Decrease In Flow Rate Research Articles

Possible Effects of Changes in Carbonate Concentration and River Flow Rate on Photochemical Reactions in Temperate Aquatic Environments.

In temperate environments, climate change could affect water pH by inducing enhanced dissolution of CaSO4 followed by biological sulphate reduction, with the potential to basify water due to H+ consumption. At the same time, increased atmospheric CO2 could enhance weathering of carbonate rocks (e.g., dolomite) and increase the total concentration of dissolved carbonate species. Both processes enhance phototransformation by the carbonate radical (CO3•-), as shown for the non-steroidal anti-inflammatory drug paracetamol, provided that the dissolved organic carbon of water does not undergo important fluctuations. Climate change could also affect hydrology, and prolonged drought periods might considerably decrease flow rates in rivers. This is a substantial problem because wastewater pollutants become less diluted and, as a result, can exert more harmful effects due to increased concentrations. At the same time, in low-flow conditions, water is also shallower and its flow velocity is decreased. Photochemical reactions become faster because shallow water is efficiently illuminated by sunlight, and they also have more time to occur because water takes longer to cover the same river stretch. As a result, photodegradation of contaminants is enhanced, which offsets lower dilution but only at a sufficient distance from the wastewater outlet; this is because photoreactions need time (which translates into space for a flowing river) to attenuate pollution.

A Temperature-Controlled Apparatus for Gas Permeability under Low Gas Pressure

The measurement of soil gas permeability is influenced by the temperature and pressure fluctuation in the low gas pressure region. In order to investigate these influences, a soil temperature-controlled apparatus connected to a low-gas-pressure supply equipment is proposed in this study. The low constant gas pressure is supplied by two Mariotte bottles, by which the airflow rate is measured. Meanwhile, the soil specimen is controlled by a temperature-controlled apparatus. During the test, the negative pore water pressure and volume change of the soil specimen are measured. Through the temperature-controlled apparatus, it is observed that as the temperature increases from 25 °C to 60 °C, there is a corresponding increase in soil sample porosity by 5.4%, while the negative pressure of pore water decreases by 11.1%. This can be attributed to the reduction in the surface tension of contractile skin caused by elevated temperatures. Furthermore, due to variations in gas viscosity with temperature, there was a significant decrease in the gas flow rate by 50.5%. And, the relationship between permeability and volumetric gas content at different temperatures in low-pressure regions well confirms the existing power-law model. In addition, the existence of a temperature-independent critical negative pore water pressure is observed, beyond which the intrinsic permeability remains constant. At 36 kPa of negative pore water pressure, the intrinsic permeability at 60 °C exhibits an 81.8% reduction compared to that at 25 °C. This decline in intrinsic permeability can be attributed to a diminished pore connectivity, resulting from elevated temperatures.

Thermal‒hydraulic‒mechanical‒chemical coupling analysis of enhanced geothermal systems based on an embedded discrete fracture model

Enhanced geothermal system (EGS) is subject to the comprehensive effects of multiple physical fields during the long-term heat extraction process, including hydraulic (H), thermal (T), mechanical (M) and chemical (C) fields. The embedded discrete fracture model (EDFM) can effectively simulate the variations of flow, temperature, mechanical and concentration fields in fractured reservoirs. At present, however, the thermo-hydro-mechanical-chemical (THMC) coupling model based on EDFM is less researched. In this paper, the THMC coupling model of fractured reservoir is established based on EDFM by considering the changes in reservoir heterogeneity and physical properties as well as water–rock reactions. Then, the spatiotemporal evolution of flow, temperature, displacement and concentration fields in the operation process of EGS is simulated and analyzed. And the following research results are obtained. First, when the permeability of the basement rock is low, the production temperature decrease during exploitation is gradual, allowing EGS to maintain a high exploitation temperature for an extended period. However, lower permeability may result in a decrease in the quality flow rate from production wells, thereby affecting net heat extraction power. Second, when fracture permeability or fracture opening changes, EGS can output higher temperature stably for a certain period and then the temperature decreases at different amplitudes. When the fracture permeability increases to a certain value or the fracture opening decreases to a certain value, the influence of the change in fracture parameters on production temperature gets weak. Third, After 40 years of EGS operation, considering variable property fluids results in a 22 °C lower exploitation temperature compared to using constant property fluids, and considering water–rock reactions results in a 15 °C lower exploitation temperature, with a 12.5 % increase in reservoir average porosity. In conclusion, when researching a long-term operating EGS, it is necessary to comprehensively consider the influences of reservoir rock parameters, physical properties of injected fluid, water–rock reaction and other factors. And in the future, attention shall be paid to the two-way coupling of chemical reaction and mechanical deformation of other mineral compositions in the reservoir to the hydro-thermo-chemical field influence, so as to provide more accurate and reliable prediction for the engineering development and utilization of EGS reservoirs.

Comparison of the Efficacy of Low Dose Tadalafil with Tamsulosin against Lower Urinary Tract Symptoms and Sexual Dysfunction after Low Dose Rate Prostate Brachytherapy.

Patients with clinically localized prostate cancer (PCa) can be curatively treated with different modalities, including low dose rate (LDR) prostate brachytherapy (PB). LDR-PB allows the patient a relatively short recovery time compared with other treatment modalities such as prostatectomy. However, PB might exert distinct impact on quality of life, lower urinary tract symptoms (LUTS) and sexual dysfunction (SD) are two major concerns. The aim of present study was to assess prospectively the efficacy of low dose tadalafil treatment on both SD and LUTS compared with tamsulosin treatment in patients treated PB for localized PCa. Patients scheduled for PB with I-125 seeds for low or intermediate-risk localized PCa at our institution were eligible for this study. The prescribed dose was set at 160 gray. Participants were randomized into two groups; those started treating with a daily use of 0.2 mg of tamsulosin hydrochloride or 5 mg of tadalafil just after PB. The duration of the study was 12 months and the patients were assessed for urinary and sexual function status at baseline, and 1, 3, 6, and 12 months after PB. The primary study endpoints were both changes from baseline in urinary and sexual function status. Between July 2015 and August 2020, 120 participants were enrolled in this study. The median age was 68 years with the median PSA of 6.5 ng/ml. A total 15 patients were excluded within 6 months after randomization. All subjective LUTS findings, including International Prostate Symptom Score (IPSS), and Over Active Bladder Symptom Score (OABSS), were significantly deteriorated at 1, 3, and 6 months after PB compared with baseline in both groups, respectively (p<0.05). Among objective LUTS findings, a significant decrease in maximum urinary flow rate (Qmax) was found at 1, 3, 6, and 12 months after PB compared with baseline in both groups, respectively (p<0.05). A significant increase in post void residual urine (PVR) was found at 1, 3, and 6 months after PB compared to baseline in tadalafil group, whereas no significant increase was seen in tamsulosin group. There were no statistically significant differences between the 2 groups in scores of the total International Index of Erectile Function (IIEF)-15 and Erection Hardness Score (EHS) before and at 1 month post PB. The EHS was significantly higher in tadalafil group compared with tamsulosin group at 3, 6 and 12 months (p = 0.001, p = 0.004, and p = 0.019, respectively). The EHS after PB in tadalafil group was not significantly decreased from baseline. After LDR-PB, tamsulosin treatment significantly decreased PVR compared with tadalafil. On the other hand, tadalafil contributed to maintain erection hardness compared with tamsulosin.

Effect of insert plate on the inlet pressure distortion of the aero-engine

The shape of the inlet duct and other factors cause distortion of the total pressure, leading to a decrease in engine stability. This article inserts flat plate into the inlet port of a certain type of aviation turbojet engine to conduct an inlet distortion test on the entire engine. The characteristics of entire flow field after inserting the board are obtained through experiments and numerical simulations, and it is concluded that the depth of the board is positively correlated with the reflux area and total pressure loss. The area of the insertion plate increase leads to an increase in the distortion index, and a decrease in engine flow rate. Meanwhile, angle plate device is designed to simulate inlet distortion caused by elevation takeoff. Summarize the relationship between the depth of the insertion plate and the intake distortion, a comprehensive distortion index simulation formula is fitted. The distortion simulation device designed by combining prediction formulas can achieve continuous adjustment of comprehensive distortion index 2%–13%, meeting the distortion index requirements for aircraft engine anti distortion testing. This device can replace complex intake systems to save test costs and cycles, and quickly and effectively carry out aircraft engine related distortion testing.

Studi Perencanaan Ulang Perpipaan Sistem Filtrasi Air Skala Rumah Tangga

Clean water is a primary necessity for human survival, but due to limited access to clean water sources, wells are often used to meet this need. However, water from wells cannot be used directly because its quality varies depending on the soil conditions. Due to these differences, a filtration system needs to be installed in the treatment of raw water from the well. In the process, well water, after being processed through the filtration system, experiences a decrease in flow rate before being stored in water tanks. This creates a problem, namely excessive electricity consumption and insufficient water flow for household use. In this research, the researcher attempts to implement the SNI (Indonesian National Standard) standards in household-scale clean water treatment, whereas previous research focused more on water quality testing. The objectives of this research are to reduce electricity consumption and increase water flow to meet household needs.&#x0D; Regarding the research method, the researcher conducted a literature review, data collection, pre-improvement testing, redesigned pipeline planning, performance testing of the improvement results, and analysis of the outcomes. The results of this research show that for the 1-liter container testing, the required time has increased, with the fastest time being 6.4 seconds and the slowest being 6.7 seconds, compared to the initial testing, which had a range of 13.2 seconds to 13.6 seconds. As for electricity consumption, there has been a significant decrease, from 2.76 A in the initial testing to 1.76 A, resulting in an average power consumption of 200.3 watt, compared to the previous 603.7 watt.

Surge Process of a High-Speed Axial–Centrifugal Compressor

The surge is a typical aerodynamic instability phenomenon in the compression system, which can lead to serious consequences such as engine performance degradation and structural damage. A deep understanding of the surge process can support the development of a compressor with a wider operating range. In this paper, an experimental study was carried out and high-responding pressure sensors were used to obtain the aerodynamic instability process and the post-surge characteristics of an axial–centrifugal compressor at design and off-design speeds. The evolution of the flow field and instability behavior before and after the surge were analyzed. The results showed that the inlet temperature change can reflect the aerodynamic instability to some extent, and as the operating condition moves from the choke to surge boundary, the inlet temperature undergoes a sudden increase at a certain condition and further increases with the decrease in mass flow rate. At the design speed, the instability of the combined compressor featured a deep surge with an obvious rotating stall behavior before its inception, and the amplitude of the stall cell was gradually enhanced, finally leading to the surge. At the off-design speed, affected by the stage mismatching, the axial stage mainly worked near the unstable operating condition. Therefore, the compressor successively experiences two modes of mild surge and deep surge, and the rotating stall can also be observed during the surge cycle.

Вероятностная оценка эффективности применения метода циклического заводнения нефтяных пластов

Extraction of hard-to-recover hydrocarbons is becoming an urgent task for the entire world oil community. The development of new technologies and methods, as well as the improvement of existing ones, have become the main issue in the extraction of hydrocarbons at existing fields. The aim of the work was to develop the technology of hydrodynamic impact on the hydrocarbon deposit. The process of oil reservoirs flooding is one of the most widespread and traditional in the application of extraction of hard–to-recover oil. The most effective in terms of impact is the cyclic regime of flooding of oil reservoirs – periodic changes in fluid flow rates at injection and production wells with a phase shift of oscillations for individual groups of wells. The use of cyclic flooding in combination with an increase in the average level of injection pressures can give a significant increase in the coefficient of reservoir coverage in power. The degree of hydrodynamic connectivity of the layers along the section has a significant impact on the effectiveness of cyclic flooding. The coefficient of lithological connectivity of formations is determined by the ratio of the area of the reservoir confluence to the total area of the deposit and can characterize the hydrodynamic connectivity of formations along the section. Using the example of the D3 of the Korotkoye field, an assessment of the start-up of the wells of the PPD system was done as well as the analysis of the nature of its influence on the volume and water content of the extracted products of the D3 formation of the Korotkoye field under various injection modes using cyclic flooding. It is determined that when both injection wells are stopped for a long period, the output of the produced products decreases to 25%. The analysis of the total oil flow rate showed that in the variants with well shutdowns there is a stronger decrease in oil flow rate than in the variants with cyclic injection, in the variants with cyclic operation of the PPD system the highest indicators of accumulated oil production are achieved for a certain period.

The significance of ternary hybrid cross bio-nanofluid model in expanding/contracting cylinder with inclined magnetic field

Significance: Bio-nanofluids have achieved rapid attention due to their potential and vital role in various fields like biotechnology and energy, as well as in medicine such as in drug delivery, imaging, providing scaffolds for tissue engineering, and providing suitable environments for cell growth, as well as being used as coolants in various energy systems, wastewater treatment, and delivery of nutrients to plants.Objective: The present study proposes a novel mathematical model for the ternary hybrid cross bio-nanofluid model to analyse the behaviour of blood that passes through a stenosed artery under the influence of an inclined magnetic field. The model considers the effect of expanding/contracting cylinder, infinite shear rate viscosity, and bio-nanofluids.Methodology: The considered model of the problem is bounded in the form of governing equations such as PDEs. These PDEs are transformed into ODEs with the help of similarity transformations and then solved numerically with the help of the bvp4c method.Findings: The results show that the flow rate and velocity decrease as the inclination angle of the magnetic field increases. Additionally, research has found that the presence of nanoparticles in the bio-nanofluid has a significant impact on the velocity and flow rate. Therefore, the flow rate decreases, in general, as the stenosis becomes more severe.Advantages of the study: The results obtained from this study may provide insights into the behaviour of blood flow in stenosed arteries and may be useful in the design of medical devices and therapies for the treatment of cardiovascular diseases.

Analysis of unsteady non-Newtonian Jeffrey blood flow and transport of magnetic nanoparticles through an inclined porous artery with stenosis using the time fractional derivative

In the present study, a Caputo–Fabrizio (C–F) time-fractional derivative is introduced to the governing equations to present the flow of blood and the transport of magnetic nanoparticles (MNPs) through an inclined porous artery with mild stenosis. The rheology of blood is defined by the non-Newtonian visco-elastic Jeffrey fluid. The transport of MNPs is used as a drug delivery application for cardiovascular disorder therapy. The momentum and transport equations are solved analytically by using the Laplace transform and the finite Hankel transform along with their inverses, and the solutions are presented in the form of Laplace convolutions. To display the solutions graphically, the Laplace convolutions are solved using the numerical integration technique. The study presents the impacts of different governing parameters on blood and MNP velocities, volumetric flow rate, flow resistance, and skin friction. The study demonstrates that blood and MNP velocities boost with an increase in the fractional order parameter, Darcy number, and Jeffrey fluid parameter. The volumetric flow rate decreases and flow resistance increases with enhancement in stenosis height. The non-symmetric shape of stenosis and the rheology of blood decrease skin friction, whereas enhancement in MNP concentration increases skin friction. A comparison of the present result with the previous work shows excellent agreement. The present study will be beneficial for the field of medical science to further study atherosclerosis therapy and other similar disorders.

Energy and Mass Matching Characteristics of the Heat-Absorbing Side of the Ammonia Energy Storage System under Nonuniform Energy Flow Density.

Ammonia thermochemical energy storage is based on a reversible reaction and realizes energy storage and utilization by absorbing and releasing heat. Under different energy flow densities, the efficiency of an ammonia reactor composed of multiple ammonia reaction tubes is different. Based on the coupling model of light, heat, and chemical energy of an ammonia decomposition reaction system, taking a 20 MW solar thermal power plant as the research object, this paper proposes a new model of ammonia energy storage system, which places the ammonia decomposition side in a low-pressure environment and the ammonia synthesis side in a high-pressure environment. The effects of different inlet temperatures, inlet flow rates, flow distribution, and energy flow density distribution on the ammonia energy storage system were studied. The results show that the increase of inlet temperature and the decrease of inlet flow rate are beneficial to the improvement of thermal efficiency and exergy efficiency of the system to a certain extent, but when the inlet temperature increases or the inlet flow rate decreases to a certain extent, the efficiency of the system will decline. Under the condition of nonuniform energy flow density and nonuniform inlet flow distribution, more ideal system thermal efficiency and exergy efficiency can be obtained.

ORGANIZATIONAL AND TECHNOLOGICAL SOLUTIONS FOR THE REPAIR AND RESTORATION OF SEWAGE TUNNELS IN THE PLACES ADJACENT TO EXPLORATION MINES

The analysis of the occurrence of typical accidents of water drainage networks indicates a number of reasons for their failure, namely: a 2-3 times decrease in the amount of sewage over the last 20 years; increase in aggressiveness of wastewater, decrease in flow rate and increase in rainfall. During operation beyond the regulatory term, the reinforced concrete vault of the tunnel is almost completely destroyed as a result of biogenic corrosion. The listed reasons for the destruction of sewage tunnels built more than 50 years ago are generally similar in nature. From the above, it follows that the specifics of the operation of sewer tunnels can be highlighted - the cross-section diameter is more than 1500 mm and the laying depth is more than 5-7 m. It should be noted that the sections of the tunnels at the points of connection with inspection shafts, as well as the structure of inspection shafts, experience the greatest corrosion. A significant role in the repair and restoration of water drainage structures is played by the selection of materials and structures capable of counteracting the aggressive effects of hydrogen sulfide and other gases. In Ukraine and abroad, considerable experience has been accumulated in the repair and restoration of drainage network structures using materials and structures with high acid and alkali resistance. Conducted research has shown that products based on basalt have a number of advantages: high strength, fairly low weight, reliability during operation in a wide temperature range, they are not prone to corrosion and have high chemical resistance. The experience of working with pneumatic formwork gives them special importance, because they ensure the following requirements:quick installation and dismantling of the formwork; the possibility of using it for curved spatial surfaces forms, even with large spans;multiple reversibility of the formwork. The technology for the construction of the vaulted part of the sewer tunnel with internal finishing with stone casting tiles involves the following stages:dismantling of emergency sections of the tunnel (vaults, walls);clearing the tray part of the tunnel;restoration of the section of the tunnel part of the tunnel (if the tunnel is destroyed);cleaning of the existing fittings to ensure the joint operation of the tray and the protective coating of the vault being erected;installation of pneumatic formwork for the construction of the tunnel vault with internal finishing with stone casting tiles;laying stone casting tiles;installation of the necessary fittings for the protective lining of the vault made of monolithic reinforced concrete;creation of inventory formwork;laying the concrete mixture of the monolithic part of the vault;dismantling of pneumatic and inventory formwork after gaining strength of concrete;backfilling of the trench with compaction. The main period of restoration of the observation shaft with the help of lining the walls with stone-cast basalt tiles: dismantling of floor slabs; cleaning of walls from corrosion products; injection of anti-corrosion concrete on a small filler of space at the junctions of the tunnel; reinforcement of the mine walls (in case of deep corrosion of the walls); facing the walls of the observation shaft with stone-cast basalt tiles; treatment of the inner surface of operational areas and stairs with anti-corrosion epoxy polyurethane compound "AQUAKHIM". To justify the feasibility of using the proposed technology, two options for restoring the destroyed tunnel were considered: the method using stone casting tiles; the method of replacing destroyed pipes with polyethylene ones (an open method of restoration with dismantling of the destroyed tunnel). The option of restoring the sewer tunnel using stone casting tiles is almost 3 times more economical and expedient in terms of the cost of materials compared to the use of SPIRO PE pipe. The advantage of restoring sewage tunnels in this way is the durability and resistance of this material to aggressive effects, a sufficient amount of natural material in the country, and low cost. Keywords: sewage tunnel, inspection shaft, basalt, pneumatic formwork, technological solutions, open method.

Flow physics of annular and semi-annular fanjet and integration scheme with aircraft wing

Aerodynamic forces created on the lifting body, like an aircraft wing, can be optimized by modifying the flow field around it. These aerodynamic forces directly influence fuel consumption, thus the economy of flight. Various techniques have been developed and tested on wings for improving aerodynamic efficiency. The present work deals with the integration schemes of fanjets with aircraft wings for the same reason. Fanjets, like bladeless fans, can induce and entrain surrounding air for generation of lift and thrust; however, they are not yet integrated with the wing for modification of aerodynamic forces. In this novel research, the flow physics of the fanjet is explored by varying various geometric parameters. With an increase in the fanjet radius, the mass flow rate decreases, whereas the drag increases. A similar trend was observed for an increase in the jet width. For variation in the angle of attack, the maximum mass flow rate and minimum drag were observed at an angle of 0°. A similar analysis was carried out for semi-annular fanjets. Based on the results, the preferred selection for geometric parameters of annular and semi-annular fanjets was documented for integration with the aircraft wing.

Innovative high-pressure water scrubber for biogas upgrading at farm-scale using vacuum for water regeneration

Biogas upgrading is becoming essential in the valorization path for biogas. Biomethane from anaerobic digestion is identified to be one of the main resources to decarbonize the energy requirement. However, small-scale (especially farm-scale) applications suffer from a lack of implementation worldwide, mainly limited by the cost of the upgrading process. As one of the most used technologies, High Pressure Water Scrubbing presents a great margin for improvement. The most expansive items in this technology remain the packing column used for absorption and the stripping column used for water regeneration. In this work, the stripping column is replaced by a flash tank submitted to a rough vacuum (up to 0.2 bar in absolute pressure) associated to a static mixer to promote the gas desorption and thus the complete regeneration of the water. The implementation of an anisotropic packing, with properties evolving with the height of the column and adapted to the reduction of the gas flowrate due to absorption, is also investigated in order to reduce the size of the absorption column. A full-scale prototype was developed and implemented on a farm anaerobic digester. The range of application is from 20 to 40 Nm3/h of raw biogas. These field experiments associated to a complete description of the gas fluxes allowed to characterize the device in terms of carbon dioxide absorption efficiency, biomethane purity and methane recovery. Influences of six parameters (absorption pressure, desorption pressure, temperature, water flowrate, biogas flowrate, column height) were elucidated regarding those performances. Results highlight the great improvement of the water regeneration conducted under rough vacuum. From 0.8 to 0.2 bar in absolute pressure, the biomethane purity increased by 10%, the carbon dioxide elimination rate by 14%, and the methane recovery by 19%. With an increase in the packing height using an anisotropic configuration (modification of the packing properties with the column height) suited to the gas flowrate decrease into the column, a biomethane purity over 97% was obtained. The energy consumption associated was measured at 0.8 kWh/Nm3 of raw biogas but can be reduced to 0.3 kWh/Nm3. The overall energy efficiency for biogas upgrading can reach up to 91%. These results could pave the way for gas grid injection and vehicle fuel applications for small-scale anaerobic digestion.

Asymmetry of flow in aortic root and its application in hypertrophic obstructive cardiomyopathy.

The aortic root (AR) performs sophisticated functions regulating the blood dynamics during the cardiac cycle. Such complex function depends on the nature of flow in the AR. Here, we investigate the potential of new quantitative parameters of flow asymmetry that could have clinical implications. We developed a MATLAB program to study the AR hemodynamics in each sinus of Valsalva using two-dimensional (2-D) cardiac magnetic resonance imaging during systole and particularly at peak systolic flow in 13 healthy volunteers and compared with 10 patients with hypertrophic obstructive cardiomyopathy (HOCM). We show that the effective area of the aortic jet in healthy volunteers is significantly higher at peak systolic flow and on average during systole. The flow asymmetry index, indicating how the jet is skewed away from the left coronary sinus (LCS), is small in healthy volunteers and much larger in HOCM at peak systole. The average of this index over systole is significantly more different between cohorts. Looking in more detail at the flow in the sinuses during systole, we show that the AR jet in healthy volunteers is more symmetrical, affecting the three sinuses almost equally, unlike the asymmetric AR jet in patients with HOCM that has decreased flow rate in the LCS and increased fractional area of backward flow in the LCS. The percentage of backward flow in the sinuses of Valsalva calculated over systole is a potential indicator of perturbed AR hemodynamics and the distribution of vortical flow and could be used as a measure of flow asymmetry.NEW & NOTEWORTHY The aortic root is a vital organ responsible for performing sophisticated functions to regulate the blood flow dynamics during the cardiac cycle. Such synchronized complex performance affects and is affected by the flow symmetry and type of flow reaching the aorta. Here, we report flow asymmetry in the aortic root which could have clinical implications, and we investigate the potential of various quantitative parameters as measures of flow asymmetry in hypertrophic obstructive cardiomyopathy.

Characterizing bubble behavior in a pseudo‐2D fluidized bed of wet particles

AbstractBy applying digital image analysis on the bubble characteristics in a two dimensional wet‐particle fluidized‐bed, we report two‐stage evolution of bubble characteristics with increasing liquid content. In the first stage, bubble number and uniformity of bubble fraction increase, while bubble average diameter and aspect ratio decrease. In the second stage, these characteristics shift toward an opposite direction. This two‐stage evolution of bubble characteristics are analogous to that of reducing particle size in dry‐particle fluidization, and the fluidizing properties of particles shifts from Geldart Group B to Group A and then to Group C. Furthermore, liquid addition causes a continuous decrease of bubble fraction and bubble flow rate. This is different from dry‐particle fluidization, in which reducing particle size causes an increase trend. An explanation for this difference is that liquid addition increases the equivalent size of agglomerates in wet‐particle fluidization, which is opposite to the effect of reducing particle size.

Experimental investigation on centrifugal granulation of molten yellow phosphorus slag

Centrifugal granulation with waste recovery was proposed to recover the waste heat from the molten yellow phosphorus slag produced by an electric arc furnace and reduce pollution. The yellow phosphorus slag was heated to the same temperature as industrial electric furnaces and then granulated by centrifugal granulation. The study mainly investigated the effect of operating parameters on particle diameter distribution, flight distance distribution, and fiber mass fraction during the granulation process. The results showed that the average diameter was mainly 1.5–3 mm, and tended to decrease with the decrease of the mass flow rate, the increase of the rotating speed, and the increase of the rotary cup diameter. The particle diameter obeyed a log-normal distribution. As the rotating speed increased and the rotary cup diameter increased, the average flight distance and the distribution of flight distance were dispersed. The average flight distance was related to the linear velocity at the edge of the rotary cup. Increasing slag temperature, mass flow rate, and decreasing rotary cup diameter can reduce the fiber mass fraction. Re and We numbers can determine whether fibers produce.

Aortic hemodynamic and morphological analysis before and after repair of thoracoabdominal aortic aneurysm using a G-Branch endograft.

Background and objective: The G-Branch endograft is a novel multibranched "off-the-shelf" device used to repair thoracoabdominal aortic aneurysms (TAAAs). This report describes the hemodynamic and morphological performance of the G-Branch endograft in a human patient with TAAA. Materials and methods: We retrospectively reviewed the computed tomography angiography scans and clinical data of a woman in whom TAAA was treated using a G-Branch endograft. Patient-specific three-dimensional models were reconstructed, and computational fluid dynamics and morphological and hemodynamic indicators were analyzed before and after implantation of the device. Results: From a morphological perspective, there was an increase in cross-sectional area in the G-Branch endograft and all bridging stent grafts over time. Blood flow was redistributed among the renovisceral arteries, with a decrease in flow rate in the celiac artery and an increase in the left renal artery. Laminar blood flow was smoother and more rapid after implantation of the G-Branch device and remained stable during follow-up. In the bridging stent grafts, flow recirculation zones were found in the bridging zones of the celiac artery and superior mesenteric artery as well as the distal sealing zones of both renal arteries. Furthermore, higher time-averaged wall shear stress and a lower oscillatory index and relative resident time were found in the G-Branch endograft and bridging stent grafts. Quantitative analysis showed obvious reduction in the surface area ratio of the elevated time-averaged wall shear stress area and surface area ratio of the relative resident time after G-branch implantation. Conclusion: The revascularization of branch vessels occurred following G-branch implantation, with improvements arising not only from morphological changes but also from hemodynamic alterations. The long-term performance of the G-Branch endograft needs further investigation and clinical validation.

Thermo-hydro-mechanical coupling model of elastic modulus characteristic curve for unsaturated soils

The settlement has been reported to regularly be a fundamentalfactorin controllingthe stability of geotechnical structures. Because the theory of elasto-plasticity is widely employedto predict the settlement, the elastic modulus isa vital parameter that is regularly utilized for theoretical calculation. Moreover, thermomechanical behaviour of unsaturated soils has recently received considerable attention because its importance in various energy geostructures applications, as well as in relation to climate change. This paper presents a coupled thermo-hydro-mechanical model of the elastic modulus characteristic curve (EMCC) that was developed based on the effective stress theories of unsaturated soils. The proposed model uses the soil–water characteristic curve (SWCC) and the modulus of elasticity under saturated conditions to predict the variation of modulus of elasticity with matric suction for unsaturated soils. The successful prediction performance of the proposed model is demonstrated by the comparison of measured and predicted outcomes for various published data sets in the literature related to different soil types. The proposedmethod was thenused to present a parametric study considering the coupled impact of some important parameters on SWCC and EMCC. The analysis results indicated that the normalized elastic modulus rate increases with increasing matric suction, hydraulic conductivity, soil density, andwith decreasing flow rates, temperatures, and normal stresses.

Numerical study on spray characteristics of liquid jets in supersonic crossflow

The spray characteristics of liquid jets in supersonic crossflow at different injection jet-gas momentum ratios are investigated numerically. The compressible two-phase flow large eddy simulation (LES) method is based on the Eulerian-Lagrangian scheme. The average droplet volume fraction is defined to quantify spray concentration distribution, which can also reflect the oscillation boundary of the spray. The LES predicted the spray boundaries at different injection jet-gas momentum ratios in the central and cross-sectional planes, which agree reasonably well with the experiment. Two sets of counter-rotating vortex pair (CVP) are in the gas-liquid mixing region. As injection momentum ratio q increases, the upper CVP increases. Still, the absolute size of the wall CVP remains almost unchanged, which means that the relative size of the wall CVP to the upper CVP becomes smaller. As q increases, the spray's overall distribution position is generally upward, and the number of droplets entering the near-wall region becomes small. Thus, droplet-wall interactions are weakened. The spray body increases with the increase of q, while the spray foot decreases gradually. In the central plane, the coherent structures near the wall are mainly composed of splashed droplets, and this phenomenon gradually weakens as q increases. Although the increase of q can increase the total droplet mass flow rate, the proportion of the droplet mass flow rate in the near-wall region to the total mass flow rate decreases, and the droplet mass flow rate in the near-wall region decreases.