Range Of Static Pressures Research Articles

GET 43-2022 State Primary Standard for the unit of excess pressure within the static pressure range of 10–1600 MPa and the pulse pressure range of 1–1200 MPa and the effective area of piston-cylinder assemblies in deadweight testers within the range of 0.05–1 cm2

GET 43-2022 State Primary Standard for the unit of excess pressure within the static pressure range of 10–1600 MPa and the pulse pressure range of 1–1200 MPa and the effective area of piston-cylinder assemblies in deadweight testers within the range of 0.05–1 cm2

State primary standard of the unit of overpressure in the range of static pressure from 10 to 1600 MPa and in the range of impulse pressure

The necessity and relevance of precision pulse pressure measurements in industry (high-speed technological processes) and transport (existing and new types of engines) is shown. The device, the principle of operation and the result of metrological studies of the State Primary Standard of the unit of overpressure in the range of static pressure from 10 to 1600 MPa and in the range of pulse pressure from 1 to 1200 MPa and the effective area of piston pairs of piston pressure gauges in the range from 0.05 to 1 cm2 GET 43-2022 are presented. The GET 43-2022 includes hydraulic and pneumatic installations, as well as an ultra-high pressure valve designed to compare installations from the GET 43-2022 composition working with different standard fl uids in the range of 250-1200 MPa. The reproduction range of the pulse pressure unit GET 43-2022 is 1-1200 MPa. The method of reproducing the pulse pressure unit in liquid and gas media using hydraulic and pneumatic installations is described. The metrological characteristics of GET 43-2022 are investigated, the budget of measurement uncertainty is calculated when reproducing the pulse pressure unit. The results obtained make it possible to meet the needs of the development of a fl eet of working standards for pulse pressure measuring instruments traceable to GET 43-2022.

A High-Sensitivity Resonant Differential Pressure Microsensor Based on Wafer-Level Eutectic Bonding

This article presented a high-sensitivity resonant differential pressure microsensor based on wafer-level eutectic bonding, where dual resonators were embedded in the pressure-sensitive diaphragm to sense differential pressures, and a silicon cap was used to form a vacuum cavity. Differential pressures applied to the developed microsensor caused deflections of the pressure-sensitive diaphragm, resulting in shifts in resonant frequencies. This microsensor was designed based on finite element simulations with optimized structural parameters, which indicated high differential pressure sensitivities. Micro fabrications with key processes of deep reactive-ion etching (DRIE), lithography, and wafer-level eutectic bonding were adopted for device fabrication. The following experimental characterizations were conducted, producing the differential-pressure sensitivity of 181.53 Hz/kPa, the maxing fitting error of less than 80 Pa, under the differential pressure range of 0–100 kPa, the static pressure range of 110–200 kPa, and the temperature range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C to 60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C. These results show that developed resonant differential pressure microsensors have excellent performances for differential-pressure measurements.

A MEMS Resonant Differential Pressure Sensor With High Accuracy by Integrated Temperature Sensor and Static Pressure Sensor

This letter presents a MEMS resonant differential pressure sensor with an integrated temperature sensor and a static pressure sensor to address the issue of side effects of temperature and static pressure on measurement accuracies of resonant differential pressure microsensors. In this microsensor, two resonators were employed on the pressure sensitive diaphragm to sense differential pressure while a Pt-film-resistor was included as the temperature sensor and an additional resonator was positioned on the framework as the static pressure sensor. Microfabrication was conducted to manufacture the resonant microsensor and key performances were quantified as 79.76 Hz/kPa (~1036 ppm/kPa) of differential pressure sensitivity, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.22 \Omega $ </tex-math></inline-formula> /°C of temperature sensor sensitivity and −0.47 Hz/kPa of static pressure sensor sensitivity. Based on compensations of temperature and static pressure, a measurement accuracy of 0.02%FS was achieved for the developed microsensor under the differential pressure range from 0 to 100 kPa, the temperature range from −20°C to 60°C and the static pressure range from 110 kPa to 200 kPa.

A Resonant Differential Pressure Microsensor With Temperature and Static Pressure Compensations

This paper presents a resonant differential-pressure (DP) microsensor with temperature (T) and static-pressure (SP) compensations. In this microsensor, three resonators were positioned on and beside the pressure-sensitive diaphragm and the corresponding intrinsic frequencies were translated into differential pressure under the interferences of temperature and static pressure. Finite element simulation was conducted for device modeling, locating the relationship between the intrinsic resonant frequencies of three resonators and values of differential pressure, temperature and static pressure. Microfabrication (e.g., photolithography, deep reactive-ion etching and anodic bonding) was employed to manufacture the microsensor with key fabrication results displayed in this study. Experimental characterizations were conducted, which indicated that the maximum fitting error of the fabricated microsensor was deceased from 2145.7 Pa (before compensation) to 98.2 Pa (after compensation) under a differential-pressure range from 0 kPa to 100 kPa, a temperature range from 10 °C to 60 °C and a static-pressure range from 110 kPa to 200 kPa.

First-principles investigation of the structural stability of TKX-50 under high pressure

Dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) is a kind of energetic material with high energy, low sensitivity, environmental friendliness, and low toxicity. To understand the structural stability of TKX-50 under high pressure, the lattice parameters, band gaps, intermolecular bond length and bond angle, phonon spectrum and Raman spectra of TKX-50 with pressure were calculated based on the GGA-PBE + G functional by using the first-principles density-functional theory (DFT). There is a good stability of TKX-50 in lattice dynamics under a wide range of static pressures (0–165 GPa). TKX-50 shows strong anisotropy in compressibility and stability. c-axis is the most stable in compressibility and structural stability than a and b-axis. At 149 GPa, a fracture of the intramolecular hydrogen-bond O2–H1⋯O1 occurred, which should lead to the structure phase transition.

An evaluation of measured and predicted air blast parameters from partially confined blast waves

Understanding the physical mechanisms by which blast waves interact with their surroundings is paramount to protecting the safety of armed service personnel and equipment. This study evaluates and discusses modern technology used in blast pressure measurement as it relates to primary blast injuries such as traumatic brain injury. Factors influencing primary blast injury were established as peak overpressure, impulse, number, and frequency of shock impacts based on a literature review. A simulated confined-corridor breaching environment was used to establish the potential for variability in these key parameters depending on location in a confined blast environment. Wearable blast pressure monitors were compared experimentally to not only laboratory grade pressure transducers but also simulated and empirically modeled blast pressure and impulse predictions at scaled distances between 3.1 and $$13.6\,\hbox {m/kg}^{1/3}$$ from 100-g and 200-g suspended Composition C-4 detonations partially confined by the ground. surface ground reflection. Each measurement and predictive technique is detailed and comparatively summarized. Average deviation from the mean in collected pressure and impulse data ranged between 10 and 15%. The disparity in the measured data was lowest in the static pressure range where mild traumatic brain injury is reported to occur.

A High-Sensitivity Resonant Differential Pressure Microsensor Based on Bulk Micromachining

This paper presents a high-sensitivity micromachined resonant differential pressure sensor based on bulk silicon. The sensor includes a sensing unit made of a SOI wafer, which is vacuum packaged by a glass-on-silicon (GOS) wafer. More specifically, two resonators located in the SOI device layer were coupled to the GOS glass layer and deployed on the central and side areas of the pressure-sensitive diaphragm respectively, enabling differential outputs. According to the relevant theory of elasticity, the differential pressure sensitivity is high, where the conversion efficiency of the differential pressure to resonators stress is improved by the special cap design, large pressure-sensitive diaphragm and narrow resonators. The developed differential pressure microsensors were manufactured leveraging well-established microfabrication steps including lithography, etching and boning. Characterization of the micromachined sensors was conducted, reporting averaged differential pressure sensitivities of 1) -143.17 Hz/kPa (~2051 ppm/kPa) and a linear correlation coefficient of 0.999992 under a static pressure of 110 kPa and a temperature range from -°C to 40°C; 2) -143.36 Hz/kPa (~2051 ppm/kPa) and a linear correlation coefficient of 0.999997 under a static pressure range from 110 kPa to 250 kPa and a temperature of 25°C. Compared to previous study, the high differential pressure sensitivity of the sensor can pave ways for the subsequent high-precision measurement of differential pressures, which can be used to measure micro differential pressure in the field of nuclear power.

Spectroscopic Studies of Longitudinal Discharges in a Supersonic Air Flow during the Injection of Propane, Ethylene, and Oxygen into the Discharge Zone

The paper presents the results of studies of longitudinal electric discharges in a supersonic air flow with a Mach number of M = 2 in the range of static pressures (2.94−4.9) × 104 Pa (∼220−367 Torr) and discharge currents of ∼1.5−1.8 A during the injection of propane, ethylene, and hydrogen, along with oxygen, into the discharge zone through the two types of upstream electrodes (anodes). The design of the electric-discharge modules was such that the discharge was carried downstream by the supersonic flow and closed, mainly to the cathode located downstream. Emission spectroscopy was used to obtain data on the composition of the emitting products that arose in the processes of converting a fuel-air mixture in a discharge and their spatial distribution. In particular, data on the distribution of the radiation intensity of CN, C2 molecules, and OH radical, as well as atomic hydrogen and oxygen in a number of sections of the discharge channel, are presented. The used methodology allowed us to determine the change in the transverse dimensions of the discharge channels along the length and the value of the rotational temperature of molecule C2 for discharges with the injection of propane and ethylene into the discharge zone. The relationship between its value and the conditions for the formation of the discharge and the coefficient of excess oxygen injected into the discharge is established.

Experimental Study of the Effect of Static Pressure on Turbulent Friction Reduction in Gas Saturation of Boundary Layer

The article presents the results of an experimental study of the effect of static pressure on reduction of turbulent friction on a plate in gas saturation of the boundary layer. The experiments were carried out on the hydrodynamic stand of the Research Institute of Mechanics of the Moscow State University in the flow rate range U = 4–11 m/s and the static pressure range P = 10–200 kPa, the Reynolds number varied in the range of (3–8)×106. The local friction was measured with a “floating wall” sensor on a strain gage balance, and the gas was blown through a special permeable coating. It was shown that increase in the gas flow rate through a porous wall of flat plate test model could make the reduction of the local friction as high as 80–90%. However, increase in the static pressure in the flow significantly lowered the efficiency of control of the turbulent shear stresses. The friction reduction due to gas saturation of boundary layer depends on the gas flow rate (ceteris paribus) and the static pressure in the flow, which one should take into account when performing integral estimate of the efficiency of the method and assessing the energy loss for gas inlet into the flow.

A novel flexible pressure sensor array for depth information of radial artery

Pulse wave collection from multi-points of radial artery under different static pressures is an essential method to diagnose diseases. However, there are some problems in the currently-used measuring instruments. Single-type sensor has limitations to pulse wave acquisition. It is not enough to set three sampling points to detect variation trend of radial artery pulse wave. Adaptation to different wrist surfaces and mutual interference of sensors are neglected. This paper proposes a novel flexible compound pressure sensor array for measuring radial artery pulse wave to overcome the problems mentioned above. Our compound pressure sensor consists of a piezoelectric sensor and a piezoresistive sensor which are used to measure pulse wave and static pressure separately. A bending structure of the sensor could guarantee the signal intensity and prevent the occurrence of inverted waveform. In this study, poroelastic materials are used to achieve flexible connection and decrease interference among sensors. In addition, the amplitude characteristics of pulse wave in radial artery are described and the arrangement and size of the sensor array is designed based on statistical data. Anti-interference, repeatability and validation experiments are carried out to evaluate the performance of the sensor array. The results show that the flexible compound pressure sensor array not only reflects depth information of radial artery pulse wave under a wide range of static pressures, but also has good repeatability and anti-interference performance.

Experimental characterisation of the self-excited vibrations of spring-loaded valves

Valves are omnipresent in industrial processes. As a result, they must perform reliably according to their specifications. Spring-loaded valves are particularly susceptible to vibrations, as they are inherently flexible, often operate at small openings, and therefore they are more likely to interact with the surrounding flow. The current study experimentally investigates the self-excitation mechanism of a model spring-loaded valve with an emphasis on the interaction between the system flow and sound fields, and the valve structure. Tests are performed for various values of valve stiffness and maximum allowable valve lift. In each case, the pressure drop across the valve is increased gradually until the valve becomes fully open. The valve was found to oscillate at the fully coupled resonance frequency resulting from the interaction of the valve vibration with the acoustic field of the piping system. The oscillation amplitude was found to be positively correlated to both the pipe length and spring stiffness value. Furthermore, initial spring compression was found to have only moderate effects on the range of static pressures that would cause instability.

Ventilation rate measurements at a mechanically-ventilated pig finishing quad barn

With concentrated animal feeding operations (CAFOs) becoming larger and more intensive, air pollutant emissions from these facilities are of increasing concern for regulators and the public, and on-farm measurements of emissions are needed. A critical step in determining air pollutant emissions from the barns at these facilities is the accurate assessment and continuous monitoring of the barn ventilation rates. One of the most recent efforts to accurately determine barn ventilation rate was to continuously monitor fan operation, differential static pressure, fan speed, and air density related environmental variables, coupled with in-situ fan performance assessments at a range of static pressures, as applied in the 24-month National Air Emissions Monitoring Study (NAEMS). Uncertainty analyses associated with these calculations aided in characterising and qualifying the measurements. This paper describes methods used in the NAEMS to determine ventilation rates of four rooms (rooms 5–8) in a mechanically-ventilated pig finishing quad barn. The overall 2-yr average daily dry-standard ventilation rates (mean ± SD) were 13.5 ± 11.3, 13.8 ± 11.6, 14.5 ± 12.9, and 13.6 ± 12.9 m3 [dry-standard] s−1 for rooms 5–8, respectively. Thorough uncertainty analyses demonstrated that the estimated uncertainty of the ventilation rate (dry-standard) under typical site conditions decreased from 9.4% to 4.1% between the minimum (3.7 m3 [ds] s−1) and maximum (45.2 m3 [ds] s−1) capacities of the ventilation system. These results confirmed that larger numbers of operating fans lead to lower relative uncertainties for barn ventilation rates and that the uncertainty of ventilation rate measurements can be reduced by improved and more frequent in-situ fan calibrations.

Pressure Dependence of Dielectric Barrier Discharge Plasma Flow Actuators

Single dielectric barrier discharge plasma actuators were investigated for a range of static pressures from 0.17 to 9.0 bar. The actuatorminimum ionization voltage and static thrust weremeasured and similar data in the literature. The minimum ionization voltage decreased with decreasing pressure; however, at a given pressure, the ionization voltage scaled with the actuator capacitance per unit area. The static thrust was found to have a minimum at a pressure of approximately 2 bar. A narrow local maximum was found near 0.9 bar, below which the thrust decreased. A second broad local maximum occurred near 6 bar. The location of the two local maxima, respectively, moved to lower and higher pressures as the actuator voltage increased. At any pressure, thrust scaledwith voltage to a power. The power-law exponent increased linearly with increasing pressure from the lowest pressure tested to approximately 5 bar. Above 5 bar, the power-law exponent asymptotes to approximately 7.3, which was approximately twice that at atmospheric pressure. The experimental results were evaluated using a space–time lumped-element model for single dielectric barrier discharge plasma actuators. The overall trends were found to be best modeled through a pressure dependence of the minimum ionization voltage and the electron density.

Pressure Dependence of Laser-Induced Dielectric Breakdown in Water

The effects of pressure on laser-induced breakdown events at superthreshold irradiances in water were investigated over a range of pressures from 0 to 1380 bar. Breakdown events were generated using 5-ns Nd:YAG laser pulses of wavelength 532-nm. Observations of breakdown events were made using imaging and single detector techniques. Applications for use as a static and/or acoustic pressure sensor were explored. Using imaging techniques over a range of static pressures from 0 to 275 bar, it was observed that the laser-induced breakdown threshold increased with increasing pressure. An ability to infer acoustic pressure via optical breakdown techniques using imaging was demonstrated. Single detector measurements over the same pressure range were observed to follow a similar trend.

Wet Gas Metering Using a Revised Venturi Meter and Soft-Computing Approximation Techniques

In this paper, a novel approach is presented to the measurement of wet gas flows by using a throat-extended Venturi meter (TEVM) and soft-computing approximation techniques. Results obtained by using an industrial-scale test rig suggest that the flow rate of wet gas flowing in the TEVM is related not only to the static features but also to the dynamic features of the differential pressures (DPs) across the converging and the extended throat sections of the Venturi meter, as well as the static pressure and temperature signals within the Venturi meter. The relation between the signal features and the gas/liquid flow rates of wet gas is established through the use of backpropagation (BP) artificial neural network (ANN) and support vector machine (SVM) approximation techniques. The experimental test carried out within static pressure range of 0.3-0.8 MPa, gas flow rate range of 0.0139-0.0444 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> /s, and liquid flow rate range of 3.0556 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> -0.0015 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> /s suggested that it is a cost-effective and viable method to solve the problem of wet gas metering by combining a revised Venturi meter and soft-computing approximation techniques.

Inertial cavitation threshold dependence on high static pressures.

The creation of a bubble in a liquid is energetically favorable when the liquid is subject to a net/an overall tension less than of its saturated vapor pressure. This gain is offset by the creation of a liquid-vapor/gas interface, and only bubbles larger than some critical size will spontaneously grow. The magnitude of the acoustic pressure required to produce a cavity of the critical size is termed the cavitation threshold of the liquid. The dependence of the cavitation threshold on hydrostatic pressure has previously been reported up to 130 bars in terms of electrical power applied to the acoustic driving transducer. These measurements used a standing wave set-up in a stainless steel spherical resonator (24.1 cm outer diameter, 1.9 cm thick) with a Q &amp;gt; 10 000 when fluid loaded. This work will extend into higher pressure regimes and will be used to extrapolate the cavitation threshold at 1 kbar.

Characterization of condenser microphones under different environmental conditions for accurate speed of sound measurements with acoustic resonators

Condenser microphones are more commonly used and have been extensively modeled and characterized in air at ambient temperature and static pressure. However, several applications of interest for metrology and physical acoustics require to use these transducers in significantly different environmental conditions. Particularly, the extremely accurate determination of the speed of sound in monoatomic gases, which is pursued for a determination of the Boltzmann constant k by an acoustic method, entails the use of condenser microphones mounted within a spherical cavity, over a wide range of static pressures, at the temperature of the triple point of water (273.16 K). To further increase the accuracy achievable in this application, the microphone frequency response and its acoustic input impedance need to be precisely determined over the same static pressure and temperature range. Few previous works examined the influence of static pressure, temperature, and gas composition on the microphone's sensitivity. In this work, the results of relative calibrations of 1/4 in. condenser microphones obtained using an electrostatic actuator technique are presented. The calibrations are performed in pure helium and argon gas at temperatures near 273 K and in the pressure range between 10 and 600 kPa. These experimental results are compared with the predictions of a realistic model available in the literature, finding a remarkable good agreement. The model provides an estimate of the acoustic impedance of 1/4 in. condenser microphones as a function of frequency and static pressure and is used to calculate the corresponding frequency perturbations induced on the normal modes of a spherical cavity when this is filled with helium or argon gas.

Technical Note: Upstream vs. Downstream Placement of FANS Device to Determine Ventilation Fan Performance in Situ

Accurate ventilation rate (VR) data are essential to maximizing the quality of aerial emission measurements. The Fan Assessment Numeration System (FANS) has been widely used by U.S. researchers in measuring aerial emissions from mechanically ventilated livestock and poultry facilities. The FANS device is used to measure airflow rates of ventilation fans in situ, thereby developing fan performance curves under field conditions. The FANS device was originally intended to be placed upstream of the fan to be calibrated. However, certain field situations make it impractical to apply the FANS device as such. This study was conducted to assess use of the FANS device downstream of a ventilation fan, with the gaps between the FANS device and the discharge cone of the exhaust fan sealed using a non-permeable fabric. Nine exhaust fans (1.22 or 1.32 m diameter) in laying hen and turkey houses were tested with the FANS device placed upstream and downstream for a building static pressure range of 10 to 40 Pa. The results revealed that downstream placement of the FANS device yielded 0.6% 0.4% to 4.0% 0.9 % (mean SE) higher but not significantly different (P > 0.28) VR values as compared to upstream placement for the exhaust fans tested. This magnitude of discrepancy is considered acceptable for in situ measurement of fan performance.

A nonlinear finite-element model of the newborn ear canal.

A three-dimensional nonlinear finite-element model of a 22-day-old newborn ear canal is presented. The geometry is based on a clinical x-ray CT scan. A nonlinear hyperelastic constitutive law is applied to model large deformations. The Young's modulus of the soft tissue is found to have a significant effect on the ear-canal volume change, which ranges from approximately 27% to 75% over the static-pressure range of +/-3kPa. The effects of Poisson's ratio and of the ratio C10: C01 in the hyperelastic model are found to be small. The volume changes do not reach a plateau at high pressures, which implies that the newborn ear-canal wall would not be rigid in tympanometric measurements. The displacements and volume changes calculated from the model are compared with available experimental data.