scholarly journals Evaluation of Shock Tube Retrofitted with Fast-Opening Valve for Dynamic Pressure Calibration

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4470
Author(s):  
Eynas Amer ◽  
Mikolaj Wozniak ◽  
Gustav Jönsson ◽  
Fredrik Arrhén
Keyword(s):  
Shock Wave ◽  
Shock Tube ◽  
Dynamic Pressure ◽  
Pressure Measurements ◽  
Pressure Calibration ◽  
Nominal Pressure ◽  
Shock Wave Formation ◽  
Dynamic Pressure Measurements ◽  
Calibration Laboratories ◽  
Double Diaphragms

Accurate dynamic pressure measurements are increasingly important. While traceability is lacking, several National Metrology Institutes (NMIs) and calibration laboratories are currently establishing calibration capacities. Shock tubes generating pressure steps with rise times below 1 µs are highly suitable as standards for dynamic pressures in gas. In this work, we present the results from applying a fast-opening valve (FOV) to a shock tube designed for dynamic pressure measurements. We compare the performance of the shock tube when operated with conventional single and double diaphragms and when operated using an FOV. Different aspects are addressed: shock-wave formation, repeatability in amplitude of the realized pressure steps, the assessment of the required driver pressure for realizing nominal pressure steps, and economy. The results show that using the FOV has many advantages compared to the diaphragm: better repeatability, eight times faster to operate, and enables automation of the test sequences.

scholarly journals Reproducibility of C. I. P.-compatible dynamic pressure measurements

2020 ◽  
Vol 87 (10) ◽  
pp. 630-636
Author(s):  
Oliver Slanina ◽  
Susanne Quabis ◽  
Robert Wynands
Keyword(s):  
Dynamic Pressure ◽  
Storage Conditions ◽  
Dynamic Measurement ◽  
Gas Pressure ◽  
Pressure Measurements ◽  
Small Arms ◽  
Minimum Pressure ◽  
Maximum Value ◽  
Preliminary Study ◽  
Dynamic Pressure Measurements

AbstractTo ensure the safety of users like hunters and sports shooters, the dynamic pressure inside an ammunition cartridge must not exceed a maximum value. We have investigated the reproducibility of the dynamic measurement of the gas pressure inside civilian ammunition cartridges during firing, when following the rules formulated by the Permanent International Commission for the Proof of Small Arms (C. I. P.). We find an in-house spread of 0.8 % between maximum and minimum pressure for runs with the same barrel and of 1.8 % among a set of three barrels. This sets a baseline for the expected agreement in measurement comparisons between different laboratories. Furthermore, a difference of more than 3 % is found in a preliminary study of the influence of ammunition storage conditions.

Application of side-hole fibers for dynamic pressure measurements

2000 ◽  
Author(s):  
Wojtek J. Bock ◽  
Magdalena S. Nawrocka ◽  
Waclaw Urbanczyk
Keyword(s):  
Dynamic Pressure ◽  
Pressure Measurements ◽  
Side Hole ◽  
Dynamic Pressure Measurements

Distribution of Flow Across the Radius of an Axisymmetric Shock Tube With Variable Cross-Sectional Area

1991 ◽  
Author(s):  
Stephen J. Schraml ◽  
Richard J. Pearson
Keyword(s):  
Shock Tube ◽  
Dynamic Pressure ◽  
Computer Code ◽  
Turbulence Modelling ◽  
Variable Cross ◽  
Cross Sectional ◽  
Flow Simulations ◽  
First Order ◽  
Series Of Experiments ◽  
Dynamic Pressure Measurements

Abstract Experiments were conducted to study the characteristics of unsteady flow in a small, axisymmetric shock tube. These experiments have been supplemented by calculational results obtained from the SHARC hydrodynamic computer code. Early calculational results indicated that a substantial gradient in flow velocity and dynamic pressure may exist along the cross-section of the shock tube. To further investigate this phenomenon, a series of experiments was performed in which dynamic pressure measurements were made at various radii in the expansion section of the shock tube. Additional calculations with the SHARC code were also performed in which turbulence modelling, artificial viscosity and second order advection were employed. The second set of calculations agree very well with the experimental results. These results indicate that the dynamic pressure is nearly constant across the radius of the shock tube. This contradicts the early computational results which were performed with first order advection and without turbulence modelling. As a result of these findings, it was concluded that turbulence modelling was necessary to obtain accurate shock tube flow simulations.

Highly sensitive fiber optic sensor for dynamic pressure measurements

1999 ◽  
Author(s):  
Magdalena S. Nawrocka ◽  
Wojtek J. Bock ◽  
Waclaw Urbanczyk ◽  
Jan Wojcik
Keyword(s):  
Fiber Optic ◽  
Dynamic Pressure ◽  
Fiber Optic Sensor ◽  
Pressure Measurements ◽  
Optic Sensor ◽  
Highly Sensitive ◽  
Dynamic Pressure Measurements

Experimental Study on Pressure Fluctuations in the Boundary Layer of an Axisymmetric Body

2011 ◽  
Vol 66-68 ◽  
pp. 1488-1493
Author(s):  
Hong Xiao ◽  
Chao Gao ◽  
Zhen Kun Ma
Keyword(s):  
Boundary Layer ◽  
Experimental Study ◽  
Mach Number ◽  
Dynamic Pressure ◽  
Pressure Fluctuations ◽  
Axisymmetric Body ◽  
Pressure Measurements ◽  
Fluctuating Pressure ◽  
Frequency Domains ◽  
Dynamic Pressure Measurements

The characteristics of the fluctuating pressure in the boundary layer of an axisymmetric body have been investigated experimentally using dynamic pressure measurements and Schlieren photograghs. Data were acquired at subsonic and super-sonic Mach numbers. The angles of attack ranged from 0° to 5°. Pressure signals were measured simultaneously in several positions along the model and were analyzed both in the time and frequency domains. The Mach number shows the relevant influence on . Furthermore, the pressure fluctuations’ level decreases with the increasing of Mach number except M=1.15. And it is shown that, the location along the axis of the model and the angles of attack have small effect on pressure fluctuations.

Comparison Between Self-Excited and Forced Flame Response of an Industrial Lean Premixed Gas Turbine Injector

2011 ◽  
Author(s):  
Stephen Peluso ◽  
Bryan D. Quay ◽  
Jong Guen Lee ◽  
Domenic A. Santavicca
Keyword(s):  
Heat Release ◽  
Gas Turbine ◽  
Dynamic Pressure ◽  
Variable Length ◽  
Finite Limit ◽  
Pressure Measurements ◽  
Operating Condition ◽  
Lean Premixed ◽  
Flame Response ◽  
Dynamic Pressure Measurements

An experimental study was conducted to compare the relationship between self-excited and forced flame response in a variable-length lean premixed gas turbine (LPGT) research combustor with a single industrial injector. The variable-length combustor was used to determine the range of preferred instability frequencies for a given operating condition. Flame stability was classified based on combustor dynamic pressure measurements. Particle velocity perturbations in the injector barrel were calculated from additional dynamic pressure measurements using the two-microphone technique. Global CH* chemiluminescence emission was used as a marker for heat release. The flame’s response (i.e. normalized heat release fluctuation divided by normalized velocity fluctuation) was characterized during self-excited instabilities. The variable-length combustor was then used to tune the system to produce a stable flame at the same operating condition and velocity perturbations of varying magnitudes were generated using an upstream air-fuel mixture siren. Heat release perturbations were measured and the flame transfer function was calculated as a function of inlet velocity perturbation magnitude. For cases in this study, the gain and phase between velocity and heat release perturbations agreed for both self-excited and forced measurements in the linear and nonlinear flame response regimes, validating the use of forcing measurements to measure flame response to velocity perturbations. Analysis of the self-excited flame response indicates the saturation mechanism responsible for finite limit amplitude perturbations may result from nonlinear driving or damping processes in the combustor.

An Experimental and Theoretical Investigation of Wave Propagation in Teflon and Nylon Tubing With Methods to Prevent Aliasing in Pressure Scanners

2013 ◽  
Author(s):  
Adam M. Hurst ◽  
Joe VanDeWeert
Keyword(s):  
Frequency Response ◽  
Dynamic Pressure ◽  
Sampling Rate ◽  
Aircraft Design ◽  
Experimental Results ◽  
Analytical Models ◽  
Pressure Measurements ◽  
Pressure Transmission ◽  
Dynamic Pressure Measurements ◽  
Nylon Tubing

Accurate static and dynamic pressure measurements provide the feedback needed to advance gas turbine efficiency and reliability as well as improve aircraft design and flight control. During turbine testing and aircraft flight testing, flush mounting pressure transducers at the desired pressure measurement location is not always feasible and recess mounting with connective tubing is often used as an alternative. Resonances in the connective tubing can result in aliasing within pressure scanners even within a narrow bandwidth and especially when higher frequency content DC to ∼125Hz is desired. We present experimental results that investigate tube resonances and attenuation in 1.35mm inner diameter (ID) (used on 0.063in tubulations) and 2.69mm ID (used on 0.125in tubulations) Teflon and Nylon tubing at various lengths. We utilize a novel dynamic pressure generator, capable of creating large changes in air pressure (<1psi to 10psi, <6.8kPa to 68.9kPa), to determine the frequency response of such tubing from ∼1Hz to 2,800Hz. We further compare these experimental results to established analytical models for propagation of pressure disturbances in narrow tubes. While significant theoretical and experimental work relating to the frequency response of connective tubing or transmission lines has been published, there is limited literature presenting experimental frequency response data with air as the media in elastic tubing. In addition, little progress has been made in addressing the issue of tubing-related aliasing within pressure scanners, as the low sampling rate in scanners often makes post-processing antialiasing filters ineffective. The experimental results and analytical models presented herein can be used as a guideline to prevent aliasing and signal distortion by guiding the proper design of pressure transmission systems, resulting in accurate static and dynamic pressure measurements with pressure scanners. The data presented here should serve as a reference to instrumentation engineers so that they can make higher frequency measurements (up to ∼125Hz, currently) and are able to quantify the expected pressure transmission line (tube) attenuation and know if aliasing will be a concern. This information will give engineers greater measurement capability when using pressure scanners to make static and dynamic pressure measurements.

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