共查询到20条相似文献,搜索用时 31 毫秒
1.
单双腔抗性消声器压力损失CFD研究 总被引:3,自引:1,他引:3
利用三维计算流体力学(CFD)方法计算了4种单腔和两种双腔抗性消声器的压力损失。研究了内插管、偏置输入管、偏置输出管和膨胀腔长度等消声器结构以及进口空气流速对单腔消声器压力损失的影响,中间挡板位置和空气流速对双腔消声器压力损失的影响,得出了相应结构对消声器的压力损失的影响规律,为抗性消声器的设计提供帮助。用实际算例验证了CFD方法计算压力损失的可行性,提供了一种利用计算流体动力学进行消声器压力损失的计算和分析流程,方便在设计阶段对消声器进行压力损失的近似预测。 相似文献
2.
3.
4.
Jian-Hua Fang Yi-Qi Zhou Xiao-Dong Hu Li Wang 《International Journal of Precision Engineering and Manufacturing》2009,10(5):59-66
Through analyzing the harm of the exhaust noise from the excavator, this paper illuminated the importance of the noise measurement
and analysis work,. According to some correlative measurement standards, using some instruments in hand, a set of exhaust
noise measurement system especially for the excavator was designed. The exhaust engine noise from an excavator produced by
a construction machinery corporation was measured and analyzed, and then, seven mufflers with different structures were designed.
After analyzing the frequency spectrums of seven impedance mufflers of different structures respectively, we selected the
muffler j which was of best noise elimination performance among the seven mufflers. The highest noise elimination of muffler
j was up to 16.3dB, which could reduce the exhaust noise from the excavator in a larger degree. At last, we analyzed the structures
and corresponding effects of noise elimination for the seven mufflers and made some important conclusions. 相似文献
5.
扩张室式消声器气流噪声的试验研究 总被引:7,自引:0,他引:7
探讨了在有气流的条件下,扩张室式消声器的腔室直径、腔室长度、尾管直径以及连接管形式的变化对消声器消声效果的影响,对于消声器的设计改进有一定指导意义。 相似文献
6.
7.
In this paper,a novel Voltage-Controlled Oscillator(VCO)using the harmonic control circuit based on the quad-band Composite Right/Left-Handed(CRLH)Transmission Line(TL)is presented to reduce the phase noise without the reduction of the frequency tuning range and miniaturizing the circuit size.The phase noise has been reduced by the quad-band harmonic control circuit which has the short impedance for the second-and third-and fourth-and fifth-harmonic components.The CRLH TL with two Left-Handed(LH)(backward)and two Right-Handed(RH)(forward)pass bands are used to design the quad-band harmonic control circuit.The high-Q resonator has been used to reduce the phase noise,but it has the problem of the frequency tuning range reduction.However,the frequency tuning range of the proposed VCO has not reduced because the phase noise has reduced without the high-Q resonator.The miniaturization of the circuit size is achieved by using the quad-band CRLH TL instead of the conventional RH TL.The phase noise of VCO is-124.43~-122.67 dBc/Hz at 100 kHz in the tuning range of 5.729~5.934 GHz. 相似文献
8.
Hanson GR Wilgen JB Bigelow TS Diem SJ Biewer TM 《The Review of scientific instruments》2010,81(10):10D920
A critical issue in the design of the ITER low field side reflectometer is the transmission line (TL) system. A TL connects each launcher to a diagnostic instrument. Each TL will typically consist of ~42?m of corrugated waveguide and up to ten miter bends. Important issues for the performance of the TL system are mode conversion and reflections. Minimizing these issues are critical to minimizing standing waves and phase errors. The performance of TL system is analyzed and recommendations are given. 相似文献
9.
Takahashi K Kajiwara K Oda Y Kasugai A Kobayashi N Sakamoto K Doane J Olstad R Henderson M 《The Review of scientific instruments》2011,82(6):063506
High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system. 相似文献
10.
探究消声器进出口轴向角度影响消声器消声性能时,多针对单腔消声器,鉴于此,针对某汽车抗性消声器,研究多腔汽车消声器进出口轴向角度对消声性能的影响规律。采用声学有限元法,借助于VirtualLab声学仿真软件,计算消声器进气管伸进长度、第二腔室支撑板间距等结构参数改变时的消声性能。固定消声器结构参数,研究不同进出口轴向角度下消声器的消声性能,结果表明,当进出口轴向角度为60°时,多腔消声器的消声性能良好,与原消声器相比,改进后的消声器具有良好的消声性能。 相似文献
11.
马雪皎 《机械工程与自动化》2011,(6):64-65,68
介绍了一种新的发动机性能仿真软件GT-Power,它是以一维模型计算为基础,采用有限容积法对流体进行模拟运算的软件。综述了排气消声器的几种常用的研究方法,介绍了各种方法的优点和缺点,并分析了不同参数对各种消声器消声效果的影响。 相似文献
12.
《Measurement》2015
Registration of thermoluminescence (TL) spectra technique for irradiated samples in Perkin Elmer LS 55 spectrometer using developed high-temperature accessory during single heating cycle is shown. Functionality of serial instrument for RT–773 K temperature range is significantly widen. Spectrally resolved TL dependencies for h-BN micropowders and bulk AlN single crystals following UV irradiation are studied. TL spectral features of h-BN powders, synthesized by carbamide and plasma-chemical techniques, are determined and quantified. It is shown that the difference between TL curves obtained by the described and the standard modes does not exceed 10%. 相似文献
13.
TL16C752B是TI公司生产的双通道异步收发芯片,该芯片可在通信系统中的实时性要求较高时,用来实现系统的高效多串口通信,从而增强系统的通信接口控制能力,本文介绍了TL16C752B的性能特点及与通信有关的寄存器,给出了用TL16C752B对DSP器件TMS320C6416多串口扩展的硬件框图以及通过TMS320C6416初始化TL16C752B的软件编程,并且使用了CPLD做为片选逻辑控制。 相似文献
14.
The acoustic characteristics of a dual Helmholtz resonator in the presence of flow is investigated theoretically and experimentally. A lumped parameter model is introduced, including the damping effect and neck inertia, and the predicted transmission loss (TL) is compared with experiments performed with a flow-impedance tube setup. ^Predicted and measured results with flow exhibit a good agreement, while capturing the key variations in peak TL magnitude and the shifts in peak TL frequency. Theoretical approach demonstrates that the damping of the first neck inertia of the dual Helmholtz resonator has a marked impact not only on the magnitude of the first peak TL but also the second peak TL. 相似文献
15.
16.
17.
为进一步研究固体材料在机械压力作用下产生的发光现象及机制,自行研制一套摩擦发光探测装置。该装置由机械系统、控制系统和测量系统三部分组成,可实现不同转速、不同载荷、不同摩擦副下的摩擦发光光强和光谱的探测。通过测量不同转速、不同载荷以及不同摩擦副下的摩擦发光实验,发现重复多次测量,实验结果数据稳定且有一定规律性,证明了摩擦发光探测装置的可行性。 相似文献
18.
19.
Thermal lens (TL) spectroscopy was applied to biofuels to test its potential to distinguish diesel from biodiesel in blended fuels. Both the heat and mass diffusion effects observed using a TL procedure provide significant information about biodiesel concentrations in blended fuels. The results indicate that the mass diffusivity decreases 32% between diesel and the blend with 10% biodiesel added to the diesel. This simple TL procedure has the potential to be used for in loco analyses to certify the mixture and quality of biodiesel-diesel blends. 相似文献
20.
将前向离心风机原有的直蜗舌结构改进为倾斜蜗舌结构之后,风机噪声已有比较明显的下降。在此基础上,本文在倾斜蜗舌前向离心风机出口分别配置简易共振消声器和简易阻性消声器,并进行了气动性能和噪声特性的实验测量。结果表明:对于具有倾斜蜗舌结构的前向离心风机,在出口配置阻性消声器可以继续取得良好的降噪效果,但是配置共振消声器降噪效果却不理想。对于同一风机,两种降噪措施单独使用时均可取得良好的降噪效果,但同时使用时,各自的降噪效果却不一定具有预期的迭加性,文中对产生这种现象的原因做了初步分析。 相似文献