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

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.

2000 ◽  
Author(s):  
Wojtek J. Bock ◽  
Magdalena S. Nawrocka ◽  
Waclaw Urbanczyk

1999 ◽  
Author(s):  
Magdalena S. Nawrocka ◽  
Wojtek J. Bock ◽  
Waclaw Urbanczyk ◽  
Jan Wojcik

2011 ◽  
Vol 66-68 ◽  
pp. 1488-1493
Author(s):  
Hong Xiao ◽  
Chao Gao ◽  
Zhen Kun Ma

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.


Author(s):  
Stephen Peluso ◽  
Bryan D. Quay ◽  
Jong Guen Lee ◽  
Domenic A. Santavicca

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.


Author(s):  
Adam M. Hurst ◽  
Joe VanDeWeert

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.


Sign in / Sign up

Export Citation Format

Share Document