Behavior of Jet From an Orifice in a Pipe Under Pulsating Flow

2007 ◽  
Author(s):  
Ema Tamura ◽  
Junjiro Iwamoto
Keyword(s):  
Unsteady Flow ◽  
Flow Rate ◽  
Sound Pressure Level ◽  
Measurement Errors ◽  
Sound Pressure ◽  
Pressure Level ◽  
Flow Meter ◽  
Orifice Flow ◽  
Accuracy Of Measurement ◽  
Orifice Flow Meter

An orifice flow meter is widely used in industry to measure the flow rate of gas or liquid in the pipe because of its simplicity. The accuracy of measurement is acceptable when the steady flow is measured. However, it is often the case in industry that the unsteady flow must be measured. It is not yet known, under unsteady flow conditions, how accurate the flow rate can be measured using the orifice flow meter and where the measurement errors come from. In the present paper to answer these questions a pulsating air flow is considered as the simplest of the various types of unsteady flow patterns and the measurement of the flow field in the pipe with orifice is made in detail. The sound pressure level is also measured by probe tube microphone. A comparison is made of power spectrum densities obtained by measurement of sound pressure level and by the velocity measurement from laser Doppler anemometer.

Clarification of Measurement Error of Orifice Flow Meter in Wet Steam Flow

2011 ◽  
Author(s):  
Ryo Morita ◽  
Shuichi Umezawa ◽  
Tatsuya Funaki ◽  
Fumio Inada ◽  
Masayuki Sakai ◽  
...  
Keyword(s):  
Measurement Error ◽  
Flow Rate ◽  
Measurement Errors ◽  
Correction Method ◽  
Steam Flow ◽  
Wet Steam ◽  
Flow Meter ◽  
Orifice Flow ◽  
Wet Steam Flow ◽  
Orifice Flow Meter

It is well known that the wetness of steam flow sometimes causes measurement errors of the steam flow meter. However, it is difficult to clarify a particular error quantitatively in actual plants and factories, and thus far, there has been no established method for estimating the error caused by the wetness of steam flow. Therefore, wet steam flow rate measurement experiments were conducted to clarify the measurement error caused by the wetness of steam flow in a plant and a factory. In this study, as the first step, the orifice flow meter was applied because it is the main flow meter in actual plants. Experiments were conducted with the steam flow apparatus by changing the flow rate, pressure and wetness. As a result, the correlation between the measurement error and the flow condition was clarified. Moreover, for the correction of the error, a new correction method was applied and was confirmed to be better than existing methods now being used.

scholarly journals Experimental study of aerodynamic noise performance of improved air distributor for ships

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110012
Author(s):  
Yuejiao Guo ◽  
Guozeng Feng ◽  
Shuya Lei ◽  
Bo Meng ◽  
Yang Xu
Keyword(s):  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Static Pressure ◽  
Resistance Coefficient ◽  
Pressure Level ◽  
Channel Structure ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Reduction Effect

In ships, aerodynamic noise from the variable-air-volume fan is a common problem. This study experimentally explores the strategy of reshaping the traditional C-shaped channel structure to an L-shape to reduce noise. The noise level and resistance coefficient of the improved air distributor are analysed, and the results show that the noise of the original air distributor is 56.3 dB(A) under the rated working conditions (static pressure of 800 Pa and flow rate of 350 m3/h), which exceeds the International Maritime Organisation’s (IMO) ship noise limit (55 dB(A)). For the improved air distributor, the noise pressure level is 38.5 dB(A), the sound pressure level of high-frequency noise is reduced by 48% and the peak sound pressure level appears at 125 to 250 Hz, a frequency below the threshold of human hearing. Thus, the reshaping of the channel has a significant noise reduction effect. When the static pressure is 400 Pa and the flow rate is 100 to 500 m3/h, the sound pressure level of the improved air distributor is reduced by 29.9% to 32.2% to become less than 55 dB(A). Thus, the sound pressure level at the outlet of the improved air distributor meets the IMO ship noise standard.

scholarly journals Prediction of oil flow rate through an orifice flow meter: Artificial intelligence alternatives compared

Petroleum ◽  
2018 ◽  
Author(s):  
Hamzeh Ghorbani ◽  
David A. Wood ◽  
Abouzar Choubineh ◽  
Afshin Tatar ◽  
Pejman Ghazaeipour Abarghoyi ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Flow Rate ◽  
Flow Meter ◽  
Oil Flow ◽  
Orifice Flow ◽  
Orifice Flow Meter

Evaluation of Orifice Flow Meter Accuracy under Pulsation Conditions

2015 ◽  
Vol 1115 ◽  
pp. 472-475
Author(s):  
Muhammad Abdullah ◽  
Moumen Idres
Keyword(s):  
Measurement Errors ◽  
Industrial Applications ◽  
Square Root ◽  
Sampling Errors ◽  
Flow Meter ◽  
Measuring Device ◽  
Orifice Flow ◽  
Flow Through ◽  
Averaging Time ◽  
Orifice Flow Meter

Orifice meter is a flow measuring device which is widely used in various industrial applications. Although the device gives accurate measurement during steady flow, measurement errors related to square root and sampling errors are unavoidable if pulsations exist. This research investigatesand improves the performance of an orifice plate flow meter under pulsation effects. A simple model for the pulsating flow through an orifice meter is presented. Square root error (SRE) is estimated. Sampling errors (SE) are reduced by proper selection of the averaging time.

OPTIMIZATION OF LOW NOISE BIONIC FAN USING GRAY RELATIONAL ANALYSIS COUPLED WITH ENTROPY MEASUREMENT

2014 ◽  
Vol 13 (01) ◽  
pp. 1450005 ◽  
Author(s):  
SHUMING CHEN ◽  
YONGQI GUO ◽  
DENGFENG WANG ◽  
SHAOMING SUN
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Gray Relational Analysis ◽  
Acoustic Performance ◽  
Relational Analysis ◽  
Entropy Measurement

This research presents a hybrid optimization method for the determination of the optimal geometry parameters which can minimize the A-weighted sound pressure level of bionic fan on condition that the mass flow rate of the bionic fan is as high as possible. A hybrid approach of gray relational analysis (GRA), Taguchi method, and entropy measurement has been used to obtain better acoustic performances with three basic geometry parameters, which are blade number, boss ratio, and blade stagger angle. A L9(34) orthogonal array has been used for conducting the experiment for optimization of flow and acoustic performances. The problem of multiple performance indices is simplified into single performance index by using gray relational grade. The designed experimental results are utilized in GRA, and the weights of the flow and acoustic performances are determined by using the entropy measurement method. Meanwhile, the optimal combination of bionic fan parameters is determined by using GRA method. Moreover, the validation tests show that the overall sound pressure level (SPL) reduces by 15.50% at the cost of mass flow rate reducing by 3.00%. The comparison of the A-weighted SPL for acoustic tests between original fan and optimized bionic fan demonstrates that the acoustic performance obviously improve from 20 Hz to 6300 Hz. Therefore, it is clearly shown that the proposed approach in this paper can be an useful tool to improve acoustic performance of bionic fan.

Numerical prediction of aerodynamic noise from impeller blowers of straw threshing machines

2019 ◽  
Vol 51 (1-2) ◽  
pp. 21-32
Author(s):  
Zhai ZhiPing ◽  
Li ZhuWei ◽  
Zhang Long ◽  
Yang Zhongyi ◽  
Lan Yuezheng
Keyword(s):  
Unsteady Flow ◽  
Sound Pressure Level ◽  
Optimization Design ◽  
Sound Pressure ◽  
Pressure Level ◽  
Aerodynamic Noise ◽  
Dipole Source ◽  
Discrete Phase Model ◽  
Full Field ◽  
Rotating Impeller

An impeller blower is one of the major aerodynamic noise sources in straw threshing machines. To reduce its aerodynamic noise, it is essential to understand the mechanism of gas-material-coupled unsteady flow causing aerodynamic noise. However, it is difficult to clarify the mechanism through measurement. Therefore, the following topics are studied in this article. First, a full-field transient numerical simulation of the gas and solid particulates’ unsteady flow inside the impeller blower was carried out using a dense discrete phase model and a large eddy simulation turbulence model. Second, based on the Ffowcs Williams–Hawkins equation, the aerodynamic noise of the impeller blower of the straw threshing machines was numerically calculated. Finally, the numerical results were verified by aerodynamic noise test. The results indicate that (1) sound pressure level at the inlet of the impeller blower is the highest, mainly at 100 Hz, which is the fundamental frequency of the rotating impeller, while the sound pressure level at the fourth harmonic frequency of 400 Hz is the main source of the outlet. The total sound pressure level at the inlet is greater than that at the outlet. It is concluded that the dipole source of the rotating impeller is the main noise source, which was generated by the interaction of blade with the air and material as the impeller rotated. Also, acoustic attenuation, acoustic resonance, and impact noise of material and machinery play important roles in aerodynamic noise distribution. (2) The test and simulation results show good agreement, so the numerical model of aerodynamic noise is reliable. This study will provide a reference for the structural and acoustic optimization design of impeller blowers and their integration into threshing machines.

Regulatory Mechanism of Voice Intensity Variation

1964 ◽  
Vol 7 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Nobuhiko Isshiki
Keyword(s):  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Low Frequency ◽  
Intensity Variation ◽  
Pressure Level ◽  
Expiratory Muscle ◽  
Laryngeal Control ◽  
The Relationship ◽  
The Voice

The relationship between the voice intensity (sound pressure level), the subglottic pressure, the air flow rate, and the glottal resistance was investigated. Simultaneous recordings were made of the sound pressure level of voice, the subglottic pressure, the flow rate, and the volume of air utilized during phonation. The glottal resistance, the subglottic power, and the efficiency of voice were calculated from the data. It was found that on very low frequency phonation the flow rate remained almost unchanged or even slightly decreased with the increase in voice intensity while the glottal resistance showed a tendency to augment with increased voice intensity. In contrast to this, the flow rate on high frequency phonation was found to increase greatly, while the glottal resistance remained almost unchanged as the voice intensity increased. On the basis of the data it was concluded that at very low pitches, the glottal resistance is dominant in controlling intensity (laryngeal control), becoming less so as the pitch is raised, until at extremely high pitch the intensity is controlled almost entirely by the flow rate (expiratory muscle control).

scholarly journals Complexity Study on the Unsteady Flow Field and Aerodynamic Noise of High-Speed Railways on Bridges

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Jufeng Su ◽  
Yamin Sun ◽  
Yuyang Liu
Keyword(s):  
Unsteady Flow ◽  
Sound Pressure Level ◽  
High Speed ◽  
Sound Pressure ◽  
Pressure Level ◽  
Noise Model ◽  
Aerodynamic Noise ◽  
High Speed Railway ◽  
Wake Flows ◽  
Flat Ground

To study complexity distributions of unsteady flow field and aerodynamic noise of a high-speed railway on bridges, an aerodynamic noise model of a railway was obtained. Meanwhile, detailed structures such as 6 bogies, 3 air conditioning units, 1 pantograph fairing, and 1 pantograph were considered. Numerical simulation was conducted to flow fields around the high-speed railway running on the bridge under a crosswind-free environment, with running speed of 350 km/h. Hence, unsteady flow behavior characteristics of the complete high-speed railway were obtained. Numerical simulation was conducted to noises of the railway on the bridge in combination with detached eddy simulation and acoustic analogy theory. Meanwhile, the broadband noise model was used for the quantitative analysis on distribution characteristics of the dipole noise source and quadrupole noise source of the high-speed railway on the bridge. Studied results proved that aerodynamic noise of the railway was caused by eddy shedding and fluid separation. Main noise sources of the high-speed railway include areas such as pantographs, train head streamline, bogies, windshield, and an air conditioning unit. Maximum sound pressure level and average sound pressure level of the high-speed railway on the bridge were 2.7 dBA and 2.3 dBA, respectively, more than those of the high-speed railway on a flat ground. On the bridge, the maximum sound pressure level of the pantograph on the bridge was 3.1 dBA larger than that on the flat ground. In addition, incoming flows of the high-speed railway on the bridge had greater impacts on aerodynamic noises around the railway compared with those of wake flows. Meanwhile, in directions of incoming flows and wake flows, linear relationship was between the sound pressure levels of noise monitoring points which had different distances from the train head nose and the logarithm of the distances.

Exploration on relationship between flow rate and sound pressure level of piezoelectric pump

2019 ◽  
Vol 26 (2) ◽  
pp. 609-616 ◽  
Author(s):  
Lipeng He ◽  
Xiaoqiang Wu ◽  
Da Zhao ◽  
Wei Li ◽  
Guangming Cheng ◽  
...  
Keyword(s):  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Piezoelectric Pump

Contributions of Voice and Nonverbal Communication to Perceived Masculinity–Femininity for Cisgender and Transgender Communicators

2020 ◽  
Vol 63 (4) ◽  
pp. 931-947
Author(s):  
Teresa L. D. Hardy ◽  
Carol A. Boliek ◽  
Daniel Aalto ◽  
Justin Lewicke ◽  
Kristopher Wells ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Vocal Tract ◽  
Presentation Mode ◽  
Pressure Level ◽  
Presentation Modes ◽  
Audiovisual Stimuli ◽  
Vocal Tract Resonance ◽  
Point Light

Purpose The purpose of this study was twofold: (a) to identify a set of communication-based predictors (including both acoustic and gestural variables) of masculinity–femininity ratings and (b) to explore differences in ratings between audio and audiovisual presentation modes for transgender and cisgender communicators. Method The voices and gestures of a group of cisgender men and women ( n = 10 of each) and transgender women ( n = 20) communicators were recorded while they recounted the story of a cartoon using acoustic and motion capture recording systems. A total of 17 acoustic and gestural variables were measured from these recordings. A group of observers ( n = 20) rated each communicator's masculinity–femininity based on 30- to 45-s samples of the cartoon description presented in three modes: audio, visual, and audio visual. Visual and audiovisual stimuli contained point light displays standardized for size. Ratings were made using a direct magnitude estimation scale without modulus. Communication-based predictors of masculinity–femininity ratings were identified using multiple regression, and analysis of variance was used to determine the effect of presentation mode on perceptual ratings. Results Fundamental frequency, average vowel formant, and sound pressure level were identified as significant predictors of masculinity–femininity ratings for these communicators. Communicators were rated significantly more feminine in the audio than the audiovisual mode and unreliably in the visual-only mode. Conclusions Both study purposes were met. Results support continued emphasis on fundamental frequency and vocal tract resonance in voice and communication modification training with transgender individuals and provide evidence for the potential benefit of modifying sound pressure level, especially when a masculine presentation is desired.

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