Showing papers on "Pressure measurement published in 2016"
TL;DR: A gas pressure sensor based on an antiresonant reflecting guidance mechanism in a hollow-core fiber (HCF) with an open microchannel is experimentally demonstrated for gas pressure sensing.
Abstract: A gas pressure sensor based on an antiresonant reflecting guidance mechanism in a hollow-core fiber (HCF) with an open microchannel is experimentally demonstrated for gas pressure sensing. The microchannel was created on the ring cladding of the HCF by femtosecond laser drilling to provide an air-core pressure equivalent to the external environment. The HCF cladding functions as an antiresonant reflecting waveguide, which induces sharp periodic lossy dips in the transmission spectrum. The proposed sensor exhibits a high pressure sensitivity of 3.592 nm/MPa and a low temperature cross-sensitivity of 7.5 kPa/°C. Theoretical analysis indicates that the observed high gas pressure sensitivity originates from the pressure induced refractive index change of the air in the hollow-core. The good operation durability and fabrication simplicity make the device an attractive candidate for reliable and highly sensitive gas pressure measurement in harsh environments.
94 citations
TL;DR: A microbubble resonator, with a wall thickness of 500 nm and an intrinsic Q-factor of 10(7) in the telecommunications C-band, is used to investigate aerostatic pressure sensing via stress and strain of the material.
Abstract: Sensors based on whispering gallery resonators have minute footprints and can push achievable sensitivities and resolutions to their limits. Here, we use a microbubble resonator, with a wall thickness of 500 nm and an intrinsic Q-factor of 10(7) in the telecommunications C-band, to investigate aerostatic pressure sensing via stress and strain of the material. The microbubble is made using two counter-propagating CO(2) laser beams focused onto a microcapillary. The measured sensitivity is 19 GHz/bar at 1.55 μm. We show that this can be further improved to 38 GHz/bar when tested at the 780 nm wavelength range. In this case, the resolution for pressure sensing can reach 0.17 mbar with a Q-factor higher than 5 × 10(7).
83 citations
TL;DR: In this article, the influence of stand-off distance on the dynamic response of thin ductile plates subjected to airblast loading was investigated, and the results showed that the maximum response is driven by the positive impulse from the airblast, as it occurred after the positive duration of the pressure pulse.
73 citations
Patent•
15 Jul 2016TL;DR: In this paper, a valve provided in a first pipe connected to a gas source is closed, and a second valve provided by a second pipe on a downstream side of the first valve is opened.
Abstract: Leaks in valves provided in a plurality of pipes connected to a plurality of gas sources are inspected. In a method of an embodiment, a first valve provided in a first pipe connected to a gas source is closed, and a second valve provided in a first pipe on a downstream side of the first valve is opened. A pressure increase is detected by a pressure gauge on a downstream side of the first pipe. In addition, the first valve is opened, and the second valve is closed. A pressure increase is detected by a pressure gauge on a downstream side of the first pipe.
61 citations
TL;DR: In this paper, the authors evaluated the performance of a new shock tube facility used to produce blast loading in controlled laboratory environments and found that the properties of the shock wave proved to be a function of driver length and driver pressure, and the positive phase of the measured pressure time histories was similar to those generated from actual far-field explosive detonations.
Abstract: This study evaluates the performance of a new shock tube facility used to produce blast loading in controlled laboratory environments. The facility was found to generate a planar shock wave over the tube cross section by measuring the pressure distribution on a massive steel plate located at the end of the tube. The properties of the shock wave proved to be a function of driver length and driver pressure, and the positive phase of the measured pressure–time histories was similar to those generated from actual far-field explosive detonations. However, the shock tube is also suited to investigate fluid–structure interaction effects and the behaviour of materials in blast events. This was demonstrated using a three-dimensional digital image correlation technique to measure the deformation field of thin steel plates. Synchronization of the three-dimensional digital image correlation and pressure measurements enabled a thorough investigation of the entire experiment and identification of fluid–structure intera...
58 citations
TL;DR: In this paper, experiments are performed to study the explosion characteristics of DME (dimethyl ether) -air mixtures using a standard 20-L spherical explosion test apparatus, and the experimental data reported in this paper includes: the maximum explosion pressure (pmax), flammability limits, maximum rate of pressure rise (dp/dt)max, and combustion properties (i.e., laminar burning velocity, flame radius) of DAMA-air mixture at different initial conditions.
53 citations
Patent•
02 Jun 2016
TL;DR: In this article, the authors proposed a configuration of a fluid control apparatus that makes it possible to dramatically reduce the width dimension over a conventional size without incurring reduction in pressure measurement sensitivity.
Abstract: PROBLEM TO BE SOLVED: To downsize a fluid control apparatus by a configuration that makes it possible to dramatically reduce the width dimension over a conventional size without incurring reduction in pressure measurement sensitivity, and to reduce the width dimension of a casing while securing the mechanical strength of the casing.SOLUTION: The fluid control apparatus comprises a body unit 1, a fluid control valve 4, pressure sensors 2A, 2B, and casing 7, the fluid control valve 4 being attached to a component attachment face 1x of the body unit 1, the pressure sensors 2A, 2B being attached to the component attachment face 1x in such a way that their pressure sensitive face 2b1 is almost perpendicular to the component attachment face 1x and almost parallel to the longitudinal direction. The inner faces of the side walls 7a, 7b of the casing 7 are ruggedly shaped, the portions facing the fluid control valve 4 and the pressure sensors 2A, 2B are made to be thin-walled parts P1-P3, and at least some of the portions not facing the fluid control valve 4 and the pressure sensors 2A, 2B is made to be a thick wall part Q1 greater in wall thickness than the thin-walled parts P1-P3.SELECTED DRAWING: Figure 1
46 citations
TL;DR: In this paper, a practical optical fiber sensor is proposed for hydraulic pressure measurement, where two fiber Bragg gratings (FBGs) are used in the sensor probe, one stuck on the outer wall of thin-walled cylinder along the circumferential direction to measure the deformation of the cylinder.
Abstract: A practical optical fiber sensor is proposed for hydraulic pressure measurement. A thin-walled cylinder is used as the sensing device, which will be deformed with the applied pressure. Two fiber Bragg gratings (FBGs) are used in the sensor probe. One is stuck on the outer wall of thin-walled cylinder along the circumferential direction to measure the deformation of the cylinder. The other FBG is stuck in the groove which is on the top of the thin-walled cylinder and acts as a temperature measurement device. The accurate pressure can be obtained by monitoring the difference of the two shifted Bragg wavelengths. Theoretical relation between the wavelength shift difference and pressure has been established by the theoretical analysis. Meanwhile, the experiments have been carried out to verify the feasibility. Experiment results show that the sensitivity of the proposed pressure sensor is 69.4 pm/MPa in the region of $0\sim 16$ MPa. Compared with other references, the proposed pressure sensor in this letter is more compact with good sensitivity and wide measurement range.
41 citations
TL;DR: In this paper, an efficient fiber Bragg grating (FBG)-based sensing pad that is capable of measuring the interface pressure within prosthetic sockets, and exhibits required sensitivity, enhanced durability, and the lowest possible hysteresis error.
Abstract: This paper presents an efficient fiber Bragg grating (FBG)-based sensing pad that is capable of measuring the interface pressure within prosthetic sockets, and exhibits required sensitivity, enhanced durability, and the lowest possible hysteresis error. Three key fabrication parameters were studied to assess their effects on the performance of different sensing pad designs. These parameters included the FBG embedding depth (top, bottom, and neutral layers of the sensing pad), the sensing pad thickness (1, 2, and 3 mm), and finally, different embedding materials. Each sensing pad was studied while attached to Pe-lite and silicone prosthetic liners. Afterward, the sensing pad design that exhibited the best performance was employed to fabricate an expandable array of FBGs for interface pressure measurements within prosthetic sockets. One transtibial amputee participated in this paper to further assess the in situ performance of the sensing pad. To validate the findings, the results were also compared with the pressure measurements using the F-socket sensors. The results revealed that the FBGs embedded in the neutral layer of harder and thicker sensing pads exhibited the highest sensitivity as well as excellent accuracy. In addition, they could successfully measure the interface pressure inside the prosthetic socket. Higher pressure values were logged by the FBG sensors compared with the F-socket. Yet, the trend of pressure changes was similar for both sensor types. This paper is hoped to form a robust platform for the researchers intending to utilize the FBG sensors in such applications.
40 citations
TL;DR: In this paper, a fiber Fabry-Perot interferometer (FPI) is proposed and demonstrated for the measurement of gas pressure and temperature, which is fabricated by fusion splicing a short segment of capillary tube to a standard single mode fiber, followed by inserting a glass microsphere into the tube, the air gap between the SMF end face and the glass micro sphere then forms a fiber FPI.
Abstract: A fiber Fabry–Perot interferometer (FPI) is proposed and demonstrated for the measurement of gas pressure and temperature. The interferometer is fabricated by fusion splicing a short segment of capillary tube to a standard single mode fiber (SMF), followed by inserting a glass microsphere into the tube, the air gap between the SMF end face and the glass microsphere then forms a fiber FPI. Due to the additional reflection occurred on the rear surfaces of the microsphere, the reflection spectrum of the device is a three-beam interference pattern. Owing to the dependence of refractive index of gas on the pressure applied and the thermal-optical effect of glass microsphere, different dips in the interference fringe pattern exhibit different responses to the changes in gas pressure and temperature, which enables a simultaneous gas pressure and temperature sensing. The proposed device has the advantages of compact size, robust structure, easy fabrication, high gas pressure sensitivity, and supporting of range tunable operation.
40 citations
TL;DR: The proposed high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit is expected to be highly applicable to pressure measurements in harsh environments.
Abstract: This paper focuses on the design and fabrication of a high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit, which consists of an encapsulated pressure-sensitive chip, a temperature compensation circuit and a signal-conditioning circuit. A silicon on insulation (SOI) material and a standard MEMS process are used in the pressure-sensitive chip fabrication, and high-temperature electronic components are adopted in the temperature-compensation and signal-conditioning circuits. The entire pressure sensor achieves a hermetic seal and can be operated long-term in the range of −50 °C to 220 °C. Unlike traditional pressure sensor output voltage ranges (in the dozens to hundreds of millivolts), the output voltage of this sensor is from 0 V to 5 V, which can significantly improve the signal-to-noise ratio and measurement accuracy in practical applications of long-term transmission based on experimental verification. Furthermore, because this flexible sensor’s output voltage is adjustable, general follow-up pressure transmitter devices for voltage converters need not be used, which greatly reduces the cost of the test system. Thus, the proposed high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit is expected to be highly applicable to pressure measurements in harsh environments.
TL;DR: In this paper, the coupling effect of hypobaric pressure and spray distance on the surface heat transfer dynamics of R134a pulsed flashing spray cooling was investigated, where the absolute pressure within the vacuum chamber (ie spray back pressure) could be adjusted from 100kPa to 1kPa, and the spray distance was from 10mm to 50mm.
TL;DR: In situ high-pressure diffraction experiments on single-crystal α-quartz under quasi-hydrostatic conditions up to 19"GPa were performed with diamond-anvil cells as mentioned in this paper.
Abstract: In situ high-pressure diffraction experiments on single-crystal α-quartz under quasi-hydrostatic conditions up to 19 GPa were performed with diamond-anvil cells. Isotropic pressures were calibrated through the ruby-luminescence technique. A 4:1 methanol–ethanol mixture and the densified noble gases helium and neon were used as pressure media. The compression data revealed no significant influence of the pressure medium at room temperature on the high-pressure behavior of α-quartz. In order to describe its compressibility for use as a pressure standard, a fourth-order Birch–Murnaghan equation of state (EoS) with parameters KT0 = 37.0 (3) GPa, KT0′ = 6.7 (2) and KT0′′ = −0.73 (8) GPa−1 was applied to fit the data set of 99 individual data points. The fit of the axial compressibilities yields MT0 = 104.5 (8) GPa, MT0′ = 13.7 (4), MT0′′ = −1.04 (11) GPa−1 (a axis) and MT0 = 141 (3) GPa, MT0′ = 21 (2), MT0′′ = 8.4 (6) GPa−1 (c axis), confirming the previously reported anisotropy. Assuming an estimated standard deviation of 0.0001% in the quartz volume, an uncertainty of 0.013 GPa can be expected using the new set of EoS parameters to determine the pressure.
TL;DR: A new hydrophone design comprising a steel foil front protection layer has been developed, manufactured, characterized, tested, and optimized, and good agreement was found if detection bandwidth and spatial averaging were taken into account when comparing results of numerical nonlinear sound field simulations.
Abstract: The output characterization of medical high intensity therapeutic ultrasonic devices poses several challenges for the hydrophones to be used for pressure measurements. For measurements at clinical levels in the focal region, extreme robustness, broad bandwidth, large dynamic range, and small receiving element size are all needed. Conventional spot-poled membrane hydrophones, in principle, meet some of these features and were used to detect large amplitude ultrasonic fields to investigate their applicability. Cavitation in water was the limiting effect causing damage to the electrodes and membrane. A new hydrophone design comprising a steel foil front protection layer has been developed, manufactured, characterized, tested, and optimized. The latest prototypes additionally incorporate a low absorption and acoustic impedance matched backing, and could be used for maximum peak rarefactional and peak compressional pressure measurements of 15 and 75 MPa, respectively, at 1.06 MHz driving frequency. Axial and lateral beam profiles were measured also for a higher driving frequency of 3.32 MHz to demonstrate the applicability for output beam characterization at the focal region at clinical levels. The experimental results were compared with results of numerical nonlinear sound field simulations and good agreement was found if detection bandwidth and spatial averaging were taken into account.
TL;DR: This study is the first report of direct EUS-guided portal pressure measurements by using a digital pressure wire, routinely performed in minutes and provides real-time pressure tracings via wireless transmission.
TL;DR: In this paper, a dual-parameter sensing structure based on a fiber Bragg grating incorporated side-open Fabry-Perot cavity (FPC) is proposed and experimentally demonstrated for simultaneous measurements of gas pressure and temperature.
Abstract: A dual-parameter sensing structure based on a fiber Bragg grating (FBG) incorporated side-open Fabry-Perot cavity (FPC) is proposed and experimentally demonstrated for simultaneous measurements of gas pressure and temperature. The side-open FPC consisted of a micro-piece of chemical etched side-hole fiber acts as a pressure sensing unit. Two samples with different cavity lengths of 60 μm and 100 μm were fabricated and tested for gas pressure and temperature sensing in the experiment. Linear gas pressure responses of 4.063 pm/kPa and 4.071 pm/kPa in a large measuring range of 0-1000 kPa were obtained, respectively, which agree well with the theoretical analysis. Meanwhile, the temperature cross-sensitivities were measured as 214 Pa/° and 204 Pa/°. As a local temperature monitor, the incorporation of a short FBG in the leading single mode fiber was used to compensate the temperature cross-sensitivity of the sensor. This kind of compact and highly sensitive fiber sensor is appropriate for simultaneous gas pressure and temperature sensing in harsh micro environment.
TL;DR: In this paper, the instantaneous volumetric pressure in the near-wake of a truncated cylinder is measured by use of tomographic particle tracking velocimetry (PTV) using helium-filled soap bubbles (HFSB) as tracers.
Abstract: The instantaneous volumetric pressure in the near-wake of a truncated cylinder is measured by use of tomographic particle tracking velocimetry (PTV) using helium-filled soap bubbles (HFSB) as tracers. The measurement volume is several orders of magnitude larger than that reported in tomographic experiments dealing with pressure from particle image velocimetry (PIV). The near-wake of a truncated cylinder installed on a flat plate (ReD = 3.5 × 104) features both wall-bounded turbulence and large-scale unsteady flow separation. The instantaneous pressure is calculated from the time-resolved 3D velocity distribution by invoking the momentum equation. The experiments are conducted simultaneously with surface pressure measurements intended for validation of the technique. The study shows that time-averaged pressure and root-mean-squared pressure fluctuations can be accurately measured both in the fluid domain and at the solid surface by large-scale tomographic PTV with HFSB as tracers, with significant reduction in manufacturing complexity for the wind-tunnel model and circumventing the need to install pressure taps or transducers. The measurement over a large volume eases the extension toward the free-stream regime, providing a reliable boundary condition for the solution of the Poisson equation for pressure. The work demonstrates, in the case of the flow past a truncated cylinder, the use of HFSB tracer particles for pressure measurement in air flows in a measurement volume that is two orders of magnitude larger than that of conventional tomographic PIV.
TL;DR: In this paper, an implantable piezoresistive pressure sensor was activated using inductive power transmission for an Intracranial Pressure (ICP) monitoring application, which generated sufficient power and voltage at the sensor input to monitor the pressure changes.
Abstract: This paper presents the results of pressure measurements taken after the successful activation of an implantable piezoresistive pressure sensor. The sensor was activated using inductive power transmission for an Intracranial Pressure (ICP) monitoring application. This generated sufficient power (4.47 mW) and voltage (1.894 V) at the sensor input to monitor the pressure changes. Although the changes in voltage were monitored through wires, the required electronics for wireless voltage transfer and measurement in a biological environment are planned in the future. The simulated and measured results of the wireless link, along with the measured changes in pressure are presented. The results are the first step towards a wirelessly powered implant for ICP monitoring.
TL;DR: In this article, the Pound-Drever-Hall (PDH) technique was used to lock a laser to a whispering gallery mode (WGM) of a microbubble resonator, to show that linear tuning of the WGM and the corresponding locked laser display almost zero hysteresis.
Abstract: The tunability of an optical cavity is an essential requirement for many areas of research. Here, we use the Pound–Drever–Hall technique to lock a laser to a whispering gallery mode (WGM) of a microbubble resonator, to show that linear tuning of the WGM, and the corresponding locked laser, display almost zero hysteresis. By applying aerostatic pressure to the interior surface of the microbubble resonator, optical mode shift rates of around 58 GHz/MPa are achieved. The microbubble can measure pressure with a detection limit of $2\times 10^{-4}$ MPa, which is an improvement made on pressure sensing using this device. The long-term frequency stability of this tuning method for different input pressures is measured. The frequency noise of the WGM measured over 10 min for an input pressure of 0.5 MPa has a maximum standard deviation of 36 MHz.
Patent•
10 Nov 2016
TL;DR: In this article, a system including a sensing device including a pressure sensor configured to measure pressure of water in a water system of a structure is described, where the sensing device can be configured to generate pressure measurement data representing the pressure of the water as measured by the pressure sensor.
Abstract: A system including a sensing device including a pressure sensor configured to measure pressure of water in a water system of a structure The sensing device can be configured to generate pressure measurement data representing the pressure of the water as measured by the pressure sensor The system also can include one or more processing units including one or more processors and one or more non-transitory storage media storing machine executable instructions configured when run on the one or more processors to perform detecting a non-cyclical pressure event corresponding to a water leak in the water system of the structure during a first time period based on an analysis of information including the pressure measurement data The information analyzed in the analysis does not include any flow measurement data that represents a total amount of flow of the water in the water system of the structure during the first time period The pressure sensor can be coupled to the water system of the structure at a single location of the water system of the structure when measuring the pressure of the water in the water system of the structure Other embodiments are provided
TL;DR: A new, simple and non-destructive method to precisely measure the thickness of thin wall micro bubble resonators (MBRs) by using internal aerostatic pressure sensing with high measurement accuracy is developed.
Abstract: We develop a new, simple and non-destructive method to precisely measure the thickness of thin wall micro bubble resonators (MBRs) by using internal aerostatic pressure sensing. Measurement error of 1% at a bubble wall thickness of 2 μm is achieved. This method is applicable to both thin wall and thick wall MBR with high measurement accuracy.
TL;DR: In this article, a dual waveguide Bragg gratings (WBGs)-based microelectromechanical system pressure sensors with silicon micromachined diaphragm is presented.
Abstract: The wavelength shift of single Bragg grating integrated into a waveguide in optical MEMS pressure sensors gives inaccurate result due to the cross sensitivity caused by multiple external factors including temperature. Novel dual waveguide Bragg gratings (WBGs)-based microelectromechanical system pressure sensors with silicon micromachined diaphragm are presented here. The sensor consists of a curved waveguide with two identical WBGs located on the diaphragm. When pressure is applied on the diaphragm, the pitch of the gratings changes, and hence, there is a shift in the corresponding Bragg wavelength. The effect of temperature is assumed to be the same for both the gratings. As temperature shifts the Bragg wavelength of the two gratings equally, the error due to the temperature change on pressure sensitivity is eliminated. This method of pressure measurement effectively cancels out the temperature sensitivity. Three different configurations of the sensor with circular, square, and rectangular diaphragms are designed and simulated using COMSOL Multiphysics. Pressure sensitivity for the circular diaphragm configuration is found to be 2.1 and 0.744 pm/Pa for the two gratings, which are higher than the square and rectangular diaphragm configuration. Hence, the circular diaphragm configuration is better suited for multiplexing. The temperature independent properties of the sensors as well as the adjustability of sensitivity and measurement range by means of altering the dimensions of the sensors are studied. The temperature sensitivity is the same for both the gratings and is found to be 11.6 ppm/°C. Using modulation techniques and suitable designs, these sensors find applications in remote distributed sensing.
TL;DR: The present study is the first investigation of parenchymal pressure detection in liver undergoing LA: the successful detection of intra-tissue pressure may be a key asset for improving LA, as pressure levels have been correlated to scattered recurrences of tumors by different studies.
Abstract: We report the first-ever intra-tissue pressure measurement performed during 1064 nm laser ablation (LA) of an ex vivo porcine liver. Pressure detection has been performed with a biocompatible, all-glass, temperature-insensitive Extrinsic Fabry-Perot Interferometry (EFPI) miniature probe; the proposed methodology mimics in-vivo treatment. Four experiments have been performed, positioning the probe at different positions from the laser applicator tip (from 0.5 mm to 5 mm). Pressure levels increase during ablation time, and decrease with distance from applicator tip: the recorded peak parenchymal pressure levels range from 1.9 kPa to 71.6 kPa. Different pressure evolutions have been recorded, as pressure rises earlier in proximity of the tip. The present study is the first investigation of parenchymal pressure detection in liver undergoing LA: the successful detection of intra-tissue pressure may be a key asset for improving LA, as pressure levels have been correlated to scattered recurrences of tumors by different studies.
TL;DR: Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.
Abstract: The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.
TL;DR: In this paper, a pressure sensing unit based on a unique corona discharge setup using symmetrical electrode arrangement with simultaneous positive and negative corona generation is presented, which enables reliable air pressure measurement in the range of 80-105kPa, tested with five prototypes.
Abstract: We present a pressure sensing unit based on a unique corona discharge setup using symmetrical electrode arrangement with simultaneous positive and negative corona generation. The device generates stable corona discharge and enables reliable air pressure measurement in the range of 80–105 kPa, tested with five prototypes. The current–voltage characteristics of bipolar discharge system is analyzed in general form and three governing parameters, namely electrode geometry, electrode distance and discharge current, are studied in relation with absolute pressure. The sensors are driven with constant discharge current as low as 1 μA. The measured sensitivity is in good agreement with theoretical prediction and the sensor stability has been confirmed with 20-h continuous test without sensitivity deterioration. The sensitivity does not depend on the tested temperature range and its variation between devices is small, approximately ±3.0%. The advantage of the proposed system compared with similar corona-based constructions is its stable operation at low current with low power consumption and minimum electrode deterioration, which provides a cost effective and reliable solution.
TL;DR: In this paper, the authors report the results of a pressure monitoring program, which was conducted to measure pressure fluctuations during events of pressure transients in three selected network sections in Australia, and several selected failures were reported in this article.
Abstract: Ageing water infrastructure is one of the major problems faced by water utilities around the world at present, and urgent solutions are required in order to maintain the integrity of the water supply network. In order to use pipe failure prediction models, accurate information about loads acting on these pipes is important. Water pressure (steady-state and transient) is one of the key loads that needs to be estimated accurately in order to improve the predictability of pipe failures. This paper reports the results of a pressure monitoring program, which was conducted to measure pressure fluctuations during events of pressure transients in three selected network sections in Australia. Pressure measurements were conducted in network sections which were considered as susceptible to pressure transients. Potential sources of pressure transients were identified, and high speed data loggers were installed in selected locations of each network to measure and monitor pressure transients. Pressure transients that were generated during normal operation were measured for a period of one month in each selected section. Further, some of the pressure transients were manually made to simulate the different pressures due to pump start-ups within the network. Pressure fluctuations that could potentially lead to pipe failures were measured at many locations during the monitoring program (several selected failures were reported in this article). Therefore, the effect of pressure transients must not be ignored in pipe failure prediction.
TL;DR: In this paper, electrical capacitance tomography (ECT) combined with pressure transducers are used to investigate the flow hydrodynamics of gas-solids flow in a top-spray fluidized bed for wetting and drying.
04 Jan 2016
TL;DR: In this article, a rotating parallel ray omni-directional integration (ROROMI) was proposed for non-intrusive instantaneous pressure measurement in incompressible flow field.
Abstract: This paper presents a novel pressure reconstruction method featuring rotating parallel ray omni-directional integration. It is an improvement over the circular virtual boundary integration method for non-intrusive instantaneous pressure measurement in incompressible flow field. Unlike the old method, where the integration path is originated from a virtual circular boundary at a finite distance from the integration domain, the new method utilizes parallel rays, which can be viewed as being originated from a distance of infinity, as guidance for integration paths. By rotating the parallel rays, omni-directional paths with equal weights coming from all directions toward the point of interest at any location within the computation domain are generated, thus eliminating the inherent location dependence of the integration weight in the old algorithm. By implementing this new algorithm, the accuracy of the reconstructed pressure for a synthetic rotational flow in terms of r.m.s. error from theoretical values is reduced from 1.03% to 0.30%. Improvement is further demonstrated from the comparison of the reconstructed pressure with the direct numerical simulation generated pressure from the Johns Hopkins University isotropic turbulence database (JHTDB).
TL;DR: In this article, a conformal pressure sensor array comprising carbon black-doped-silicon closed-cell foam (CBPDMS foam) was developed for use in marine applications.
Abstract: Spatially-dense pressure measurements are needed on curved surfaces in marine environments to provide marine vehicles with the detailed, real-time measurements of the near-field flow necessary to improve performance through flow control. To address this challenge, a waterproof and conformal pressure sensor array comprising carbon black-doped-silicone closed-cell foam (CBPDMS foam) was developed for use in marine applications. The response of the CBPDMS foam sensor arrays was characterized underwater using periodic hydrodynamic pressure stimuli from vertical plunging and surface water waves, from which a piecewise polynomial calibration was developed to describe the sensor response. Inspired by the distributed pressure and velocity sensing capabilities of the fish lateral line, the CBPDMS foam sensor arrays have significant advantages over existing commercial sensors for distributed flow reconstruction and control. Experimental results have shown the sensor arrays to have sensitivity underwater on the order of 5 Pa, dynamic range of 50⬜500 Pa; are contained in a waterproof and completely flexible package, and have material cost less than $10 per sensor.
TL;DR: A bio-inspired absolute pressure sensor network, made on a 4’’ wafer, has 77 nodes and can be mounted on various curved surfaces to cover an area up to 0.64 m × 0.
Abstract: A bio-inspired absolute pressure sensor network has been developed. Absolute pressure sensors, distributed on multiple silicon islands, are connected as a network by stretchable polyimide wires. This sensor network, made on a 4’’ wafer, has 77 nodes and can be mounted on various curved surfaces to cover an area up to 0.64 m × 0.64 m, which is 100 times larger than its original size. Due to Micro Electro-Mechanical system (MEMS) surface micromachining technology, ultrathin sensing nodes can be realized with thicknesses of less than 100 µm. Additionally, good linearity and high sensitivity (~14 mV/V/bar) have been achieved. Since the MEMS sensor process has also been well integrated with a flexible polymer substrate process, the entire sensor network can be fabricated in a time-efficient and cost-effective manner. Moreover, an accurate pressure contour can be obtained from the sensor network. Therefore, this absolute pressure sensor network holds significant promise for smart vehicle applications, especially for unmanned aerial vehicles.