P-04 An Interior Noise Analysis of KTX Trains on Various Operating Conditions

2007 ◽  
Vol 2007.6 (0) ◽  
pp. _P-04-1_-_P-04-4_
Author(s):  
Chan-Woo Lee ◽  
Jae-Chul Kim
Keyword(s):  
Noise Analysis ◽  
Operating Conditions ◽  
Interior Noise

Design, Analysis and System-Level Modelling of a Single Axis Capacitive Accelerometer

2016 ◽  
Author(s):  
Zakriya Mohammed ◽  
Owais Talaat Waheed ◽  
Ibrahim (Abe) M. Elfadel ◽  
Aveek Chatterjee ◽  
Mahmoud Rasras
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Noise Analysis ◽  
Linear Displacement ◽  
Operating Conditions ◽  
System Level ◽  
Complete Analysis ◽  
Capacitive Accelerometer ◽  
Static Capacitance ◽  
Cross Axis

The paper demonstrates the design and complete analysis of 1-axis MEMS capacitive accelerometer. The design is optimized for high linearity, high sensitivity, and low cross-axis sensitivity. The noise analysis is done to assure satisfactory performance under operating conditions. This includes the mechanical noise of accelerometer, noise due to interface electronics and noise caused by radiation. The latter noise will arise when such accelerometer is deployed in radioactive (e.g., nuclear power plants) or space environments. The static capacitance is calculated to be 4.58 pF/side. A linear displacement sensitivity of 0.012μm/g (g = 9.8m/s2) is observed in the range of ±15g. The differential capacitive sensitivity of the device is 90fF/g. Furthermore, a low cross-axis sensitivity of 0.024fF/g is computed. The effect of radiation is mathematically modelled and possibility of using these devices in radioactive environment is explored. The simulated noise floor of the device with electronic circuit is 0.165mg/Hz1/2.

Using a Dynamometer Along With Road Tests to Measure Vehicle Rolling and Wind Noise

2008 ◽  
Author(s):  
Richard E. Wentzel ◽  
Allan Aubert
Keyword(s):  
Operating Conditions ◽  
Interior Noise ◽  
Wind Tunnels ◽  
Sport Utility Vehicle ◽  
Wind Noise ◽  
Pickup Truck ◽  
The Road ◽  
Noise Data ◽  
Rolling Noise ◽  
Utility Vehicle

The consumer today places greater demands upon the vehicle acoustical engineer than in the past. Product quality has always been associated with a quiet ride. Automotive engineers recognize that the predominant sources of vehicle interior noise are wind, tire-road or rolling noise, and the powertrain. This paper suggests a test protocol for measuring wind and rolling noise using a chassis rolls dynamometer and road tests. Automotive engineers are frequently confronted by customer complaints concerning wind noise. Usually, engineers resort to using wind tunnels to address these concerns and to conduct diagnostic studies to remedy wind noise problems. Unfortunately, wind tunnels are expensive to rent and difficult to schedule. As an alternative, the engineer can learn a great deal about the wind noise of a vehicle by using a chassis rolls dynamometer along with road tests [1,2]. If the chassis rolls surface texture closely matches that of the road surface, the tire-road or rolling noise signal in both situations can be assumed to be equivalent. The powertrain noise source can be minimized by shifting the vehicle into neutral and coasting. Wind noise is a source for the road measurements, but not for the chassis rolls. Hence, the wind noise can be calculated by measuring the cab interior noise for both operating conditions, and subtracting the rolling noise measured on the chassis rolls. The two vehicles tested in this study included a pickup truck and a sport utility vehicle. The acoustical data revealed significantly different rolling and wind noise characteristics. The pickup truck had significantly louder rolling noise, and the wind noise was dominated by low frequency sound. The sport utility vehicle was much quieter overall and was significantly quieter for rolling noise than the pickup. The wind noise of the sport utility vehicle also was dominated by high frequency components. Both vehicles showed that rolling and wind noise trends increase linearly with speed. However, the slope of wind noise data for the sport utility vehicle was much steeper than the pickup, which suggested that it was more sensitive to wind noise as speed increased. Exterior noise data from both vehicles showed that the tire-road signal from the road differed significantly from that of the chassis rolls dynamometer. Rolling & wind noises will become even more critical as the motor vehicle industry adopts hybrid electric and, in the future electric fuel cell vehicles, because powertrain noise sources in the vehicle will likely be reduced. The procedure suggested here provides an inexpensive simple approach to assessing rolling and wind noise in the vehicle.

An integrated performance analysis for a small axial-flow fan

2010 ◽  
Vol 224 (9) ◽  
pp. 1981-1994 ◽  
Author(s):  
S-C Lin ◽  
M-L Tsai
Keyword(s):  
High Performance ◽  
Noise Analysis ◽  
Technical Information ◽  
Axial Flow ◽  
Operating Conditions ◽  
Numerical Control ◽  
Field Analysis ◽  
Axial Flow Fan ◽  
Fan Performance ◽  
Efficiency Estimation

Owing to the high system resistance and space limitations on computer devices, many researchers have begun to pay more attention to developing high-performance axial-flow fans. Evidently, evaluating the fan performance under different operating conditions is essential for both designer and practical engineering applications. However, previous studies do not provide a detailed flow-field analysis, torque prediction, efficiency estimation at various operating points, and qualitative numerical prediction of sound generation. Thus, this comprehensive study was performed with the aim to offer the aforementioned technical information and completely evaluate the fan performance. In this study, computational fluid dynamics (CFD) simulations and experimental measurements are utilized to perform flow visualization, torque calculation, efficiency estimation, and noise analysis. For demonstration purposes, a 120 mm-diameter axial-flow fan is designed and fabricated via computer numerical control (CNC) to serve as the research subject. The result indicates that the P— Q curve and the sound pressure level (SPL) spectrum of the experiment are in agreement with those of numerical simulations. The numerical deviations in maximum volumetric flowrate and static pressure are approximately 7 per cent and 13 per cent, respectively. Regarding the acoustic characteristics, the overall SPLs for measured spectra and large eddy simulation (LES) calculation are 51.3 dB and 48.1 dB, respectively. Consequently, this study establishes an integrated aerodynamic, acoustic, and electro-mechanical evaluation approach that can be used as an important tool for fan designers.

scholarly journals Noise conversion of Schottky diodes in mm-wave detectors under different nonlinear regimes: modeling and simulation versus measurement

2015 ◽  
Vol 8 (3) ◽  
pp. 479-493 ◽  
Author(s):  
Jéssica Gutiérrez ◽  
Kaoutar Zeljami ◽  
Enrique Villa ◽  
Beatriz Aja ◽  
Maria Luisa de la Fuente ◽  
...  
Keyword(s):  
Transfer Functions ◽  
Noise Analysis ◽  
Schottky Diodes ◽  
Source Parameters ◽  
Low Frequency ◽  
Operating Conditions ◽  
Noise Sources ◽  
Wave Detector ◽  
Detector Output ◽  
Conversion Matrix

This paper presents and discusses several methods for predicting the low-frequency (LF) noise at the output of a mm-wave detector. These methods are based on the extraction of LF noise source parameters from the single diode under a specific set of bias conditions and the transfer or conversion of these noise sources, under different operating conditions including cyclostationary regime, to the quasi-dc output of a mm-wave detector constructed with the same model of diode. The noise analysis is based on a conversion-matrix type formulation, which relates the carrier noisy sidebands of the input signal with the detector output spectrum through a pair of transfer functions obtained in commercial software. Measurements of detectors in individual and differential setups will be presented and compared with predictions.

scholarly journals A Systematic Approach to Identify Sources of Abnormal Interior Noise for a High-Speed Train

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jie Zhang ◽  
Xinbiao Xiao ◽  
Xiaozhen Sheng ◽  
Zhihui Li ◽  
Xuesong Jin
Keyword(s):  
High Speed ◽  
Sound Pressure ◽  
Systematic Approach ◽  
Noise Analysis ◽  
Interior Noise ◽  
Sound Insulation ◽  
High Speed Train ◽  
Main Contributor ◽  
Vibration Data ◽  
High Speed Trains

A systematic approach to identify sources of abnormal interior noise occurring in a high-speed train is presented and applied in this paper to resolve a particular noise issue. This approach is developed based on a number of previous dealings with similar noise problems. The particular noise issue occurs in a Chinese high-speed train. It is measured that there is a difference of 7 dB(A) in overall Sound Pressure Level (SPL) between two nominally identical VIP cabins at 250 km/h. The systematic approach is applied to identify the root cause of the 7 dB(A) difference. Well planned measurements are performed in both the VIP cabins. Sound pressure contributions, either in terms of frequency band or in terms of facing area, are analyzed. Order analysis is also carried out. Based on these analyses, it is found that the problematic frequency is the sleeper passing frequency of the train, and an area on the roof contributes the most. In order to determine what causes that area to be the main contributor without disassembling the structure of the roof, measured noise and vibration data for different train speeds are further analyzed. It is then reasoned that roof is the main contributor caused by sound pressure behind the panel. Up to this point, panels of the roof are removed, revealing that a hole of 300 cm2 for running cables is presented behind the red area without proper sound insulation. This study can provide a basis for abnormal interior noise analysis and control of high-speed trains.

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