Estimation and experimental test of the sound-absorption coefficient of a pin-holder structure (Case of sound waves incidence upon the side surfaces of a group of cylinders)

2021 ◽  
Vol 263 (3) ◽  
pp. 3714-3719
Author(s):  
Takamasa Sato ◽  
Shuichi Sakamoto ◽  
Isami Nitta ◽  
Shunsuke Unai ◽  
Takunari Isobe ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Propagation Constant ◽  
Characteristic Impedance ◽  
Physical Property ◽  
Sound Absorption Coefficient ◽  
Accurate Estimation ◽  
Sound Waves ◽  
Acoustic Characteristics ◽  
Measuring Tube

In this study, we conducted theoretical analyses and experiments related to the acoustic characteristics of the situation where sound waves are incident upon the side surfaces of a group of cylinders forming a pin-holder structure. The sound-absorption coefficient, entering its clearance between cylinders through the geometrical dimension of the clearance or the physical property of gas, was calculated. In the analytical model, the gap part of the pin-holder structure was divided into elements and approximated as a gap surrounded by two parallel planes. The characteristic impedance and propagation constant of the approximate gap were obtained and treated as one-dimensional transfer matrices; the sound-absorption coefficient was then calculated using the transfer-matrix method. The calculated value was compared to that obtained in an experiment with a sample prepared using a 3D printer; the sound-absorption coefficient was measured using a 2-microphone impedance-measuring tube. We attempted to make a simple yet accurate estimation of sound-absorption coefficient using these procedures. Our theoretical values displayed a similar tendency to that obtained by experiment.

A Modification of the Standard Weather Bureau Rain Gage for Summer and Winter Use 1

1961 ◽  
Vol 42 (5) ◽  
pp. 311-313
Author(s):  
F. B. Gomm
Keyword(s):  
Laboratory Test ◽  
Field Tests ◽  
Rubber Stopper ◽  
Standard Unit ◽  
Weather Bureau ◽  
Rain Gage ◽  
Collection Tube ◽  
Standard Collection ◽  
Measuring Tube ◽  
Vent Tube

This article describes a modified collection unit for the standard Weather Bureau-type rain gage. The described unit, consisting of a polyethylene bottle, rubber stopper, vent tube and adapter funnel, replaces the metal collection tube of the standard gage. In a laboratory test, evaporation from the modified system was not great enough in a 30-day period to measure with a standard measuring tube. Field tests showed the described unit superior to the standard collection unit and equal to the standard unit with a 0.20-inch oil film in the reduction of evaporation. The described unit, which eliminates recharging with oil or antifreeze after each reading, has been in field use for two years without damage from freezing.

Phase-Shift Determination in Coriolis Flowmeters With Added Masses

2010 ◽  
Author(s):  
Mergen H. Ghayesh ◽  
Marco Amabili ◽  
Michael P. Pai¨doussis
Keyword(s):  
Phase Shift ◽  
Equation Of Motion ◽  
Approximate Analytic Solution ◽  
Analytical Technique ◽  
Flow Prediction ◽  
At Resonance ◽  
Coriolis Flowmeter ◽  
Added Masses ◽  
Measuring Tube ◽  
Secular Terms

In this study, an approximate analytic solution for phase-shift (and thus mass flow) prediction along the length of the measuring tube of a Coriolis flowmeter is investigated. A single, straight measuring tube is considered; added masses at the sensor locations, are included in the model, and thus in the equation of motion. The method of multiple timescales, an approximate analytical technique, has been applied directly to the equation of motion, and the equations of order one and epsilon have been obtained analytically for the system at resonance. The solution of the equation of motion is obtained by satisfying the solvability condition (making the solution of order epsilon free of secular terms). The measuring tube is excited by the driver, and the phase-shift is measured at two symmetrically located points on either side of the mid-length of the tube. The effects of system parameters on the measured phase-shift are discussed.

scholarly journals Models for measuring the liquid level in thetank of rocket carrier

2017 ◽  
Vol 21 (3) ◽  
pp. 88-96
Author(s):  
N.I. Klyuev ◽  
O.P. Filatov
Keyword(s):  
Differential Equation ◽  
Cauchy Problem ◽  
Order Differential Equation ◽  
Viscous Incompressible Fluid ◽  
Linear Time ◽  
Parabolic Type ◽  
Liquid Level ◽  
Fluid Level ◽  
Measuring Tube ◽  
Rocket Carrier

The models for measuring the level of a viscous incompressible fluid in the tank by liquid level in the measuring tube are considered. The tank is in the gravitational field and the level of liquid inside varies according to some law. The base model is the first boundary value problem for nonlinear integro-differential equation of parabolic type. The empirical model is Cauchy problem for nonlinear ordinary second order differential equation. It is numerically founded that for linear time-decreasing level of fluid tank fluid level in the measuring tube oscillates about level in the tank with damping amplitude.

scholarly journals Each-Phase Metering with Gas-Liquid Stratified Flow Based on the Multi-Frequency Coriolis Principle

2020 ◽  
Vol 10 (21) ◽  
pp. 7747
Author(s):  
Chenquan Hua ◽  
Yixiang Yin ◽  
Shuning Sun ◽  
Hao Zhu ◽  
Lanchang Xing
Keyword(s):  
Resonance Effect ◽  
Stratified Flow ◽  
Single Frequency ◽  
Total Density ◽  
Vibrational Modes ◽  
Third Order ◽  
Two Phase ◽  
Mass Flowrate ◽  
Measuring Tube ◽  
Frequency Correction

Gas-liquid two-phase flows generally have the characteristics of complex and variable flow patterns and flow rate uncertainty of each phase. The entrainment of gas increases errors of the existing non-separated multiphase metering. A novel metering method based on the multi-frequency Coriolis principle is proposed to solve the above problems. Compared to the conventional Coriolis mass flowmeter, the third-order mode of the measuring tube is used to improve the accuracy of the measurement. The influences of bubble effect and resonance effect on vibration responses in different vibrational modes were studied to determine the deviations of the apparent values of total density and mass flowrate by simulation. Simulation results with a single-frequency Coriolis flowmeter show that the maximum relative deviations of total density and total mass flowrate are −37.3% and −9.3%, respectively. Driven by different frequencies, the same two phase fluid in the measuring tube can have different responses of the primary mode and the higher vibrational modes. The vibrational responses characteristics corresponding to the first-order and third-order modes of measuring tube were selected and analyzed. Combined with advantages of high precision and multi-parameter measurement of traditional single-frequency Coriolis flowmeters, a multi-frequency correction model suitable for stratified flow was proposed. The results show that the corrected total density and mass flow deviations of gas-containing fluid are within ±4% and ±3%, respectively, which are significantly reduced. Corrected flowrate deviations of the gas-phase and liquid-phase are ±9.1% and ±7.2%, correspondingly, which also meet the metering requirements of the wellhead.

scholarly journals A Method for Measuring Tube Metal Temperature of Ethylene Cracking Furnace Tubes Based on Machine Learning and Neural Network

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 158643-158654
Author(s):  
Junfeng Zhao ◽  
Zhiping Peng ◽  
Delong Cui ◽  
Qirui Li ◽  
Jieguang He ◽  
...  
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Metal Temperature ◽  
Measuring Tube ◽  
Ethylene Cracking Furnace ◽  
Tube Metal
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