Radial Flow Research Articles

The ALMaQUEST Survey XIV: do radial molecular gas flows affect the star-forming ability of barred galaxies?

ABSTRACT We investigate whether barred galaxies are statistically more likely to harbour radial molecular gas flows and what effect those flows have on their global properties. Using 46 galaxies from the ALMA-MaNGA QUEnching and STar formation (ALMaQUEST) survey, we identify galaxies hosting optical bars using a combination of the morphological classifications in Galaxy Zoo 2 and HyperLEDA. In order to detect radial molecular gas flows, we employ full 3D kinematic modelling of the ALMaQUEST 12CO(1–0) data cubes. By combining our bar classifications with our radial bar-driven flow detections, we find that galaxies classed as barred are statistically more likely to host large-scale radial gas motions compared to their un-barred and edge-on galaxy counterparts. Moreover, the majority of barred galaxies require multicomponent surface brightness profiles in their best-fitting models, indicative of the presence of resonance systems. We find that galaxies classed as barred with radial bar-driven flows (‘barred + radial flow’ subset) have significantly suppressed global star-formation efficiencies compared to barred galaxies without radial bar-driven flows and galaxies in the other morphological sub-samples. Our ‘barred + radial flow’ subset galaxies also possess consistently centrally concentrated molecular gas distributions, with no indication of depleted gas mass fractions, suggesting that gas exhaustion is not the cause of their suppressed star formation. Furthermore, these objects have higher median gas mass surface densities in their central 1 kpc, implying that central gas enhancements do not fuel central starbursts in these objects. We propose that dynamical effects, such as shear caused by large-scale inflows of gas, act to gravitationally stabilize the inner gas reservoirs.

Digital artery flow hemodynamics: An ultrasonographic study

BackgroundThere is a lack of data regarding the baseline hemodynamic blood flow parameters of the wrist and digits. Therefore, we aimed to quantify the digital and radial artery blood flow parameters using ultrasound and assess the influence of patient characteristics on hemodynamics. MethodsWe analyzed ultrasonographic data from 25 patients (50 hands) between October 2019 and December 2021. Variables of interest included dimensions of the radial artery and index finger (IF) ulnar and radial digital arteries at the palmodigital crease and their corresponding flow parameters. We compared variables among men and women and patients with and without diabetes using Wilcoxon Rank Sum test. ResultsOur cohort consisted of 18 women (36 hands) and three participants with diabetes (six hands). The mean diameter of the IF radial digital artery was 7 mm, and that of the ulnar digital artery was 10 mm. The average peak systolic velocity for the radial digital artery was 21.31 cm/sec, and for the ulnar digital artery, it was 30.03 cm/sec. Comparing men and women, the only significant difference found was in the time-averaged mean velocity for the ulnar digital artery (men:5.66 cm/sec vs. women:9.68 cm/sec, P = 0.02) and volume of flow for the ulnar digital artery (men:10.87cc/min vs. women:18.58cc/min, P = 0.03). We found no differences in blood flow parameters comparing participants with and without diabetes. ConclusionThese data provide a baseline measurement of digital flow hemodynamics that can be used in future studies to model vascular flow after replantation.

Analysis of the experience and procedural complications of trans-radial access versus trans-femoral access for hepatic arterial perfusion chemotherapy in patients with advanced hepatic malignancies:a retrospective study

Objective: To analyze the differences between trans-radial access (TRA) and trans-femoral access (TFA) in hepatic arterial perfusion chemotherapy (HAIC) in terms of patient experience, postoperative complications, and patient preferences; explore whether TRA in HAIC is associated with better patient experience and compliance; and determine whether it is safer than TFA. Methods: The study was a retrospective cohort study of patients with advanced hepatocellular carcinoma and liver metastases from colorectal cancer treated with HAIC. We enrolled a total of 91 patients with advanced liver malignancies treated with HAIC from November 2022 to May 2023 in the Department of Interventional Therapy and Hepatobiliary Medicine at Tianjin Medical University Cancer Hospital. The patients were divided into three groups: group TRA (n=20, receiving TRA HAIC only), group TFA (n=33, receiving TFA HAIC only), and crossover group [n=19, receiving TFA HAIC (Cross-TFA group) first, followed by TRA HAIC (Cross-TRA group)]. Meanwhile, to facilitate the expression of partial results, all patients receiving TRA HAIC were defined as the TRA-HAIC group (n=39, TRA+Cross-TRA group), and all patients receiving TFA HAIC were defined as the TFA-HAIC group (n=52, TFA+Cross-TFA group). The primary research index was the Quality of Life (QOL) visualization scale score. The secondary research index included approach-related and catheter-related adverse events, duration of surgery, and mean length of patient stay. We used various statistical methods such as Mann-Whitney U test, t-test, Chi-square test, Fisher's exact test, univariate logistic regression analysis, and multi-factor analysis. Results: TRA patients had significantly lower QOL scores than TFA patients (all P<0.001). The QOL scores of the Cross-TRA group were significantly lower than those of the Cross-TFA group (pain at the puncture site Z=-3.24, P=0.001, others P<0.001). The QOL scores of the Cross-TRA group were compared with those of the TRA group, which showed that the scores of the Cross-TRA group in overall discomfort (Z=-3.07,P=0.002), postoperative toilet difficulty (Z=-2.12, P=0.034), and walking difficulty (Z=-2.58, P=0.010) were significantly lower than those of the TRA group. Satisfaction scores were significantly higher in the Cross-TRA group than in the Cross-TFA group (Z=-3.78, P<0.001), and patients were more likely to receive TRA HAIC as the next procedure (χ2=30.42, P<0.001). In terms of mean length of stay, patients receiving TRA HAIC had a significantly lower mean length of stay than those receiving TFA HAIC (50.1±3.2 h vs. 58.4±6.4 h, t=7.98, P<0.001). The incidence of radial artery occlusion (RAO) as an approach-related adverse event was 15.4% (6/39) in the TRA-HAIC group, which was significantly higher than that in the TFA-HAIC group (15.4% vs. 0, χ2=8.56, P=0.005). Notably, multifactorial analysis of RAO-related factors showed that intraoperative enoxaparin use and patency of radial artery flow during pressure were significantly associated with a reduced risk of postoperative RAO (P=0.037 for enoxaparin use and P=0.049 for pressure). Conclusions: With respect to procedure approach, TRA was significantly better than TFA in terms of patient satisfaction and mean length of stay. Through further process optimization and prevention of adverse reactions, the incidence of adverse reactions can be maintained at a relatively low level, so that patients can benefit from TRA in future operations in terms of cost-effectiveness and medical efficiency.

Fluid Contamination Transient Analysis

Successful in-situ fluid cleanup and sampling operations are commonly driven by a fast and reliable analysis of pressure, rate, and fluid contamination measurements. Techniques such as pressure transient analysis (PTA) provide important information to quantify reservoir complexity, while fluid contamination measurements are commonly overlooked for reservoir description purposes. We introduce a new interpretation technique to relate fluid contamination measurements with near-wellbore fluid-transport properties by identifying early- and late-time flow regimes in fluid contamination and its derivative function. The derivative methods used in PTA inspired the development of the new fluid contamination interpretation method. Contamination transient analysis (CTA) evaluates transient measurements acquired during cleanup of mud-filtrate invasion to infer important reservoir flow conditions. Center-point derivative methods are applied to the fluid pumpout volume and time evolution of fluid contamination to identify flow regimes in cases of water-based mud invading either water- or hydrocarbon-bearing formations. We document synthetic examples of the new interpretation method for seven reservoir cases, numerically simulated to obtain contamination data, namely, homogeneous isotropic reservoir, radial boundaries, vertical boundaries, thin-laminated formations, mud-filtrate invasion radius, petrophysical properties, and permeability anisotropy. Single-phase flow and multiphase flow cases are also compared in the analysis. Reservoir boundaries and features are identified in the flow regimes obtained from the combined interpretation of the fluid contamination derivative (FCD) and the log-log plot of the contamination transform. The seven reservoir cases assume fixed reservoir and operational parameters, such as reservoir geometry, rock properties, fluid properties, invasion radius, time of invasion, maximum pumpout rate, and maximum drawdown pressure, to allow for a controlled sensitivity analysis enabling the identification of cleanup trends. It is emphasized that real-time field conditions could trigger certain limitations of the transient techniques developed in this work, such as noisy downhole formation testing measurements, active mud-filtrate invasion, or tool failure. To validate the assumptions, observations, and results of the numerical simulations, a field case is examined to (a) highlight the value of CTA in real-time fluid sampling operations and (b) further investigate its limitations. An alternative validation of the method is performed by applying the derivative directly to the formation testing measurements during fluid cleanup, reducing the uncertainty in the contamination estimation and the interpretation of transient trends. The new approach of the FCD is an alternative to improve fluid cleanup efficiency and to detect the spatial complexity of the reservoir during real-time downhole fluid sampling. Using log-log plots of fluid contamination and the FCD method, we encounter characteristic slopes defining late-time flow regimes. The spherical flow regime gives rise to a slope of –2/3, which has been previously documented by homogeneous isotropic analytical models. Radial flow exhibits a steeper slope of –3 that can be detected when the vertical limits are attained. Boundary effects are evident when the late-time slope of the FCD is equal to –1/3. In addition to the detection of reservoir boundaries, the CTA techniques developed in this paper enable the identification of reservoir fluid type and shale laminations and provide a foundation for the quantification of invasion radius and permeability anisotropy. It is found that cleanup efficiency could be improved based on contamination transient analysis by identifying the flow regimes taking place in the reservoir during filtrate cleanup, hence improving the prediction of the time required to acquire non-contaminated fluid samples.

A numerical study of clogging analysis in submersible drainage pump

Erosion of material surface due to collisions with solid particles has become a challenge to several engineering fields. Therefore, it is necessary to effectively design radial flow pumps that mitigate the sediment particles’ clogging effect from the system performance. This study aims to analyse and identify the clogging development of a newly designed submersible pump using computational fluid dynamics (CFD) techniques. The particle trajectory was accounted Tabakoff–Grant erosion model for predicting the clogging impact. The experimental pump performance results obtained by this study were used to validate the numerical results of the submersible pump. Pump results revealed a good agreement between the two marks, especially the head of the pump was obtained at a flow rate of 0.165 m3/min. When considering the motor power factor of 0.78, the pump efficiency was found to be 46%, and the test result was well-matched. Also, for combined cavitation-erosion, the performance characteristics of erosion rate density increase linearly. At a flow rate of 0.16 m3/min, the erosion rate density of the original model was more significant than the revised model. Furthermore, compared to the original model significantly reduced the adverse clogging effects on the impeller blades of the revised model.

An Analytical Model of Material Deformation During Friction Welding of Alloy 718

A new model of the material flow in rotary friction welding of tubes is proposed. The material flow proposed is based on 3D microcomputer tomography scans of welds performed with tungsten tracers. The tracers indicate a bifurcation of flow into two deformation paths. The material in Path 1 interacts with the weld interface and exhibits large azimuthal flow. The material in Path 2 transitions from axial to primarily radial flow with little or no azimuthal flow. The directional transition in this path is compared to orthogonal machining and equal channel angular pressing. The process to estimate the variables needed to calculate strain and strain rates using the equations from orthogonal machining and equal channel angular pressing is defined. Strain and strain rate in Path 2 are dependent upon feed rate and upset and decrease throughout the welding process. The strain rate is higher than previously reported for rotary friction welding as a result of the deformation model proposed.

Numerical study of non-toroidal inertial modes withl=m+ 1 radial vorticity in the Sun’s convection zone

Various types of inertial modes have been observed and identified on the Sun, including the equatorial Rossby modes, critical-latitude modes, and high-latitude modes. Recent observations have further reported the detection of equatorially antisymmetric radial vorticity modes that propagate in a retrograde direction about three times faster than those of the equatorial Rossby modes, when seen in the corotating frame with the Sun. Here, we study the properties of these equatorially antisymmetric vorticity modes using a realistic linear model of the Sun’s convection zone. We find that they are essentially non-toroidal, involving a substantial radial flow at the equator. Thus, the background density stratification plays a critical role in determining their dispersion relation. The solar differential rotation is also found to have a significant impact by introducing the viscous critical layers and confining the modes near the base of the convection zone. Furthermore, we find that their propagation frequencies are strikingly sensitive to the background superadiabaticity,δ, because the buoyancy force acts as an additional restoring force for these non-toroidal modes. The observed frequencies are compatible with the linear model only when the bulk of the convection zone is weakly subadiabatic (−5 × 10−7 ≲ δ ≲ −2.5 × 10−7). Our result is consistent with but tighter than the constraint independently derived in a previous study (δ &lt; 2 × 10−7), employing the high-latitude inertial mode. It is implied that, below the strongly superadiabatic near-surface layer, the bulk of the Sun’s convection zone might be much closer to adiabatic than typically assumed or it may even be weakly subadiabatic.

SIMULATION OF A WELL JET PUMP WORKING PROCESS

A mathematical model of the movement of the working flow in the flow part of the jet pump was developed based on the use of a radial function of a complex variable with a shifted leakage center. According to the accepted model, the working fluid radially asymmetrically exits from the displaced leakage center in all directions. The distance to the center of the leak has an inverse effect on the rate of spread of the working fluid. The offset turn of the radial function allows you to take into account the misalignment of the working nozzle and the mixing chamber due to poor manufacturing of jet pump parts. The vector of the complex potential with a shifted origin is defined as the difference of vectors whose origin is at the center of coordinates, and the endpoints characterize the initial and final positions of the shifted function. Using the equation of the potential of velocities and the stream function, the relationship for the complex potential of the plane-radial and spatial working flow with one-way and two-way displacement of the leakage center is obtained. The kinematic picture of the movement of the working medium is determined by a spatial hydrodynamic grid formed by equipotential surfaces and flow surfaces of leakage functions, which has the form of orthogonally placed coaxial spheres and radial meridional planes. The leakage displacement determines the deviation of the axis of the working nozzle from the axis of the displacement chamber of the jet pump. It is established that the velocity profiles of the radial flow with a displaced leak lose their similarity and the series of kinematic curves cannot be replaced by a single dimensionless dependence that would determine the flow kinematics regardless of the distance between the leak point and the inlet cross- section of the mixing chamber of the jet pump. The displacement of the leakage center has an inverse effect on the radial flow rate and decreases with increasing distance to the mixing chamber. As the value of the leakage displacement increases, the asymmetry of the velocity profile increases and its unevenness increases. Superimposition of the obtained characteristic function of the asymmetric radial flow and the vortex function of the complex variable allows to determine the structure of the mixed flow equation when simulating the rotation process of the jet pump in the well.

Fracture surface morphology effect on radial seepage flow in a horizontal single granite fracture

Fracture surface morphology effect on radial seepage flow in a horizontal single granite fracture

The Effects of Rotation and Solidity on the Aerodynamic Behavior of Low-Pressure Axial Flow Fans

Abstract Implicit axial flow fan models are commonly used for the numerical analysis of industrial heat exchanger systems. However, these fan models perform poorly within the often complex off-design flow environments characteristic of these systems, as their low-order formulations lose applicability under highly 3D flow conditions. At off-design flow conditions, rotation and blade solidity effects cause physical fan blade behavior to deviate from the anticipated 2D behavior characterized by the implicit models. Physical fan blade behavior at off-design flow conditions, however, remains uncertain and the specific effects of rotation and solidity are not yet widely understood. This study investigates off-design fan blade behavior by presenting explicit 3D computations of two low-pressure axial flow fans. The effects of rotation and blade solidity are then identified through a side-by-side comparison of the computed 3D fan blade data against isolated 2D airfoil data. The rotating fan blade lift characteristics are shown to be distinct from the comparative 2D airfoil trends. At low-flow (off-design) operating conditions, rotation establishes large radial flow movements, and the high blade solidities cause standing vortices to develop within the rotating blade passages. The radial outflow energizes the blades' boundary layers, and the vortices inhibit the flow from separating from the blades' surfaces. Consequently, blade stall is avoided and high lift coefficient values are realized. The presented fan blade lift characteristics are unique relative to literature on other turbomachines of lower blade solidity, highlighting the importance of considering solidity effects in implicit rotor model developments.

Analysis of flow characteristics of continuous cementing slurry mixing system

A thorough literature review demonstrates that the research on the flow characteristics of continuous cementing slurry mixing system has not been reported. This research work was to analyze the influences of various factors on the uniformity of slurry with the continuous mixers via the CFD method and establish the novel correlation for the power of this system. The Euler multiphase flow model, the k-e model and The MRF method are used. A method of “dynamic monitoring assignment” is proposed to calculate the secondary mixing process of the continuous system, which can improve the accuracy of the numerical calculation results and make it closer to the engineering application. The results indicate that the rotation speed and diameter of the impeller are not the larger the better. The higher the diameter and rotation speed, the smaller the uniformity of the slurry (when the uniformity reaches the maximum), but the power increases more. The lower impeller of the system has less influence on power than the upper impeller, and the power consumption of the radial flow impeller is less than that of the axial flow impeller. The simulation method and results can provide a new direction for the design and optimization of a continuous cementing slurry mixing system.

Optimization design of radial inflow turbine combined with mean-line model and CFD analysis for geothermal power generation

It is a considerable challenge to determine the key parameters affecting the efficiency and propose an accurate loss prediction model for radial flow turbine design. In current investigation, a one-dimensional mean-line model combined with particle swarm optimization algorithm and Kriging response surface surrogate model based on 3D numerical results were proposed to optimize radial flow turbines and evaluate performance. The loss model was carried out to analyze the relationship between geometric parameters, operating conditions and turbine performance. CFD numerical simulations were employed to revealed the mechanism of enhancing the turbine performance. The total-static efficiency was increased from 88.5 % to 91.7 %, and the clearance loss and passage loss were reduced by 18.4 % and 35.8 %, respectively,by optimized design. It is attributed to mitigate the curvature-induced boundary layer separation and vortex at the outlet, which reduces the secondary flow losses.The correlation between the predicted values of the Kriging response surface and the numerical results was up to 98.3 %. The results showed that the angle of attack was in the range of -10-0°, the blade has less influence on the flow loss. The current study effectively combined the flow path structure parameters and flow characteristics to realize the efficient optimization of ORC turbine.

Three-dimensional transient CFD simulation of lignite chemical looping gasification in a circulating fluidized bed

In this work, a full-loop 3D computational fluid dynamics (CFD) numerical simulation of the chemical looping gasification (CLG) process of lignite in a circulating fluidized bed (CFB) was performed using a two-fluid Eulerian-Eulerian model. The results showed that the CFD simulation effectively captured the axial and radial velocities of the particles. More radial flow occurred in the bottom part of the riser and inside the cyclone. The exothermic reaction became dominant within 7s, while the heat-absorbing reaction became dominant between 7 and 15s. The aggregation regions of syngas moved up with that of the high-temperature zone, and CO was the main contributor to the syngas. The particle size in the range of 175–225 μm was inversely proportional to the size of the average heat transfer coefficient (HTC) in the riser. Extremely small particle size saturated the bed, suppressing the HTC. The peak of the HTC was 387.7 W/(m2·K), which occurred in the upper-middle region of the riser and reached. The maximum HTC average value was 180.6 W/(m2·K). Finally, experimental data were used to verify the reliability of the model.

Enhancing plasma arc penetration ability with radial gas flow

Enhancing plasma arc penetration ability with radial gas flow

Effect of inhaled air temperature on mucus dynamics in the proximal airways

The aim of the present study is to understand the role of steam/cold-air inhalation on the mucus layer dynamics in the proximal airways. We model these flows as a viscoelastic liquid (lining the inner side of a tube) sheared by a turbulent airflow and subjected to a radial heat flow. The linear stability analysis of the resulting flow is carried out using numerical and thin-film approaches. The air–mucus interface tension, coupled with the azimuthal curvature, leads to the previously predicted axisymmetric capillary mode responsible for airway closure in distal airways. The viscoelasticity of the mucus leads to axisymmetric and new non-axisymmetric elastic modes, with the former possessing a higher growth rate. The axisymmetric elastic and capillary modes merge to give rise to a new ‘elasto-capillary mode’ possessing a growth rate nearly equal to the combined growth rate of the elastic and capillary modes. The analysis predicts a strong stabilising effect of the thermocapillarity induced by steam inhalation on the elasto-capillary mode. Thus steam decreases airway resistance, which could explain the observed therapeutic effect of steam inhalation. The opposite is the case when the inhaled air is colder than the body temperature, in agreement with the observations. The theoretical predictions are corroborated by the physical mechanism explaining the suppression/amplification of the elasto-capillary mode due to thermocapillarity.

Design, Development, and Performance Evaluation of Plastic-based Radial-flow Settling Unit for NFT Aquaponics

Highlights Inclusion of the designed radial flow settler to the aquaponic system helps to remove more than 80% TSS, which is on par with or better in comparison to the TSS removal efficiency of the existing models. Removing excess suspended solids in traditional aquaponic setups could help prevent biofilter choking and hence, water contamination further down the line. The developed radial flow is simple in design, cost-effective, and yet, efficient. Abstract. One cylindrical settler of capacity 200 L (Ø 0.6×0.7 m) with a center-bottom inlet has been designed and developed in High-Density Poly Ethylene (HDPE) under the All-India Co-ordinated Research Project on Plastic Engineering in Agriculture Structures &amp;amp; Environment Management (AICRP on PEASEM) center at ICAR-CIFA, Bhubaneswar for fitting to the developed Nutrient Film Technique (NFT) aquaponics system. The water flow into the settling unit comes from a single-drain fish culture tank with the outlet at the bottom-center with a downward slope of 1:22. The experiment was carried out for the evaluation of the efficiency of Total Suspended Solid (TSS) removal in the developed radial-flow settling unit. The performance is assessed in terms of capturing the suspended solids from the water of aquaculture operation with varying specific gravity (1=SG&amp;gt;2) as well as the skimming of the floating organic surfactants before entering into the biofilter. During the 90 days of study, a total of 60 water samples were collected from the outlet of the fish culture tank and the overflow of the settler, which were filtered through the standard 11 µm pore paper filter for further processing in the laboratory. The average TSS concentration removed was calculated to be 128.55 mg/L on dry weight basis and a mean efficiency of 80.06 ± 9.36% was observed in the experiment with a surface loading rate of 0.00103 m3/min-m2 of the radial flow settler. The right-angle submerged overflow of the settler helped in complete surfactant removal. Keywords: Aquaponics, NFT, Radial-flow, Specific gravity, Suspended solid.

Perceptual Thresholds for Radial Optic Flow Distortion in Near-Eye Stereoscopic Displays.

We provide the first perceptual quantification of user's sensitivity to radial optic flow artifacts and demonstrate a promising approach for masking this optic flow artifact via blink suppression. Near-eye HMOs allow users to feel immersed in virtual environments by providing visual cues, like motion parallax and stereoscopy, that mimic how we view the physical world. However, these systems exhibit a variety of perceptual artifacts that can limit their usability and the user's sense of presence in VR. One well-known artifact is the vergence-accommodation conflict (VAC). Varifocal displays can mitigate VAC, but bring with them other artifacts such as a change in virtual image size (radial optic flow) when the focal plane changes. We conducted a set of psychophysical studies to measure users' ability to perceive this radial flow artifact before, during, and after self-initiated blinks. Our results showed that visual sensitivity was reduced by a factor of 10 at the start and for ~70 ms after a blink was detected. Pre- and post-blink sensitivity was, on average, ~O.15% image size change during normal viewing and increased to ~1.5- 2.0% during blinks. Our results imply that a rapid (under 70 ms) radial optic flow distortion can go unnoticed during a blink. Furthermore, our results provide empirical data that can be used to inform engineering requirements for both hardware design and software-based graphical correction algorithms for future varifocal near-eye displays. Our project website is available at https://gamma.umd.edu/ROF/.

Numerical analysis of seepage law for radial fluid flow in a single fracture: Comparison between smooth and rough fractures

This paper investigated the differences for the hydraulic characteristics in a single fracture between using the Navier–Stokes (N–S) equation and Darcy's law, which would be benefit to understand the seepage mechanism in the fracture. A numerical model of the radial flow was established considering the aperture size and water injection flow rate. Some conclusion could be given. First, the Darcy's law only described the seepage characteristics when the flow rate was small when the flow rate and pressure response have a linear relationship. While the N–S equation could describe the linear and nonlinear seepage characteristics, resulting in a better model of the actual fracture seepage flow. Second, the aperture size had a limited influence on the water pressure and seepage velocity inside the fracture when the flow rate was small. It began to have a significant impact influence on the seepage characteristics inside the fracture with the aperture increased. Third, the flow–pressure response conformed to the Forchheimer equation in the fracture. The critical Reynold number would decrease from 1.2 to 0.0116 when fracture aperture decreased from 3 to 0.5 mm using the N–S equation. The degree of nonlinearity of the fluid flow increases with fracture roughness increasing. This work gave a guidance to the difference in the two seepage theories and correction for the result by Darcy law, which was widely used in the engineering calculation.

NUMERICAL SIMULATIONS OF LIQUID FILM PRIMARY BREAKUP IN A PINTLE INJECTOR: A PARAMETRIC STUDY

In the present study, numerical simulations have been conducted to investigate the primary breakup of the liquid film in the gas-liquid pintle injector, using the volume of fluid (VOF) method with the adaptive mesh refinement to capture the gas-liquid interface. The film breakup and atomization characteristics in the pintle injector are studied by changing the structure parameters and the momentum ratio. The results show that increasing the radial liquid flow rate to raise the momentum ratio promotes the atomization performance, while decreasing the axial gas flow rate deteriorates the atomization performance. The two methods of altering the momentum ratio both cause the spray angle to increase with the momentum ratio, but the first routine leads to a slower increase. With the increase of opening distance, the velocity of the liquid flow decreases, and the thickness of the liquid film increases significantly, making the film hard to break up. The skip distance negatively influences the film breakup and atomization when the skip distance exceeds one. Moreover, the hollow region of the spray is decreased with a longer skip distance, which is detrimental to fuel combustion.

Selecting Monoclonal Cell Lineages from Somatic Reprogramming Using Robotic-Based Spatial-Restricting Structured Flow.

Somatic cell reprogramming generates induced pluripotent stem cells (iPSCs), which serve as a crucial source of seed cells for personalized disease modeling and treatment in regenerative medicine. However, the process of reprogramming often causes substantial lineage manipulations, thereby increasing cellular heterogeneity. As a consequence, the process of harvesting monoclonal iPSCs is labor-intensive and leads to decreased reproducibility. Here, we report the first in-house developed robotic platform that uses a pin-tip-based micro-structure to manipulate radial shear flow for automated monoclonal iPSC colony selection (~1 s) in a non-invasive and label-free manner, which includes tasks for somatic cell reprogramming culturing, medium changes; time-lapse-based high-content imaging; and iPSCs monoclonal colony detection, selection, and expansion. Throughput-wise, this automated robotic system can perform approximately 24 somatic cell reprogramming tasks within 50 days in parallel via a scheduling program. Moreover, thanks to a dual flow-based iPSC selection process, the purity of iPSCs was enhanced, while simultaneously eliminating the need for single-cell subcloning. These iPSCs generated via the dual processing robotic approach demonstrated a purity 3.7 times greater than that of the conventional manual methods. In addition, the automatically produced human iPSCs exhibited typical pluripotent transcriptional profiles, differentiation potential, and karyotypes. In conclusion, this robotic method could offer a promising solution for the automated isolation or purification of lineage-specific cells derived from iPSCs, thereby accelerating the development of personalized medicines.