最为明显.这种类型的发动机在起飞过程中产生高速热排气射流，产生大量的噪音。虽然目前使用涡轮喷气发动机飞行的商用飞机较少，但包括高性能军用飞机在内的超音速飞机使用具有类似排气流特性的发动机。普惠公司的F100-PW-229，如图1a所示，是为F-15和F-16战斗机提供动力的发动机的一个例子。涡轮风扇发动机是为亚音速运输机开发的，除了更好的燃油效率外，还有助于通过降低喷气排气速度来减轻发动机噪音。这些发动机是在20世纪60年代末推出的，并为今天的大多数商业船队提供动力。多年来，对于现代涡轮风扇发动机，如通用电气公司的GE-90发动机，涵道比（即通过风扇涵道的质量流量与通过发动机核心的质量流量之比）已增加到接近9的值（图1b）。高涵道比（HPBR）发动机的降噪效益来自于降低核心射流速度和温度以及降低风扇的叶尖速度和压力比，这两者都是涵道比增加的结果。HBPR发动机的直径通常非常大，最大的发动机可以产生超过100，000磅的推力。今天飞行的第三种发动机是涡轮轴发动机，它主要用于为涡轮螺旋桨飞机和直升机提供动力。图1C显示了这种类型发动机的一个例子，这是为CH-47支奴干直升机提供动力的霍尼韦尔T55发动机的示意图。由于涡轮轴发动机的主要噪声来自螺旋桨或直升机转子，因此，就社区噪声考虑而言，对这些发动机的关注较少。本章将主要集中在涡轮风扇发动机噪声，并将突出其噪声预测和降低的常用方法。
Aircraft noise has been a problem near airports for many years. It is a quality of life issue that impacts millions of people around the world. Solving this problem has been the principal goal of noise reduction research that began when commercial jet travel became a reality. While progress has been made in reducing both airframe and engine noise, historically, most of the aircraft noise reduction efforts have concentrated on the engines. This was most evident during the 1950 s and 1960 s when turbojet engines were in wide use. This type of engine produces high velocity hot exhaust jets during takeoff generating a great deal of noise. While there are fewer commercial aircraft flying today with turbojet engines, supersonic aircraft including high performance military aircraft use engines with similar exhaust flow characteristics. The Pratt & Whitney F100-PW-229, pictured in Figure la, is an example of an engine that powers the F-15 and F-16 fighter jets. The turbofan engine was developed for subsonic transports, which in addition to better fuel efficiency also helped mitigate engine noise by reducing the jet exhaust velocity. These engines were introduced in the late 1960 s and power most of the commercial fleet today. Over the years, the bypass ratio (that is the ratio of the mass flow through the fan bypass duct to the mass flow through the engine core) has increased to values approaching 9 for modern turbofans such as the General Electric s GE-90 engine (Figure lb). The benefits to noise reduction for high bypass ratio (HPBR) engines are derived from lowering the core jet velocity and temperature, and lowering the tip speed and pressure ratio of the fan, both of which are the consequences of the increase in bypass ratio. The HBPR engines are typically very large in diameter and can produce over 100,000 pounds of thrust for the largest engines. A third type of engine flying today is the turbo-shaft which is mainly used to power turboprop aircraft and helicopters. An example of this type of engine is shown in Figure IC, which is a schematic of the Honeywell T55 engine that powers the CH-47 Chinook helicopter. Since the noise from the propellers or helicopter rotors is usually dominant for turbo-shaft engines, less attention has been paid to these engines in so far as community noise considerations are concerned. This chapter will concentrate mostly on turbofan engine noise and will highlight common methods for their noise prediction and reduction.