柴油发电机组排气消声器耦合研究与分析

发布时间：2019-06-08 09:06

【摘要】：本文以降低柴油发电机组排气噪声为最终研究目的,针对某型220kW的柴油发电机组设计一款排气消声器,并对该消声器进行了如下研究:1、研究了消声器内部流体流速和声固耦合效应对其传声损失的影响。首先,对单级简单抗性消声器传声损失进行理论分析和仿真分析,经过对比两种分析的结果,验证了仿真方法的可信性;然后,仿真计算了单级简单抗性消声器在有、无流体流速影响下的传声损失,结果表明消声器内部流体的流速使其传声损失有所降低;最后,仿真分析了单级简单抗性消声器结构模态和声模态,并对其结构进行改进,分析改进后的消声器结构在有、无声固耦合作用下的传声损失,对比分析结果,得知,声固耦合作用对传声损失的影响主要发生在各阶结构模态和声模态频率处,在这些频率处传声损失发生突变,但突变却没有规律性。2、研究了两级抗性消声器中两个扩张室之间的相互耦合作用。分别仿真计算了两个简单抗性消声器以及由二者串联得到的两级抗性消声器的传声损失,对比分析了两个简单抗性消声器传声损失的数值直接相加和两级抗性消声器的传声损失值,结果表明:两级抗性消声器中的两个扩张室相互之间的耦合作用使得两级抗性消声器的传声损失值普遍低于两个简单抗性消声器传声损失的简单数值相加,同时,在低频段,两节抗性消声器的传声损失曲线多了一个波谷,且谷值接近零,也就是说,耦合作用使消声器多了一个通过频率。为进一步提升两级抗性消声器声学性能,将内插管和尾管引入到该消声器,仿真计算其传声损失,并依据仿真结果对内插管的结构进行了改进,得到了性能更好的两级抗性消声器。3、研究了小孔喷注管对消声器性能的提升作用。对比分析了单级抗性消声器与小孔喷注单级抗性消声器的传声损失,结果表明,小孔喷注管的引入,使得抗性消声器的传声损失明显提高,尤其是在低频段,小孔喷注单级抗性消声器的传声损失十分可观。4、为得到能够满足柴油发电机组消声量要求的消声器,将两个声学性能较好且相互之间可以互补的小孔喷注单级抗性消声器与带有内插管的两级抗性消声器复合得到小孔喷注多级抗性消声器,并在小孔喷注多级抗性消声器内部合理填充吸声材料得到小孔喷注阻抗复合消声器。研究了两个消声器复合对消声器性能的提升作用。仿真分析了小孔喷注多级抗性消声器的传声损失,并与复合前的两个消声器的传声损失对比,结果表明:复合后,消声器的传声损失提升明显,但仍存在不少频率处传声损失偏低的情况。也证明了引入阻性消声部分的必要性。研究了阻性消声部分对消声器性能的提升作用。仿真分析了小孔喷注阻抗复合消声器的传声损失,并与小孔喷注多级抗性消声器的传声损失对比,结果表明:阻性消声器的引入使得消声器传声损失曲线变得平滑了许多;小孔喷注阻抗复合式消声器在计算的频率范围内传声损失数值可观,可基本满足该柴油发电机组消声量的要求。
[Abstract]:The purpose of this paper is to design an exhaust muffler for a 220 kW diesel generator set by reducing the exhaust noise of the diesel generator set. The effect of the fluid flow velocity and the acoustic-solid coupling effect on the acoustic loss of the muffler is studied. First of all, the theoretical analysis and simulation analysis of the sound transmission loss of a single-stage simple-resistance silencer are carried out, the credibility of the simulation method is verified by comparing the results of the two analysis, and then, the sound transmission loss under the influence of a single-stage simple-resistance silencer under the influence of no fluid flow rate is calculated, The results show that the flow velocity of the fluid in the muffler is reduced, and finally, the mode and the acoustic mode of the single-stage simple-resistance muffler are simulated and the structure is improved, and the sound transmission loss of the improved muffler structure under the action of silent solid coupling is analyzed. The results of the comparative analysis show that the effect of the acoustic-solid coupling on the transmission loss mainly occurs at the frequency of the structure and the acoustic mode of each stage, and the acoustic loss at these frequencies is mutated, but the mutation has no regularity. The mutual coupling between two expansion chambers in two-stage resistant muffler is studied. In this paper, two simple resistance silencers and two-stage resistance silencers, which are connected in series by the two simple resistance silencers, are respectively simulated. The results show that the two simple resistance silencers and the two-stage resistance silencers are directly added and the sound transmission loss of the two-stage resistance silencers is analyzed. The results show that: the coupling effect between the two expansion chambers in the two-stage resistance muffler is such that the acoustic loss value of the two-stage resistance muffler is generally lower than the simple numerical addition of the sound transmission loss of the two simple resistance silencers, The sound transmission loss curve of two resistance silencers is more than one wave trough, and the valley is close to zero, that is, the coupling effect makes the muffler more than one pass frequency. In order to further improve the acoustic performance of the two-stage resistant silencer, the inner cannula and the tail pipe are introduced into the muffler, the sound transmission loss is calculated by the simulation, the structure of the inner cannula is improved according to the simulation result, and the two-stage resistant muffler with better performance is obtained. The effect of small-hole injection tube on the performance of the muffler was studied. The sound transmission loss of the single-stage resistance silencer and the small-hole injection single-stage resistance silencer is compared and analyzed, and the result shows that the introduction of the small-hole injection pipe makes the sound transmission loss of the resistant muffler be obviously improved, especially in the low-frequency section, the sound transmission loss of the small-hole injection single-stage resistance silencer is very significant, and 4, to obtain the muffler which can meet the noise elimination amount requirement of the diesel generator set, a single-stage resistance silencer and a two-stage resistant muffler with an inner tube can be combined to obtain a small-hole injection multi-stage resistance silencer by combining two small holes with better acoustic performance and complementary to each other and a two-stage resistant muffler with an inner tube, And the sound-absorbing material is reasonably filled in the small-hole injection multi-stage resistance silencer to obtain a small-hole injection-impedance composite muffler. The improvement of the performance of the two silencers on the performance of the silencers is studied. The sound transmission loss of the multi-stage resistance silencer is simulated and analyzed, and the sound transmission loss of the two mufflers before the composite is compared. The results show that the sound transmission loss of the muffler is obviously improved after the composite, but there are still many cases where the sound transmission loss is low at many frequencies. The necessity of introducing the resistive muffler is also demonstrated. The effect of the resistive muffler on the performance of the muffler is studied. In this paper, the sound transmission loss of a small-hole injection-impedance composite muffler is simulated and compared with the sound-transmission loss of the multi-stage resistance silencer. The results show that the introduction of the resistive muffler makes the acoustic loss curve of the muffler become smooth. The small-hole injection-impedance composite muffler has a considerable acoustic loss in the calculated frequency range, and can basically meet the requirement of the noise elimination amount of the diesel generator set.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM314

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