Leav O, Cazzolato B, Howard C
School of Mechanical Engineering, University of Adelaide, Adelaide, Australia.
J Acoust Soc Am. 2021 Jul;150(1):82. doi: 10.1121/10.0005489.
Sound propagation through hot exhaust plumes with cooler cross-winds is present in many real world systems. One particular example is the sound propagation from exhaust stacks attached to open cycle gas turbine power stations. The research presented in this paper investigates the sound propagation from a reduced-scale exhaust stack, with a cross-flow from experiments conducted in a wind tunnel. Experimental measurements of the flow and temperature fields provide insight into the complex sound radiation characteristics. Results from the acoustic measurements show the change in the sound directivity arising from the inclusion of the hot exhaust plume, leading to non-axisymmetric sound directivity and a concentration of sound downwind of the exhaust stack outlet. In certain cross-flow conditions, the hot exhaust plume can increase the sound observed downwind by up to 11 dB when compared to the scenario of sound propagation from an exhaust stack in the absence of a heated jet or cross-flow. This paper describes the acoustic directivity at various radial distances from the exhaust stack, acoustic frequencies, jet temperatures, and cross-flow free-stream velocity. The results from this paper emphasise the importance of taking into consideration the hot exhaust plume with cooler cross-flow when estimating sound levels downwind of the stack.
在许多实际系统中都存在声音通过带有较冷空气侧风的热排气羽流传播的情况。一个特别的例子是来自与开式循环燃气轮机发电站相连的排气烟囱的声音传播。本文所呈现的研究通过在风洞中进行的实验，对带有横向气流的缩尺排气烟囱的声音传播进行了研究。对流动和温度场的实验测量有助于深入了解复杂的声辐射特性。声学测量结果表明，由于热排气羽流的存在，声音指向性发生了变化，导致出现非轴对称的声音指向性，并且在排气烟囱出口的顺风方向声音集中。在某些横向气流条件下，与没有加热射流或横向气流时排气烟囱声音传播的情况相比，热排气羽流可使顺风方向观测到的声音增加高达11分贝。本文描述了在距排气烟囱不同径向距离、声学频率、射流温度和横向气流自由流速度下的声学指向性。本文的结果强调了在估计烟囱顺风方向的声级时考虑带有较冷空气侧风的热排气羽流的重要性。
