Wall Pressure Profile Around Cylindrical Rods in Yawed Gas Flow

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
R. G. Marino ◽  
A. Clausse ◽  
V. A. Herrero ◽  
N. Silin ◽  
G. Saravia
Keyword(s):  
Flow Rate ◽  
Inclination Angle ◽  
Atmospheric Pressure ◽  
Gas Flow ◽  
Pressure Coefficient ◽  
Pressure Profile ◽  
Inviscid Flow ◽  
Cylindrical Tubes ◽  
Flow Through ◽  
Good Agreement

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.

Pressure-Driven Gas Flow through Nano-Channels at High Knudsen Numbers

2017 ◽  
Vol 50 ◽  
pp. 116-127
Author(s):  
Stamatina Karakitsiou ◽  
Bodil Holst ◽  
Alex Christian Hoffmann
Keyword(s):  
Porous Media ◽  
Cross Section ◽  
Flow Rate ◽  
Gas Flow ◽  
Pressure Profile ◽  
Anodic Bonding ◽  
Pressure Data ◽  
Flow Models ◽  
Knudsen Numbers ◽  
Flow Through

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.

Facile growth of centimeter-sized single-crystal graphene on copper foil at atmospheric pressure

2015 ◽  
Vol 3 (15) ◽  
pp. 3530-3535 ◽  
Author(s):  
Jing Li ◽  
Xuan-Yun Wang ◽  
Xing-Rui Liu ◽  
Zhi Jin ◽  
Dong Wang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Flow Rate ◽  
Atmospheric Pressure ◽  
Copper Foil ◽  
Gas Flow ◽  
Gas Flow Rate ◽  
Single Crystalline ◽  
Slowing Down ◽  
Cu Foil

By mildly oxidizing Cu foil and slowing down the gas flow rate, centimeter-sized single-crystalline graphene was grown on Cu at atmospheric pressure.

Studying of Plasma- Polymerized Pyrrole at Variable Gas Flow Rates Via Plasma Jet

2021 ◽  
Vol 19 (48) ◽  
pp. 44-51
Author(s):  
Saba Jawad Kadhem
Keyword(s):  
Flow Rate ◽  
Atmospheric Pressure ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Atmospheric Pressure Plasma ◽  
Optical Emission ◽  
Plasma Jet ◽  
Nonequilibrium Plasma ◽  
Nano Particles ◽  
Vis Spectroscopy

     In this manuscript has investigated the synthesis of plasma-polymerized pyrrole (C4H5N) nano-particles prepared by the proposed atmospheric pressure nonequilibrium plasma jet through the parametric studies, particularly gas flow rate (0.5, 1 and 1.5 L/min). The plasma jet which used operates with alternating voltage 7.5kv and frequency 28kHz. The plasma-flow characteristics were investigated based on optical emission spectroscopy (OES). UV-Vis spectroscopy was used to characterize the  oxidization  state for polypyrrole. The major absorption appears around 464.1, 449.7 and 435.3  nm at the three flow rate of argon gas. The chemical composition and structural properties of the contained samples which synthesized at 0.5 L/min as a argon flow rate were analyzed by scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), Raman spectroscopy and X-ray diffraction (XRD). SEM point to a uniform distribution of polypyrrole (PPY) nanoparticles matrix. XRD technique showed a semicrystalline pattern for PPY)thin film. It is expected, that the high-quality plasma polymer grown by atmospheric pressure plasma jet method contributes to serving as conducting materials.

Experimental, Numerical, and Statistical Investigation of Two Phase Flow in a Cylindrical Perforation Tunnel

2021 ◽  
Author(s):  
Ekhwaiter Abobaker ◽  
Abadelhalim Elsanoose ◽  
Mohammad Azizur Rahman ◽  
Faisal Khan ◽  
Amer Aborig ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Statistical Analysis ◽  
Flow Rate ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Gas Flow Rate ◽  
Two Phase ◽  
Flow Through

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.

The Relationship Between Breach Development and the Depressurization Transient During Axial Rupture of a Gas-Pressurized Steel Pipe

1982 ◽  
Vol 104 (1) ◽  
pp. 20-24 ◽  
Author(s):  
M. R. Baum
Keyword(s):  
Rarefaction Wave ◽  
Gas Flow ◽  
Theoretical Models ◽  
Observation Point ◽  
Steel Pipe ◽  
Growth Data ◽  
Flow Through ◽  
The Relationship ◽  
Experimental Pressure ◽  
Good Agreement

Theoretical models are developed to predict the depressurization generated by a propagating axial rupture in a gas-pressurized steel pipe. The pressure transient is composed of a relatively slow depressurization within the rarefaction wave which propagates through the undisturbed gas ahead of the developing breach and a rapid depressurization within the breach zone. The models combine a simplified one-dimensional treatment of the gas flow local to the breach with experimental breach area growth data. An instantaneous steady flow through the developing breach is assumed to determine the boundary condition for the rarefaction wave. The breach zone depressurization is assumed to be dominated by the transverse wave action initiated by the arrival of the breach at the observation point. In both cases the predicted transients are in good agreement with experimental pressure histories.

scholarly journals Computation of Transonic Flows in and About Turbine Cascades With Viscous Effects

1984 ◽  
Author(s):  
U. K. Singh
Keyword(s):  
Inviscid Flow ◽  
Viscous Effects ◽  
Trailing Edge ◽  
Pressure Surface ◽  
Integral Methods ◽  
Interaction Treatment ◽  
Time Marching ◽  
Flow Through ◽  
Turbine Cascades ◽  
Good Agreement

An inviscid-viscous interaction treatment has been developed to predict the flow through transonic axial turbine blade cascades. The treatment includes a trailing-edge base pressure model. This model is based on treating the area between the points of flow separation on the blade surfaces at the trailing-edge and the point of downstream confluence of the suction and pressure surface flows as a region of constant pressure. A time marching technique is used to calculate the inviscid flow and viscous flow is calculated by integral methods for laminar and turbulent boundary layers. Good agreement with experimental data has been obtained.

Experimental Study of Entrance Effects on Laminar Gas Flow Through Silicon Orifices

2005 ◽  
Author(s):  
Aaron J. Knobloch ◽  
Joell R. Hibshman ◽  
George Wu ◽  
Rich Saia
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Flow Area ◽  
Fully Developed Flow ◽  
Flow Rates ◽  
Flow Models ◽  
Entry Length ◽  
Orifice Flow ◽  
Measured Flow ◽  
Flow Through

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.

Liquid Transport Properties in Sub-Micron Channel Flows

2001 ◽  
Author(s):  
K. Johan A. Westin ◽  
Kenneth S. Breuer ◽  
Chang-Hwan Choi ◽  
Peter Huang ◽  
Zhiqiang Cao ◽  
...  
Keyword(s):  
Flow Rate ◽  
Low Flow ◽  
Slip Boundary Conditions ◽  
Liquid Transport ◽  
Flow Rates ◽  
Slip Boundary ◽  
Laminar Channel Flow ◽  
Flow Through ◽  
Set Up ◽  
Good Agreement

Abstract An experimental set-up for pressure driven liquid flow through microchannels have been designed and tested. The flow rate is determined by tracking the free liquid surface in a precision bore hole using a laser distance meter. Measurements of the flow rate through silicon microchannels with a height of less than 0.9 μm show good results for Newtonian fluids (silicon oil, ethanol) at flow rates as low as 0.2 nl/s. The experimental results are also in very good agreement with predictions based on laminar channel flow using no-slip boundary conditions, indicating that standard macroscopic assumptions are still valid for these fluids under these conditions. However, experiments with aqueous solutions show anomalies in the form of unexpectedly low flow rates and time dependent variations. Possible explanations to these observations are discussed.

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