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自洁式空气过滤系统消声器应用研究 被引量:1
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作者 熊鸿斌 朱静坤 《安全与环境学报》 CAS CSCD 北大核心 2018年第4期1509-1515,共7页
自洁式空气过滤器属于空气分离工艺中主要噪声源之一,为寻求良好的治理方案,通过研究位于某3类声功能区的液化空气公司空分站中自洁式空气过滤器噪声污染状况,根据其A声级噪声频谱图,选取具有代表性的自洁式空气过滤系统进风口噪声源进... 自洁式空气过滤器属于空气分离工艺中主要噪声源之一,为寻求良好的治理方案,通过研究位于某3类声功能区的液化空气公司空分站中自洁式空气过滤器噪声污染状况,根据其A声级噪声频谱图,选取具有代表性的自洁式空气过滤系统进风口噪声源进行分析,其噪声治理主要有以下几个难点:1)通风量大,机组运行时产生高分贝、中高频带的噪声;2)下游空压机工艺段产生的低频带噪声通过风管传播至扩散口;3)空滤系统匹配的消声器需有较小的压头损失。不同的距离以不同的噪声模型进行预测,以最近距离的厂界为敏感目标,预测噪声源的噪声水平距离衰减规律,并通过AWA型噪声分析仪在不受天气等外界因素干扰的情况下,测得1 min等效A声级作为实测数据,并检验预测结果。根据预测结果和实际检测数据设计一套针对空气过滤系统风量大、压头损失小、噪声分贝值高、宽频带的空气过滤机组整体降噪工艺。经检验,治理后结果好于GB12348—2008《工业企业厂界噪声排放标准》中的3类标准的夜间55d B的标准。该研究设计技术工艺、参数先进合理,费用低且实际简单,有较高的实用价值。 展开更多
关键词 环境工程学 空分噪声 自洁式气过滤器 复合消声器
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Air flow patterns and noise analysis inside high speed angular contact ball bearings 被引量:3
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作者 翟强 闫柯 +2 位作者 张优云 朱永生 王亚泰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3358-3366,共9页
The vortex formed around the rolling ball and the high pressure region formed around the ball-raceway contact zone are the principle factors that barricades the lubricant entering the bearing cavity, and further cause... The vortex formed around the rolling ball and the high pressure region formed around the ball-raceway contact zone are the principle factors that barricades the lubricant entering the bearing cavity, and further causes improper lubrication. The investigation of the air phase flow inside the bearing cavity is essential for the optimization of the oil-air two-phase lubrication method. With the revolutionary reference frame describing the bearing motion, a highly precise air phase flow model inside the angular contact ball bearing cavity was build up. Comprehensive factors such as bearing revolution, ball rotation, and cage structure were considered to investigate the influences on the air phase flow and heat transfer efficiency. The aerodynamic noise was also analyzed. The result shows that the ball spinning leads to the pressure rise and uneven pressure distribution. The air phase velocity, pressure and cage heat transfer efficiency increase as the revolving speed increases. The operating noise is largely due to the impact of the high speed external flow on the bearing. When the center of the oil-air outlet fixes near the inner ring, the aerodynamic noise is reduced. The position near the inner ring on the bigger axial side is the ideal position to fix the lubricating device for the angular contact ball bearing. 展开更多
关键词 high speed angular contact ball bearing air phase flow heat transfer efficiency cage structure
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Influence of Separated Vortex on Aerodynamic Noise of an Airfoil Blade 被引量:2
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作者 Soichi Sasaki Hajime Takamatsu +2 位作者 Masao Tsujino Haruhiro Tsubota Hidechito Hayashi 《Journal of Thermal Science》 SCIE EI CAS CSCD 2010年第1期60-66,共7页
In order to clarify the mechanism by which aerodynamic noise is generated from separated flow around an airfoil blade,the relation between the attack angle and the aerodynamic noise of the blade was analyzed using a w... In order to clarify the mechanism by which aerodynamic noise is generated from separated flow around an airfoil blade,the relation between the attack angle and the aerodynamic noise of the blade was analyzed using a wind tunnel experiment and a CFD code.In the case of rear surface separation,the separated vortex which has a large-scale structure in the direction of the blade chord is transformed into a structure that concentrates at the trailing edge with an increase in the attack angle.The aerodynamic noise level then becomes small according to the vortex scale in the blade chord.When the flow is separated at the leading edge,a separated vortex of low pressure is formed at the vicinity of the trailing edge.The pressure fluctuations on the blade surface at the vicinity of the trailing edge become large due to the vortex in the wake.It is considered that the aerodynamic noise level increases when the flow is separated at the leading edge because the separated vortex is causing the fluctuations due to wake vortex shedding. 展开更多
关键词 VORTEX Aerodynamic Noise Shear Flow SEPARATION AIRFOIL
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