Orifice Plate Flowmeter Research Articles

CFD study of the transient wet gas flow behavior through orifice plate flow meters

Differential pressure flow meters are widely used in wet gas flow measurement, typically, combined with a method to determine the liquid fraction. An alternative with significant advantages for industry, in term of cost, operation and maintenance, is determining the liquid fraction based on its relation with the statistical parameters of transient differential pressure signal fluctuations. In this way, a single measurement device can provide mass flow rate and liquid fraction simultaneously. For this method to be more feasible in the wet gas flow measurement, it is essential to understand how the differential pressure signal fluctuations and the gas–liquid flow behavior at the restriction are correlated. On this basis, this paper presents a transient 3D Computational Fluid Dynamics (CFD) study of the wet gas flow through an orifice plate, operating under field conditions, using the two-fluid model. Steady-state results, calculated from the time averaging of the transient solution, for the over-reading OR parameter were validated with experimental field data and results obtained by correlations available in the literature, showing very good agreement. The transient results from simulations presented a trend in agreement with experimental data from the literature, showing a positive correlation of the standard deviation of differential pressure signal with liquid fraction upstream of the orifice plate. However, these results should be analyzed qualitatively due to model limitations, mainly related to the interfacial transfer closure in gas–liquid flows with changing phase morphologies. Despite this fact, some important insights regarding the 3D transient flow structure with a practical value were obtained from the model.

Investigation on different scenarios of two-phase flow measurement using Orifice and Coriolis flow meters: Experimental and modeling approaches

In this study, various methods for multiphase flow metering were introduced. These techniques include measurement of gas-liquid average density by a Coriolis flow meter and determining the gas volume fraction by discharge coefficient of an orifice plate. Application of Orifice plate and Coriolis flow meters were investigated for gas-liquid flow metering. The principle of using these instruments as single-phase flow meters, for measurement of the two-phase flow was not focused in previous studies. In the second part, gas volume fraction was predicted by a soft sensor. Variation of Coriolis meter factor with gas volume fraction and Reynolds number was studied. Moreover, changes of pressure drop and discharge coefficient of Orifice with Reynolds number was investigated. On the other hand, 250 data sets were collected to develop a soft sensor using 2-layer and 3-layer neural networks optimized by genetic algorithm and Least Square Support Vector Machine. Increasing Reynolds number led to decrease in Coriolis meter factor. Among various computational intelligence methods, 3-layer neural network was the best, with mean square error and mean absolute percent error of 0.91% and 3%, respectively and computation time of 0.0001 s.

Experimental and numerical study of the flow characteristics of a novel olive-shaped flowmeter (OSF)

A novel differential pressure flowmeter with an olive-shaped flowmeter (OSF) is proposed and investigated both experimentally and numerically. The streamline, pressure and velocity are obtained and numerically analysed. The results indicate that the proposed OSF exhibits less permanent pressure loss than the orifice plate flowmeter (OPF). The pressure also tends to be more stable in the OSF, which ensures high measurement accuracy and repeatability. The OSF is superior to the OPF in terms of relative pressure loss, streamline distribution, pressure distribution and velocity distribution. In the experiment, an oil pump transported diesel oil into the measurement pipe, through the check valve, filter, pressure-regulating container, and flow-regulating valve, before it was finally returned to the fuel tank. The experimental results showed that the pressure loss of the OSF was only about 14.94% of that of the OPF under the same conditions. The pressure loss curve of the OPF increased rapidly by up to 2,700 Pa with each 1 m3/h increase in the flow rate, whereas that of the OSF increased only slightly.

Development of the instrumentation system for gas-and-diesel fuelled BelAZ dump truck

The prospects for the use of natural gas as a motor fuel are considered. The state-run program for the development of natural-gas-fuelled vehicles will entail an increase in the share of transport operating on natural gas. The data on the thermal performance of natural gas from various fields, the volumetric heat values of the stoichiometric mixture of which is almost the same, are given. The analysis of the operation of gas-diesel-fuelled BelAZ dump truck, which burns liquefied natural gas, is conducted. The schematic diagram for engine power supply with liquefied natural gas is given. The calculation of the liquefied natural gas supply system with the replacement of diesel fuel by 33% was made. As a result of the calculation, the diameter of a fuel manifold after injectors, which provides the recommended gas velocity through a manifold, was determined. The instrumentation system for controlling the amount of supplied natural gas is proposed. The complex allows obtaining data on the instantaneous gas flow rate and the total flow rate over a period of time. A pulsation damper used as part of the system allowed reducing gas pulsation in fuel manifolds after injectors, to create conditions for the use of orifice plate flow meters, and ensured the uniform supply of natural gas to both banks of cylinders, which favourably affected the engine.

Characterization of flow homogeneity downstream of a slotted orifice plate in a two-phase flow using electrical resistance tomography

Two-phase flows are complex and unpredictable in nature, commonly encountered in a majority of fluid transport systems. The accurate measurement of two-phase flow is critical for a wide range of applications from wet stream to multiphase flows. There are different methods to meter two-phase flow in various industries. One approach is to produce a flow meter that does not require the individual flow components to be separated and measured separately. This goal can be met if a homogenized mixture is produced which can be measured by a standard single phase flow meter. The slotted orifice plate was invented as a flow meter for single phase flows, it is independent upon upstream flow conditions. Slotted orifice plate flow meter's utilization in two-phase flow revealed that it is highly capable of working as a flow conditioner transforming most of the multiphase flow regimes into a fairly uniform mixture. This study measures how the relative homogeneity of an air/water mixture varies downstream of the slotted plate in a horizontal pipe for various upstream conditions including elongated bubble and slug flow regimes using electrical resistance tomography (ERT). According to this study, the optimal location with a maximum homogeneity was determined to be between 1.5 and 2.5 pipe diameters downstream of the slotted orifice plate. This indicates that placing a slotted orifice plate at the obtained distance upstream of another flow meter such as a venturi coupled with a density measuring device like a radiation based densitometer or an electrical impedance device will help in obtaining accurate multiphase flow rate measurement.

Evaluation of Orifice Flow Meter Accuracy under Pulsation Conditions

Orifice meter is a flow measuring device which is widely used in various industrial applications. Although the device gives accurate measurement during steady flow, measurement errors related to square root and sampling errors are unavoidable if pulsations exist. This research investigatesand improves the performance of an orifice plate flow meter under pulsation effects. A simple model for the pulsating flow through an orifice meter is presented. Square root error (SRE) is estimated. Sampling errors (SE) are reduced by proper selection of the averaging time.

Experimental Study of Various Porosity of Fractal Flow Conditioner for Orifice Plate Flowmeters

The plant industry is required to measure flow rate more accurately to meet plant operation and cost accounting objectives. The opposing concern of improving flow meter accuracy is resolved by using flow conditioners. The distance of implementation of flow conditioner upstream of the orifice plate flowmeter is also need to be addressed. Hence, in present study, an analysis of the porosity of fractal flow conditioner towards orifice plate flowmeter’s accuracy and the best distance of fractal flow conditioner upstream of the orifice plate flowmeter was determined. In an experimental work, a different porosity of the fractal flow conditioners were installed with different distance upstream of the orifice plate in conjunction with the different disturbances to assess the effects of these devices on the measurement of the mass flow rate. Data gained for all the plates showed that there is increment of pressure drop and change in discharge coefficient of the orifice with lower β value of fractal flow conditioner. Good comparisons with the previous experimental work demonstrate the fractal flow conditioner can preserve the accuracy of metering up to the level required in the standards.

Multiphase flow measurements using coupled slotted orifice plate and swirl flow meter

Multiphase flow metering is a major focus for oil and gas industries. The performance of a modified version of a close coupled slotted orifice plate and swirl flow meter for multiphase flow was evaluated to provide further development of a new type of multiphase flow meter. The slotted orifice provides well homogenized flow for several pipe diameters downstream of the plate. This characteristic provides a homogeneous mixture at the inlet of the swirl meter for a wide range of gas volume fractions (GVF) and flow rates. In order to evaluate the performance of the designed flow-meter, its response was investigated for varying pressures and water flow rates. The proper correlations were established to provide high accurate two-phase flow measurements. The new proposed approach provides the GVF measurement with less than ±0.63% uncertainty for GVF range from 60% to 95%.

Experimental Research on Pressure Loss of an Olivary Flowmeter

The olivary flowmeter, a new type of differential pressure flowmeter, was presented. Its pressure loss was explored through experimental research. The experimental medium is diesel. In the condition of the same effective area of circulation, the pressure loss of the olivary and the orifice plate flowmeter was compared. As a result, the pressure loss of the olivary flowmeter is 14.9% of the orifice plate flowmeter at most, 7.2% on average. The olivary flowmeter can reduce energy consumption.

An orifice meter for bidirectional air flow measurements: Influence of gas thermo-hygrometric content on static response and bidirectionality

This paper presents the design and calibration of an ISO non-compliant orifice plate flowmeter whose intended use is for respiratory function measurements in the bidirectional air flow range ±9L/min.The novelty of the proposed sensor consists of a plate beveled in both upstream and downstream sides: a symmetrical geometry is adopted in order to perform bidirectional measurements of flow rate. A mathematical model is introduced to quantify the influence of temperature on the sensor output. Four different positions of the pressure static taps are evaluated in order to maximize bidirectionality. An index is also introduced in order to quantitatively estimate the anti-symmetry of the sensor's response curve.Trials are carried out to evaluate the influence on sensor output of air temperatures (22°C, 30°C and 37°C) at different values of relative humidity (5%, 55% and 85%). Experimental data show a quite good agreement with the theoretical model (R2>0.98 in each condition).The influence of air temperature on the sensor output is minimized by introducing a correction factor based on the theoretical model leading to measurement repeatability better than 2% in overall range of calibration. The mean sensitivity in the calibration range is about 2kPaL−1·min allowing to obtain a sensor discrimination threshold lower than 0.2L/min in both directions. The time constant of the whole measurement system, equal to 2.40±0.03ms, leads to a bandwidth up to 80Hz making the sensor suitable for respiratory function measurements.

Design and development of primary orifice plate flowmeter

Accurate and stable gas flows are very important in different applications like, the performance study of vacuum pumps, gauge calibration, leak detection and advance research in low pressure physics. Primary Orifice Plate Flowmeter (OPF) has been designed and developed indigenously. This flowmeter consists of two orifice plates. Orifice-1 (O1) acts as a flow restriction, while orifice-2 (O2) enables continuous pumping mode. By varying upstream pressure P1, a change in downstream pressure P2 is recorded, and the flow-rate is calculated from the conductance "C" of the orifice O1 and pressure difference by the relation Q = C(P1 − P2). Main feature of this primary OPF is that it is very simple and compact. A stable and reproducible flow-rate has been achieved in the range of 10−5 to 10−6 mbar.l/s. A variation in Q has been observed with a change in temperature of orifice and orifice diameter.

Development of a liquid-flow pulsator

The increasing demands for more accurate flow measurements have made the study of pulsating flow effects crucial for the further development of flowmeters. This paper presents the development of an experimental test facility with an integrated water-flow pulsator for experimental investigations of the water pulsation effects on flowmeters. The mechanical implementation of the measurement system with a built-in diaphragm pulsator and integrated expansion chambers was developed with the help of mathematical modeling of the entire test system using the method of characteristics. The mathematically obtained frequency characteristic of the pulsator shows typical resonances, which depend on the acoustic properties of the measurement system and the mechanical properties of the pulsator’s diaphragm. The water-flow pulsator’s characteristics were experimentally confirmed by a spectral analysis of the generated water flow pulsations, which were measured with an orifice plate flowmeter. The developed flow pulsator with integrated expansion chambers is able to generate reproducible water flow pulsations with defined properties, such as the frequency and amplitude of the pulsating flow.

Discharge coefficient performance of Venturi, standard concentric orifice plate, V-cone and wedge flow meters at low Reynolds numbers

The relation between the Reynolds number and differential producer discharge coefficient was obtained through solutions to the steady, Reynolds-averaged Navier–Stokes equations. Discharge coefficients were also obtained experimentally for the purpose of validating the numerical results. The focus of the study was directed toward low Reynolds numbers commonly associated with pipeline transportation of viscous fluids, however high Reynolds number were also considered. The study indicates that, at low Reynolds numbers, the discharge coefficients decrease rapidly with decreasing Reynolds number for Venturi, V-cone, and wedge flow meters. The orifice plate meter did not follow the general trends of the other meters, but rather as the Reynolds number decreased, the discharge coefficient increased to a maximum before sharply dropping off with further decrease in the Reynolds number. The results presented herein provide an improved understanding of differential flow meters operating at low Reynolds numbers, and demonstrate the usefulness of computational fluid dynamics in predicting discharge coefficient trends at very low Reynolds numbers.

The fractal flow conditioner for orifice plate flow meters

The sensitivity of orifice plate flow meters to the quality of the approaching flow continues to be a cause for concern in flow metering. The distortions caused by pipe fittings such as valves, bends, compressors and other devices located upstream of the orifice plate can lead to non-standard velocity profiles and give errors in measurement. The design of orifice plate meters that are independent of the initial flow conditions of the upstream is a major goal in flow metering. Either using a long straight pipe, or a flow conditioner upstream of an orifice plate, usually achieves this goal. The effect of a fractal flow conditioner for both standard and non-standard flow conditions was obtained in experimental work and also using simulations. The measurement of mass flow rate under different conditions and different Reynolds numbers was used to establish a change in discharge coefficient relative to a standard one. The experimental results using the fractal flow conditioner show that the combination of an orifice plate and a fractal flow conditioner is broadly insensitive to upstream disturbances. The simulation results also show that the device can be used as a part of a flow metering package that will considerably reduce installation lengths. Previous work with orifice plates has shown that a combination of flow conditioner and orifice plate was promising. The results of using a combination of the fractal flow conditioner and orifice plate for non-standard flow conditions including swirling flow and asymmetric flow show that this package can preserve the accuracy of metering up to the level required in the Standards.

Pressure Loss and Energy Consumption of an Inner-cone Flowmeter and Orifice Plate Flowmeter in the Product Pipeline

Numerical simulation is carried out on pressure loss of an inner-cone flowmeter by fluid software. The experimental medium of numerical simulation is gasoline. An inner-cone flowmeter and orifice plate flowmeter are frequently used in product pipeline. In the condition of the same flow area, the two experimental results of pressure loss are compared. As a result, the pressure loss of the inner-cone flowmeter is only 22% of the orifice plate flowmeter. The application of inner-cone flowmeter, in measuring mixing flowrate in the product pipeline, can reduce energy consumption.

Slotted Orifice Plate Flow Meter

Pressure differential flow meters and especially orifice plate flow meters continue to dominate industrial flow measurement despite the flood of ingenious and spohisticiated new instruments in the past three decades. This dominance is partly dependent on the essential simplicity of these devices and partly on the confidence that their performance can be predicted without the need for extensive calibration. The invention, Slotted Orifice Plate Flow meters, patented by Hall et al. is discussed in this paper. This new design helps minimize the difficulties caused by upstream flow disturbances and multi-phase fluids, thus making the orifice meter an even more desirable flow metering device. Keywords: Orifice flow meter, slotted orifce plate, flow measurement

Numerically based design of an orifice plate flowmetering system for human respiratory flow monitoring.

During certain medical procedures, it is important to continuously measure the respiratory flow of a patient, as lack of proper ventilation can cause brain damage and ultimately death. The monitoring of the ventilatory condition of a patient is usually performed with the aid of flowmeters. However, water and other secretions present in the expired air can build up and ultimately block a traditional, restriction-based flowmeter; by using an orifice plate flowmeter, such blockages are minimized. This paper describes the design of an orifice plate flowmetering system including, especially, a description of the numerical and computational techniques adopted in order to simulate human respiratory and sinusoidal air flow across various possible designs for the orifice plate flowmeter device. Parallel computation and multigrid techniques were employed in order to reduce execution time. The simulated orifice plate was later built and tested under unsteady sinusoidal flows. Experimental tests show reasonable agreement with the numerical simulation, thereby reinforcing the general hypothesis that computational exploration of the design space is sufficiently accurate to allow designers of such systems to use this in preference to the more traditional, mechanical prototyping techniques.

Comparison of orifice and slotted plate flowmeters

The performance of a standard β = 0.50 orifice flowmeter is compared to the same flowmeter with a slotted orifice plate replacing the standard orifice plate. The slotted orifice plate has the same total open area as the standard plate and consists of three concentric rings, each of which contains several radial slots. The flow upstream of both orifice plates in preconditioned using a concentric pipe device to produce a wide range of axial velocity profiles without swirl. The discharge coefficient of the standard plate varies from the base value by −1% to +6%, while that of the slotted orifice plate varies by only ±0.25%. When swirl is generated upstream of the orifice plates, the discharge coefficients vary by 5% and 2% for the standard and slotted orifice plates, respectively. These data indicate that the slotted orifice flowmeter is superior to the standard orifice flowmeter in maintaining its calibration over a wide range of inlet flow conditions. The slotted orifice plate can be a ‘drop in’ replacement for a standard orifice plate.

The influence of pulsating flows on orifice plate flowmeters

The progress of research conducted over the last 70 years into pulsation effects on orifice flowmeters is briefly reviewed. The guidance offered in documents issued by standards organizations is also discussed. The main body of the paper, however, is devoted to descriptions of the contributions made by CERT/ONERA in France and by the University of Surrey in the UK. Work already completed is discussed in detail and plans for current and future research are outlined. The main conclusion is that the major influences on orifice plate behaviour are well defined but that more work is required before all the effects can be accurately predicted and the meter output appropriately corrected for all pulsation conditions.

The Production of Peaked Velocity Profiles

In many internal flow problems, the velocity profile of the flow in a duct of a given cross section is of major importance. In combustion chamber flow, for example, the entry velocity profile is a critical factor in determining the relative amounts of primary and secondary combustion air. Further, in the flow in an axial compressor, the peaked velocity profile between the root and the tip of the rotor blades has a marked effect upon the design of the blading. Recent work by Zanker has shown the effect of variation in velocity profile upon the accuracy of orifice-plate flowmeters.