scholarly journals Learning The Fluid/Flow Properties Using Microfluidics

2019 ◽  
Vol 215 ◽  
pp. 10002
Author(s):  
Pooria Hadikhani ◽  
Navid Borhani ◽  
S. Mohammad H. Hashemi ◽  
Demetri Psaltis

Deep neural networks (DNN) are employed to measure the flow rate and the concentration of the liquid using the images of the droplets in a microfluidic device. The trained networks are able to measure flow rates and concentrations with good accuracy.

2021 ◽  
pp. petgeo2020-062
Author(s):  
Jingtao Zhang ◽  
Haipeng Zhang ◽  
Donghee Lee ◽  
Sangjin Ryu ◽  
Seunghee Kim

Various energy recovery, storage, conversion, and environmental operations may involve repetitive fluid injection and, thus, cyclic drainage-imbibition processes. We conducted an experimental study for which polydimethylsiloxane (PDMS)-based micromodels were fabricated with three different levels of pore-space heterogeneity (coefficient of variation, where COV = 0, 0.25, and 0.5) to represent consolidated and/or partially consolidated sandstones. A total of ten injection-withdrawal cycles were applied to each micromodel at two different flow rates (0.01 and 0.1 mL/min). The experimental results were analyzed in terms of flow morphology, sweep efficiency, residual saturation, the connection of fluids, and the pressure gradient. The pattern of the invasion and displacement of nonwetting fluid converged more readily in the homogeneous model (COV = 0) as the repetitive drainage-imbibition process continued. The overall sweep efficiency converged between 0.4 and 0.6 at all tested flow rates, regardless of different flow rates and COV in this study. In contrast, the effective sweep efficiency was observed to increase with higher COV at the lower flow rate, while that trend became the opposite at the higher flow rate. Similarly, the residual saturation of the nonwetting fluid was largest at COV = 0 for the lower flow rate, but it was the opposite for the higher flow rate case. However, the Minkowski functionals for the boundary length and connectedness of the nonwetting fluid remained quite constant during repetitive fluid flow. Implications of the study results for porous media-compressed air energy storage (PM-CAES) are discussed as a complementary analysis at the end of this manuscript.Supplementary material: Figures S1 and S2 https://doi.org/10.6084/m9.figshare.c.5276814.Thematic collection: This article is part of the Energy Geoscience Series collection available at: https://www.lyellcollection.org/cc/energy-geoscience-series


Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 841 ◽  
Author(s):  
Reza Taherdangkoo ◽  
Alexandru Tatomir ◽  
Mohammad Taherdangkoo ◽  
Pengxiang Qiu ◽  
Martin Sauter

Hydraulic fracturing of horizontal wells is an essential technology for the exploitation of unconventional resources, but led to environmental concerns. Fracturing fluid upward migration from deep gas reservoirs along abandoned wells may pose contamination threats to shallow groundwater. This study describes the novel application of a nonlinear autoregressive (NAR) neural network to estimate fracturing fluid flow rate to shallow aquifers in the presence of an abandoned well. The NAR network is trained using the Levenberg–Marquardt (LM) and Bayesian Regularization (BR) algorithms and the results were compared to identify the optimal network architecture. For NAR-LM model, the coefficient of determination (R2) between measured and predicted values is 0.923 and the mean squared error (MSE) is 4.2 × 10−4, and the values of R2 = 0.944 and MSE = 2.4 × 10−4 were obtained for the NAR-BR model. The results indicate the robustness and compatibility of NAR-LM and NAR-BR models in predicting fracturing fluid flow rate to shallow aquifers. This study shows that NAR neural networks can be useful and hold considerable potential for assessing the groundwater impacts of unconventional gas development.


2019 ◽  
Vol 19 (1) ◽  
pp. 53-63
Author(s):  
Arti Saxena ◽  
Vijay Kumar ◽  
JB Shukla

Background: In this paper, a four layer model of the simultaneous and coaxial flow of moist air, mucus, mixture of mucin and periciliary liquid and serous fluid (assumed to be incompressible and Newtonian fluids) in a circular tube under time dependent pressure gradient representing prolonged cough is analyzed to study the mucus transport in an airway in the presence of prolonged cough. It is assumed that air and mucus flow under quasi steady state turbulent conditions while the mixture of mucin and periciliary liquid and serous layer surrounding mixture layer flows under unsteady laminar condition in presence of immotile cilia carpet. Result: It is shown that the mucus transport increases as the viscosity of serous fluid decreases. Also the mixture and serous fluid flow rates increase as the viscosity of serous fluid decreases. It is also observed that the effect of resistance to flow by serous fluid in the cilia bed is to decrease flow rates. The flow rates of mucus and mixture of mucin and periciliary fluid increase as the viscosity of mixture decreases also air and mixture of mucus and periciliary fluid flow rates increase as the thickness of mixture increases. Conclusion: As the thickness of mucus increases its flow rate increases on the other hand the mixture flow rate, mucus and serous fluid flow rate decreases with the increase of the mixture thickness. Bangladesh Journal of Medical Science Vol.19(1) 2020 p.53-63


2018 ◽  
Vol 2018 ◽  
pp. 1-4
Author(s):  
Vorasruang Thongsukh ◽  
Chanida Kositratana ◽  
Aree Jandonpai

Introduction. In patients who require a massive intraoperative transfusion, cold fluid or blood transfusion can cause hypothermia and potential adverse effects. One method by which to prevent hypothermia in these patients is to warm the intravenous fluid before infusion. The aim of this study was to determine the effect of the fluid flow rate on the efficacy of a fluid warmer. Methods. The room air temperature was controlled at 24°C. Normal saline at room temperature was used for the experiment. The fluid was connected to an infusion pump and covered with a heater line, which constantly maintained the temperature at 42°C. The fluid temperature after warming was measured by an insulated thermistor at different fluid flow rates (100, 300, 600, 900, and 1200 mL/h) and compared with the fluid temperature before warming. Effective warming was defined as an outlet fluid temperature of >32°C. Results. The room temperature was 23.6°C ± 0.9°C. The fluid temperature before warming was 24.95°C ± 0.5°C. The outlet temperature was significantly higher after warming at all flow rates (p<0.001). The increases in temperature were 10.9°C ± 0.1°C, 11.5°C ± 0.1°C, 10.2°C ± 0.1°C, 10.1°C ± 0.7°C, and 8.4°C ± 0.2°C at flow rates of 100, 300, 600, 900, and 1200 mL/h, respectively. The changes in temperature among all different flow rates were statistically significant (p<0.001). The outlet temperature was >32°C at all flow rates. Conclusions. The efficacy of fluid warming was inversely associated with the increase in flow rate. The outlet temperature was <42°C at fluid flow rates of 100 to 1200 mL/h. However, all outlet temperatures reached >32°C, indicating effective maintenance of the core body temperature by infusion of warm fluid.


2021 ◽  
Vol 9 ◽  
Author(s):  
Srivats Sarathy ◽  
Marco A. Nino ◽  
Abduldattar H. Alsaedi ◽  
Srinivasan Rajagopal ◽  
Syed Mubeen ◽  
...  

In vivo measurement of the flow rate of physiological fluids such as the blood flow rate in the heart is vital in critically ill patients and for those undergoing surgical procedures. The reliability of these measurements is therefore quite crucial. However, current methods in practice for measuring flow rates of physiological fluids suffer from poor repeatability and reliability. Here, we assessed the feasibility of a flow rate measurement method that leverages time transient electrochemical behavior of a tracer that is injected directly into a medium (the electrochemical signal caused due to the tracer injectate will be diluted by the continued flow of the medium and the time response of the current—the electrodilution curve—will depend on the flow rate of the medium). In an experimental flow loop apparatus equipped with an electrochemical cell, we used the AC voltammetry technique and tested the feasibility of electrodilution-based measurement of the flow rate using two mediums—pure water and anticoagulated blood—with 0.9 wt% saline as the injectate. The electrodilution curve was quantified using three metrics—change in current amplitude, total time, and change in the total charge for a range of AC voltammetry settings (peak voltages and frequencies). All three metrics showed an inverse relationship with the flow rate of water and blood, with the strongest negative correlation obtained for change in current amplitude. The findings are a proof of concept for the electrodilution method of the flow rate measurement and offer the potential for physiological fluid flow rate measurement in vivo.


2021 ◽  
pp. 32-41
Author(s):  
Rustam Rashidovich Tukhvatullin ◽  
Alexey Valentinovich Shchelchkov

In the context of the needs of the leading sectors of the world economy, the current state of metrological support for measuring units of mass and volume of a liquid in a flow, mass and volume flow rates of a liquid in the range of micro-flow rates of 10–5–103 ml/min is considered. Based on the results of the analytical review, the main metrological and operating characteristics of national standards are presented. The basic principles of generating a fluid flow in national gravimetric and volumetric standards when measuring the mass and volume of a fluid by the dynamic weighing method have been determined. Constructive solutions and principles of operation of key modules of national standards are considered. Methods for filling a liquid into a storage tank and designs of storage tanks are determined, taking into account the minimization of the effect of liquid evaporation, the influence of capillary force and buoyancy. The main sources of uncertainty in measuring the mass and volume of a liquid by the dynamic weighing method and methods for minimizing these uncertainties are considered. A modified model of dynamic measurement of liquid mass flow rate is proposed, taking into account the main sources of uncertainty. A comparative assessment of the influence of sources of uncertainty on the metrological characteristics of national standards is presented.


2008 ◽  
Vol 2 (3) ◽  
Author(s):  
Philippe Sucosky ◽  
Lakshmi P. Dasi ◽  
Matthew L. Paden ◽  
James D. Fortenberry ◽  
Ajit P. Yoganathan

Extracorporeal membrane oxygenation (ECMO) with a renal replacement therapy such as continuous venovenous hemofiltration (CVVH) provides life-saving temporary heart and lung, and renal support in pediatric and neonatal intensive care units. However, studies have shown that this approach may be hampered due to the potentially inaccurate fluid delivery∕drainage of current intravenous (IV) fluid pumps, creating potential for excessive fluid removal and undesired degrees of dehydration. We present a simple and novel accurate fluid management system capable of working against the high volume flow and pressures typically seen in patients on ECMO. The accuracy of the in-line system implemented at Children’s Healthcare of Atlanta at Egleston was assessed experimentally. The data assisted in the development of a novel automated and accurate fluid management system that functions based on a conservation of volume approach to limit the inaccuracies observed in typical clinical implementations of CVVH. IV pump accuracy measurements demonstrated a standard error in net ultrafiltrate volume removed from the patient of up to 848.5±156ml over a period of 24h, supporting previous observations of patient’s dehydration during the course of a combined ECMO-CVVH treatment and justifying the need for a new fluid management system. The innovative design of the new device is expected to achieve either a perfect or controlled negative fluid balance between the ultrafiltrate and replacement fluid flow rates. Perfect fluid balance is achieved by imposing an identical displacement on two pistons, one delivering replacement fluid to the circuit and the other draining ultrafiltrate from the hemofilter. Fluid removal is managed via a second syringe-pump system that reduces the net replacement fluid flow rate with respect to the ultrafiltration flow rate. The novel fluid management system described in this paper is expected to provide an effective method to control precisely fluid flow rates in patients on ECMO. Therefore, this device could potentially improve the efficacy of ECMO therapy and constitute a safe and effective way of reducing fluid overload in patients with cardiorespiratory failure.


2021 ◽  
Author(s):  
Sudad H Al-Obaidi

The stresses acting in the vicinity of wells have a significant impact on the flow properties of the reservoir and, as a result, on the flow rate of oil wells. The magnitude of such stresses depends on the deformation properties of the rock and on the oil pressure at the bottom of the well. In this work, an attempt to study the effect of flow fields (formation flow rate, well flow rates) on rocks in near-wellbore zones was performed. For this purpose, the correlation of such indicators as the fluid flow rate and the risk of destruction of the rocks of the productive deposits of one of the gas fields were experimentally studied. The experiments were performed on chosen core samples with quite wide range of flow and volumetric reservoir properties. It was concluded that the rock samples of the productive deposits of the studied formation do not collapse under the influence of pressure gradients corresponding to the design flow rates.


Author(s):  
J. Soman ◽  
B. Mathew ◽  
T. J. John ◽  
H. Hegab

This paper deals with the analyses of fluid flow distribution in a microfluidic device with in-line manifolds. The analysis was performed using commercially available microfluidic simulation software called CoventorWare™. The number of channels in the microfluidic device considered for this study was kept at ten due to limitations on the number of nodes and computational time. Channels with only square profile were analyzed for flow rates varying between 1 to 60 ml/min. The length of the channels was maintained at 1.5 cm for all simulations. The fluid flow distribution characteristics for different channel widths/depths (200, 100, and 75 μm) were investigated. It was observed that the flow rate decreased from the central channels to the outer channels. The flow per channel was symmetric about the geometric centre of the microdevice. The uniformity in flow was accessed using the root mean square value of flow per channel and it decreased with decrease in channel width/depth for a specific flow rate. The difference in the flow rate through the channels increased with increase in total flow rate. Similarly, the spacing between the channels was varied (300, 200, and 100 μm) for a microdevice with channel width/depth of 100 μm and its corresponding flow characteristics were studied for flow rate ranging between 1 ml/min and 60 ml/min. Finally, the length of each manifold was varied between 2500 μm and 1000 μm for understanding the effect of manifold length on flow distribution. The standard deviation of flow per channel did not show much variation with changes in spacing and manifold length. In addition each design of the manifolds was analyzed on the basis of pressure and flow rate as well as velocity profile in each of the channels.


1984 ◽  
Vol 106 (3) ◽  
pp. 633-637 ◽  
Author(s):  
A. B. Jarze˛bski

Simple expressions are presented for calculating approximate dimensions of spiral heat exchangers to give minimum annual cost of heating surface plus energy required to pump the fluids. The case of spiral–spiral flow is considered. Equations are derived for exchangers with and without distance holders between plate strips and for two sets of input data: (i) both volumetric fluid flow rates V1, V2 and all inlet and appropriate outlet temperatures are given; (ii) the flow rate of the process fluid V1 and the effectiveness e1 are imposed, while the flow rate of the working fluid V2 is an additional variable subject to optimization. For the latter case, appropriate optimum values of V2 can readily be found from the graphs provided.


Sign in / Sign up

Export Citation Format

Share Document