On the problem of a vertical gas flow through an orifice with non-standard pressure tappings locations

2015 ◽  
Vol 42 (8) ◽  
pp. 563-569 ◽  
Author(s):  
Yana Nec ◽  
Greg Huculak

A comprehensive model was developed to compute the flow rate in a vertical pipe collecting gas in a landfill facility. The model accounts for gravity, viscosity, adjustable orifice diameter and non-standard locations of the pressure tappings, so placed to prevent damage to certain measuring sensors caused by atomized water entrained in the gas and pooling at the orifice plate.

Author(s):  
Guang Yin ◽  
Bjørnar Nitter ◽  
Muk Chen Ong

Abstract Orifice flow meters are widely used in industries to measure the flow rate in pipelines. The flow rate inside the pipe can be calculated using the relationship between the flow velocity and the pressure drop across the orifice plate. In the present study, numerical simulations have been carried out using three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations combined with the k-ω SST turbulence model to thoroughly investigate the turbulent flow through a circular square-edged orifice with various orifice plate thicknesses and orifice diameters inside a pipe at different Reynolds numbers ranging from 2500 to 40000. The orifice thickness to pipe diameter ratio (t) varies between 0.125 and 2 and the orifice diameter to pipe diameter (ß) varies between 0.25 and 0.75. The resulting centerline profiles of the streamwise velocity and pressure of the present study are compared with the previous published numerical results and experimental data as the validation study. The effects of Reynolds numbers and orifice geometries on the pressure, the flow velocity and vorticity distribution in the orifice are discussed in detail. It is found that for the fixed ß, the discharge coefficient increases with the increasing t and the vortical structure inside the orifice is separated into two regions located at the two edges of the orifice. For the fixed t, the size of the large recirculation motions behind the plate increases and the vorticity around the plate becomes stronger with the decreasing ß.


2020 ◽  
Author(s):  
Guang Yin ◽  
Bjørnar Nitter ◽  
Muk Chen Ong

Abstract Orifice flow meters are widely used in industries to measure the flow rate in pipelines. The flow rate inside the pipe can be calculated using the relationship between the flow velocity and the pressure drop across the orifice plate. In the present study, numerical simulations have been carried out using three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations combined with the k-ω SST turbulence model to thoroughly investigate the turbulent flow through a circular square-edged orifice with various orifice plate thicknesses and orifice diameters inside a pipe at different Reynolds numbers ranging from 2500 to 40000. The orifice thickness to pipe diameter ratio (t) varies between 0.125 and 2 and the orifice diameter to pipe diameter (β) varies between 0.25 and 0.75. The resulting centerline profiles of the streamwise velocity and pressure of the present study are compared with the previous published numerical results and experimental data as the validation study. The effects of Reynolds numbers and orifice geometries on the pressure, the flow velocity and vorticity distribution in the orifice are discussed in detail.


Author(s):  
B.S. Soroka ◽  
V.V. Horupa

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.


2021 ◽  
Author(s):  
Ekhwaiter Abobaker ◽  
Abadelhalim Elsanoose ◽  
Mohammad Azizur Rahman ◽  
Faisal Khan ◽  
Amer Aborig ◽  
...  

Abstract Perforation is the final stage in well completion that helps to connect reservoir formations to wellbores during hydrocarbon production. The drilling perforation technique maximizes the reservoir productivity index by minimizing damage. This can be best accomplished by attaining a better understanding of fluid flows that occur in the near-wellbore region during oil and gas operations. The present work aims to enhance oil recovery by modelling a two-phase flow through the near-wellbore region, thereby expanding industry knowledge about well performance. An experimental procedure was conducted to investigate the behavior of two-phase flow through a cylindrical perforation tunnel. Statistical analysis was coupled with numerical simulation to expand the investigation of fluid flow in the near-wellbore region that cannot be obtained experimentally. The statistical analysis investigated the effect of several parameters, including the liquid and gas flow rate, liquid viscosity, permeability, and porosity, on the injection build-up pressure and the time needed to reach a steady-state flow condition. Design-Expert® Design of Experiments (DoE) software was used to determine the numerical simulation runs using the ANOVA analysis with a Box-Behnken Design (BBD) model and ANSYS-FLUENT was used to analyses the numerical simulation of the porous media tunnel by applying the volume of fluid method (VOF). The experimental data were validated to the numerical results, and the comparison of results was in good agreement. The numerical and statistical analysis demonstrated each investigated parameter’s effect. The permeability, flow rate, and viscosity of the liquid significantly affect the injection pressure build-up profile, and porosity and gas flow rate substantially affect the time required to attain steady-state conditions. In addition, two correlations obtained from the statistical analysis can be used to predict the injection build-up pressure and the required time to reach steady state for different scenarios. This work will contribute to the clarification and understanding of the behavior of multiphase flow in the near-wellbore region.


2009 ◽  
Vol 36 (1) ◽  
pp. 137-147 ◽  
Author(s):  
K.I. Ashley ◽  
D.S. Mavinic ◽  
K.J. Hall

A pilot-scale, full lift, hypolimnetic aerator was used to examine the effect of diffuser pore diameter, depth of diffuser submergence, and gas flow rate on oxygen transfer, using four standard units of measure for quantifying oxygen transfer: (a) KLa20 (h–1), the oxygen transfer coefficient at 20 °C; (b) SOTR (g O2·h–1), the standard oxygen transfer rate; (c) SAE (g O2·kWh–1), the standard aeration efficiency and (d) SOTE (%), the standard oxygen transfer efficiency. Diffuser depth (1.5 and 2.9 m) exerted a significant effect on KLa20, SOTR, SAE, and SOTE, with all units of measure increasing in response to increased diffuser depth. Both KLa20 and SOTR responded positively to increased gas flow rates (10, 20, 30, and 40 L·min–1), whereas both SAE and SOTE responded negatively. Orifice diameter (140, 400, and 800 µm) exerted a significant effect on KLa20, SOTR, SAE, and SOTE, with all units of measure increasing with decreasing orifice size. These experiments demonstrate how competing design factors interact to determine overall oxygen transfer rates in full lift hypolimnetic aeration systems. The practical application for full lift hypolimnetic aerator design is to maximize the surface area of the bubbles, use fine (i.e., ~140 μm) pore diameter diffusers, and locate the diffusers at the maximum practical depth.


Author(s):  
Aaron J. Knobloch ◽  
Joell R. Hibshman ◽  
George Wu ◽  
Rich Saia

This study summarizes a fundamental investigation of flow through an array of silicon micromachined rectangular slots. The purpose of the study is to evaluate the effect of entrance pressure, flow area, orifice thickness, slot length, and slot width of the orifice on flow rate. These orifices were fabricated using a simple frontside through wafer DRIE process on a 385 μm thick wafer and wafer bonding to create thicker orifices. The dies were then packaged as part of a TO8 can and flow tested. To complement the results of this experimental work, two simple flow models were developed to predict the effect of geometrical and entrance conditions on the flow rate. These models were based on macroscale assumptions that were not necessarily true in the case of thin orifices. One relationship was based on Pouiselle flow which assumes fully developed flow conditions. Calculation of the entry length required for fully developed flow indicate that in the low Reynolds Number regime (32-550) evaluated, the entry flow development requires 2-8 times the thickness of the thickest orifices used for this study. Therefore, calculations of orifice flow based on a Pouiselle model are an overestimate of the actual measured flow rates. Another model examined typical orifice relationships using head loss at the entrance and exit of the slots did not accurately capture the particular flow rates since it overestimated the expansion or constriction losses. A series of experiments where the pressure was varied between 75 and 1000 Pa were performed. A comparison of the Pouiselle flow solution with experimental results was made which showed that the Pouiselle flow model overpredicts the flow rates and more specifically, the effect of width on the flow rates. The results of these tests were used to develop a transfer function which describes the dependence of flow rate on orifice width, thickness, length, and inlet pressure.


2017 ◽  
Vol 50 ◽  
pp. 116-127
Author(s):  
Stamatina Karakitsiou ◽  
Bodil Holst ◽  
Alex Christian Hoffmann

Flow through nano-channels is important in several fields, ranging from natural porous media to microfluidics. It is therefore important to study the flow under controlled conditions. While quite a lot of work has been done on the flow of liquids through nano-channels, comparatively little systematic work has been done on gas flow. Here we present a study of the flow of argon through nano-channels. We study samples with 2000 parallel nano-channels, with quadratic cross section. Each side is 100nm. The total length is 20 m. The nano-channels are made by patterning a Si<110> wafer usingelectron beam lithography (EBL) followed by reactive ion etching and with subsequent anodic bonding between silicon and a borosilicate glass as a top plate. The samples were investigated using a home-built apparatus which allows us to measure flow at high Knudsen numbers (from around 10 to 550). We compare our results with a range of theoretical flow models. As innovation this work provides measurements of gas transport from the home-built apparatus. The system records the pressure profile of each sample and the mass flow rate is calculated numerically from the pressure data.


The use of natural gas in several countries, especially in Indonesia is essential. In gas distribution, every industry and household will not be separated from the measurement system that aims to find out how much natural gas has been used. For this reason, the use of a gas flow meter is necessary. There are several types of gas flow meter can be used in measuring the gas volume. Some types of gas flow meters are gas turbine meters, rotary gas meters and diaphragm gas meters. The primary difference of each type of gas flow meter is the pressure capacity and the speed of the gas flow through it. Flow meter gas turbine is one type of gas flow rate measuring device. There are moving parts consisting of a propeller whose rotation speed is proportional to the flow rate through the flow meter. The type of gas turbine meter is Fluxi 2000/TZ. Fluxi 2000/TZ is designed to measure natural gas and various non-corrosive gases. This tool can be used to measure low gas flow and high gas flow. This tool can also be used to measure flow under various pressure conditions. Corus is the name of the type of gas volume converter. Corus is one instrument that supports the reading process of various gas meters, and one of them is a gas turbine meter. Corus is designed to achieve high levels of performance and accuracy from robust electronic equipment so that the results of reading the fluid volume available on the gas turbine meter can be calculated more accurately regard to the amount of temperature, pressure and compressibility. The working principle and characteristics of the two instruments make the measurements more accurate.


2011 ◽  
Vol 133 (7) ◽  
Author(s):  
R. G. Marino ◽  
A. Clausse ◽  
V. A. Herrero ◽  
N. Silin ◽  
G. Saravia

The distribution of wall pressures in yawed flow through an array of cylindrical tubes inclined at different angles between 30° and 90° was experimentally studied using air at atmospheric pressure for 2290 ≤ Re ≤ 6100. The experiments show that the pressure coefficient is strongly influenced by the inclination angle, and only marginally affected by the flow rate within the tested range. The pressure behavior at the gap was calculated by assuming curved streamlines and inviscid flow, showing good agreement with measurements performed at the rod wall in the gap position.


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