Analysis Of Gas Flow Research Articles

Impact of Gas Accumulation on the Stability of Parallel Upward Ventilation in High-Temperature Sloped Shafts of Deep Wells

To explore the causes and influencing factors of wind flow oscillations in high-temperature inclined aisles of deep wells under parallel upward ventilation, this study conducts a comprehensive investigation using theoretical analysis and numerical simulations. Based on the kinetic analysis of gas flow, a discriminant formula for wind flow reversal in the side branch is derived. Further analysis identifies initial wind speed and branch length as key factors influencing the reversal. Both gas pressure and thermal pressure contribute to wind flow reversal in the side branch, and the opposing directions of these pressures cause high-temperature gas to periodically flow between the two branches, resulting in wind flow oscillations. A higher initial wind speed can effectively reduce the oscillation amplitude due to increased initial kinetic energy and a larger pressure difference, but it does not extend the oscillation duration. Increasing the branch length can suppress wind flow oscillations by increasing airflow frictional resistance and damping.

Creation and Preclinical Testing of a Spirometer with Extended Functionality

RELEVANCE. We present the results of preclinical testing of an upgraded portable AR­1 gas flow analyzer produced by JSC Krasnogvardeets (Saint Petersburg) in order to create import-substituting technologies and develop practical and scientific spheres of healthcare.THE AIM OF THE STUDY. was to substantiate the possibility of clinical use of the upgraded device, originally intended for testing ventilators and inhalation anesthesia devices, as a monitor of the external respiration apparatus function.MATERIAL AND METHODS. The preclinical study of the upgraded gas flow analyzer was conducted at the V.A. Almazov National Medical Research Center in comparison with devices for conventional (Bellavista 950, Berner Ross Medical, Russia) and high-frequency (IPV-2C, Intrapulmonary Percussive Ventilation, Percussionaire Corporation, USA) mechanical ventilation in volume- and pressure-controlled modes using an artificial lung. The following reflected spirometry parameters were compared: tidal and minute volume under inhalation and exhalation, respiratory rate, maximum and minimum flows, peak and positive end expiratory pressure, fraction of inspired oxygen.RESULTS. A high accuracy of parameter matching shown by the gas flow analyzer and ventilators was demonstrated.CONCLUSION. The upgraded model of the gas flow analyzer can be used clinically as a portable spirometer at the prehospital and hospital stages.

Analysis of droplet motion in cavity zone of rotating packed bed

Droplet motion in outer cavity zone of rotating packed bed is a complex phenomenon that requires analysis of liquid and gas flow to clarify influences of factors such as rotation speed, liquid flow rate, or gas flow rate. In this study, hydrodynamics is described using laser Doppler velocimetry and high-resolution visualization for droplet motion characterization. The results reveal that droplet motion initially depends on the peripheral velocity of the packing, while further from the packing, it loses kinetic energy mainly due to the drag force caused by the surrounding gas. Two-way coupling is investigated as both phases interact with each other. Rankine vortex theory is applied to simulate gas flow in the outer cavity zone. A model, based on Newton’s second law, is developed to predict droplet dynamics, including impingement velocity, trajectory length, and total residence time. Validation of the model shows that it can predict the liquid velocity in the outer cavity zone accurately. Upon impingement of droplets on the casing, part of the liquid rebounds as secondary droplets into the cavity, where they circulate with the gas flow. Overall, this study provides insights into droplet dynamics in the rotating packed bed and offers a basis for optimizing process efficiency and design in various applications, including chemical processing and environmental engineering.

MPNG: A MATPOWER-Based Tool for Optimal Power and Natural Gas Flow Analyses

MPNG is an open-source simulation package for solving Optimal Power and Natural Gas Flow (OPNGF) problems. It is coded in <small>Matlab</small> and developed using the widely-used tool for power systems research and education, <small>Matpower</small>. MPNG assembles a nonlinear steady state OPNGF formulation for analyzing the integration of electricity and natural gas networks with order-of-priority classes of consumers and gas nodal price-controlled storage facilities. This paper presents the details of the nonlinear optimization model behind MPNG, as well as several features that were designed into it for the purpose of achieving robustness. These include an approximation of the Weymouth equation for handling bi-directional gas flows in pipelines, a per-unit representation for the natural gas network, and penalized slack variables for power and gas balances. Simulation results using a test case and the Colombian power and natural gas networks are presented to highlight MPNG&#x0027;s capabilities to solve OPNGF problems.

Development of a High Flow Oxygen Analyzer for Monitoring Oxygen Therapy in Adults Using High Flow Nasal Cannula (HFNC)

Oxygen is a necessity of life that is very rarely owned even though it has a very high value for humans. Our respiratory system directly takes oxygen intake from the surrounding air either or not consciously. Oxygen therapy is a method of administering oxygen at a higher concentration than ambient oxygen, with the treatment or prevention of symptoms and the appearance of hypoxia. The oxygen concentration to be administered to a person is determined by the flow titration required for sufficient SPO2. The accuracy of the oxygen flow delivery system to the patient is very high, so it is necessary to calibrate to determine the correctness of the indication of measuring instruments and measuring instruments stated. This study uses an Arduino microcontroller to process the oxygen concentration output from the OOA101-1 oxygen concentration sensor, then the processed oxygen concentration will be displayed on the TFT LCD. The variable in this study is the oxygen concentration setting value, while the independent variable is the OOA101-1 oxygen concentration sensor. The concentration value is set using an oxygen blender, while the comparison tool used is a gas flow analysis (Citrex H3). At the testing stage, the measurement value is 50% to 100% with a time of 1 minute at each point. Based on the measurements that have been made, the largest error value is obtained at a concentration of 50%, which is 3.07% and the smallest error value is at 100%, which is 0.40%. Data retrieval using a compressor and central oxygen is very influential on the results of the flow and oxygen concentration. The results obtained are more stable than without the use of a compressor and central oxygen.From these results, the calibrator module has an error (value) that is still within the relative limits of the conclusion, which is ±5%. And also the design of this tool is portable and low cost and made for use in hospital establishments as maintenance of HFNC equipment.

Thermal design considerations for a L-PBF built metal component: effects of Inter-Layer Cooling Time, Preheating Temperature and Gas Flow

The paper aims to investigate some important thermal effects that could affect the Additive Manufacturing (AM) process of Laser Powder Bed Fusion. This analysis starts with investigating the variation of the material substrate temperature due to a variation of the Interlayer Cooling-Time (ILCT); then, the paper analyzes the effect of Preheating temperature on the material microstructure of the first building layers. Finally, we assess the effect of variation in gas flow speed as a function of part position on the building platform. In addition, in this work, the previously mentioned thermal aspects are evaluated in detail under particular geometrical and printing conditions considered the most critical for the L-PBF process. All cases studied are performed on IN718 superalloy specimens. In particular, for ILCT investigation, 60 microns layered specimens are printed for Preheating temperature analysis 40 and 60 layered specimens and for gas flow speed evaluation 40 microns one. All the results are evaluated through a porosity and melt pool analysis. The results obtained in this work highlight a critical range for low ILCT, 2-6 seconds, for part integrity that could be affected by overheating effects. To avoid this criticality, inserting ghost parts during the printing or reducing the laser power value is suggested. Concerning the preheating temperature effect, the first 1.2 mm of printed layers are found to be critical and affected by melt pool instability. In this case, a sacrificial substrate used in the first layers could save the quality of a few layers height part. The gas flow analysis highlights how some areas of the building platform are affected by particular thermal conditions negatively influencing material printability. To minimize this issue as much as possible, modify the job layout to avoid printing parts in the critical zones.

Analysis of gas flow and PM movement characteristics inside diesel particulate filter channel

Based on experimental data from engine after-treatment tests, the diesel particulate filter (DPF) microscopic channel model was constructed using UG, and the accumulation of particulate matter (PM) in the deep bed filter layer and carbon deposit layer was analyzed through computational fluid dynamics (CFD). A comprehensive study was conducted on the exhaust gas flow characteristics and PM movement within the DPF channel, and focus on the effects of PM distribution type on capture and regeneration characteristics. The results show that with the increase in particle size in the exhaust, the distribution of PM concentration along the axial position of the channel shows a trend of gradually shifting from 0.2 to 0.25 m (rear section) to 0.125–0.2 m (front section). In particular, PM with 1 μm particle size has a large motion inertia, which is easy to move out of the airflow and deposit in the middle part of the channel. For PM in the front and middle sections of the channel, the airflow obstruction is relatively small, but the heat transfer loss is large, which is not beneficial for PM regeneration in the rear section. Therefore, with the distribution of LID, PD-1, and PD-2, the regeneration efficiency is relatively low, at 50.84%, 55.01%, and 54.59%, respectively.

Regular reflection of shock waves in steady flows: viscous and non-equilibrium effects

Numerical analysis of a steady monatomic gas flow about the point of the regular reflection of a strong oblique shock wave from the symmetry plane is conducted with the Navier–Stokes–Fourier (NSF) equations, the regularized Grad 13-moment (R13) equations and the direct simulation Monte Carlo (DSMC) method. In contrast to the inviscid solution to this problem completely defined by the Rankine–Hugoniot (RH) relations, all three models predict a complicated flow structure with strong thermal non-equilibrium and a long wake with flow parameters not predicted by the RH relations. The temperature $T_y$ related to thermal motion of molecules in the direction normal to the symmetry plane has a maximum inside the reflection zone while in a planar shock wave the maximum is observed for the $T_x$ temperature. The R13 equations predict these features much better than the NSF equations and are in good agreement with the benchmark DSMC results. An analysis of the flow with the conservation equations was conducted in order to evaluate the effects of various processes on a fluid element moving along the symmetry plane. In contrast to the shock wave where effects of viscosity and heat conduction are one-dimensional with zeroth net contribution to the fluid-element energy across the shock, the flow across the zone of the shock reflection is dominated by two-dimensional effects with positive net contribution of viscosity and negative contribution of heat conduction to the fluid-element energy. These effects are believed to be the main source of the wake with parameters deviating from the RH values.

Determination of the Reserved Gap Between the Obturator Ring and the Breechblock in the Metallic Obturation Mechanism of a Large Caliber Gun Howitzer

A reserved gap between the obturator ring and the breechblock in the obturation mechanism of a large-caliber gun is required in the locked state of the gun, which is the main cause of gas leakage. In this study, the finite element analysis of the dynamic contact between the obturator ring and the breechblock and the computational fluid dynamics (CFD) analysis of the high-pressure gas flow through the gap between the obturator ring and the breechblock are conducted. The results show that the smaller the reserved gap is, the shorter the time period during which the contact pressure is zero after the obturator ring contacts with the breechblock will be under a low-bore pressure condition. The results also demonstrate that the leakage flow at the outlet of the gap and the gas flow in the external domain increase with the reserved gap size, and the gas flow in the external domain decays rapidly if the reserved gap is less than or equal to 0.02 mm under a high bore pressure condition. Based on the simulation results, the appropriate reserved gap value is determined and adopted in the studied gun, and good results are achieved in the firing tests.

Removal and determination of carbon monoxide based on copper oxide immobilized on Zeolite 13X Nanocatalyst by catalytic oxidation process and gas flow analyzer

Carbon monoxide is one of the main air pollutants, mainly produced from the incomplete combustion of fossil fuels. This study aims to oxidize carbon monoxide by copper oxide nanoparticles immobilized on zeolite13X substrate. The present investigation was conducted to determine the effect of carbon monoxide concentration parameters (in the range of 200-1400 ppm) and reaction temperature (in the range of 100-500 °C) on the efficiency of carbon monoxide conversion by CuO/Zeolite 13X nanocatalyst. The design of the experiment and the determination of the number of experiments were analyzed using the central composite design method, and the statistical test of analysis of variance was done using the response surface method. Also, the structural and morphological characteristics of the nanocatalyst were investigated using BET, BJH, FE-SEM, EDX, and XRF tests. The results show that CuO/Zeolite 13X nanocatalyst efficiently oxidizes carbon monoxide. The highest conversion efficiency of 82.6% was obtained at a temperature of 400 °C and a carbon monoxide concentration of 500 ppm as the optimal conditions. According to the EDX test results, copper oxide nanoparticles with a weight percentage of 5.9% were loaded on the Zeolite 13X substrate. Design Expert11 software reduced the cubic model with an R2 coefficient of 0.98.

Water drop impacts on regular micropillar arrays: Asymmetric spreading

Eye-catching shapes are produced when water drops land vertically and spread on horizontal surfaces with micropillars arranged in regular square arrays. The positions of protrusions and fingers are often determined by the microstructure design and may be produced repeatably, which suggests possible manufacturing and analytical applications. This paper uses high-speed imaging of droplet shapes following impact to record and analyze asymmetries as drop spreading reaches its maximum extent. The range of experimental parameters used produced results varying (often non-monotonically) from symmetric spreading to many fingers. Impact Weber numbers (We) were systematically adjusted between 50 and 250, while surface microstructures featured circular (◯) and square (□) cross-sectional pillars of width d = 20 μm; height h = 15, 22, or 30 μm; and pitch p = 40, 60, or 80 μm. Many observed trends correlate with the extent of the fully wet impact region, including a general increase in asymmetry with We, p, and for □ rather than ◯ pillars. More detailed understanding of asymmetry mechanisms is also developed. For example, protrusions may be nucleated by jetting in directions of high gas flow within 100 μs of impact. A new analysis of gas flow under the drop, which accounts for Laplace pressure, explains anomalous spreading and asymmetry measurements. Reduced spreading velocity is identified as the cause of finger suppression where the microstructure is wet.

Evaluation of Spatial Gas Temperature and Water Vapor Inhomogeneities in TDLAS in Circular Multipass Absorption Cells Used for the Analysis of Dynamic Tube Flows.

The use of optical circular multipass absorption cells (CMPAC) in an open-path configuration enables the sampling free analysis of cylindrical gas flows with high temporal resolution and only minimal disturbances to the sample gas in the pipe. Combined with their robust unibody design, CMPACs are a good option for many applications in atmospheric research and industrial process monitoring. When deployed in an open-path configuration, the effects of inhomogeneities in the gas temperature and composition have to be evaluated to ensure that the resulting measurement error is acceptable for a given application. Such an evaluation needs to consider the deviations caused by spectroscopic effects, e.g., nonlinear effects of temperature variations on the intensity of the spectral line, as well as the interaction of the temperature and concentration field with the characteristic laser beam pattern of the CMPAC. In this work we demonstrate this novel combined evaluation approach for the CMPAC used as part of the tunable diode laser absorption spectroscopy (TDLAS) reference hygrometer in PTB's dynH2O setup for the characterization of the dynamic response behavior of hygrometers. For this, we measured spatially resolved, 2D temperature and H2O concentration distributions, and combined them with spatially resolved simulated spectra to evaluate the inhomogeneity effects on the line area of the used H2O spectral line at 7299.43 cm-1. Our results indicate that for dynH2O, the deviations caused by the interaction between large concentration heterogeneities and the characteristic sampling of the beam pattern of the CMPAC are three orders of magnitude larger than deviations caused by small temperature heterogeneity induced spectroscopic effects. We also deduce that the assumption that the "path-integrated" H2O concentration derived with the open-path CMPAC setup represents an accurate H2O area average in the flow section covered by the CMPAC in fact shows significant differences of up to 16% and hence does not hold true when large H2O concentration gradients are present.

A Study on the Optimization of Nozzle Design through Acetylene Gas Flow Analysis and DOE

A Study on the Optimization of Nozzle Design through Acetylene Gas Flow Analysis and DOE

Mathematical Model for Flow of High-pressure Gas in Microscale

Fused silica micro-tubes, whose size is similar to the pore throat in a low permeability reservoir, simplify the complex and tortuous of channels and throats and are used in this study to stimulate the flow pattern with micro-scale methods. A high-pressure micro-tube holder (designed and developed independently with a patent for invention) has been used to study gas flow patterns within the pressure range of 0.1MPa-30MPa. Moreover, we establish a gas flow equation and analysis the applicability of different inlet pressure based on the experiment result. The result shows: First, the pressure drop in the micro-tube is predominantly induced by friction resistance at low inlet pressure. While under relatively high inlet pressure, the impact of kinetic energy conversion and throttling effect on pressure drop shall be considered. Second, we build up a gas-flow equation in a micro-tube considering friction resistance, kinetic energy loss, and throttling effect. We also analyze the applicability for different diameters and inlet pressure. These research achievements were enriched in microtubule flow; different conditions have been identified for a different equation which has significant meaning to gas flow regulation in tight sandstorm reservoirs.

Analysis of Stability and Accuracy of Gas Flow in High Flow Nasal Canule for COVID-19 Patients

In December 2019, the world was introduced to a new coronavirus, severe acute respiratory syndrome (COVID-19).The primary strategy for COVID-19 patients is supportive care, using high-flow nasal oxygen therapy (HFNC) reported to be effective in improving oxygenation. Stability is the ability of a medical device to maintain its performance [1]. Medical equipment must have the stability necessary to maintain critical performance conditions over a period of time. Accuracy is the closeness of agreement between the value of a measuring quantity, and the value of the actual quantity of the measuring quantity[2].The purpose of this study is to ensure that the readings of the HFNC device are accurate and stable so that it is safe and comfortable when used on patients. The development of the equipment that will be used by the author adds graphs to the TFT LCD to help monitor stable data in real time so that officers can monitor the flow and fraction of oxygen in the device to be stable. This study uses Arduino Nano while the sensor used is the GFS131 sensor, then the results are displayed on the Nextion TFT LCD. The test is carried out with comparing the setting value of the HFNC tool that appears on the TFT LCD with a gas flow analyzer with a measurement range of 20 LPM to 60 LPM 5 times at each point. Based on measurements on the gas flow analyzer, the HFNC module has an average error (error (%)) of6.40%. Average uncertainty (Ua) 0.05. Conclusion from these results that the calibrator module has a relative error (error value) that is still within the allowable tolerance limit, which is ±10%, the tool is precise because of the small uncertainty and good stability of the stability test carried out within a certain time.&#x0D;

Acidic ascites inhibits ovarian cancer cell proliferation and correlates with the metabolomic, lipidomic and inflammatory phenotype of human patients

BackgroundThe poor prognosis of ovarian cancer patients is strongly related to peritoneal metastasis with the production of malignant ascites. However, it remains largely unclear how ascites in the peritoneal cavity influences tumor metabolism and recurrence. This study is an explorative approach aimed at for a deeper molecular and physical–chemical characterization of malignant ascites and to investigate their effect on in vitro ovarian cancer cell proliferation.MethodsThis study included 10 malignant ascites specimens from patients undergoing ovarian cancer resection. Ascites samples were deeply phenotyped by 1H-NMR based metabolomics, blood-gas analyzer based gas flow analysis and flow cytomertry based a 13-plex cytokine panel. Characteristics of tumor cells were investigated in a 3D spheroid model by SEM and metabolic activity, adhesion, anti-apoptosis, migratory ability evaluated by MTT assay, adhesion assay, flowcytometry and scratch assay. The effect of different pH values was assessed by adding 10% malignant ascites to the test samples.Results The overall extracellular (peritoneal) environment was alkaline, with pH of ascites at stage II-III = 7.51 ± 0.16, and stage IV = 7.78 ± 0.16. Ovarian cancer spheroids grew rapidly in a slightly alkaline environment. Decreasing pH of the cell culture medium suppressed tumor features, metabolic activity, adhesion, anti-apoptosis, and migratory ability. However, 10% ascites could prevent tumor cells from being affected by acidic pH. Metabolomics analysis identified stage IV patients had significantly higher concentrations of alanine, isoleucine, phenylalanine, and glutamine than stage II-III patients, while stage II-III patients had significantly higher concentrations of 3-hydroxybutyrate. pH was positively correlated with acetate, and acetate positively correlated with lipid compounds. IL-8 was positively correlated with lipid metabolites and acetate. Glutathione and carnitine were negatively correlated with cytokines IL-6 and chemokines (IL-8 & MCP-1).ConclusionAlkaline malignant ascites facilitated ovarian cancer progression. Additionally, deep ascites phenotyping by metabolomics and cytokine investigations allows for a refined stratification of ovarian cancer patients. These findings contribute to the understanding of ascites pathology in ovarian cancer.

Slope Stability Analysis Method of Unsaturated Soil Slopes Considering Pore Gas Pressure Caused by Rainfall Infiltration

The variation of pore gas pressure caused by rainfall infiltration is an important factor that leads to slope failures. The purpose of this study is to propose a new slope stability analysis method that considers pore gas pressure and examines the effect of airflow on slope stability by using a numerical method. A water-air two-phase flow analysis was conducted to investigate the distribution of pore air pressure, pore water pressure, and water saturation triggered by rainfall infiltration. Then the variation of the load resulting from pore gas pressure was incorporated into the slope stability analysis method based on the unsaturated soil shear strength theory and the residual thrust method to simulate the influence of airflow on the Tanjiahe landslide in China. In order to study the infiltration behavior with respect to initial saturation, water and gas flow analyses were performed considering various initial states of saturation under similar settings. Results showed that the pore gas pressure between the slope surface and the slip band clearly varied and that it decreased during the process from the slide bed to the deep direction. Then, the pore water pressure formed in the saturated zone was transferred by the airflow to the slope toe. As a result, because the pore gas pressure gradient increased the thrust of the slide mass, the safety factor decreased over time. Moreover, in the first step, the magnitude of infiltration decreased with an increase in initial saturation, while when the magnitude dropped to the minimum value, it then went up with an increase in initial saturation. The maximum value was usually reached at a saturation degree of 0% or 100%. When evaluating slope stability, the safety factor obtained by the slope stability analysis method that considered the water-gas coupling effect was much lower than when it was not considered during the process of a similar seepage. The impact on the slope failure was significant and may provide a practical reference for hazard assessments to control rainfall-induced landslides.

Extension of Non-invasive Ventilation Capabilities of MASI for the Care of Patients Affected by COVID-19.

The MASI mechanical ventilator was developed in a state of emergency to meet the demand for ventilators caused by COVID-19. Although it has obtained positive results in its use with patients in intensive care units, not having an optimal quality non-invasive ventilation (NIV) modality prevents it from being used in the early treatment of patients, which has been shown to prevent admission to the ICU and reduce mortality. Therefore, the following study focuses on evaluating MASI's ability to provide NIV using different accessories in order to compare their performance and determine which one would work best with MASI, and under which conditions. To do this, the high-flow nasal cannula, facial mask, and ventilation helmet accessories were tested under different pressure parameter settings. The data was collected using a gas flow analyzer. After that, a statistical analysis of the results was carried out, which showed that the face mask is the best accessory to use for NIV with MASI, and that it performs with optimal accuracy and precision when the peak inspiratory pressure is set at a value lower than 25 cmH20. Clinical Relevance- This study presents an optimization of the non-invasive ventilation (NIV) modality of the MASI me-chanical ventilator by evaluating its performance with different accessories.

3D modeling and analysis of gas flow in the interblade channel

Based on the equations obtained from the solution of the differential equation of curvature-inverse problem, processed in Mathcad, curves of flat contours, a geometric model of the blade airfoil profile was created in three sections - root, middle and peripheral. The distribution of velocities along the back and trough of the profile is presented. A 3D model of a blade based on a section and guide lines was built in SolidWorks and exported in the parasolid format to the ANSYS AIM 17.2 software package. For engineering analysis, the boundary conditions were determined - the type of working substance, the absolute temperature, the inlet velocity of the molasses, the static pressure at the outlet, etc. For the interblade channel, a hexagonal (structured) finite element mesh was created in an automated version. Careful selection of the boundary conditions leads to the accuracy of determining the results of the flow parameters. Based on carefully processed results, the blade optimization was carried out. Keywords: curvature; profiling; back curve; ideal gas; numerical simulation; turbulent flow; solid model.

PytuTester: RaspberryPi open-source ventilator tester

PytuTester is an open-source ventilator tester developed to help bio-engineers in the design and verification of new ventilator prototypes. A ventilator tester allows measuring the flow, pressure, volume, and oxygen concentration provided to the patient. During the global pandemic COVID-19, several open-source ventilators prototypes were developed; however, due to high cost and demand testers, they were not available. In this context, a low-cost tester was developed using a Raspberry Pi and medical-grade sensors for the test ventilators prototypes. This paper presents the design files, software interface, and validations tests. Our results indicate that the tester has good accuracy to evaluate the efficacy and performance of new prototypes. When tested on two ventilator designs developed in Paraguay, PytuTester reported flow profiles that were concordant with the industry-standard VT650 Gas Flow Analyzer. PytuTester was then field deployed to test several DIY ventilator designs in low-resource areas.