Differential Pressure Sensor Research Articles

Effect of cohesive powders on pressure fluctuation characteristics of a binary gas-solid fluidized bed

The effect of cohesive particles on the pressure fluctuations was experimentally investigated in a binary gas-solid fluidized bed. The pressure fluctuation signals were measured by differential pressure sensors under conditions of various weight percentages of cohesive particles. The cohesive particles increased the fixed bed pressure drop per unit height and decreased the minimum fluidization velocity. The Wen & Yu equation well predicts the minimum fluidization velocity of the binary system. The addition of cohesive particles slightly decreased the bubble size in bubbling flow regime when the cohesive particles and the coarse particles mixed well, while the bubble size greatly decreased when the cohesive particles agglomerated on the bed surface. The time series of pressure fluctuations was analyzed by using the methods of time domain, frequency domain and wavelet transformation. The normalized standard deviation of pressure fluctuations decreased with increasing weight percentages of cohesive particles. A wide bandwidth frequency of 0 to 1Hz got narrower with a single peak around 0.6Hz with an increase in proportion of the cohesive particles. The meso-energy and micro-energy of pressure fluctuations were decreasing with increasing cohesive particles proportions, which indicated that adding cohesive particles could reduce the energy dissipation of bubble and particle fluctuations.

Experimental Study of the Aerodynamic Interaction between the Forewing and Hindwing of a Beetle-Type Ornithopter

Beetles have attracted attention from researchers due to their unique combination of a passively flapping forewing and an actively flapping hindwing during flight. Because the wing loads of beetles are larger than the wing loads of other insects, the mechanism of beetle flight is potentially useful for modeling a small aircraft with a large weight. In this paper, we present a beetle-type ornithopter in which the wings are geometrically and kinematically modeled after an actual beetle. Furthermore, the forewing is designed to be changeable between no-wing, flapping-wing, or fixed-wing configurations. Micro-electro-mechanical systems (MEMS) differential pressure sensors were attached to both the forewing and the hindwing to evaluate the aerodynamic performance during flight. Whether the forewing is configured as a flapping wing or a fixed wing, it generated constant positive differential pressure during forward flight, whereas the differential pressure on the hindwing varied with the flapping motion during forward flight. The experimental results suggest that beetles utilize the forewing for effective vertical force enhancement.

Temperature Insensitive and Integrated Differential Pressure Sensor for Liquid Level Sensing Based on an Optical Fiber Fabry–Perot Interferometer

We propose a temperature insensitive optical fiber Fabry-Perot (FP) sensor for liquid level measurement. The sensor is based on a silicon diaphragm and borosilicate glass ferrules. Through the combination of different ferrules, the FP cavity is fabricated without a seal to eliminate the influence of the residual air in the FP cavity, thereby the temperature cross-sensitivity is significantly reduced. The opened FP cavity constitutes a differential pressure sensing structure at the same time. To verify the performance of this sensor, an experiment with an optical fiber pressure and temperature experiment system is carried out. The measuring range is 0.5-1.3 MPa. The sensor has a good monotonic linear response with an accuracy less than 0.4% F.S. (full scale). The measuring error caused by the temperature drift is lower than 0.0007 MPa/K, i.e., 0.09% F.S./K.

Highly sensitive giant magnetoresistance (GMR) based ultra low differential pressure sensor

In this study, we demonstrate a simple, cost-effective, giant magnetoresistance (GMR) based magnetic pressure sensor. The basic principle lies behind the measurement of the change in the magnetic field profile generated by the deflected diaphragm attached with a permanent magnet. This magnetic field profile change on the sensor surface was measured by highly sensitive magnetoresistive gradiometer sensor. Based on studied magnetic field distribution of a magnet, a prototype pressure sensor was designed and fabricated, which consists of a polymer diaphragm, a permanent magnet and a giant magnetoresistance based magnetic field gradient sensor. The fabricated prototype was calibrated for ultra-low differential pressure range and it shows: (i) sensitivity up to 16.67 μV/V/Pa and (ii) nonlinearity of 1.5% FS in the range of 0–300 Pa. The real time application was demonstrated where, the sensor was flush mounted on a NACA 4415 airfoil, and both the static and the dynamic suction pressures were recorded as a function of the wind velocity and also with different angle of attack (AOA). The measured pressure was found to be highly accurate while compared with existing static measurement system.

Mathematical modeling of optical MEMS differential pressure sensor using waveguide Bragg gratings embedded in Mach Zehnder interferometer

This paper presents theoretical analysis of a silicon based micro-machined differential pressure sensor using a square shaped clamped diaphragm and surface relief waveguide Bragg gratings embedded in a Mach Zehnder interferometer (MZI). Each of the arms of the MZI has one surface relief Bragg grating embedded in it. Each grating is mounted at the edge of a micro-machined diaphragm so as to obtain maximum stress. Coupled mode theory has been used to design the directional coupler to equally couple the light into both of the arms of MZI and also to design and analyse the shifts in the wavelengths of the Bragg gratings due to applied pressures. The wavelength shift difference of the two gratings gives the differential pressure sensitivity and also eliminates the noise due to temperature variation. Simulation results indicate that the differential pressure measurement sensitivity is 0.2 pm/Pa.

Experimental study of a vacuum fluid transportation system

The authors proposed a method of calculation the main parameters of a vacuum fluid transportation system. In this paper a designed experimental stand for verification of the proposed method was proposed. Selection of the required equipment including vacuum pumps, differential pressure sensors and control valves was made. The body and covers of the pumped vacuum chamber were made using additive manufacturing techniques. A subsequent identification of the selected vacuum pumps’ characteristics was carried out taking into account the conductivity of the connecting pipelines. The pressure difference established in the chamber was calculated taking into account the relationship between the pumping speed and the pressure obtained during the experiment. As a result of the experiment, the pressure values in the mechanical and hydraulic compartments of the chamber, the volume of liquid pumped by the vacuum system were obtained.

New calibration procedure for differential pressure using twin pressure balances for flowrate measurement

Reliable pressure measurements are essential in all activities of society and industry. Indeed, the concern with traceability has notably improved and has received considerable interest due to the intensification of international trade, the need for environmental issues, safety and health requirements, for example in medical instruments, as well as devices for measuring the flow of Fluids Based on the pressure change. Differential pressure sensors are widely used in fluid flow processes, such as for monitoring the flow conditions and to determine flowrate or fluid velocity (example are the Pitot tube, Venturi, orifice plate etc.). This study focused on the precise generation of differential pressures in the range of 500 kPa to 20 MPa using gas-operated twin pressure balances. The metrological characteristics of a differential pressure manometer were evaluated.

Hydromorphological Classification Using Synchronous Pressure and Inertial Sensing

Classification of river morphology is often based on hydromorphological units (HMUs) identified from field measurements. Established survey methods rely on expert judgment or collection of field point measurements. When used for HMU classification, these methods can suffer from high errors due to the variations in the sampling environment, causing low repeatability. In order to expedite field data collection and increase HMU classification accuracy, we propose a multisensory device, the hydromast. Each hydromast provides a new source of data to classify HMUs. The modules are inexpensive and highly portable, consisting of a synchronous array of commodity pressure and inertial sensors. Rapid, local changes in the flow field are recorded with absolute and differential pressure sensors. At the same time, slower depth-integrated flow signals are obtained from a small damped cylindrical mast, driven by vortex-induced vibrations. In contrast to existing passive flow measurement technologies, the hydromast uses fluid–body interactions to provide flow measurements. This allows for minimal signal processing and simple feature extraction. An array of three hydromasts was used to collect ten samples in three river HMUs with shallow depths and highly turbulent flows with smooth and rough beds. We investigated classification accuracy using single, dual, and triple hydromast arrays with pressure, inertial, and combined features using linear regression, a genetic algorithm, and a neural network. Although limited in scope, the set of spot measurements covering three HMUs showed that a single multimodal sensor could deliver an overall classification accuracy of 89% of the HMUs, and an increase of up to 99% was achieved using a multimodal triple hydromast array. These preliminary results show promise in using hydromasts for rapid and robust HMU classification, providing a new way to collect and assess river survey data.

Electrode-Shared Differential Configuration for Pressure Sensor Made of Carbon Nanotube-Filled Silicone Rubber Composites

To develop the differential pressure sensor made of carbon nanotube-filled silicone rubber composites with a simplified structure, an electrode-shared differential configuration is designed. The configuration includes the top and bottom sandwich layers. The top sandwich layer is composed of the top film, the intermediate film, and the composite film with low carbon nanotube content between them. The bottom sandwich layer is composed of the intermediate film, the bottom film, and the composite film with high carbon nanotube content between them. The electrode in the intermediate film is shared by the top and bottom sandwich layers, which can make the sensor probe more concise. The electrical resistance of the composite film with high/low carbon nanotube content increases/decreases with the increase of the pressure, and increases with the increase of the temperature. The top and bottom sandwich layers are connected to the neighboring arms of an electrical bridge to construct a differential system. The experiments verify the feasibility of using the electrode-shared configuration to construct the differential piezoresistive sensor made of the composite to decrease the temperature-induced drift and increase the sensitivity.

Experimental study of near-field structure and thermo-hydraulics of supercritical CO2 releases

CO2 transportation safety can directly affect the implementation of carbon capture, utilization and storage (CCUS) projects. The assessment of consequences of accidental release of supercritical CO2 are very important in the consideration of CO2 transportation safety. To ensure accurate prediction of the consequence of an accidental CO2 release, the near-field source terms including thermo-hydraulics have to be investigated, as the near-field jet flow structure significantly affects the evolution of solid CO2 particles. The aim of this work is to understand the under-expanded jet structure and thermo-hydraulics characteristics of supercritical CO2 releases from pressure vessels or pipelines. Experiments were developed to carry out controllable CO2 release from a high pressure vessel. The under-expanded jet structure of supercritical CO2 was recorded by a high speed camera. The jet velocity was measured using differential pressure sensors and a hot wire anemometer. In addition, the jet temperature, CO2 concentration, pressure and mass flow rate were also monitored. Through varying the release orifices in the experiment, the effects of size and pattern of the release orifices were analyzed.

A Fast and Easily-Realized Concentration Sensor for Binary Gas Mixtures and Its Design Analysis

A low-cost and easily-realized sensing device used for the detection of gas mixtures at different concentrations is presented. Its sensing part includes a small critical nozzle, a laminar structure, and a differential pressure sensor. When gas flows through the laminar structure, there is a pressure drop between both ends of it, and for different components of gas, the pressure drop is different. Based on this feature, the concentration detection is achieved. Concentration tests for two types of fire extinguishing agents CBrF3 and C3HF7 are presented. The results show the characteristics of fast response/recovery time, high accuracy, and good repeatability. Based on the theoretical analysis, the effects of the design parameters on the sensing performance to concentration detection are discussed in detail.

Modeling analysis and fabrication of MEMS capacitive differential pressure sensor for altimeter application

This paper proposes the modeling analysis of MEMS highly sensitive Capacitive Differential Pressure Sensor (CDPS) and also the development of a fabrication process for CDPS structures for aircraft altimeter applications. Highly sensitive CDPS structure models using circular and square sandwich polyimide diaphragm membranes, with and without center boss, were adopted, whereas other studies report on silicon diaphragms. CDPS characterization was carried out to analyze the deflection sensitivity, capacitive sensitivity, stress on diaphragm membrane and the effect of temperature on capacitive sensitivity. Simulation results of square diaphragm without center boss show better characteristics than other proposed diaphragm structures. This design yields 145.8 nm/mbar and 0.574 fF/mbar of deflection and capacitive sensitivity, respectively. The maximum stress developed on the diaphragm at maximum working pressure is less than the yield stress of polyimide material by a factor of 1.77 and capacitive sensitivity deviates at ±0.00195%/°C. From the modeling analysis, square diaphragm CDPS structure yields better characteristics and hence the fabrication process for CDPS has been developed, and its fabrication process flow verified using Intellisuit virtual fab tool.

Modeling, fabrication, and characterization of SiC concentrically matched differential capacitance output pressure sensors

This paper describes modeling, optimization, fabrication, and characterization of silicon carbide (SiC) absolute pressure sensors that have concentrically matched differential capacitance output. The differential capacitance scheme is achieved by utilizing a concentric ring and a circular diaphragm to cancel out common-mode noise. The sensors have been fabricated by a surface micromachining process where SiC is chosen as the structural layer to sustain various high temperature environment conditions. Characterization is conducted in a custom-built temperature-controlled pressure chamber up to 180 ℃ that is similar to a low-temperature geothermal well. Results show that under an applied pressure range of 0.5–1.4 MPa, structures with a 160 μm-diameter diaphragm have sensitivities of 1.03 fF/kPa and 0.92 fF/kPa under the temperatures of 20 ℃ and 180 ℃, respectively. On the other hand, the mechanically much stiffer ring structure with the same device area as the circular diaphragm maintains a constant capacitance of 0.14 pF under the same pressure ranges of the two different temperatures. In addition, an array of circular capacitive pressure sensors are also fabricated to obtain higher capacitance outputs. The sensor array is also characterized up to 1.4 MPa and the sensitivities of 13.7 fF/kPa and 13.4 fF/kPa is observed at temperatures of 20 ℃ and 180 ℃, respectively.

Spalling in concrete arches subjected to shock wave and CFRP strengthening effect

The purpose of the present study is to put forward an innovative method to improve dynamic response behaviors of protective concrete arches subjected to blast load. To achieve this goal eight arches were made, of which six were strengthened with carbon fiber reinforced polymers (CFRPs) on the intrados. Field explosion experiments were designed and carried out to reveal the strengthening effects of different CFRP strengthening schemes. The dynamic structural responses of the tested arches were recorded through linear variable differential transformers (LVDTs) and pressure sensors. The results of the experiments, such as the distribution of concrete cracks and the debonding length of the CFRP strips, indicate that CFRPs are effective in reducing concrete cracking and spalling of the protective arches, and that the fully-bonding method is significantly more effective than the partially-bonding method. Meanwhile, when the scaled standoff distance decreases, the strengthened arches experience failures ranging from ductile cracking to dynamic spalling. Simplified analysis models are proposed to estimate the equivalent static load and to reveal the protective mechanism of the CFRP strengthening. The research confirms that by using the CFRP bonding technique, an efficiently protective concrete arch structure with excellent anti-explosion performance could be constructed.

Differential Pressure Sensors for Underwater Speedometry in Variable Velocity and Acceleration Conditions

Autonomous underwater vehicles require estimation of their velocity relative to the surrounding flow to perform essential navigation tasks. Available technologies for speed estimation rely on Doppler velocity logs or acoustic Doppler current profilers and are not suitable for application in small low cost or energy consumption vehicles. Encouraged by the successful results of our previous lab-scale investigations using pressure-based speedometry, we developed differential pressure sensor speedometry as an alternative to conventional technologies. We built a full-scale physical prototype, compared analog and digital differential pressure sensors and evaluated the performance in variable velocity (0–2 m/s) and acceleration (0–2 m2/s) conditions in a marine tow tank. A simple equation based on the conservation of energy accurately estimated the velocity, with estimated mean absolute errors of 0.0087 m/s for analog and 0.0107 m/s and digital configurations. This equation is shown to hold under variable velocity and acceleration conditions. We conclude that differential pressure sensor speedometry is a valid solution to perform underwater speedometry and we confirm that the system can provide instantaneous and stable velocity estimates with a sampling rate higher than 10 Hz.

Preliminary study on the performance of biomorphic silicon carbide as substrate for diesel particulate filters

This paper presents the results of a preliminary experimental study to assess the performance of biomorphic silicon carbide when used for the abatement of soot particles in the exhaust of Diesel engines. Given its optimal thermal and mechanical properties, silicon carbide is one of the most popular substrates in commercial diesel particulate filters. Biomorphic silicon carbide is known for having, be-sides, a hierarchical porous microstructure and the possibility of tailoring that microstructure through the selection of a suitable wood precursor. An experimental rig was designed and built to be integrated within an engine test bench that allowed to characterizing small lab-scale biomorphic silicon carbide filter samples. A particle counter was used to measure the particles distribution before and after the samples, while a differential pressure sensor was used to measure their pressure drop during the soot loading process. The experimental campaign yielded promising results: for the flow rate conditions that the measuring devices imposed (1 litre per minute; space velocity = 42,000 L/h), the samples showed initial efficiencies above 80%, pressure drops below 20 mbar, and a low increase in the pressure drop with the soot load which allows to reach almost 100% efficiency with an increase in pressure drop lower than 15%, when the soot load is still less than 0.01 g/L. It shows the potential of this material and the interest for advancing in more complex diesel particle filter designs based on the results of this work.

Сравнение генетического алгоритма и метода наименьших квадратов для определения калибровочной функции дифференциального датчика давления

Сравнение генетического алгоритма и метода наименьших квадратов для определения калибровочной функции дифференциального датчика давления

Monitoring of Inhalation Using a Pressurized Metered-dose Inhaler (pMDI) Fitted with a Differential Pressure Sensor and Its Applications in Inhalation Therapy

Monitoring of Inhalation Using a Pressurized Metered-dose Inhaler (pMDI) Fitted with a Differential Pressure Sensor and Its Applications in Inhalation Therapy

The Influence of Flooding Phenomenon to Pressure Drop on Hotleg Simulator with L/D=25

Cooling system in nuclear reactor is much influenced by counter-current flow. When a leakage is occured, coolant in primary circuit of hotleg and hot steam from reactor will flows in counter-current condition. An experimental investigation has been performed to examine the effect of flooding phenomenon on the pressure drop. It was observed using acrylic complex pipe as hotleg simulator consisting of three parts: horizontal, bend and inclined pipe. Geometrical sizes of pipes was in scale of 1/30 of the actual hotleg geometrical size in the PWR with inner diameter=25.4 mm, the horizontal pipe length L=635 mm, and inclined pipe length was 20 mm with an angle of 50o. Pressure drop was meassured by using differential pressure sensor installed in the lower-tank (RPV simulator) dan upper-tank (SG simulator). Pressure drop was observed before, during and after flooding. Based on the observation, it was found that the change of flow pattern is followed by the change of pressure drop. The results of this study were also compared with some correlations using the dimensionless superficial velocity parameter by Wallis correlation. Wallis correlation can be written as JG*1/2 + 0,3974 JL*1/2 = 0,4832 .

X-ray Microtomography of Intermittency in Multiphase Flow at Steady State Using a Differential Imaging Method.

We imaged the steady state flow of brine and decane in Bentheimer sandstone. We devised an experimental method based on differential imaging to examine how flow rate impacts impact the pore‐scale distribution of fluids during coinjection. This allows us to elucidate flow regimes (connected, or breakup of the nonwetting phase pathways) for a range of fractional flows at two capillary numbers, Ca, namely 3.0 × 10−7 and 7.5 × 10−6. At the lower Ca, for a fixed fractional flow, the two phases appear to flow in connected unchanging subnetworks of the pore space, consistent with conventional theory. At the higher Ca, we observed that a significant fraction of the pore space contained sometimes oil and sometimes brine during the 1 h scan: this intermittent occupancy, which was interpreted as regions of the pore space that contained both fluid phases for some time, is necessary to explain the flow and dynamic connectivity of the oil phase; pathways of always oil‐filled portions of the void space did not span the core. This phase was segmented from the differential image between the 30 wt % KI brine image and the scans taken at each fractional flow. Using the grey scale histogram distribution of the raw images, the oil proportion in the intermittent phase was calculated. The pressure drops at each fractional flow at low and high flow rates were measured by high‐precision differential pressure sensors. The relative permeabilities and fractional flow obtained by our experiment at the mm‐scale compare well with data from the literature on cm‐scale samples.