Standard Orifice Research Articles

Study on the measurement accuracy of an improved cemented carbide orifice flowmeter in natural gas pipeline

Standard orifice flowmeter has been widely used in the field of natural gas metering. However, the traditional stainless steel orifice flowmeter (TSSOF) is not resistant to wear and corrosion, especially the entrance sharpness will gradually increase. In order to improve the measurement accuracy and working life of the orifice flowmeter, the cemented carbide is embedded in the opening place of the TSSOF, thus, an improved carbide orifice flowmeter (ICOF) is manufactured. For conducting the field comparison experiment, four ICOF and four TSSOF were installed in four natural gas pipelines, respectively. The experiment results show that the variation ranges of the entrance sharpness of them are 9.863–26.438µm and 9.192–57.329µm, respectively; the entrance sharpness is increased with the increasing of the use time, but the change rate of the ICOF is smaller. The CFD simulation was also carried out. The simulated discharge coefficient values were compared with the calculated discharge coefficient values by the ISO empirical correlation. The results show that the accuracy of the two types of orifice flowmeter display a same decreasing trend with the increasing of the use time, and the absolute value of the relative error ranges are 0.51–2.28%, 0.13–4.25%, respectively, but the descent rate of the ICOF is smaller; the measurement accuracy of the ICOF is improved up to 2.39 times compared with the TSSOF, and it is more stable when the gas flow rate changes in the pipeline. Additionally, the effect of downstream inclination angle was studied. The result demonstrate that the measurement accuracy can be improved by 0.34%, when the downstream inclination angle is 60° at the gas flow rate of 5–15m/s, which is superior to the commonly used inclination angle of 45°. In summary, the ICOF can be better applied to engineering practice.

An investigation of wet gas over-reading in orifice plates under ultra-low liquid fraction conditions using dimensional analysis

Wet gas represents a special gas-liquid two-phase flow case which is often encountered in the oil and gas industry, such as wet natural gas extraction from a condensate field. The on-line, non-separation measurement of wet gas under ultra-low liquid fraction conditions is an important research area that presents significant technical challenges. In this paper, a method based on dimensional analysis is investigated that may enable predictions of the over-reading parameter in wet gas with liquid fractions less than 0.5% using non-separation measurement. A standard orifice plate with a diameter of 50 mm and a beta ratio of 0.55 was used as the flow measurement device. The dimensional analysis method was used to investigate the flow characteristics of a wet gas flowing through an orifice plate for Lockhart-Martinelli parameters ranging from 0 to 0.08, gas Froude numbers ranging from 0.5 to 2.4 and liquid gas density ratios ranging from 75 to 170. A measurement-based correlation of the wet gas over-reading parameter in an orifice plate is derived using dimensionless parameters combined with physical analysis. The experimental data shows that the relative deviation of this correlation is less than ±2% in experimental verification. The results of this study show that this method can be applied to the non-separation measurement of wet natural gas from the ultra-low liquid fraction of an oil and gas field in the future.

On the performance of perforated plate with optimized hole geometry

Perforated plates have many advantages compared to other differential type flow meters. Their permanent pressure loss could be lower than that of the standard orifice plates but significantly higher than that of the flow nozzles and the venturi meters. This high permanent pressure loss increases the energy consumption and hence the cost of flow metering. Therefore, the present study aims at minimizing the permanent pressure loss of perforated plates by optimizing their hole geometry. A convergent–divergent hole geometry is proposed for use with perforated plates. This geometry was numerically investigated and optimized by solving the Reynolds Averaged Navier–Stocks Equation (RANS) at different hole geometries. Numerical results show that the optimized convergent–divergent hole geometry reduces the permanent pressure loss by 51.7% at Reynolds number Re=3.5×104. The discharge coefficient of the optimized perforated plate is higher than that of the flow nozzle and comparable to that of the venturi meter. Moreover, a significant improvement of the cavitation number was recorded for the perforated plate with optimized convergent–divergent hole geometry.

A Comparative Analysis of the Discharge Coefficients of Variable Pressure-Drop Flowmeters

Possible additional errors in measurements of flow rate and quantity of gas with the use of the discharge coefficient of standard orifices are considered.

Implementation aspects of an exhaust back pressure (P3) estimator for a series sequential 2-stage boosting system

Exhaust back pressure (EBP) is an important parameter for controlling the flow of exhaust gases, so-called exhaust gas recirculation (EGR), for the reduction of harmful nitrogen oxides, NOx and for turbine durability, limiting the pre-turbine pressure. Since the exhaust conditions are severe, including soot, thermal effects and harmful gases, normally a sensor is not considered for mass production. Hence, a cost benefit can be realised which also reduces warranty claims. However, the EBP needs therefore to be estimated, not measured. In single-stage turbocharged engines, a model-based algorithm controls the EGR flow using the available airpath actuators, namely throttle and EGR valve, scheduling the flows using the standard orifice flow equation and estimating EBP using normal turbine design parameters like corrected flow, pressure ratio and variable nozzle turbine position (VNT where applicable). However, for two-stage systems, with two turbines in series, the estimator concept needs to be revised, as well as the sensor set, and this is the topic of this technical paper, complete with both simulation, engine and vehicle results.

Measurement of Roughness of Internal Surface of Measuring Pipeline in Real Time for Standard Orifice Plates

Methods for measuring the roughness of the internal surface of a measuring pipeline for projected rectilinear sections of a measuring pipeline and for rectilinear sections that are in operation have been determined. The new equations for calculating the hydraulic resistance coefficient of friction of natural gas on the internal surface of the measuring pipeline, the average value of natural gas pressure along the section of a measuring pipeline and the equivalent roughness were obtained. These equations provide improvement of accuracy of natural gas flow rate and volume measurement bymeans of the differential pressure method. The equation for calculating the Reynolds number from the conditions of the roughness measurement in real time was obtained. The technique of selection of methods of the roughness measuring was presented. Functional scheme of process automation of measurement the equivalent roughness of the internal surface of the measuring pipeline was developed. Визначені методи вимірювання шорсткості внутрішньої поверхні вимірювального трубопроводу для прямолінійних ділянок вимірювального трубопроводу, які проектуються, і для прямолінійних ділянок, які знаходяться в експлуатації. Отримано нові рівняння для визначення коефіцієнта гідравлічного опору тертя природного газу об внутрішню поверхню вимірювального трубопроводу, середнього значення тиску природного газу на довжині вимірювального трубопроводу та еквівалентної шорсткості в реальному часі. Ці рівняння дають можливість підвищити точність вимірювання витрати та кількості природного газу методом змінного перепаду тиску. Отримано рівняння для визначення числа Рейнольдса з умови вимірювання шорсткості в реальному часі. Наведена методика вибору методу вимірювання шорсткості. Розроблено функціональну схему автоматизації вимірювання еквівалентної шорсткості внутрішньої поверхні вимірювального трубопроводу.

Grand challenge: on the way to scarless visceral surgery.

Grand challenge: on the way to scarless visceral surgery.

Optimization of orifice meter's energy consumption

Orifice meters are commonly used in many industrial facilities and pipelines. However, they increase the annual energy consumption and cost due to their high pressure loss. The present research introduces a new design that reduces this high pressure loss by inserting a ring downstream the standard orifice meter. Maximum reduction of pressure loss is achieved by optimizing the downstream ring geometry. Numerical optimization is implemented using CFD simulation together with a genetic algorithm. Accurate CFD simulation is performed to solve the flow field at different downstream ring geometries while the genetic algorithm is used to estimate the optimum ring geometry. Optimization results show 29.8–33.5% reduction of orifice meter pressure loss for a Reynolds number Re=1.84×104 to 8.69×104. An increase of the discharge coefficient by 17.7–22% is also obtained within the investigated operating range. Both the effect of upstream distance and inlet flow disturbance and distortion are investigated. This investigation shows that the downstream ring reduces the pressure loss of standard orifice meters by 31–33.2% even under high flow disturbance and short upstream length. The proposed design adds many new advantages to the well known standard orifice meters.

Hydraulics of large diameter gated flexible fluming

Gated flexible or 'layflat' fluming is used in furrow irrigation to supply water to individual furrows. Laboratory experiments were conducted to establish the flow characteristics of these pipes under the low heads and high flow rates typical of furrow irrigation of cotton in Australia. Two different diameters of layflat were used in the study, 222.8 and 425mm. Proprietary 50mm diameter outlets (gates) were installed in the layflat at 1m spacings. Tests were conducted at various pressures and flow rates to determine; the geometric characteristics of the fluming and their relationship to pressure, the friction loss coefficient for the fluming with and without the outlets installed, and the head-discharge characteristic for the outlets. It was shown that the fluming is capable of supplying the desired flow rates (about 6l s-1 per furrow) at pressure heads <1m. The head-discharge characteristic for the proprietary outlets followed a similar form to the standard orifice equation. No evidence was found to suggest that the velocity head played any significant role in determining the outlet discharge. The Hazen-Williams coefficient (CHW) of the fluming with the outlets installed was a low 80 compared to a value of about 140 for the fluming without gates. This clearly illustrates the increase in energy losses caused by the protrusion of the gates into the flow and that these losses far exceed the losses due simply to pipe friction. These experimentally derived coefficients and characteristic equations were used to validate the simulation program GPIPE.

Influence of Ground Conditions on Intrusion Flows through Apertures in Distribution Pipes

This paper presents a new, tractable analytical expression to describe the intrusion of fluids into buried pipes under steady-state conditions. The expression is validated with results from novel experiments. The derivation is based on the combination of the relevant existing models of flows through porous media and the losses through an orifice, with the resulting expression relating the intrusion flow rate to an applied driving pressure. The expression is shown to yield results directly equivalent to those generated from a full three-dimensional (3D) computational fluid dynamics (CFD) model of the intrusion process. Results from the experiments, quantifying volumetric intrusion from a realistic 3D porous media, presented here, compare favorably with calculated values, validating the expression. Although the experimental and analytical results show a high level of agreement, it was found that the analytical expression tends to slightly underestimate the intrusion rate seen experimentally. The absolute difference in the values is low and is thought to be attributed to preferential flow path at the porous media and pipe interface that the analytical expression and CFD model do not include. It is shown mathematically and verified experimentally that the viscous and inertial resistance to flow in the porous media reduces the intrusion (or leakage) flow over that predicted by the standard orifice equation and places additional dependencies of the flow on the size of the intrusion orifice. The values obtained from the expression should be considered as a lower bound to intrusion (and leakage) rates, with upper bounds being provided by the standard orifice equation. Although developed to aid in the quantification of intrusion risk, such as that associated with water distribution systems, the expression is also validated for leakage for the limited case that the external porous media is considered to be fully compacted, consolidated, and immobile.

Study on discharge coefficient of perforated orifices as a new kind of flowmeter

A perforated orifice is promising in measuring flowrates accurately as a differential pressure device. In this study, the discharge coefficient of a perforated orifice, characterizing the relationship between the volumetric flowrate and the pressure drop across the orifice is presented. Different structures are tested experimentally including orifice thickness, porosity, hole distribution and upstream disturbance. For each case, a wide range of flowrate was tested in a horizontal single-phase water pipe with an I.D. of 29mm. For comparison, the discharge coefficient was also obtained for the corresponding standard orifice with the same porosity and thickness. Meanwhile, the effect on the discharge coefficients of the structural parameters was assessed in terms of pressure drop. The theoretical analysis shows that a perforated orifice yields a weaker distortion to the flow than the corresponding standard orifice, indicating a lower pressure drop and a more stable flow field for the former. The experimental results show that the discharge coefficient of a perforated orifice is 22.5–25.6% larger but with a weaker scattering than that of the corresponding standard orifice. Furthermore, a perforated orifice has a lower critical Reynolds number and a stronger anti-disturbance ability. As a flowmeter, the perforated orifice is comparable to the newly developed differential pressure orifices, e.g. V-cone and slotted orifices, but with a simpler structure.

Single-incision right hemicolectomy for malignancy: a feasible technique with standard laparoscopic instrumentation

Single-incision laparoscopy is a rapidly evolving technique in the spectrum 'standard laparoscopy-natural orifice transluminal endoscopic surgery (NOTES)'. From a commercial perspective, purchase of articulating instruments is advised. However, here we present our early experience with single-incision laparoscopy for right hemicolectomy with standard laparoscopic instrumentation. Between June 2010 and December 2011, 25 patients presenting with malignant disease underwent single-incision laparoscopy for right hemicolectomy. Four different ports (SILS™ port, Covidien; SSL(®) Access system, Ethicon; X-Cone/S-Portal(®) , Storz; and OCTO™ port, AFS Medical) were used. Patients were recruited prospectively and all data were processed retrospectively. Twenty-five patients were included in our study (and their characteristics, described later in this paragraph, are expressed as median (range)). Four conversions to standard laparoscopy were performed. The age of patients was 69 (36-89) years, and they had a body mass index (BMI) of 24.5 (19.1-34.2). The duration of surgery was 110 (70-148) min with a healed skin incision length of 35 (20-60) mm. Hospital stay was 5 (2-15) days. In four patients discharge was delayed because of comorbidity. One patient suffered an overwhelming pneumonia. Single-incision laparoscopy using standard laparoscopic instruments appears to be a safe and feasible technique for malignant disease requiring right hemicolectomy. Randomized, prospective trials are ongoing to prove the benefits of this technique and to compare its oncological outcome measures with those of conventional laparoscopy. In our experience, a low-profile port with a wide intra-abdominal range of motion is most preferable.

Multiple electrosprays generated from a single polycarbonate microstructured fibre

Electrospray ionization (ESI) has been invaluable to the mass spectrometric detection of biomolecules, due largely to the sensitivity afforded by the ionization technique. Lower flow rates, e.g. in the nanoelectrospray regime, result in smaller initial electrosprayed droplets, leading to higher ionization efficiency and greater signal. One approach to improving sensitivity without lowering flow rate is to generate multiple electrosprays (MESs) from the same sample, essentially splitting one larger flow into smaller flows in the nanoESI regime. Presented here is a series of novel MES emitters in the form of polycarbonate fibres. Based on microstructured fibre (MSF) technology whereby a set of homogeneous parallel channels are formed in a heat-drawn fibre intended to conduct light, a custom design was fabricated in which 3, 6, 9 and 12 holes were arranged in a radial pattern to prevent inhomogeneities in the electric field. The MSFs have dimensions that are compatible with current standards in nanoESI equipment, and the tip is more compatible with standard MS orifices than other larger multielectrospray emitters. By measuring the spray current provided by the various emitters under the same solvent/voltage/total flow rate conditions, a plot was obtained clearly demonstrating the expected dependence on the square root of the number of holes, i.e. the number of independent electrosprays. With this firm proof of principle using this design/format, further effort is justified in developing similar emitters in alternative materials that better prevent surface wetting and allow greater hole density, ultimately leading to greater signal enhancement.

Study on the Portable and Integrated Type Pore Plate Flow Measureing Device for Condensate Water of 300MW Steam Turbine

In order to insure the accuracy of steam turbine thermal test in power plant, the flowrate measurement accuracy of condensate water should be insured. In this paper, the portable and integrated type flow measuring device for condensate water of 300MW steam turbine flow is designed, which is based on the condensate water parameters and the specific pipeline conditions at the exit of the No. 5 low pressure heater for 300MW unit. A integration of non standard differential pressure orifice flow meter is designed in this paper Through calibration in standard experimental system, the reason of the large error is that the flow field is disturbed by the origin plate type downward welding connecting flanges. Then the welding neck flanges is designed for the connecting flanges. The distribution of connecting flanges of flow field is weaken, and the measurement accuracy can meet the demand of steam turbine thermal test.

Biomechanical effects of the inclusion of holes to facilitate the integration in monofilament polypropylene meshes: An experimental study

ObjectiveTo evaluate the biomechanical properties of a type of monofilament polypropylene mesh used to repair vaginal prolapse, as well as the effects of the inclusion of standard size orifices, called “helper orifices,” on the interface resistance in the receiving area. Material and methodsForty, 3 month-old, female Wistar rats received an implant of monofilament polypropylene mesh, measuring 24mm×11mm with no orifices, on the left side of the abdominal wall (block 1). On the right side, a similar mesh with two circular orifices (6mm diameter) was implanted (block 2). The rats were euthanized 90 days later and their abdominal walls were removed and divided into two blocks. The biomechanical study used a precision tensiometer in which the mesh was uniaxially tensioned until it was loosened from the tissue interface. In order to determine the tissue adherence and elasticity in each group, the following variables were analyzed: maximum load; deflection at maximum load; work to maximum load; stiffness as well as load, deflection and work at detachment of the mesh. ResultsWith the exception of stiffness, all the other variables showed statistical differences between the groups, considering that they were increased in meshes with orifices (p<0.001). The inclusion of standard size orifices reduced 30% of the mesh weight. ConclusionBesides reducing the weight and amount of material, the inclusion of standard size orifices in the monofilament macroporous polypropylene mesh improved the elasticity and adherence to the tissues when implanted in the interface of the abdominal wall in adult female rats.

Wet Gas Measurement with Slotted Orifice Meter--Effect of Geometry of Slots and Pressure

Wet gas metering by differential pressure flow meters is gaining prominence in the oil and gas industry, owing to their simple construction. Slotted orifice, a modified version of the standard orifice meter has been found promising by many researchers. This novel flow meter is shown to be insensitive to the upstream flow profile with lower head loss and faster pressure recovery compared to the standard orifice. In the present work, the effect of geometry of slots and pressure on the performance of the slotted orifice has been studied by CFD modeling of the wet gas flow. The performance of slotted orifice with rectangular perforations (1.5 ≤ l/w ≤ 3.0) and circular perforations has been compared with that of the standard orifice having same β-ratio of 0.40. Simulation results reveal that the shape of perforation of the slotted orifice has no effect on the differential pressure. However, the pressure recovery with the rectangular slots is found to increase with increasing aspect ratio. Moreover, at low pressure, slotted orifice is found to be more sensitive to liquid presence than the standard orifice. The relatively higher over reading values obtained in this work is consistent with the results of Geng et al (2006) that for slotted orifice, a low beta ratio is more sensitive to the liquid presence in the stream and hence is preferable for wet gas metering. Homogeneous model, Steven’s and De Leeuw’s correlations, are found to be better than orifice correlations for wet gas mass flow prediction.

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.

Efectos biomecánicos de la inclusión de orificios facilitadores de la integración en mallas de polipropileno monofilamento: estudio experimental

Objective To evaluate the biomechanical properties of a type of monofilament polypropylene mesh used to repair vaginal prolapse, as well as the effects of the inclusion of standard size orifices, called “helper orifices,” on the interface resistance in the receiving area. Material and methods Forty female Wistar rats, 3 month-old, received an implant of monofilament polypropylene mesh, measuring 24 x 11 mm with no orifices, on left side of the abdominal wall (block 1). On the right side, a similar mesh with two circular orifices (6 mm diameter) was implanted (block 2). The rats were euthanized 90 days later and their abdominal walls were removed and divided into two blocks. The biomechanical study used a precision tensiometer in which the mesh was uniaxially tensioned until it was loosened from the tissue interface. In order to determine the tissue adherence and elasticity in each group, the following variables were analyzed: maximum load; deflection at maximum load; work to maximum load; stiffness as well as load, deflection and work at detachment the mesh. Results With the exception of stiffness, all the other variables showed statistical differences between the groups, considering that they were increased in meshes with orifices (p < 0.001). The inclusion of standard size orifices reduced 30% of the mesh weigth. Conclusion Besides reducing the weight and amount of material, the inclusion of standard size orifices in the monofilament macroporous polypropylene mesh improved the elasticity and adherence to the tissues when implanted in the interface of the abdominal wall in adult female rats.

Pure SILS Floppy Nissen Fundoplication with Hiatal Repair: A Case Report

Background. Single-incision laparoscopic surgery has recently became popular on behalf of inventing less invasive procedures. In this paper, we present a case of Pure SILS Nissen Fundoplication. Patient and Methods. In February 2010 a 29-year old male patient with a 4 cm sliding hiatus hernia presenting with reflux symptoms had undergone a standard floppy Nissen Fundoplication with a hiatus repair via single 2 cm incision in umbilicus. Results. The procedure had obeyed the standard natural orifice surgery rules, and no needlescopic assistance for any stage of the operation was used so to be a pure single-incision procedure. The operation lasted for 120 minutes without any need of conversion, and the patient was discharged the following day of operation. Conclusion. In the recent time, hybrid single incision laparoscopy techniques have been defined with the use of extra-abdominal supplements for retraction of liver or stomach for Nissen procedure. In addition the main issue in single-incision upper GI and/or hiatus surgery is still the retraction of liver. We succeeded to retract the left lobe of liver through the incision and completed the operation without any need for supplemental access besides the umbilical incision till the end. SILS Hiatus Surgery can be safely and effectively done but the issue needs further clinical studies to state the efficacy when compared to standard laparoscopy.

ICONE19-43330 DISCHARGE COEFFICIENT ANALYSIS OF PERFORATED ORIFICE PLATES

As a new device to measure flow rate, performances of perforated orifice plate, especially its discharge coefficient, is studied theoretically and experimentally. First, we disclose the relationship between discharge coefficient and flow structure by a new theory, field synergy theory. Then we design different structures and test their performances experimentally in singlephase water. To further understand the characteristics, we compare the performances of perforated and the corresponding standard orifices. From the results, field synergy theory is applicable to disclose the working principle of all the differential pressure devices. Compared with standard orifices, perforated ones have more stable discharge coefficients and broader application ranges with smaller critical Reynolds number. Many parameters have effect on the performances such as hole diameter, plate thickness, plate porosity, and spatial distribution. Each parameter has not monotonic but complex effect on perforated orifices, which should be optimized for engineering applications.