Thin Zone Research Articles

A Numerical Investigation on Effects of Hydrogen Enrichment and Turbulence on NO Formation Pathways in Premixed Ammonia/Air Flames

ABSTRACT NO x emission reduction is one of the major challenges when using ammonia/hydrogen blends as an alternative fuel for carbon-free combustion. In this study, chemical reaction pathways of NO formation in planar premixed flames of stoichiometric ammonia/hydrogen/air at atmospheric pressure and reactants temperature of 298 K are investigated under laminar and decaying turbulent conditions using quasi-DNS with detailed chemistry and the mixture-averaged transport model. The sweep parameter, , is the volumetric ratio of hydrogen to the ammonia/hydrogen mixture. Here, for unstrained laminar conditions, = 0, 0.4, and 0.6 and for turbulent condition, = 0.4 within the thin reaction zones region ( 34.2) are studied. Under 1D laminar conditions, increasing enhances NO formation drastically, around 3 times when comparing = 0 and 0.6. At different , despite the high activity of the reactions which belong to the Zeldovich pathway, the contribution of this pathway is insignificant in NO formation. However, HNO and N2O pathways have the most significant roles. For instance, at = 0.4, R85 (NH+NO N2O+H) in the N2O pathway and R144 (HNO+H NO+H2) in the HNO pathway have major roles in NO formation. Higher NO formation at larger is found to be due to the increased H and O radicals within the reaction zone as well as the increased reaction rates because of the higher flame temperature. Under the 3D turbulent condition ( = 0.4), it is observed that turbulence does not switch the pathways trends across the flame brush compared to the laminar condition. In the reaction zone, however, it is observed that NO formation is lower (higher) in the regions convex (concave) toward the reactants. The underlying reason for this effect is the preferential diffusion of H2 to the regions of the flame front convex toward the reactants, which consumes NO and also depletes O and OH radicals, which are necessary for NO formation.

Seismogeological model of the terrigenous vendian deposits on the north–eastern slope of the Nepa-Botuoba anteclise

A seismogeological model of the junction zone of the Nepa-Botuoba anteclise and the Ygyattinskaya depression was built based on the results of a comprehensive interpretation of deep drilling and seismic data. The position and propagation of regional high-rank faults have been specified, and a model of tectonic faults of the study area has been constructed. All faults of the study area were divided into three classes: those that cut the entire sedimentary cover; developed in the lower part of the sedimentary section, fading in the Cambrian salt pack; complicating the upper post-salt complex of rocks. Criteria for identifying thinning zones were developed and were made use of to identify oil and gas perspective objects within the Talakh, Ulakhan and Kharystan productive horizons.

Antipodal waveform observations of seismic waves diffracting and refracting at the base of Earth's outer core

We approach this analysis of the inner-outer core boundary (IOCB) with antipodal waveform data in the distance range 179.0°–180° to test the hypothesis whether propagation at the base of the outer core is commensurate with diffraction and/or refraction. The propagation paths observed cover about two-thirds of the IOCB surface. Seismic data from seven diameters are examined—Tonga to Algeria (station code TAM), Sulawesi to Amazon (PTGA), northern Chile to Hainan Island (QIZ), two between central Chile and the mainland China (XAN, ENH), and two diameters from New Zealand to both Portugal (PTO) and Spain (ECAL). The adequacy of global Earth models—both 1-D and 1-D core +3D mantle—in fitting the antipodal observations is found to be deficient. Lateral heterogeneity among the propagation paths are mapped and projected to the Earth's surface for context. We stack data to increase signal-to-noise, and model waveform data via the 3D spectral element method on the EarthSimulator4. With the exception of one path to ENH China, none of the global Earth models match amplitudes of diffracted waves or the stacked amplitudes relative to PKIKP, which travels along the antipodal diameter. Energetic arrivals observed in the waveform data set are modeled as a combination of refraction within a low velocity zone (LVZ) at the base of the outer core, and diffraction around this structure. The observations at the base of the outer core may be further subdivided between paths with a thin low velocity zone (QIZ, XAN, PTGA), and those with a thicker, slower LVZ (TAM). The former paths are characterized by a thin LVZ (20–50 km thick, layer–gradient, respectively) with a velocity of approximately 10.0 km/s. The second group of paths shows large amplitude, complicated waveforms for TAM, corroborated by data from PTO and ECAL. TAM waveforms are modeled with a negative gradient from 100 to 50–75 km thickness above the IOCB, to a basal velocity of 8.8 km/s at IOCB. We also modeled the prospect of non-zero rigidity at the bottom of the outer core, but found no evidence of sensitivity in the core data. The structures fitting the data correlate across the inner–outer core boundary, with a velocity anomaly in PKPbc data juxtaposed immediately above the TAM path beneath SE Asia. More generally, the TAM IOCB path when projected up to the core-mantle boundary (CMB) apparently aligns with regions between the large low shear velocity provinces (LLSVP) at the CMB. Other paths with thinner or negligible LVZ at the IOCB partially underlie the LLSVP when projected to the CMB.

The True History of Cementoblastoma.

Cementoblastoma (CB) is unique among odontogenic tumors because its gross pathological anatomy is pathognomonic in most cases, i.e., a rounded calcified growth that is fused to the root of a tooth and completely encapsulated by fibrous tissue. The resulting radiographic appearance is a well-defined, globular mixed radiopaque/lucent or completely radiopaque mass obliterating some details of the root, with a thin radiolucent zone surrounding the central opacity. Although hundreds of publications have covered the clinicopathologic features of CB, almost nothing is known about its true history. Also it seems there is little understanding about how the term "CB" was originally introduced as a pathologic entity. This report covers some overlooked papers on CB dating back to the 19th century, including the first complete description in 1888 and the first radiographic presentation in 1906.

Numerical and Experimental Study on Flame Dynamics of the Premixed Methane-Air Mixture at Different Ignition Positions in a Two-Side 45° Branch Tube.

The combustion characteristics of premixed methane-air flames in a half-open tube with a two-sided 45° branch structure at different ignition positions were investigated by experiments and large eddy simulations. The numerical results were compared with the experimental results to verify the correctness of the model. The results show that the simulation results are highly consistent with the experiment. This study provides a basic understanding of the effects of the branch tube structure and the ignition position on flame dynamics. When the flame propagates to the branch interface, it forms a symmetrical vortex structure at the branch tube with the opposite rotation direction. When the ignition position is at IP0 and IP900, the maximum overpressures obtained in the experiment are 10.1 and 10.7 kPa, respectively, and 9.2 and 10.4 kPa in the simulation, respectively. At IP0, the Karlovitz number indicating the interaction intensity between the flame surface and the turbulence during flame propagation is a maximum of 9.2 and a minimum of 0.04. The premixed flame has a folded small flame, a corrugated small flame, and a thin reaction zone.

Chemical strengthening behavior of a glass substrate having locally different thickness

To understand the effect of chemical strengthening process on irregular geometry, a partially thinned glass substrate was strengthened according to the ion-exchange conditions, and the strengthening properties and the dimensional changes of the partially thinned glass were analyzed using a surface stress meter and a 3-dimensional analyzer. The results revealed that the compressive stress (CS) measured at a thin area of the glass substrate having different thicknesses was affected by the CS of a thick zone, and consequentially the CS of the thin zone was bigger than that measured at a same thickness glass. It was also found that the dimensional changes across the thin zone after chemical strengthening were relatively big, and as a result, it caused a physical deformation on the thin area due to the interference in the thick area.

The impact of N2 micro-jets on the V-to-M flame shape transition in a premixed swirl burner

Injection of N2 through micro-jets located on the dump plane of a lean premixed swirl stabilized combustor is investigated as a new method for mitigating combustion instabilities. This study focuses on the chemical and fluid dynamic processes by which the N2 micro-jets impact the flame dynamics. An experimental and numerical investigation is performed to characterize the combustion instability during the V-to-M flame shape transition in a swirl burner fueled with premixed CH4/air, at an equivalence ratio of 0.62. Reasonable agreements have been found between the experimental measurements and simulation results. Both of them present that the flame changes from V-shape to M-shape periodically, and a low-frequency instability around 10 Hz is observed accordingly. It is confirmed that intermittent flame extinction in the outer recirculation zone (ORZ) is the source of the combustion instability. Furthermore, injection of N2 through micro-jets located on the combustor dump plane, into the outer recirculation zone, results in a stable V shape flame. It is clearly seen that the ORZ dilution can eliminate the combustion instability without inhibiting the combustion efficiency. A special focus is placed on the impact of the diluent injection on the local flame-flow interaction. The nitrogen micro-jets increase the local nitrogen concentration by 7% on average, lowering the flame speed and extinction strain rates by 27% and 17% respectively. Moreover, the micro-jets increase the turbulence intensity in the ORZ, leading to a significant increase in the Karlovitz number and transferring the local combustion regime from the thin reaction zone regime to the broken reaction zone regime. Hence, the nitrogen micro-jets impact on both the turbulence and the chemical reaction rates prevents flame propagation into the ORZ and results in a stable flame.

Study on parameters limit of fracturing optimization process for thin and differential zone oil Wells

The potential target of water flooding measures has gradually changed to thin differential reservoir in three types of reservoirs. The fracturing proportion of thin differential reservoir in water flooding block oil well has reached more than 60%, and the existing fracturing design code can not fully meet the needs of thin differential reservoir fracturing. Through the effect evaluation of the technical parameters matching different types of thin differential reservoir, the field test is carried out to establish the limit of the optimal technological parameters for fracturing of thin differential reservoir oil well, which is of great significance for improving the fracturing effect and improving the technical level of fracturing in the future oilfield.

Research on hydroforming of 5A06 aluminum alloy semi-ellipsoid shell with differential thickness

For the purpose of eliminating the annular welding seams in welding structures with differential thickness, a hydroforming method using a circular 5A06 aluminum alloy plate with a radial differential thickness in coupling with a flexible polyurethane auxiliary plate was proposed to form an integrated semi-ellipsoid shell. The circular 5A06 aluminum alloy plate had a smaller in the middle and a larger thickness in the periphery. In the forming process of such aluminum alloy plates, concentrated deformation and fracture might have occurred in the thin zone. According to the size of the target specimen, the testing plates with two types of thickness ratios were obtained by mechanical processing. Furthermore, the thickness and strain of the drawn specimens with different thickness ratios were analyzed under different hydraulic pressure by means of deep drawing experiments. Compared to the conventional deep drawing, the formability of 5A06 aluminum alloy plates with differential thickness could be effectively improved by hydroforming. The integrated semi-ellipsoid shells with the thickness ratios of 2/3 and 1/2 were obtained under the hydraulic pressure of 10 MPa with maximum thinning ratios of 8.5% and 10.9%, respectively. In a word, the increase in hydraulic pressure could effectively reduce the maximum thinning ratio in the thin zone, and improve the thickness distribution uniformity.

Modelling a Turbulent Non-Premixed Combustion in a Full-Scale Rotary Cement Kiln Using reactingFoam

No alternatives are currently available to operate industrial furnaces, except for hydrocarbon fuels. Plant managers, therefore, face at least two challenges. First, environmental legislation demands emission reduction. Second, changes in the origin of the fuel might cause unforeseen changes in the heat release. This paper develops the hypothesis for the detailed control of the combustion process using computational fluid dynamic models. A full-scale mock-up of a rotary cement kiln is selected as a case study. The kiln is fired by the non-premixed combustion of Dutch natural gas. The gas is injected at Mach 0.6 via a multi-nozzle burner located at the outlet of an axially mounted fuel pipe. The preheated combustion air is fed in (co-flow) through a rectangular inlet situated above the attachment of the fuel pipe. The multi-jet nozzle burner enhances the entrainment of the air in the fuel jet. A diffusion flame is formed by thin reaction zones where the fuel and oxidizer meet. The heat formed is transported through the freeboard, mainly via radiation in a participating medium. This turbulent combustion process is modeled using unsteady Favre-averaged compressible Navier–Stokes equations. The standard k-ϵ equations and standard wall functions close the turbulent flow description. The eddy dissipation concept model is used to describe the combustion process. Here, only the presence of methane in the composition of the fuel is accounted for. Furthermore, the single-step reaction mechanism is chosen. The heat released radiates throughout the freeboard space. This process is described using a P1-radiation model with a constant thermal absorption coefficient. The flow, combustion, and radiative heat transfer are solved numerically using the OpenFoam simulation software. The equations for flow, combustion, and radiant heat transfer are discretized on a mesh locally refined near the burner outlet and solved numerically using the OpenFoam simulation software. The main results are as follows. The meticulously crafted mesh combined with the outlet condition that avoids pressure reflections cause the solver to converge in a stable manner. Predictions for velocity, pressure, temperature, and species distribution are now closer to manufacturing conditions. Computed temperate and species values are key to deducing the flame length and shape. The radiative heat flux to the wall peaks at the tip of the flame. This should allow us to measure the flame length indirectly from exterior wall temperature values. The amount of thermal nitric oxide formed in the flame is quantified. The main implication of this study is that the numerical model developed in this paper reveals valuable information on the combustion process in the kiln that otherwise would not be available. This information can be used to increase fuel efficiency, reduce spurious peak temperatures, and reduce pollutant emissions. The impact of the unsteady nature of the flow on the chemical species concentration and temperature distribution is illustrated in an accompanying video.

Emplacement dynamics of a crystal-rich, highly viscous trachytic flow of the Sancy stratovolcano, France

Emplacement dynamics of highly viscous, silicic lava flows remain poorly constrained due to a lack of consideration of crystal-rich cases. Emplacement models mostly apply to glassy or microlitic, vesiculated rhyolitic flows. However, crystalline, vesicle-free silicic lava can flow differently. We studied the Grande Cascade unit, which is a vesicle-free, phenocryst-rich, trachytic flow in the Monts Dore massif, France. Field work was carried out to define internal structures, and oriented samples were collected for chemical, petrological, and anisotropy of magnetic susceptibility analyses, allowing us to estimate emplacement temperature and viscosity. These data allow us to define a new silicic lava flow subtype that is low in temperature (800−900 °C), high in silica content (up to 66.8 wt%), high in viscosity (109−1011 Pa s), rich in phenocrysts (∼35%), and lacks vesicles. Brittle deformation of the lava occurs upon extrusion, generating a cataclasite basal layer and thin (3-m-thick) shear zone that accommodates all of the stress, allowing most of the flow’s volume to slide over its base as a 40-m-thick plug in which there is no deformation. Blocks are rare, of a single size (10 ± 1 cm), and result from localized break-up of the basal shear zone. Emplacement dynamics are different from those of glassy, pumiceous lava flows. They are closer to glacier dynamics, where most of the volume slides over a thin basal shear zone and till is generated there by abrasion and milling of the underlying layer. For the Grande Cascade lava flow, abrasion means that the flow lacks its classical blocky crust and instead the flow base is marked by a layer rich in fine-grained material. The structures and emplacement dynamics of this crystal-rich flow are consistent with ideal, gravity-driven shear flow. We thus argue for a global reassessment of silicic-rich lava emplacement based on crystal content and using a multidisciplinary approach focused on well-exposed examples in the rock record.

Enigmatic crustal and upper mantle structure in the NE Sino-Korean Craton based on nuclear explosion seismic data

We interpret the crustal and upper mantle structure along ∼2500 km long seismic profiles in the northeastern part of the Sino-Korean Craton (SKC). The seismic data with high signal-to-noise ratio were acquired with a nuclear explosion in North Korea as source. Seismic sections show several phases including Moho reflections (PmP) and their surface multiple (PmPPmP), upper mantle refractions (P), primary reflections (PxP, PL, P410), exceptionally strong multiple reflections from the Moho (PmPPxP), and upper mantle scattering phases, which we model by ray-tracing and synthetic seismograms for a 1-D fine-scale velocity model. The observations require a thin crust (30 km) with a very low average crustal velocity (ca. 6.15 km/s) and exceptionally strong velocity contrast at the Moho discontinuity, which can be explained by a thin Moho transition zone (< 5 km thick) with strong horizontal anisotropy. We speculate that this anisotropy was induced by lower crustal flow during delamination dripping. An intra-lithospheric discontinuity (ILD) at ∼75 km depth with positive velocity contrast is probably caused by the phase transformation from spinel to garnet. Delayed first arrivals followed by a long wave train of scattered phases of up to 4 s duration are observed in the 800–1300 km offset range, which are modelled by continuous stochastic velocity fluctuations in a low-velocity zone (LVZ) below the Mid-Lithospheric Discontinuity (MLD) between 120 and 190 km depth. The average velocity of this LVZ is about 8.05 km/s, which is much lower than the IASP91 standard model. This LVZ is most likely caused by rocks which are either partially molten or close to the solidus, which explains both low velocity and the heterogeneous structure.

Performance and Economic Evaluation of Low-Lignin Alfalfa ‘Hi-Gest® 360’ in Saskatchewan Canada

A three-year (2018–2020) study was conducted in Lanigan (Thin Black soil zone) and Saskatoon (Dark Brown soil zone), SK Canada to compare low-lignin alfalfa (Medicago sativa) cv. Hi-Gest® 360 (HiGest) with alfalfa- cv. AC Grazeland (Grazeland) in monoculture and binary mixtures with hybrid bromegrass (HBG; cv. AC Success) for forage yield, nutrient profile, and establishment costs. Field plots were seeded in August 2017. Stands were harvested at three maturity stages of alfalfa (1 = 10% bloom; 2 = 40% bloom; and 3 = 100% bloom). Compared to Grazeland, HiGest alfalfa yielded 25% less in Saskatoon in monoculture, but no difference was found in Lanigan. Averaged across two sites, HiGest had 8.6% less acid detergent lignin (6.51 vs. 5.95%) and 10.3% greater in vitro neutral detergent fiber digestibility (42.7 vs. 38.7% of neutral detergent fiber). In the binary mixtures, however, differences in yield and quality between the two alfalfas were negligible. The stand establishment costs averaged 300 Canadian dollar (CAD) ha−1, 205 CAD ha−1, 260 CAD ha−1, and 303 CAD ha−1 for HiGest, Grazeland, Grazeland-HBG, and HiGest-HBG, respectively. Hi-Gest® 360 alfalfa could provide higher digestible nutrients when it was used as a monoculture and could maintain quality better into later maturing stages. However, the higher seed price, and no actual advantage in mixtures may delay its adoption.

Effect of rolling reduction on the microstructure of the copper/aluminum composite strip produced by micro flexible rolling

Copper/aluminum (Cu/Al) laminated composite has been extensively applied in the fields of batteries, electronics and electrochemistry owing to its cost reduction, light weight, good conductivity and resistance to corrosion. The Cu/Al composite strips produced by micro flexible rolling consist of three regions based on different thickness, i.e. the thicker, the transition and the thinner zones, and have a broad application prospect, especially in micro-electromechanical systems (MEMS). In this study, the effect of rolling reduction on the coordinated deformation of the Cu/Al interface and the microstructure of Cu/Al matrixes at three regions were investigated. The microstructure of the specimens was characterized using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and the thickness of thin strips with varying thickness (TSVT) were measured by laser scanning microscope to explore the mechanism of microstructural evolution. The results show that the increase of rolling reduction gives a rise to the proportion of deformation occurred in the Al matrix, and the fracture of the intermetallic compounds (IMCs) is observed at the interface, which plays a significant role of transmitting and releasing stress during plastic deformation.

PARAFOVEAL INNER RETINAL THINNING AS THE BIOMARKER PREDICTING LESS RECURRENCE OF MACULAR EDEMA IN CENTRAL RETINAL VEIN OCCLUSION AFTER DISCONTINUING ANTIVASCULAR ENDOTHELIAL GROWTH FACTOR.

To identify the predictive factors for the recurrence of macular edema after the cessation of antivascular endothelial growth factor treatment in eyes with central retinal vein occlusion (CRVO). This retrospective study included participants who had discontinued intravitreal bevacizumab injections for complete resolution of macular edema related to CRVO at 3 months after the last injection. Fifty-two eyes were enrolled in this study and classified into two groups based on the recurrence of macular edema within 1 year after the stopping point, when the decision to discontinue injections was made. Clinical characteristics and optical coherence tomographic parameters at baseline and at the stopping point were investigated. Multivariate logistic regression analysis demonstrated that, at baseline, old age was associated with a significantly higher risk of macular edema recurrence (odds ratio, 1.092; P = 0.022). At the stopping point, parafoveal inner retinal thickness (odds ratio: 1.043, P = 0.014) and the presence of ellipsoid zone disruption (odds ratio: 5.922, P = 0.032) were predictive factors for recurrence. The receiver operating characteristic curve showed that parafoveal inner retinal thinning of >7 µm compared with that in the fellow eye was significantly associated with decreased recurrence of macular edema. Parafoveal inner retinal thinning and intact ellipsoid zone after resolution of macular edema by antivascular endothelial growth factor treatment were predictive of a lower risk of recurrence of macular edema in CRVO. These intuitive biomarkers may help predict future disease courses and design optimal treatment strategies.

Development of ultra-high-performance concrete with low environmental impact integrated with metakaolin and industrial wastes

Industrial waste contributes to serious environmental issues. However, these issues can be solved by utilizing them as building materials. This paper investigated the effects of substituting the cement with a variety of industrial wastes and metakaolin (MK) on ultra-high-performance concrete (UHPC) properties. The industrial wastes used in this study include silica fume (SF), granulated blast-furnace slag (GGBS), and fly ash (FA). The prepared mixtures were created by varying the amounts of Portland cement, GGBS (30–50%), FA (20–30%), or MK (15–25%), while maintaining a constant amount of SF of 15%. The mechanical, durability, and micro-structural characteristics of the mixtures were investigated. This study also uses life cycle assessment to estimate the reductions in embodied energy consumption, life cycle cost, and carbon footprint associated with integrating metakaolin and industrial waste. The results indicated that the inclusion of 15%MK led to an increase in the compressive, flexural, and splitting tensile strengths. Also, the chloride permeability resistance was enhanced. The mechanical properties and chloride-ion permeability resistance of the ternary mixtures with 50%GGBS and 25%MK were the lowest compared to other mixtures. These results were supported by SEM micrographs and EDX analysis for the UHPC structure, which demonstrate the high-density microstructure and extremely thin interfacial transition zone thickness. The inclusion of industrial waste and metakaolin can lower environmental impact of UHPC without compromising the mechanical performance. Also, the environmental assessment shows that the UHPC containing industrial waste has a lower impact on the environment, which means they could make cleaner products in the near future.

Effects of body force on the statistical behaviour and modelling of scalar variance in turbulent premixed flames

The effects of body force/external pressure gradient on the statistical behaviours of the reaction progress variable variance and the terms of its transport equation have been investigated for different turbulence intensities using DNS data of statistically planar flames. Since the extent of flame wrinkling increases with the strengthening of body force promoting unstable stratification, the scalar variance has been found to decrease under strong body force promoting stability. This trend is particularly strong for low turbulence intensities where the probability density function of the reaction progress variable cannot be approximated by a bimodal distribution. Therefore, an algebraic relation for the reaction progress variable variance, derived based on a presumed bimodal probability density function of reaction progress variable, cannot be used for general flow conditions. The contributions of chemical reaction and scalar dissipation rates in the scalar variance transport equation remain leading order source and sink, respectively for all cases irrespective of the strength and direction of the body force. The counter-gradient type transport is found to weaken with increasing body force magnitude when the body force is directed from the heavier unburned gas to the lighter burned gas side of the flame brush, and vice versa. Although a scalar dissipation rate-based reaction rate closure can be utilised to model the reaction rate contribution to the scalar variance transport accurately, the dissipation rate contribution due to the gradient of the Favre-averaged reaction progress variable cannot be ignored and it plays a key role for large magnitudes of body force promoting stable stratification. An algebraic closure of the scalar dissipation rate, originally proposed for high Damköhler number combustion, has been modified for the thin reaction zones regime combustion by incorporating the effects of Froude number. This model has been shown to predict the scalar dissipation rate accurately for all cases considered here.

Flame speed in diffusion dominated premixed flames

Development of a premixed flame theory that includes the effects of flame stretch and curvature has been at the forefront of combustion research. Diffusion dominated flames such as highly curved flame balls present a challenging flame structure that has not been included in current flame stretch theory so far. In such flames, the relationship between consumption speed and negative displacement speed usually marks the boundary of what flame stretch theory can predict. In this work, our objective is to derive a general formulation which naturally includes this relationship. We use flamelet equations derived using a mass based stretch rate and show that if the diffusion flux at the unburnt side is not ignored, as is normally done in flame stretch theory, a formulation that can describe the propagation of different types of premixed flames can be derived. Based on the thin reaction zone assumption, solutions from theory are verified against numerical results for 1D ideal flame balls. Further verification is done for multi-dimensional ball-like flames, where both convection and diffusion dominated regions are present for highly curved flames. It is shown that the extended theory is able to predict the flame kinematics in a better way by describing the diffusion dominated flame propagation as well.

The liquid film behaviors created by an inclined jet impinging on a vertical wall

Liquid films created by inclined jet-wall impingement are commonly seen in industrial applications. We investigated the liquid film behaviors created by an inclined jet impinging on a vertical glass wall using a brightness-based laser-induced fluorescence method. It was found that the typical liquid film by an inclined jet-wall impingement consists of the thin layer zone, the raised zone, the liquid node, and the trailing edge. The liquid film expands with higher impingement velocity but keeps the same elliptical shape. A normalized linear correlation is proposed to estimate the liquid film thickness. Based on the continuity equation and the empirical convection model, the Reynolds number distribution is deduced from the film thickness distribution. The Reynolds number in the thin layer zone is less than the critical Reynolds number. The surface waves in the thin layer zone are divided into the ripple waves and the disturbance waves. The disturbance waves have a larger wavelength and amplitude than the ripple waves. The quantitative measurement of the disturbance waves shows that the wavelength and amplitude increase linearly along the radial distance. The smaller impingement velocity does not change the growth rate of the wavelength but accelerates the development of the amplitude.

3-D quantitative seismic imaging of tectonically-influenced Middle-Eocene carbonates stratigraphic traps of SE-Asian basins using spectral decomposition: Implications for hydrocarbon exploration

Carbonates form energetic stratigraphic petroleum systems. The tectonic uplifting and subsidence significantly affect the overall reservoir configurations. During these stratigraphic scenarios, the prediction of accurate thickness for subsidence and uplifting zones becomes challenging. The band-limited seismic data interpretation tools fail to detect the zones of thinning and thickening of sediments along with uplifting and subsidence. The band-limited seismic does not have the tuning frequency, that can be used to predict the accurate vertical thickness of the thin-bedded carbonates. The constant wavelet-based transformation tool (WT) and inverted reservoir simulations have robust implications for the quantification of any depositional system. Especially, when the reservoir is shallow marine, the application of WT has resolved a variety of stratigraphic traps in terms of their seismic and sedimentological aspects. The stratigraphic traps are comprised of thin beds, which are not resolvable on conventional seismic. These traps require a specific tuning frequency, which is the key ingredient for the prediction of oil and gas inside them and can only be obtained by the implementation of the WT tool. Therefore, the WT, static stratigraphic thickening wedge models (SSTWM), and WT–based instantaneous spectral thickness modeling (ISTM) tools are applied on a gas field in Indus Basin, Pakistan. The 43-Hz CWT images the densely fractured and faulted network within the shoal reservoir limestone lenticular lens (SRLL) with an aerial extent of 208 km2 in southwest-northeast orientations. The band-limited attributes revealed poor imaging of sub-surface carbonate systems. The 43-Hz wavelet-based SSTWM predicts a 15-m-thick coarse-grained SRLL along subsidence and a 12-m-thick fine-grained SRLL along uplifting zones. Post-stack processing at 43-Hz CWT tuning frequency predicts the 18 and 10 m thick sediments for SRLL along the subsidence and uplifting zone. The ISTM predicts a thickness of 31 m during subsidence within the SRLL and 14 m for uplifting zones. The 43-Hz tuning frequency-based processing at ISTM predicts enhanced thicknesses of 41 and 18 m for subsiding and uplifting sediments that are trapped inside the shoal limestone petroleum systems. The quantitative visualization of AI with the predicted thicknesses at ISTM has provided robust clues for imaging the internal stratigraphic architecture of the SRLL. The linear regression analysis remained a very successful tool for assessing the quantitative aspects of SRLL with a strong R2 > 0.95, which has implicated the real-time imagining of sea-level fall and rise. Only post-stack seismic data processing at 43-Hz found a very effective exploration tactic in predicting the enhanced thicknesses, and lateral continuity of the reservoir, and improved the S/N by removing the tuning effect of ambiguous lithology/fluids, which have accurately predicted the exact location along the subsidence zones. This workflow can act as an analogue stratigraphic exploration of remaining gas fields within Asian Basins and similar geological settings.