Differential Manometer Research Articles

A Laboratory Study on the Design and Performance Evaluation of Pitot-Tube

Due to the increasing demand for water resources worldwide, this commodity and its spatial and temporal properties are of the interest of decision makers and scientists. In this respect, the accuracy in detecting the physical characteristics of the water movement such as velocity and its associated phenomena should be preauthorized in hydraulic studies. Although velocity, as the deriving factor of the water flow, can be determined with the help of theoretical or practical approaches, researchers continuously pushes the limits of science by improving the existing methods to the best. The pitot tube, which is not widely used in open channel hydraulic practices, is one of these methods. In this study, we have addressed a case from design to conducting a set of laboratory experiments. A 3D-printed pitot-tube is designed and used in a set of experiments carried out in an open channel, with different flow rates (three experiments). As a result, the relative error rates were interpreted by comparing the velocity rates obtained with the help of the water level difference in the differential manometer (Vm) and the velocity rates obtained from the flow continuity equation in the open channel (Vo). Results indicated a 50% bias in the experiments, while scatter analysis showed that the associated deviations matches a linear equation.

On-Site Sensor Calibration Procedure for Quality Assurance of Barometric Process Separation (BaPS) Measurements

Barometric process separation (BaPS) is an automated laboratory system for the simultaneous measurement of microbial respiration and gross nitrification rates in soil samples. To ensure optimal functioning, the sensor system, consisting of a pressure sensor, an O2 sensor, a CO2 concentration sensor, and two temperature probes, must be accurately calibrated. For the regular on-site quality control of the sensors, we developed easy, inexpensive, and flexible calibration procedures. The pressure sensor was calibrated by means of a differential manometer. The O2 and CO2 sensors were simultaneously calibrated through their exposure to a sequence of O2 and CO2 concentrations obtained by sequentially exchanging O2/N2 and CO2/N2 calibration gases. Linear regression models were best suited for describing the recorded calibration data. The accuracy of O2 and CO2 calibration was mainly affected by the accuracy of the utilized gas mixtures. Because the applied measuring method is based on the O2 conductivity of ZrO2, the O2 sensor is particularly susceptible to aging and to consequent signal shifts. Sensor signals were characterized by high temporal stability over the years. Deviations in the calibration parameters affected the measured gross nitrification rate by up to 12.5% and affected the respiration rate by up to 5%. Overall, the proposed calibration procedures are valuable tools for ensuring the quality of BaPS measurements and for promptly identifying sensor malfunctions.

Fracture mechanics analysis of the stress corrosion cracking failure of stainless steel hexagonal head screws in a marine-industrial environment

This paper presents the fracture mechanics analysis of hexagonal head clamping screws of a diaphragm differential manometer located at the oil discharge head of an offshore facility. The failure mechanism was identified as chlorine stress corrosion cracking (CLSCC) in a marine-industrial environment containing chloride chemical species. The cause of failure was identified as overtightening up to 1.55 times above the nominal clamp-loads during the installation of the failed screws, while the partially failed screws were tightened closer to the nominal values. Data on the fracture toughness and CLSCC growth-rate of type 304 stainless-steel in the marine-industrial environment were obtained by applying fracture mechanics and fractographic examination. The kinetics data indicates that most of the crack growth time is spent in the Stage I of SCC, so the kinetics equation for this can be used to make conservative estimations of the remaining life if a reasonable Stage I crack-size is used.

IMPROVEMENT OF METHODOLOGICAL BASIS OF DETERMINATION OF TIGHTNESS OF BUILDING COVER

Tightness and energy efficiency are among the most important parameters of buildings. The airtightness of the building ensures a reduction in energy consumption for heating, especially for buildings with a large heating volume. Currently, Ukraine does not have a regulatory framework for determining the tightness of buildings. The article analyzes the international standard for determining the airtightness of buildings ISO 9972:2015 Thermal characteristics of buildings − Determination of air permeability of buildings − Method of fan injection. On the basis of the international standard, the methodical bases for determining the tightness of the building envelope have been improved, and the methodology for determining the tightness of the building envelope has been adapted for Ukraine. The article presents the methods of measuring the tightness of the building, the rules for preparing the building for measurements, as well as the calculation of air permeability parameters. This technique contains the principle of determining the parameters of tightness in the conditions of fan injection. The hermeticity of the building, or its air permeability, is expressed by the amount of air leakage in cubic meters per hour per square meter of the area of ​​the outer shell of the building when the building is affected by a pressure drop of the internal air of 50 Pa. During the test, the fan creates a pressure drop of 50Pa. A differential manometer is used to record the pressure difference between the pressure in the room and the external pressure. Using the formulas given in the article, the volume flow of air through the enclosing structures is calculated, and the air leakage rate is also calculated. Based on the determined parameters, the air exchange rate n50 and the air exchange rate q50 at the created pressure drop ∆p were calculated. The method of determining the energy efficiency class based on the n50 parameter has been improved. Based on the results of the calculations, we have the opportunity to determine the energy efficiency class based on the determined air exchange ratio.

Particle-Size-Dependent Filtration Efficiency, Breathability, and Flow Resistance of Face Coverings and Common Household Fabrics Used for Face Masks During the COVID-19 Pandemic.

During the COVID-19 pandemic, the increase in demand for protective equipment caused a global shortage and homemade barrier face coverings were recommended as alternatives. However, filtration performances of homemade face coverings have not been fully evaluated. Test methods in the ASTM standard (F3502-21) were used to evaluate filtration efficiencies (FE) and breathability (pressure drop, Δp) of face coverings and home fabric materials commonly used during the pandemic. Submicron particulates FE was measured by particle transmission through face covering samples using a Condensation Particle Counter equipped with differential mobility analyzer and electronic manometer. Flow resistance of 0.1 μm-diameter fluorescent nanoparticles in droplets was determined by measuring fluorescence intensity of residual collected at the reverse side of samples. The size-dependent FE (3–94%) and Δp (0.8–72 mmH2O) varied considerably among fabrics. Of the 16 mask types, 31.25% and 81.25% met the minimum FE and breathability standards in the ASTM F3502-21, respectively. Overall performance (qF) was highest for velcro masks (max qF = 3.36, min qF = 2.80) and lowest for Dutch wax print fabrics (max qF = 0.12, min qF = 0.03). Most of the samples resisted the flow of 0.1 µm-diameter nanoparticles in droplets. Low flow resistance was observed in bandana, neck gaiter, t-shirt I, tank top and bedspread fabrics. GSM and fabric finishing seems to affect performance. Low performances can be improved by selecting optimum-performance fabrics in the design and manufacture of barrier face coverings.Supplementary InformationThe online version contains supplementary material available at 10.1007/s41742-021-00390-6.

Thermal and hydraulic characteristics of multiple row spiral finned tube heat exchangers

An experimental investigation for the thermal and hydraulic characteristics of a spiral finned-tube heat exchanger was performed to understand its cooling performance for a developed novel defrosting technique. Two identical spiral finned-tube heat exchangers were manufactured; one having four rows and other having five rows. Both heat exchangers tubes were arranged inline. The heat exchangers had a tube diameter of 9.36 mm, spiral fins of 23.4 mm outer diameter, and 3.6 mm fin pitch (277 fins/m). The overall heat transfer coefficient was calculated using the measured temperatures and flow rates of each stream, and utilizing the logarithmic mean temperature difference method. The air-side heat transfer coefficient was determined using the calculated overall heat transfer coefficient and the tube-side heat transfer coefficient. The air-side pressure drop across the heat exchanger was also measured using a differential pressure digital manometer. The experimental data covered Reynolds number range of 1500 to 6000 and a Prandtl number of 0.7. Empirical correlations of Nusselt number, Colburn factor and friction factor versus Reynolds number were developed using least squares regression. The results showed that there is no significant variation in air-side heat transfer coefficient for the four and five rows spiral finned-tube heat exchanger and their Colburn factor is almost constant over the tested range of Reynolds number.

Effects of the simplification in the geometry of a cyclone test facility on the swirling flow: a CFD study

A study about the influence of geometry simplification on the swirling flow of a cyclone was performed by comparing CFD results with experimental data. The numerical results were obtained by solving the mass and momentum equations with the Reynolds Stress Model (RSM) for the turbulence closure. On other hand, the experimental data were obtained in the literature, the authors used the Particle Image Velocimetry (PIV) technique to measure the velocity fields and a differential manometer to measure the pressure drop. In this work, different test facility geometries configurations were simulated: the complete test facility; and others with some simplifications downstream and upstream of the cyclone. The boundary condition for both numerical and experimental analysis was performed with inlet velocity in 10.5 and 12.25 m/s. Results showed a decrease in the gas vortex velocity in the cyclone center when simplifications in the test facility geometry are made. These bring significant consequences in the performance parameters, like almost 20% in the pressure drop values.

Effects of the Simplification in the Geometry of a Cyclone Test Facility on the Swirling Flow: a CFD Study

A study about the influence of geometry simplification on the swirling flow of a cyclone was performed by comparing CFD results with experimental data. The numerical results were obtained by solving the mass and momentum equations with the Reynolds Stress Model (RSM) for the turbulence closure. On other hand, the experimental data were obtained in the literature, the authors used the Particle Image Velocimetry (PIV) technique to measure the velocity fields and a differential manometer to measure the pressure drop. In this work, different test facility geometries configurations were simulated: the complete test facility; and others with some simplifications downstream and upstream of the cyclone. The boundary condition for both numerical and experimental analysis was performed with inlet velocity in 10.5 and 12.25 m/s. Results showed a decrease in the gas vortex velocity in the cyclone center when simplifications in the test facility geometry are made. These bring significant consequences in the performance parameters, like almost 20% in the pressure drop values.

Measurement of the isobar heat capacity of fluids in the critical area by the method of flowing adiabatic calorimeter

With regard to the problem of refining the fundamental equations of state of hydrocarbons, the methodological and design features of the experimental measurement of the isobaric heat capacity in the critical region by the method of a flow adiabatic calorimeter are considered. The pressure measurement system has been improved by introducing a differential manometer into the measuring circuit, which made it possible not only to increase the accuracy of pressure determination, but also to implement a universal scheme of calorimetric experiment. The use of a universal scheme of the calorimetric experiment allows one to determine two values of the isobaric heat capacity at pressures that differ by the value of the pressure loss in the calorimeter. Such an approach in the critical region is relevant, since it makes it possible to quite simply and reliably determine the value of the derivative of the heat capacity with respect to pressure, which is used to estimate not only the error in assigning the value of heat capacity to pressure, but also the equilibrium conditions of the experiment in a flow-through calorimeter. The technique of determining and making a correction for the inhomogeneity of the supply wires of the differential thermocouple, for the throttling of the flow of matter in the calorimeter is considered. Correct relations are obtained for determining the average temperature of the measurement experiment for various methods of measuring the temperature and temperature difference in a flow-through calorimeter. The results of experimental measurements of the isobaric heat capacity of n-pentane in the critical region, obtained using the universal scheme of the calorimetric experiment, for n-pentane were measured on an isobar of 3.400 MPa (critical pressure 3.355 MPa), which is the closest to the critical point at practice of flow calorimetry

Differential manometer with reflective optical sensor

For the purpose of the identification and quantification of the plasma effect on gas flow rate in atmospheric pressure discharges there was a strong need for differential manometer for fine and precise measurements which is indifferent on the influence of the charged particles. Therefore, a differential manometer with a completely free membrane has been constructed. Manometer is based on the use of reflective sensor CNY70. The basic request, undisturbed measurement of small value of differential pressure, up to 10 Pa, is realized with satisfying sensitivity and accuracy. Furthermore, different ranges of differential pressures measurable with the constructed instrument have been achieved by use of membranes made of different materials and with different thicknesses. The best linearity showed membranes made of copper and rubber. By means of five different membranes, the complete range of pressures from 1 Pa to 100 kPa is covered with substantial overlap.

Preliminary aero-acoustic measurements of free rotating rotor with predefined imbalance

The Rotor noise is known to be highly annoying and intrusive. Therefore, rotor noise will be one of the major design parameters for next-generation quieter rotor-crafts or drones. This will only be possible with a better understanding of rotor aerodynamics and acoustics. The present study tries to use a simplistic rotor driven by an electric motor for the noise generation. A microphone is used to measure the acoustic signals and Fast Fourier Transform is used to find the dominant frequencies or the energy distribution. A differential manometer is used to measure the averaged velocity along the radial direction. The characterization of the flow field in terms of radial velocity variation and acoustic signal characterization provides preliminary information on the physics of aerodynamics and aero-acoustics of rotor systems. The results from the experiments suggest that the predefined imbalance imposed on the rotor increases the noise due to aerodynamics and also due to structural vibrations.

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.

Experimental study on the resistance to intraluminal pressure between handsewn and stapled anastomosis. In vitro experimental study

We performed different types of stapled and manual sutures and the pressure level was measured using a differential pressure manometer. Although the hand-sewn end-to-end suture turned out to be the most resistant to pressure, statistical analysis revealed no significant differences compared to stapled suture (p = 0.49). In stump closure techniques, we observed a statistically high significance in resistance to pressure in the favour of manual stump closure (p = 0.004).Regarding side-to-side sutures we did not find any statistically significant differences in resistance to pressure between the techniques (p = 0.06). We can conclude that regarding the stump closure, the most resistant to pressure is the hand-sewn procedure, but in the other types of anastomosis, no significant differences was found between the stapled and hand-sewn techniques. Orv Hetil. 2017; 158(42): 1674-1680.

Lnvestigation of β-Emission Methods of Monitoring Coolant Water Level in Nuclear Power Plants

This investigation was performed on a vessel heat-engineering bench. The working medium was water under pressure up to it 20.5 MPa and temperature from 20 (cold) to 350°C (hot). The controllers were a β-emission sensor of level and a Sapfir-22DD differential manometer as the standard. The objective was to determine the characteristics of a β-emission sensor under the conditions of the working medium. Analysis of the experimental data showed that the indications of the β-emission sensor and differential manometer were identical and linear as a function of the level of both the cold and hot water. The characteristics of the β-emission sensor are: minimal response time and measurement error, very small dimensions, serviceability at pressures to 20.5 MPa and temperature to 350°C, at least 10 years life, and energy independence of the primary converter.

Experimental Study of Pressure Drop after the Circle Grids Fractal Orifice

Flow rate measurements are among the most important operations in modern industries dealing with increasingly expensive fluids such as petroleum, biodiesel and natural gas. The accuracy of flow meters depends mainly on their position in a pipe network and their operating conditions. Another important in designing piping system is a pressure drop across the flow measurement devices. Here, we investigate the pressure drop after the circle grids fractal orifices using a digital differential pressure manometer at different stations downstream a turbulent flow pipe then a direct comparison has been made with the pressure drop measured from regular orifices with the same flow area. Our results showed that the circle grid fractal orifices have a significant effect on pressure drop downstream the flow which is to be lower than that from ordinary orifices of the same flow area. This result could be important from point of view of losses consideration with the same flow control area. The experimental results using the circle grid fractal orifices show that these types of orifices can sense the pressure drop across them accurately with minimum losses than the regular ones.

Aerodynamics of cellular polymeric packing

created at the Moscow State University of Engineering Ecology (MGUIE), meet these requirements to a large extent. The packing is arranged in the tower in layers made from goffered (crimped) cellular flexible tubes, which ensures uniform distribution and good mixing of the liquid and gas phases. The experimental unit is shown schematically in Fig. 1. The working gas is air. The test regular cellular packing (RCP) 1 was placed in the experimental pipe 2 having an inner diameter of 100 mm. Before the packing layer, there was a hydrodynamic flow stabilization section whose length is eight times the diameter of the unit. The air was sucked into the pipe by the vacuum cleaner (pump) 3. In the course of the experiments, the air velocity (flow rate) in the pipe was measured by the thermoanemometer (hot-wire anemometer) 4. The pressure gradient Δp in the packing layer was measured by the differential spirit manometer 5. The air velocity w 0 calculated for the whole section of the empty unit varied from 2.55 m/sec to 4.46 m/sec. In Fig. 2, the hydraulic resistance Δp/H test data for the RCP-type polymeric packing is plotted against the air velocity w 0 . The hydraulic resistance data for polymeric Pall rings 25 mm and 50 mm in diameter supplied by The Pall Ring Company Ltd. [2] are also plotted there for comparison. As evident from Fig. 2, the hydraulic resistance of the RCP-type packing is close to that of Pall rings having a diameter of 50 mm. The new RCP-type packing, however, possesses four times larger specific surface (400 m 2 /m 3 ), a higher porosity (0.97 m 3 /m 3 ), and, consequently, a lower material content than Pall rings with a diameter of 50 mm whose specific surface is 100 m 2 /m 3 and porosity is 0.95 m 3 /m 3 . In comparison with Pall rings 25 mm in diameter (specific surface 209 m 2 /m 3 and porosity 0.91 m 3 /m 3 ), the RCP-type packing possesses twice as less hydraulic resistance, twice as large specific surface, and a higher porosity. The performed tests helped derive the relationship between the hydraulic resistance Δp/H (Pa/m) of dry polymeric RCP and the air velocity in the test w 0 (m/sec) range, which is described by the empirical equation:

Solubility of fluorine in liquid uranium, tungsten, and molybdenum hexafluorides

Experimental data on the solubility of fluorine in liquid uranium, tungsten, and molybdenum hexafluorides in the temperature range 66‐90°C and fluorine partial pressure 226‐1066 kPa are presented. Computed values of Henry’s constant for these systems and constants in the equation expressing the linear approximation of the temperature dependence of Henry’s constant are given. Uranium hexafluoride exists as a liquid only at temperature and pressure above the triple point, i.e., 64.05°C and 0.155 MPa. Since it is obtained for commercial purposes by means of the interaction of uranium tetrafluoride with excess fluorine gas [1], liquefaction from commercial gas from fluoridation apparatus can be done only at high pressure and in the process fluorine becomes dissolved in the liquid uranium hexafluoride. For this reason, the solubility of fluorine in liquid uranium hexafluoride affects the choice of the technological arrangement of any facility that is used to liquefy uranium hexafluoride from commercial gases containing fluorine. The objective of the present work is to determine the solubility of gaseous molecular fluorine in liquid metal hexafluorides. The solubility of fluorine in liquid uranium, tungsten, and molybdenum hexafluorides was determined using the apparatus shown schematically in Fig. 1. The nickel vessel 13 with a copper cover 4 had a magnetic mixer 10, placed in plain Teflon bearings 6 and finished on top by a bar made of a ferromagnetic material in aluminum casing 7. The mixer was put into motion by a permanent magnet 3, placed outside and rotated by an electric motor 1 with frequency ranging from 3 to 15 rpm. Three thermocouple pockets 9, made of nickel tubing with 0.2 mm thick wall were uniformly arranged over the height of the vessel. Two couplings with small, nickel, packed gland valves were present on the vessel wall. The initial components were loaded through one of them 5. First, the setup was evacuated, checked for vacuum, and passivated with fluorine gas at 100°C. Metal hexafluorides were loaded by means of condensation into a nickel vessel at liquid-nitrogen temperature. A standard manometer 2 was used to monitor the progress of the loading. The amount of condensed metal hexafluoride permitted the existence of at least 1 cm 3 of vapor above the liquid at the temperature of the experiment. When condensation was completed, fluorine was introduced into the vessel. Next, the vessel 13 with a differential manometer 8 was placed into a water thermostat 14 ,w here the temperature was maintained to within ±0.2°. The total pressure in the vessel was measured with a differential manometer 8. Samples of the liquid metal hexafluoride were extracted every 20 min into the space between the valves 11, whence the liquid sample was completely evaporated into the vessel 12 and delivered in the gas phase to a chromatograph for analysis. Equilibrium was considered to be attained when the solubility with decreasing gas pressure was the same as with increasing gas pressure. Methods for purifying the initial substances and checking their purity as well as the technique for performing chromatographic analysis of extracted samples are described in [2]. The computed error in determining the fluorine concentration did not exceed 0.1%.

Cellular-scale hydrodynamics

Microfluidic tools are providing many new insights into the chemical, physical and physicochemical responses of cells. Both suspension-level and single-cell measurements have been studied. We review our studies of these kinds of problems for red blood cells with particular focus on the shapes of individual cells in confined geometries, the development and use of a ‘differential manometer’ for evaluating the mechanical response of individual cells or other objects flowing in confined geometries, and the cross-streamline drift of cells that pass through a constriction. In particular, we show how fluid mechanical effects on suspended cells can be studied systematically in small devices, and how these features can be exploited to develop methods for characterizing physicochemical responses and possibly for the diagnosis of cellular-scale changes to environmental factors.

Effect of solid characteristics on hydrodynamic and mass transfer in a fixed bed reactor operating in co-current gas–liquid up flow

In order to understand better which parameters control the mass transfer efficiencies in biofilters, hydrodynamic and mass transfer parameters have been investigated for seven different packings in a three phase fixed bed reactor operating in co-current gas–liquid up flow. For this purpose, the packing characteristics (bed porosity, particle size and particle shape) and hydrodynamics parameters have been determined. Thus, the pressure drops, global gas hold-up, static gas fraction, slip velocities and bubble size have been investigated. For each type of solid, volumetric oxygen mass transfer coefficients have been measured under different operating conditions of gas (air) and liquid (tap water). The experiments were performed in a cylindrical PVC column with co-current up-flow of gas and liquid at laboratory temperature and atmospheric pressure. Air was injected at the bottom of the column using a porous disc diffuser. The superficial gas velocity ranged from 2.3E−3 m/s to 2.5E−2 m/s, the superficial liquid velocity varied from 1.2E−3 m/s to 3.3E−3 m/s. The column of 0.15 m in diameter and 4 m height was filled with packing. The following values were determined: • Pressure drop through the bed height was measured using differential manometers. • The average values of the global gas hold-up and static gas fraction were determined in the experimental set up by a new technique which is based on a monitoring of liquid flow. • The bubble sizes and slip velocities were determined by image acquisition and data treatment systems on a particular glass cell. • The volumetric oxygen mass transfer coefficient was determined by gas and liquid mass balance techniques. These different techniques applied on the fixed bed bubble column enabled for each type of solid a complete characterisation of hydrodynamic and mass transfer to be described. These experimental tools were used to compare and evaluate the influence of solid characteristics on the reactor performances and to initiate a mass transfer model.

An investigation into the microbial clogging potential of selected filter media as a result of biodegradation of a high-strength sulphate-rich alkaline leachate

The research examines the potential for bio-clogging in filter packs containing fine sand of the type typically used in extraction wells for pumping leachates containing fine particulate matter, such as cement kiln dust (CKD). Three filter media with different particle sizes were used: 1.7-4.75, 0.35-1.0, and 0.235-0.45 mm. Each sand filter was tested using a leachate recirculating column reactor with a free drainage layer, on top of which was placed the filtration medium which was kept saturated and at a positive hydrostatic head by a 2-l reservoir of leachate. The leachate was collected from a landfill site that had been used for the co-disposal of municipal solid waste (MSW) and CKD. The leachate used was filtered by passing through a Whatman GFA filter paper before being added to the reactors in order to eliminate as far as possible the non-biological clogging which might have resulted from the introduction of particulate matter in the form of CKD. The filters and a control experiment were run under anaerobic conditions at 35 degrees C. The bio-clogging potential was observed by taking differential manometer readings from manometers located in the drainage and reservoir sections of the reactor. No clogging was detected using the coarser of the filter media, but there was some clogging when a finer filter medium was used. Head space gas analysis indicated that methanogenic activity was inhibited and analysis of the liquid phase indicated that the microbial process responsible for removal of chemical oxygen demand (COD) was principally one of sulphate reduction.