共查询到19条相似文献,搜索用时 171 毫秒
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本文用实验方法,观察和研究了声除灰现象,初步归纳出除灰效果和声压级以及除灰时间的关系。初步找到除灰的声压级阈值。文中使用了旋笛式声了除灰器,声功率1950W,气声效率18%;哨式声除灰器,声功率680W,气声效率6.8%。本文列举辽阳石化厂加热炉,装上声除灰器后,热效率提高4.8%;广州石化厂新锅炉,装声除灰器,排烟温度比设计值低2-4℃。 相似文献
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声波除灰技术的应用研究 总被引:10,自引:0,他引:10
声波除灰技术虽然已经在国内外的电站、石化与一般丁业锅炉上推广应用,但是与之相关的多数基本问题都还没有得到很好的解决。本文通过对几例应用结果的分析,说明了声波除灰的效果;揭示了一些有待深入认识的基本现象和需要解决的问题,讨论了声波除灰的研究和应用发展方向。 相似文献
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高速压气机不稳定流动声测量技术研究 总被引:3,自引:0,他引:3
本文叙述了用声测量技术研究高速压气机的旋转不稳定特性、失速先兆及失速过程,建立了一套测量方法、测量系统,测量了高速压气机管道内声场的时域波形、频谱和管道声模态,结果分析表明:在没有激波的条件下高速压气机的管道声场中也存在低速压气机中可能存在的不稳定分量,但在有激波存在时无法分辨激波分量和不稳定分量,也未发现激波噪声分量的模态特征。所建立的测量系统具有高速、大容量、连续采集多通道信号的能力,并有快速计算频谱和模态的功能,使这种测量技术可成为一种常规研究压气机不稳定特性、失速机理和失速过程的有效方法。 相似文献
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材料高压声速是获取材料在冲击下的剪切模量、强度和相变信息的重要物理量, 对于研究材料在高速冲击下的行为非常重要. 由于飞片、样品和窗口材料阻抗失配等因素, 传统的声速分析方法无法对非对称冲击-卸载实验中单样品的窗口界面速度进行准确的分析. 本文在反向特征线方法的基础上, 考虑了飞片与样品、样品和窗口界面的相互作用, 建立了适合于仅含单一厚度样品的非对称冲击-卸载实验的特征线声速分析方法, 通过对数值实验给出的速度剖面的分析表明, 该方法能够较为准确地获得待测材料高压下的声速及卸载路径. 相似文献
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Robert J. Nemiroff 《Annalen der Physik》2018,530(2)
When an object moves faster than emissions it creates, it may appear at two positions simultaneously. The appearance or disappearance of this bifurcation is referred to as a pair event. Inherently convolved with superluminal motion, pair events have no subluminal counterparts. Common examples of superluminal motions that exhibit pair events include Cherenkov radiation, sonic booms, illumination fronts from variable light sources, and rotating beams. The minimally simple case of pair events from a single massive object is explored here: uniform linear motion. A pair event is perceived when the radial component of the object's speed toward the observer drops from superluminal to subluminal. Emission from the pair creation event will reach the observer before emission from either of the two images created. Potentially observable image pair events are described for sonic booms and Cherenkov light. To date, no detection of discrete images following a projectile pair event have ever been reported, and so the pair event nature of sonic booms and Cherenkov radiation, for example, remains unconfirmed. Recent advances in modern technology have made such pair event tracking feasible. If measured, pair events could provide important information about object distance and history. 相似文献
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基于修正的Rayleigh气泡脉动方程对水下等离子体声源放电产生的 强声冲击波的传播过程进行了分析; 利用Euler方程作为控制方程组, 建立了水下等离子体声源的聚束声场模型, 通过仿真计算获得的传播云图对冲击波负压的形成机理进行了直观的理论分析. 结果表明: 经过聚能反射罩反射汇聚得到的聚束波在反射稀疏波和水的惯性作用下, 聚束波周围水域产生了拉伸, 形成负压区, 如果拉伸力大于水的抗拉上限, 就会使得水中形成不连续现象, 即出现空化气泡; 此外聚能罩边缘处产生的衍射波进一步加剧了负压的产生, 边缘衍射波最终与拉伸波叠加, 使冲击波负压达到最大值; 通过对比仿真波形和实验波形, 从而验证和进一步揭示了冲击波负压的形成原因. 研究结果对认识水下冲击波的传播规律和进一步改进等离子体声源的设计具有指导意义.
关键词:
等离子体声源
冲击波负压
聚束声场模型
气泡 相似文献
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高温热管是公认的被动式高温传热器件,以及明显高于相同几何尺寸金属材料的当量导热率,使其成为研究热点,并具有广泛的应用前景。在高温热管的蒸汽流动中,当喉部流速达到声速后,会出现声速传热极限,主要表现为冷凝段温度持续降低,传热量停滞不增,以及蒸汽的阻塞状态。本文设计、制备了高温热管传热器件,以高频感应方式为热源,盘管式水冷套为冷源,搭建了可以定量测试高温热管声速极限的实验台,并应用理论模型进行了验证。实验测试了高温热管在高热流加热条件下的冷态启动过程,以及稳态传热状态下的温度、热流等基本物理量,并对此进行了理论分析。实验结果表明:长径比、加热热流、工作温度是影响高温热管声速极限的主要因素。 相似文献
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To improve the acoustic treatment of facings and provide appropriate solutions for noise control at workplace, it is necessary to develop methods of acoustic characterization of the walls in industrial halls. Sound absorption coefficient measurement in industrial rooms is however quite a difficult task because of the partially reverberant conditions. This work describes the measurement of the sound absorption coefficient of flat panels subject to small angle sound incidence, in an industrial hall using an experimental device equipped with an acoustic array. The directivity of this array has been optimized so that the major part of the received acoustic energy would come from one portion only of the investigated facing, this, in turn attenuating the reflected beams due to the reverberation. This new device includes an impulse sound source targeting the panels. The present article focuses mainly on the sound source design and implementation. It also describes some sound absorption measurements carried in a semi-anechoic chamber and in an industrial hall in order to examine the performance of the device. Sound absorption coefficients of several standard liners obtained through this device have been compared to those resulted from the two microphone technique. 相似文献
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研究了在Burgers方程跨声速稀疏波计算中遇到的sonic point glitch问题,对它产生的原因及其与数值格式熵条件的关系进行了分析.对若干著名格式,按照是否满足熵条件进行了分类.为了消除sonic point glitch现象,提出了一种新的两步分裂方法,并用这种方法改进了一系列典型格式.数值试验表明这是一种很好的消除sonic point glitch的方法. 相似文献
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An intact auditory system at birth is requisite for the successful accomplishment of many developmental skills. Evoked responses to auditory stimuli have been used as a sensitive test to determine the functional status of the adult and neonatal brain. It has been established that fetuses can hear in utero and respond to external acoustic stimuli. We present an overview of the transmission of sound through the maternal abdomen to the fetal ear and the recordings of an auditory evoked response obtained from the fetus using a non-invasive magnetoencephalography technique. The investigation of cortical activity of the fetus in response to auditory stimulation can help understand and track the neurological development of the fetus. 相似文献