scholarly journals Active Chemical Sampling Using Jet Discharge Inspired by Crayfish: CFD Simulations of the Flow Fields Generated by the Jet Discharge Device

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 522 ◽  
Author(s):  
Hanako Ishida ◽  
Ryuichi Takemura ◽  
Tatsuki Mitsuishi ◽  
Haruka Matsukura ◽  
Hiroshi Ishida
Keyword(s):  
Flow Fields ◽  
Sample Collection ◽  
Cfd Simulations ◽  
Surrounding Water ◽  
Water Currents ◽  
Discharge Device ◽  
Collection Device ◽  
Active Chemical ◽  
Computational Fluid Dynamics Cfd ◽  
Solute Species

Here, we report on computational fluid dynamics (CFD) simulations conducted to develop a chemical sample collection device inspired by crayfish. The sensitivity of chemical sensors can be improved when used with a sniffing device. By collecting fluid samples from the surroundings, all solute species are also collected for the sensor. Crayfish generate jet-like water currents for this purpose. Compared to simply sucking water, food smells dissolved in the surrounding water can be more efficiently collected using the inflow induced by the jet discharge because of the smaller decay of the inflow velocity with the distance. Moreover, the angular range of water sample collection can be adjusted by changing the directions of the jet discharge. In our previous work, a chemical sample collection device that mimics the jet discharge of crayfish has been proposed. Here, we report CFD simulations of the flow fields generated by the device. By carefully configuring the simulation setups, we have obtained simulation results in which the angular ranges of the chemical sample collection in real experiments is well reproduced. Although there are still some discrepancies between the simulation and experimental results, such simulations will facilitate the process of designing such devices.

scholarly journals Using Computational Fluid Dynamics to Simulate Flow Fields from various Melt Blowing Dies

2005 ◽  
Vol os-14 (1) ◽  
pp. 1558925005os-14
Author(s):  
Holly M. Krutka ◽  
Robert L. Shambaugh ◽  
Dimitrios V. Papavassiliou
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Flow Fields ◽  
Melt Blowing ◽  
Cfd Simulations ◽  
Flow Field Characteristics ◽  
Computational Fluid Dynamics Cfd ◽  
The Common

This paper is an investigation of the flow fields generated by dual rectangular jets. Specifically, the jets examined are the same as the common slot dies used in the industrial melt blowing process. In this process, a molten polymer is attenuated by air discharging from dual jets. The velocity and turbulence of these flow fields determine the rate and quality of polymer fiber production. The flow field characteristics can be simulated quickly and efficiently using computational fluid dynamics (CFD). These CFD simulations require the use of an appropriate length scale to describe the flow field. This paper describes how these CFD simulations can be used to compare the flow fields generated by different jet geometries.

scholarly journals Clinical Evaluation of the Torq Zero Delay Centrifuge System for Decentralized Blood Collection and Stabilization

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1019
Author(s):  
Kyungjin Hong ◽  
Gabriella Iacovetti ◽  
Ali Rahimian ◽  
Sean Hong ◽  
Jon Epperson ◽  
...  
Keyword(s):  
Clinical Chemistry ◽  
Blood Collection ◽  
Test Results ◽  
Sample Collection ◽  
Rapid Separation ◽  
Cell Counts ◽  
Collection Device ◽  
Precision Study ◽  
Clinically Significant ◽  
Blood Specimens

Blood sample collection and rapid separation—critical preanalytical steps in clinical chemistry—can be challenging in decentralized collection settings. To address this gap, the Torq™ zero delay centrifuge system includes a lightweight, hand-portable centrifuge (ZDrive™) and a disc-shaped blood collection device (ZDisc™) enabling immediate sample centrifugation at the point of collection. Here, we report results from clinical validation studies comparing performance of the Torq System with a conventional plasma separation tube (PST). Blood specimens from 134 subjects were collected and processed across three independent sites to compare ZDisc and PST performance in the assessment of 14 analytes (K, Na, Cl, Ca, BUN, creatinine, AST, ALT, ALP, total bilirubin, albumin, total protein, cholesterol, and triglycerides). A 31-subject precision study was performed to evaluate reproducibility of plasma test results from ZDiscs, and plasma quality was assessed by measuring hemolysis and blood cells from 10 subject specimens. The ZDisc successfully collected and processed samples from 134 subjects. ZDisc results agreed with reference PSTs for all 14 analytes with mean % biases well below clinically significant levels. Results were reproducible across different operators and ZDisc production lots, and plasma blood cell counts and hemolysis levels fell well below clinical acceptance thresholds. ZDiscs produce plasma samples equivalent to reference PSTs. Results support the suitability of the Torq System for remotely collecting and processing blood samples in decentralized settings.

scholarly journals Using CFD to Evaluate Natural Ventilation through a 3D Parametric Modeling Approach

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2197
Author(s):  
Nayara Rodrigues Marques Sakiyama ◽  
Jurgen Frick ◽  
Timea Bejat ◽  
Harald Garrecht
Keyword(s):  
Natural Ventilation ◽  
Parametric Modeling ◽  
Cfd Simulations ◽  
3D Design ◽  
Post Process ◽  
Test House ◽  
Model Set ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Passive Strategy

Predicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibit its wide application. With the primary goal of providing a pragmatic CFD application to promote wind-driven ventilation assessments at the design phase, this paper presents a study that investigates natural ventilation integrating 3D parametric modeling and CFD. From pre- to post-processing, the workflow addresses all simulation steps: geometry and weather definition, including incident wind directions, a model set up, control, results’ edition, and visualization. Both indoor air velocities and air change rates (ACH) were calculated within the procedure, which used a test house and air measurements as a reference. The study explores alternatives in the 3D design platform’s frame to display and compute ACH and parametrically generate surfaces where air velocities are computed. The paper also discusses the effectiveness of the reference building’s natural ventilation by analyzing the CFD outputs. The proposed approach assists the practical use of CFD by designers, providing detailed information about the numerical model, as well as enabling the means to generate the cases, visualize, and post-process the results.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

scholarly journals Investigations of Inducers Operating With High Rotational Speed

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Björn Gwiasda ◽  
Matthias Mohr ◽  
Martin Böhle
Keyword(s):  
Rotational Speed ◽  
Test Bench ◽  
Pressure Rise ◽  
Working Fluid ◽  
Cfd Simulations ◽  
High Rotational Speed ◽  
Rotating Speed ◽  
Performance Pressure ◽  
Computational Fluid Dynamics Cfd ◽  
Suction Performance

Suction performance, pressure rise, and efficiency for four different inducers are examined with computational fluid dynamics (CFD) simulations and experiments performed with 18,000 rpm and 24,000 rpm. The studies originate from a research project that includes the construction of a new test bench in order to judge the design of the different inducers. This test bench allows to conduct experiments with a rotational speed of up to 40,000 rpm and high pressure ranges from 0.1 bar to 40 bar with water as working fluid. Experimental results are used to evaluate the accuracy of the simulations and to gain a better understanding of the design parameter. The influence of increasing the rotating speed from 18,000 rpm to 24,000 rpm on the performance is also shown.

scholarly journals Rapid pivot feeding in pipefish: flow effects on prey and evaluation of simple dynamic modelling via computational fluid dynamics

2008 ◽  
Vol 5 (28) ◽  
pp. 1291-1301 ◽  
Author(s):  
Sam Van Wassenbergh ◽  
Peter Aerts
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Analytical Model ◽  
Dynamic Modelling ◽  
Head Rotation ◽  
Theoretical Models ◽  
Cfd Simulations ◽  
Deceleration Phase ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Effects

Most theoretical models of unsteady aquatic movement in organisms assume that including steady-state drag force and added mass approximates the hydrodynamic force exerted on an organism's body. However, animals often perform explosively quick movements where high accelerations are realized in a few milliseconds and are followed closely by rapid decelerations. For such highly unsteady movements, the accuracy of this modelling approach may be limited. This type of movement can be found during pivot feeding in pipefish that abruptly rotate their head and snout towards prey. We used computational fluid dynamics (CFD) to validate a simple analytical model of cranial rotation in pipefish. CFD simulations also allowed us to assess prey displacement by head rotation. CFD showed that the analytical model accurately calculates the forces exerted on the pipefish. Although the initial phase of acceleration changes the flow patterns during the subsequent deceleration phase, the accuracy of the analytical model was not reduced during this deceleration phase. Our analysis also showed that prey are left approximately stationary despite the quickly approaching pipefish snout. This suggests that pivot-feeding fish need little or no suction to compensate for the effects of the flow induced by cranial rotation.

Time-Dependent Computational Fluid Dynamics (CFD) Simulations of a Closing Blowout Preventer

2018 ◽  
Author(s):  
Daniel Barreca ◽  
Matthew Franchek ◽  
Mayank Tyagi
Keyword(s):  
Fluid Velocity ◽  
Maximum Pressure ◽  
Cfd Simulations ◽  
Environment Analysis ◽  
Erosion Rates ◽  
Velocity Magnitude ◽  
Blowout Preventer ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamic Meshing ◽  
Water Hammer Effect

Reliability of blowout preventers (BOP) is central for the safety of both rig workers and the surrounding environment. Analysis of dynamic fluid conditions within the wellbore and BOP can provide quantitative data related to this reliability. In cases of a hard shut in, it is suspected that the sudden closure of rams can cause a water hammer effect, creating pressure vibrations within the wellbore. Additionally, as the blowout preventer reaches a fully closed state, fluid velocity can drastically increase. This results in increased erosion rates within the blowout preventer. To investigate fluid movement and pressure vibrations during a well shut-in, CFD simulations will be conducted. Dynamic meshing techniques within ANSYS® FLUENT can be utilized to simulate closing blowout preventer configurations for both 2-D and 3-D geometries. These simulations would deliver information that could lead to a better understanding of certain performance issues during well shut-ins. Such information includes flow velocity magnitude within the BOP and maximum pressure pulse values within the wellbore.

scholarly journals Effect of hydraulic and geometric factors upon leakage flow rate in pressurized pipes

RBRH ◽  
2021 ◽  
Vol 26 ◽  
Author(s):  
Mayara Francisca da Silva ◽  
Fábio Veríssimo Gonçalves ◽  
Johannes Gérson Janzen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Leakage Flow ◽  
Cfd Simulations ◽  
Mean Velocity ◽  
Leakage Flow Rate ◽  
Geometric Factors ◽  
Leakage Area ◽  
Computational Fluid Dynamics Cfd

ABSTRACT Computational Fluid Dynamics (CFD) simulations of a leakage in a pressurized pipe were undertaken to determine the empirical effects of hydraulic and geometric factors on the leakage flow rate. The results showed that pressure, leakage area and leakage form, influenced the leakage flow rate significantly, while pipe thickness and mean velocity did not influence the leakage flow rate. With relation to the interactions, the effect of pressure upon leakage flow rate depends on leakage area, being stronger for great leakage areas; the effects of leakage area and pressure on leakage flow rate is more pronounced for longitudinal leakages than for circular leakages. Finally, our results suggest that the equations that predict leakage flow rate in pressurized pipes may need a revision.

scholarly journals Probabilistic Performance Analysis of Eroded Compressor Blades

2005 ◽  
Author(s):  
A. Kumar ◽  
P. B. Nair ◽  
A. J. Keane ◽  
S. Shahpar
Keyword(s):  
Probabilistic Analysis ◽  
Surrogate Model ◽  
Uncertainty Propagation ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Compressor Blades ◽  
Geometry Modeling ◽  
Blade Section ◽  
Computational Fluid Dynamics Cfd ◽  
Fan Blade

This paper presents a probabilistic analysis of the effect of erosion on the performance of compressor fan blades. A realistic parametric CAD model is developed to represent eroded blades. Design of Experiments (DOE) techniques are employed to generate a set of candidate points, which are combined with a parametric geometry modeling and grid generation routine to produce a hybrid mesh. A multigrid Reynolds-Averaged Navier Stokes (RANS) solver HYDRA with Spalart Allmaras turbulence model is used for Computational Fluid Dynamics (CFD) simulations. The data generated is used to create a surrogate model for efficient uncertainty propagation. This method is applied to a typical Rolls Royce compressor fan blade section. Monte Carlo Simulation, using the surrogate model, is executed for the probabilistic analysis of the compressor fan blade. Results show upto 5% increase in pressure loss for the eroded compressor fan blades.

scholarly journals Catheter placement selection for convection-enhanced delivery of therapeutic agents to brain tumors

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1415
Author(s):  
Lisa H. Antoine ◽  
Roy P. Koomullil ◽  
Timothy M. Wick ◽  
Louis B. Nabors ◽  
Ahmed K. Abdel Aal ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Tumor Volume ◽  
Therapeutic Agents ◽  
Catheter Placement ◽  
Volume Distribution ◽  
Convection Enhanced Delivery ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Magnetic Resonance Imaging Mri ◽  
Selection Of

Background: Convection-enhanced delivery (CED) of therapeutic agents to brain tumors allows clinicians to bypass the blood-brain barrier (BBB) to infuse virus therapy, biological, or chemotherapy directly into a brain tumor through convection. However, the effectiveness of infusions via CED may depend on catheter placement. Methods: This study used diffusion maps from magnetic resonance imaging (MRI) of human brain tumors and computational fluid dynamics (CFD) simulations to assess therapy volume distribution percentages based on catheter placement locations. Results: The primary outcome showed differences in volume distribution based on the catheter placement location. Total tumor volume filled ranged from 144.40 mm3 to 317.98 mm3. Percent filled of tumor volume ranged from 2.87% to 6.32%. Conclusions: The selection of the location for catheter placement using the region with the highest volume filled may provide optimal therapeutic effect.  The researchers conclude that CFD may provide guidance for catheter placement in CED of therapeutic agents.

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