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脉动气流条件下消声器特性研究的试验装置及初步结果 总被引:2,自引:0,他引:2
本文介绍了一个用于试验研究脉动气流条件下消声器气动与声学性能的试验装置。该装置可以用于模拟往复式压缩机和内燃机排气管内的流动与声学条件,从而为研究和分析脉动气流条件下的消声器特性提供了物质基础。试验结果表明,该试验装置能够较好地模拟压缩机和内燃机排气管内的流动与声学条件,并且以此为基础,获得了初步试验结果。 相似文献
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抗性排气消声器声学特性的试验研究 总被引:1,自引:0,他引:1
本文以试验研究为基础,着重介绍了几种典型抗性消声器的传声损失和插入损失,并探讨了气流的存在对消声器声学性能的影响.在气流速度较低时,考虑了气流影响因素的一维声传播理论值与试验值吻合较好;气流速度较高时,气流对消声器的声学性能影响较大。因此,必须加强对消声器中气流再生噪声问题的研究. 相似文献
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压缩机运行转速越高,其产生的噪声越大,改善制冷压缩机气流脉动诱发的排气噪声衰减变得越来越重要,其中,变频双螺杆制冷压缩机的需求尤其明显。为有效改善变频双螺杆制冷压缩机排气气流脉动诱发的气动噪声,本文研究了一种基于赫姆霍兹共振器的宽频带穿孔板气流脉动衰减器。建立了气流脉动衰减器的声学设计方法,根据测量的两相流声速,实现了共振频率的计算,通过实验测量结果对计算结果进行了验证,并进一步分析了压缩机运行转速对其衰减性能的影响。研究结果表明:油气两相流声速随着运行转速上升而增加,运行转速从3 000 rpm上升到5 100 rpm,油气两相流声速从142.8 m/s上升到144.6 m/s,增加1%。对比理论计算和实验测量结果,宽频带穿孔板气流脉动衰减器的衰减频率基本吻合,衰减效果趋势一致,在运行转速3 000~4 500 rpm区间,气流脉动基频排气噪声值下降3.0 d B(A)以上;在排气噪声较大的高转速运行区间4 500~5 100 rpm,排气噪声值下降5.0 d B(A)到7.5 d B(A)。应用宽频带穿孔板气流脉动衰减器后,变频双螺杆压缩机高转速下气流脉动基频的噪声值分别为85.8 d B(A)(4 800 rpm)和84.2 d B(A)(5 100 rpm),比相同制冷量低转速下定频压缩机3 000 rpm时噪声减小2.0 d B(A)以上,有效解决变频双螺杆压缩机气流脉动诱发的排气噪声问题。 相似文献
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针对某型号中小型商用压缩机噪声与能效问题,分别对压缩机腔内排气流道的声学和阻力特性进行数值模拟,分析压缩机腔内排气流道中一阶排气孔径、缓冲腔容积和排气路径等结构参数对压缩机传递损失和压力损失的影响。结果表明:增大一阶排气孔径对排气流道声学及阻力性能影响较小;增大缓冲腔容积且增长排气路径可以改善排气流道传递损失,但压力损失增大;进口端面与第一个缓冲腔之间没有明显压降,最大压降发生在内排气管流道中。最终进行样机制作和测试,噪声和制冷量测试结果与数值结果具有较好的一致性。 相似文献
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《制冷与空调(北京)》2016,(1)
运用试验设计(DOE)方法对压缩机噪声问题进行研究,寻找对不同频率段及整机噪声起显著影响作用的问题零件,对问题零件进行结构改进,利用声学有限元仿真分析软件进行模拟分析与样机验证。结果表明:改善后的结构方案使压缩机噪声降低了4 dB(A)左右,达到改善品质之目的。该方法减少了试验验证次数,降低了产品优化成本。 相似文献
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气流影响下的插入管消声器声学特性的实验研究 总被引:1,自引:0,他引:1
在管内气流流速10 m/s-100 m/s范围内,对长径比L/D=3.98的插入管型抗性消声器内部和外部声学特性进行了实验研究。探讨了气流流速大小和消声器结构参数的变化对插入管消声器声学特性的影响,并结合腔内气流涡模态,腔体声学模态和尾管声学模态对插入管消声器的声学特性机理进行了分析。实验及理论分析表明,气流流速对消声器内外声学特性均有明显的影响。气流影响下的插入管消声器声学特性与消声器腔体的声学模态和尾管的声学模态关系密切,而消声器腔内气流再生噪声的涡模态对其声学特性影响不大。 相似文献
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《制冷与空调(北京)》2019,(3)
螺杆制冷压缩机的振动噪声问题是目前的研究热点,本文介绍了螺杆制冷压缩机振动噪声产生的机理,从机械振动噪声和气流脉动两方面总结了若干主流减振降噪方法和技术。螺杆制冷压缩机振动噪声的进一步改善,主要应在转子材料、转子型线、气流脉动抑制、主动振动控制和有源降噪等方面深入研究。 相似文献
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本文用声电类比方法分析了声学共振器降低与放大声音的分界点,并用该方法对声学共振器固有频率共振对离心式风机噪声的影响进行了系统的理论和试验研究,提出了用λ1/4共振器降低离心风机噪声时必须注意共振器固有频率的选择这个极其重要的问题。 相似文献
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V. V. Golub A. S. Saveliev V. A. Sechenov E. E. Son D. V. Tereshonok 《High Temperature》2010,48(6):903-909
We perform an experimental study and numerical simulation of the process of periodic initiation of spark extended discharge
in air flow with a Mach number M = 2. Critical parameters of the discharge are measured in a high velocity air flow, and visualization of the gas flow in
the presence of the discharge is performed. The influence of the discharge on the flow near the body surface streamlined by
the supersonic flow is studied. 相似文献
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《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(1):81-87
The formation of fullerenes in a hollow cathode arc in an inert gas atmosphere is investigated. The effects of the carbon evaporation rate, the inert gas flow rate and the arc temperature on the fullerene yield, production rate and conversion rate are observed. A magnetic field of 100 Gauss is used to collimate the discharge and to improve the carbon evaporation rate. The agreement among experimental data and theoretical results of the model based on the equations of Smoluchovski is obtained. 相似文献
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《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1986,242(3):582-587
Single, narrow-beam densitometry has been developed as a method for determining the flow regime and void fraction for industrial liquid gas experiments at high pressures and temperatures in a vertical, thick-walled, steel vessel. To develop suitable techniques, the experimental conditions were simulated using a transparant air/water column. In the transition region from bubbly to slug flow, a time sequence of four regimes, viz. annular flow, partially developed annular flow, coalescing bubble flow and bubbly flow were visually identified in a given cross section. Gamma rays were used to interrogate a column diameter, and digital time series analysis methods were applied. Amplitude spectral densities were used to determine any periodicity in the gas phase flow. The average void fraction for periodic gas flows was obtained by analysis of probability density distributions (PDD). The time sequence of the flow regimes was obtained from the signal magnitude of the diametral void fractions and the time spent in each regime was measured by the associated probability. The results compared well with those obtained from other methods. In the bubbly flow region, the standard deviation of the PDD exceeded that expected for nuclear counting. This bubble noise was assessed with respect to bubble properties. 相似文献
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文章简介了空分设备气体放空时产生的噪声对周围环境的污染和伤害,并对放空气体噪声的控制与治理进行了分析对比;提出大型空分设备,特别是内压缩流程的空分设备,大流量低、中、高压气体放空,应采用消声塔集中排放,有效控制和治理气体放空噪声。 相似文献
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文章简介了空分设备气体放空时产生的噪声对周围环境的污染和伤害,并对放空气体噪声的控制与治理进行了分析对比;提出大型空分设备,特别是内压缩流程的空分设备,大流量低、中、高压气体放空,应采用消声塔集中排放,有效控制和治理气体放空噪声。 相似文献
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为了研究在低马赫数Ma=0.12条件下锯齿形喷嘴射流气动声学特性,对多种参数的锯齿形喷嘴射流速度剪切层外区域进行声压近场测量和远场测量。根据近场和远场的测量结果,分析声压从近场向远场发展的趋势。结合射流场数值模拟的结果,利用计算流体力学和气动声学知识,分析锯齿形尾缘喷嘴的湍流性能与近远场声压之间的关系。分析表明,在相同渗透度下,随着齿数的增加,噪声总声压级在整个指向范围有明显的降低。在相同齿数下,随渗透度的增加,锯齿形喷嘴降低低频噪声,增加高频噪声,呈现明显的指向性分布特点。 相似文献
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The first part of this paper presents an experimental analysis of different hermetic scroll compressors using different methods of injection: the first one is without injection, the second one uses vapor injection and the third one liquid injection. The analysis reveals the influence of these methods on the compressor behavior. A simplified model of the scroll compressor is then proposed that takes into account not only the different internal processes but also the refrigerant injection. It assumes that the refrigerant mass flow rate is affected by a heating-up due to a uniform wall temperature. This fictitious wall is supposed to gain heat from the electromechanical losses and from the discharged gas and to loose heat to the suction and to the ambient. The compression step is considered isentropic up to the adapted pressure and then at constant volume until the discharge pressure. The model is able to compute variables of first importance like the mass flow rate, the electric power and the discharge temperature, as well as secondary variables as suction heating-up, discharge cooling-down, and ambient losses. The validation based on 45 experimental results shows excellent results. 相似文献
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为区分输气管道泄漏音波与阀门噪声,为输气管道音波法泄漏检测提供理论依据及数据库、控制阀门噪声提供解决办法,从音波产生机理角度采用CFD软件耦合专业声学软件方法对输气管道气体流经阀门产生的气动噪声进行研究,建立气动噪声模型,探究气动噪声产生机理及传播、衰减规律。在CFD(Computational Fluid Dynamics)软件中采用大涡湍流模型对气体流经阀门时的瞬态流场求解分析,获得流场分布如脉动压力、脉动速度数据;将CFD计算所得数据导入专业声学软件进行联合仿真,生成气动噪声源项,包括偶极子声源及四极子声源,建立气动噪声产生传播模型,求解输气管道气体流经阀门的气动噪声。 相似文献
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Z. Markovi B. Todorovi -Markovi T. Nenadovi 《Fullerenes, Nanotubes and Carbon Nanostructures》2002,10(1):81-87
The formation of fullerenes in a hollow cathode arc in an inert gas atmosphere is investigated. The effects of the carbon evaporation rate, the inert gas flow rate and the arc temperature on the fullerene yield, production rate and conversion rate are observed.
A magnetic field of 100 Gauss is used to collimate the discharge and to improve the carbon evaporation rate. The agreement among experimental data and theoretical results of the model based on the equations of Smoluchovski is obtained. 相似文献
A magnetic field of 100 Gauss is used to collimate the discharge and to improve the carbon evaporation rate. The agreement among experimental data and theoretical results of the model based on the equations of Smoluchovski is obtained. 相似文献