Gas Flow Research Articles

Behavior of froth in absence and presence of particles

This work aims to study the effect of entrained and captured particles on the properties of the froth. It was established that the entrained particles act as froth suppressors, while captured particles act as froth boosters. The average liquid hold up of froths containing entrained particles increases with the increase of the gas flow rate. On the contrary, the froths with mostly captured particles exhibit the opposite dependence. Our study on the liquid hold up on the top of the froth versus the gas flow rate show that the froth with entrained particles increases its liquid hold up on the top until reaching a maximum, beyond which a decrease is observed. Surprisingly, the froth with mostly captured particles shows different behavior – its liquid hold up on the top practically does not depend on the gas flow rate, yet it can be seen at a certain minimal value. Overall, this work reports than entrained and captured particles cause substantiall different and even opposite effects on the froth stability and the liquid hold of the flotation froth.

Regulation on microstructure and mechanical properties of SiC particles reinforced AZ31 magnesium matrix composites fabricated by synchronous feeding of powder and wire in wire-arc directed energy deposition

Ceramic particles reinforced magnesium matrix composites (CMMCs) have attracted widespread attention and investigation due to their excellent comprehensive performances. However, limited research on additive manufacturing of CMMCs has been performed. In this work, the SiC/AZ31 composites were fabricated by wire-arc directed energy deposition (WA-DED) based on the synchronous feeding strategy of powder and wire. The defects, SiC particle distribution, microstructure and mechanical properties of the prepared WA-DED SiC/AZ31 composites were studied. The results indicated that SiC particles with the content range of 0.3-1.7wt% have been successfully added into the single-channel monolayer AZ31 matrix by adjusting the turret speed (TS) and the argon gas flow rate (AGFR) flowing through the powder feeder. The mathematical model is established to predict the introduced SiC particle content by correlating the relationship between SiC particle content and process parameters (TS and AGFR) of the powder feeder. The transformation from columnar to equiaxed grains occurs after adding SiC particles, more precipitated phases are formed after introducing more SiC particles. Compared to the AZ31 matrix, the WA-DED SiC/AZ31 composites exhibit the highest yield strength of 92.8 MPa and tensile strength of 213.3 MPa on the premise of almost no loss of elongation, and the maximum improvement efficiency of tensile strength reaches 56%, which is mainly ascribed to refinement strengthening, while thermal mismatch strengthening, Orowan strengthening and load-bearing strengthening play a booster action.

Coupled multi-dimensional modelling of warm plasmas: Application and validation for an atmospheric pressure glow discharge in CO2/CH4/O2

To support experimental research into gas conversion by warm plasmas, models should be developed to explain the experimental observations. These models need to describe all physical and chemical plasma properties in a coupled way. In this paper, we present a modelling approach to solve the complete set of assumed relevant equations, including gas flow, heat balance and species transport, coupled with a rather extensive chemistry set, consisting of 21 species, obtained by reduction of a more detailed chemistry set, consisting of 41 species. We apply this model to study the combined CO2 and CH4 conversion in the presence of O2, in a direct current atmospheric pressure glow discharge. Our model can predict the experimental trends, and can explain why higher O2 fractions result in higher CH4 conversion, namely due to the higher gas temperature, rather than just by additional chemical reactions. Indeed, our model predicts that when more O2 is added, the energy required to reach any set temperature (i.e., the enthalpy) drops, allowing the system to reach higher temperatures with similar amounts of energy. This is in turn related to the higher H2O fraction and lower H2 fraction formed in the plasma, as demonstrated by our model. Altogether, our new self-consistent model can capture the main physics and chemistry occurring in this warm plasma, which is an important step towards predictive modelling for plasma-based gas conversion.

Wavelength-modulated photoacoustic spectroscopic instrumentation system for multiple greenhouse gas detection and in-field application in the Qinling mountainous region of China

We present a sensitive and compact quantum cascade laser-based photoacoustic greenhouse gas sensor for the detection of CO2, CH4 and CO and discuss its applicability toward on-line real-time trace greenhouse gas analysis. Differential photoacoustic resonators with different dimensions were used and optimized to balance sensitivity with signal saturation. The effects of ambient parameters, gas flow rate, pressure and humidity on the photoacoustic signal and the spectral cross-interference were investigated. Thanks to the combined operation of in-house designed laser control and lock-in amplifier, the gas detection sensitivities achieved were 5.6 ppb for CH4, 0.8 ppb for CO and 17.2 ppb for CO2, signal averaging time 1s and an excellent dynamic range beyond 6 orders of magnitude. A continuous outdoor five-day test was performed in an observation station in China’s Qinling National Botanical Garden (E longitude 108°29’, N latitude 33°43’) which demonstrated the stability and reliability of the greenhouse gas sensor.

Applications of artificial intelligence algorithms in artificial lift systems: A critical review

In the oil and gas industry, the implementation of an artificial lift system is utilized to enhance the extraction of hydrocarbons from a reservoir that has depleted its natural energy. This can be achieved by employing pumps such as positive-displacement or centrifugal downhole pumps, or by injecting gas into the well tubing to reduce liquid hydrostatic pressure and improve fluid flow towards the surface. Recently, artificial intelligence-based algorithms have emerged as the leading approach for modelling various artificial lift parameters and problems. Consequently, there has been a renewed interest in understanding the role and effectiveness of different computational algorithms used in the artificial lift system domain. While there is an extensive body of literature on this subject, no prior research has effectively consolidated the findings from various artificial lift system domains, underscoring the need for an all-encompassing review. The purpose of this review is to create a guide that serves as a framework that helps scholars identify knowledge gaps and suggest novel ideas that would enhance the workings of artificial lift systems in the oil and gas industry. This article presents the first comprehensive analysis of artificial intelligence applications in five key areas of artificial lift systems in the oil and gas industry namely: prediction of oil and gas flow rates in artificial lift wells, prediction of artificial lift system failures, selection of artificial lift systems, parameter optimization, and the application of soft sensing technologies in artificial lift systems. The research studies pertaining to each of these areas were systematically identified from the existing literature, and their main features were highlighted. To ensure the uniqueness and novelty of this work, a critical evaluation of the artificial lift articles in each broad area was conducted. The review outcomes were then presented in clear tables that highlighted the main features of each study. Findings from the study indicate that artificial intelligence models are prevalent in almost every aspect of artificial lift systems, and the number of articles on this topic continues to grow. Some of these models have even been field tested and proven effective in improving artificial lift system operations and reducing costs. However, there is need to enhance the explicitness and interpretability of some of the predictive models by including vital details, to enhance seamless implementation and easy deployment in the field. This work will be valuable for industry operators, researchers, and students who seek a guide or reference material on artificial intelligence-based models for artificial lift systems.

A unified two-scale gas-liquid multi-fluid model with capillarity and interface regularization through a mass transfer between scales

In this contribution, we derive a gas-liquid two-scale multi-fluid model with capillarity effects to enable a novel interface regularization approach for multi-fluid models. As this unified modelling is capable of switching from the interface representation of a separated to a disperse regime it lays a new way of modelling regime transitions as it occurs in atomization processes. Above a preset length threshold at large scale, a multi-fluid diffuse interface model resolves the dynamics of the interface while, at small-scale, a set of geometric variables is used to characterize the interface geometry. These variables result from a reduced-order modelling of the small-scale kinetic equation that describes a collection of liquid inclusions. The flow model can be viewed as a two-phase two-scale mixture, and the equations of motion are obtained thanks to the Hamilton’s Stationary Action Principle, which requires to specify the kinetic and potential energies at play. We particularly focus on modelling the effects of capillarity on the mixture’s energy by including dependencies on additional variables accounting for the interface’s geometry at both scales. The regularization of the large-scale interface is then introduced as a local and dissipative process. The local curvature is limited via a relaxation toward a modified Laplace equilibrium such that an inter-scale mass transfer is triggered when the mean curvature is too high. We propose an original numerical method and assess the properties and potential of the modelling strategy on the relevant test-case of a two-dimensional liquid column in a compressible gas flow.

Nitrogen fixation and H202H2O2 ${{\rm{H}}}_{2}{{\rm{O}}}_{2}$ production by an atmospheric pressure plasma jet operated in He–H20–N2–O2 gas mixtures

AbstractAtmospheric pressure plasmas are widely used for nitrogen fixation processes to produce ammonia NH3 or nitrogen oxides NOx, including, for example, nitrite NO2− or nitrate NO3−. Small‐scale atmospheric pressure plasma jets (APPJs) can provide the production of these species on demand at the site of consumption. The species of interest are generated by the plasma and can be dissolved in liquids, for example, to use them. In this work, liquid treatments were performed by an APPJ operated in a He––– gas composition to investigate the influence of the gas composition on the production of hydrogen peroxide , and . A validation of two diagnostics showed that the spectrophotometric approach using ammonium metavanadate was interfered by other species when was added to the system. Thus, electrochemical sensing of was performed. The concentrations of and were measured by commercially available test kits based on the o‐phythalaldehyde method and the Griess reagent, respectively. At low admixtures, the dominant species was with a maximum concentration of 0.9 mM, while became dominant at admixtures of 0.5% and higher with concentrations of up to 1.5 mM. was also present in the system and could be measured at low concentrations of less than 0.2 mM in the liquid. By varying the treatment distance and the gas flow rate, insights into the transport phenomena of the species and their dissolution into the liquid could be gained. Low‐frequency pulsing of the radio frequency (RF) jet led to an accumulating effect on , a reduced production of and a switch from ‐dominated production to ‐dominated production.

Detachment of particulate structures from a fiber array due to stretching and simultaneous gas flow

Detachment of particulate structures from a fiber array due to stretching and simultaneous gas flow

Novel high-pressure/high-temperature reactor cell for in situ and operando x-ray absorption spectroscopy studies of heterogeneous catalysts at synchrotron facilities.

This paper presents the development of a novel high-pressure/high-temperature reactor cell dedicated to the characterization of catalysts using synchrotron x-ray absorption spectroscopy under operando conditions. The design of the vitreous carbon reactor allows its use as a plug-flow reactor, monitoring catalyst samples in a powder form with a continuous gas flow at high-temperature (up to 1000 °C) and under high pressure (up to 1000bar) conditions, depending on the gas environment. The high-pressure/high-temperature reactor cell incorporates an automated gas distribution system and offers the capability to operate in both transmission and fluorescence detection modes. The operando x-ray absorption spectroscopy results obtained on a bimetallic InCo catalyst during CO2 hydrogenation reaction at 300 °C and 50bar are presented, replicating the conditions of a conventional microreactor. The complete setup is available for users and permanently installed on the Collaborating Research Groups French Absorption spectroscopy beamline in Material and Environmental (CRG-FAME) sciences and French Absorption spectroscopy beamline in Material and Environmental sciences at ultra-high dilution (FAME-UHD) beamlines (BM30 and BM16) at the European Synchrotron Radiation Facility in Grenoble, France.

Foamed Cement Mitigates Gas Migration in Shallow Thermal Wells in Alberta

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214768, “Mitigating Gas Migration Using Foamed Cement on Shallow Thermal Wells in Northeast Alberta,” by Charles Sylvestre, SPE, Sanjel Energy Services; Julio Oliveira, Suncor Energy; and Heyong Jiao, Sanjel Energy Services. The paper has not been peer reviewed. _ A foamed cement solution was designed and implemented to cement shallow intermediate casing strings in a heavy oil play in northeast Alberta after conventional area-specific cementing solutions could not prevent surface casing vent flows. Foamed cement was pursued as a better alternative technical solution and ultimately led to its successful placement in the field. Significant technical and operational hurdles were overcome to confirm proper well control and ensure that the energized cement could be pumped safely and effectively. Introduction MacKay River is Alberta’s shallowest steam-assisted gravity drainage (SAGD) project, with wells typically ranging between 100 m and 150 m true vertical depth (TVD). Wells have been drilled recently at MacKay River with a horizontal length approaching 1000 m and total length exceeding 1500 m measured depth (MD). Wells at MacKay River are drilled using a slant rig because of the extremely shallow depth of the reservoir. The wells feature a three-string casing design with a shallow surface casing, an intermediate casing that runs from surface to the target formation and is landed at 90° inclination, and a horizontal production (or injection) liner hung off the intermediate casing. The intermediate casing is cemented in place and uses premium connections incorporating a metal-to-metal seal to provide a barrier between wellbore fluids and the formations overlying the reservoir. The complete paper discusses a new pad at the MacKay River SAGD operating site. The specific operations discussed are those involving intermediate cementing. Case-Well Challenges One of the most unusual features of the case wells was the discovery of gas trapped under a shallow formation at approximately 80–100 m vertical depth. The pad adjacent to this new pad has been in operation for 17 years. The second obstacle was the hole and casing size, which creates a large annulus. The open hole size was designed at 374.7 mm with the intermediate casing sized at 298.5 mm. This creates an annular gap of 38.1 mm in a gauge hole, but typically these wells require 150% cement excess to achieve cement returns to surface, meaning that, in certain areas of the well, the annulus is much larger. The next challenge presented by the case wells is that they are slanted wells, spudded at an angle of approximately 45° from the surface. The low temperature of these wells also adds to the complexity of preventing gas flow. At such low temperatures, cement sets much slower than in other well types. Finally, the shallow nature of the well, landing at only 113 m vertical depth, does not allow effective hydrostatic pressure control while the cement sets.

Influence of rheological parameters on the performance of the aerated coaxial mixer containing a pseudoplastic fluid

Gas dispersion in non-Newtonian fluids has numerous applications in many chemical and biochemical applications. However, the effect of the power-law model constants describing the rheological behavior of the pseudoplastic fluid has never been investigated. Thus, a numerical model was developed to simulate the hydrodynamics of gas dispersion in non-Newtonian fluids with a coaxial mixer. Then, a set of experiments was conducted to assess the mass transfer efficacy of a coaxial mixer to benchmark the numerical model. In this regard, various methods, including dynamic gassing-in and electrical resistance tomography methods, were used to quantify the mass transfer and gas hold-up profiles. The influence of fluid rheological properties, gas flow number, and rotating mode on the power consumption, mass transfer coefficient, bubble size profile, and hydrodynamics were examined both experimentally and numerically. The response surface model (RSM) was employed to explore the individual effects of power-law model constants on mass transfer. The RSM model utilized five levels for the consistency index (k), five levels for the flow index (n), and three levels for the gas flow number. The statistical model proposed that the absolute model constants for the flow and consistency indices were 0.0012 and 0.0010, respectively, for the co-rotating mixer. Conversely, for the counter-rotating mixer, these constants were 0.0010 and 0.0013, respectively. Therefore, this study revealed that the co-rotating coaxial mixer was well-suited for dispersing gas within a fluid with high consistency. In contrast, the counter-rotating mixer proved effective in enhancing gas dispersion within a fluid with a lower flow index.

Living emission abolish filters (LEAFs) for methane mitigation: design and operation

As one of the most potent greenhouse gases, methane is a critical target for the near-term mitigation of global warming. Efficient, scalable, easy-to-implement, and robust mitigation technologies are urgently needed to assist in reaching methane abolishment. The goal of this research was to test the applicability of active, extremophilic methanotrophic cells as a baseline concept for engineered systems aiming at methane capturing. The system, named living emission abolish filters (LEAFs), represents an array of immobilized biomaterials capable of capturing methane directly from vent streams. The biomaterials were made using cells of Methylotuvimicrobium alcaliphilum 20ZR, a robust halophilic methanotrophic bacterium with the ability to consume methane gas at low concentrations. Several critical parameters were tested, including (i) the composition of the matrix and optimal immobilization to increase catalyst load, (ii) the stability of methanotrophic cells, and (iii) the toxicity of trace gases (i.e. CO). We found that hydrogels coated with 2.3 mg cell dry weight/cm3 methanotrophic cells represent the best-performing biomaterials. The methane reduction potential of LEAFs fluctuated from 20% to 95% and depended on the methane concentration in the gas stream and the stream flow rates. The potential for commercial-scale deployment and emissions reductions was also evaluated. Total greenhouse gas emissions (combined using the global warming potential GWP100) from an example using a ventilation air methane source over a one-year period was shown to be reduced in two LEAF scenarios by 51% and 75%. Over longer time horizons, more significant reductions are possible as consistent methane consumption can be sustained. The study highlights the overall potential of the liquid-free bio-based composite methane mitigation system. Further improvements essential for system assembly and implementations should include (a) optimization of the cell immobilization protocols to improve cell load and the shelf-life of the system and (b) implementation of matrix moldings for cell immobilization to achieve optimal gas flow and increase the cell-gas interface.

Effect of near-wall distance on velocity slip and temperature jump conditions in hypersonic rarefied gas flows

In nonequilibrium slip and jump conditions, normal gas velocity and temperature gradients are used to calculate the gas slip velocity and temperature at the surface, respectively. Gökçen et al. (Computational fluid dynamics near the continuum limit, AIAA Paper No. 87-1115, 1987, and Gökçen and MacCormack, Nonequilibrium effects for hypersonic transitional flows using continuum approach, AIAA Paper No. 89-0461, 1989) stated that the tangential velocity and temperature of the gas molecules before a collision with the surface could be interpreted as the macroscopic tangential velocity and temperature of the gas molecules at the so-called near-wall distances auλ and aTλT away from the surface, respectively. The coefficients au and aT are the order of unity. In the present work, new forms of the slip and jump conditions are proposed by modifying the Gökçen slip and jump conditions to include the coefficients (au, aT). Numerical investigations are comprehensively conducted to determine the numerically proper values (au, aT) for the hypersonic rarefied gas flows. Cases such as the circular cylinder in cross-flow and sharp and blunted leading edge wedge are considered in the present work, with nitrogen as the working gas. The simulation results show the significant effects of the coefficients (au, aT) on the accuracy of the slip velocity and surface gas temperature predictions, and the values of au = 1.2 and aT = 1.1 show good agreement with the direct simulation Monte Carlo data.

Thin-airfoil aerodynamics in a rarefied gas wind tunnel: A theoretical study

We study the steady aerodynamic field and loadings about a thin flat plate placed in a wind tunnel under non-continuum conditions. Considering a two-dimensional straight tunnel configuration, the flow is driven by either density or temperature differences between the inlet and outlet tunnel reservoirs, producing a pressure gradient across the channel. Focusing on highly rarefied conditions, we derive a semi-analytic description for the gas flow field in the free-molecular limit for diffuse- and specular-wall configurations. The solution is valid at arbitrary differences between the inlet and outlet reservoirs as well as plate angles of attack α. The results are compared with direct simulation Monte Carlo calculations, indicating that the free-molecular description is valid through O(1) plate-size-based Knudsen numbers. The aerodynamic lift and drag forces are evaluated and their variations with α, reservoir conditions, and tunnel size are analyzed. At a fixed pressure ratio between the outlet and inlet reservoirs, the density-driven flow generates higher aerodynamic loads compared with its counterpart temperature-driven configuration, in line with the associated larger mass flow rate in the former. The results are discussed in light of the existing rarefied-gas description of the free-stream (non-confined) problem.

Dry Downhill Particle Motion on Mars

We recently flew a new setup on parabolic flights for the first time to study particle motion on Martian slopes under Martian gravity. Here, we describe the initial experiments. We used dust/sand beds at varying ambient pressure of a few hundred pascals. The inclination of the particle bed was varied from 0° to 45° and parts of the surface were illuminated under varying conditions. We could observe downhill motion of material related to the insolation at the lowest light flux used of 591 ± 11 W m−2 for JSC Martian simulant. Motion occurred at significantly lower inclinations under illumination than without illumination, i.e., down to about 10° compared to about 20°–30°, respectively. We attribute this reduction in slope to thermal creep gas flow in the subsoil. This induces a Knudsen compressor, which supports grains against gravity and leads to smaller angles of repose. This is applicable to recurring slope lineae and slopes on Mars in general.

Wasserstein-penalized Entropy closure: A use case for stochastic particle methods

We introduce a framework for generating samples of a distribution given a finite number of its moments, targeted at particle-based solutions of kinetic equations and rarefied gas flow simulations. Our model, referred to as the Wasserstein-Entropy distribution (WE), couples a physically-motivated Wasserstein penalty term to the traditional maximum-entropy distribution (MED) function, which serves to regularize the latter. The penalty term becomes negligible near the local equilibrium, reducing the proposed model to the MED, known to reproduce the hydrodynamic limit. However, in contrast to the standard MED, the proposed WE closure can cover the entire physically realizable moment space, including the so-called Junk line. We also propose an efficient Monte Carlo algorithm for generating samples of the unknown distribution which is expected to outperform traditional non-linear optimization approaches used to solve the MED problem. Numerical tests demonstrate that given moments up to the heat flux—that is, information equivalent to that contained in the Chapman-Enskog distribution—the proposed methodology provides a reliable closure in the collision-dominated and early transition regimes. Applications to greater rarefaction demand information from higher-order moments, which can be incorporated within the proposed closure.

Magnetron sputtering thruster operated with a compact gas feeding system using double pulsed valves

A continuous injection of gaseous water propellant into a magnetron-type sputtering propulsion device is performed in a pseudo manner by using a combination of two high-speed solenoid-type pulsed valves and a low-pressure gas reservoir . The gas injection system provides a temporally averaged gas flow rate of about 5–10 sccm with adjustment of the repetition frequencies of the pulsed valves, while the previously used single valve system attached to a liquid water tank has caused excessive gas injection. A discharge is sustained by a high voltage dc power supply; the discharge current has pulsation synchronized with the pulsed valve repetition. A temporally averaged force induced by the magnetron sputtering thruster and exerted on a pendulum plate downstream of the thruster is measured; the results are in good agreement with the previously reported force measurement under precisely controlled gas flow rate using a commercial mass flow controller. Therefore, the precise control of the gaseous water propellant with the compact gas feeding system is achieved, while maintaining a similar thruster performance to that with the mass flow controller.

Simulation of low-current DC discharges in longitudinal flows of atmospheric-pressure air

Characteristics of low-current stationary axially symmetric discharges in longitudinal laminar flows of atmospheric-pressure air calculated in the framework of a two-dimensional model are presented. Non-equilibrium discharge regimes, in the current range from 1 to 100 mA, are considered for gas flow velocities up to 50 m s−1. It is shown that variation of the flow velocity substantially affects the discharge characteristics, such as the width of discharge column, the electric field inside the gap, the current density etc. Validity of the obtained results is confirmed by their comparison with available experimental data.

Deposition and structural investigation of uniform AlN(100) films at wafer scale through RF magnetron sputtering

a-axis-oriented AlN(100) films are identified as promising candidates for surface acoustic wave devices owing to their high transversal-acoustic velocity. Achieving uniform films across a wafer scale is crucial for enhancing device performance and minimizing manufacturing costs. In this study, we employ radio-frequency magnetron sputtering to deposit AlN(100) films on 2-in Si(100) wafers. We further examine the influence of various process parameters on the nonuniformity of film thickness and structural properties, including crystallite size, microstrain, and dislocation density. The optimization of parameters leads to the selection of a gas flow ratio of N2:Ar = 4:7, a sputtering power of 160 W, and a substrate temperature of 350 °C. Under these optimized conditions, the AlN films not only demonstrate a preferred (100) orientation and remarkable crystallinity, as indicated by a full width at half maximum of the X-ray diffraction peak of just 0.03°, but also achieve an optimal film thickness nonuniformity of 1.66 %. Our results offer valuable insights for the wafer-scale fabrication of AlN(100) films, potentially enhancing industrial production yields and reducing costs.

Comparison of methanol and ethylene glycol effectiveness as chemical inhibitors in the prevention of gas hydrates in well testing barge DT-05 well Z Mahakam field

Gas hydrate is one of the production problems that are often encountered in the management of natural gas wells. Well Z is a natural gas well in the Mahakam field which routinely be tested periodically to determine the ability of flow rate and the production parameters using well testing barge. However, there are often for the formation of gas hydrate formed in several test components in well testing barge. This study aims to determine the effectiveness use of 2 inhibitor chemicals, which are methanol and glycol in handling gas hydrate in the testing barge. Natural gas flow originating from wellhead / upstream 5 MMScfd and temperature 122 °F and the operating pressure 2187 psia. From the simulation results, gas hydrate will form at 46.33 °F and it is obtained that the gas hydrate formation was predicted at the choke manifold. Fluid stream passing through the choke manifold had decreased the pressure into 254 psi and there is also a decrease in temperature from 122 °F to 41.88 °F. Methanol injection develops free of potential hydrates to form in flowlines. The temperature at which hydrates are formed changes to 33.88 °F. In the other hand, after Ethylene glycol injection in flowline, hydrates formation temperature dropped to 0.48 °F. From these results it can be resumed that the application of Ethylene Glycol injection on the process is more effective lowering the temperature of the formation of hydrates in well testing barge.