Flow Rates
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Bo Zhang ◽  
Kai Gu ◽  
Peter Bayer ◽  
Bin Shi ◽  
Fulin Xiang ◽  

Subsurface flow rates are critical for hydrology and geothermal research, while field characterization remains a challenge. There are several analytical solutions for calculating the vertical water flux based on measured temperatures. Heat is a popular natural tracer to estimate subsurface flow rates. However, quantifying flow rates is impeded by insufficient sensors spacing during field investigations or simplifying assumptions for analysis such as sinusoidal temperature boundary. The objective of this study is to develop a convenient method to investigate subsurface flow on the sub-meter scale. Here, we present a program to estimate water fluxes based on temperature-depth profiles, so-called TempFlow. TempFlow is a numerical program written in MATLAB that calculates steady state flow in transient heat tracing based on the inversion of measured high-resolution temperature-depth series observed at a certain time. In this program, the Fiber Optic Distributed Temperature Sensing (FO-DTS) is recommended for temperature collection. FO-DTS techniques provide high-resolution temperature measurements with continuous temperature profiles that account for sub-meter scale and nonperiodic boundary conditions in saturated sediments. The estimated subsurface flow using TempFlow was validated in a medium-scale tank with a series of experiments, where the hydraulic and temperature boundary conditions were well-controlled. The results indicate that the estimation using TempFlow obtained similar results as the experiments. Thus, the method could potentially be used to determine the flow rate of the subsurface.

2021 ◽  
Vol 3 ◽  
Kayla Prezelski ◽  
Megan Keiser ◽  
Joel M. Stein ◽  
Timothy H. Lucas ◽  
Beverly Davidson ◽  

Convection enhanced delivery (CED) allows direct intracranial administration of neuro-therapeutics. Success of CED relies on specific targeting and broad volume distributions (VD). However, to prevent off-target delivery and tissue damage, CED is typically conducted with small cannulas and at low flow rates, which critically limit the maximum achievable VD. Furthermore, in applications such as gene therapy requiring injections of large fluid volumes into broad subcortical regions, low flow rates translate into long infusion times and multiple surgical trajectories. The cannula design is a major limiting factor in achieving broad VD, while minimizing infusion time and backflow. Here we present and validate a novel multi-point cannula specifically designed to optimize distribution and delivery time in MR-guided intracranial CED of gene-based therapeutics. First, we evaluated the compatibility of our cannula with MRI and common viral vectors for gene therapy. Then, we conducted CED tests in agarose brain phantoms and benchmarked the results against single-needle delivery. 3T MRI in brain phantoms revealed minimal susceptibility-induced artifacts, comparable to the device dimensions. Benchtop CED of adeno-associated virus demonstrated no viral loss or inactivation. CED in agarose brain phantoms at 3, 6, and 9 μL/min showed >3x increase in volume distribution and 60% time reduction compared to single-needle delivery. This study confirms the validity of a multi-point delivery approach for improving infusate distribution at clinically-compatible timescales and supports the feasibility of our novel cannula design for advancing safety and efficacy of MR-guided CED to the central nervous system.

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2050
Bateer Baiyin ◽  
Kotaro Tagawa ◽  
Mina Yamada ◽  
Xinyan Wang ◽  
Satoshi Yamada ◽  

Unlike in soil culture, a substrate (nutrient solution) in a hydroponics system can flow, and this can affect both nutrient uptake and plant growth. In this study, we hydroponically cultivated Swiss chard (Beta vulgaris L. ssp. cicla) under different flow rates to analyze changes in the growth, nutrient uptake, and nutrient use efficiency. When the flow rate was intensified from 2 to 4 L/min, leaf area, the fresh weight, dry weight, and root length increased. However, when the flow rate was increased from 4 to 8 L/min, values of these growth parameters decreased. The nutrient uptake had a similar trend relative to the growth parameters and nutrient use efficiency of macronutrient elements, increased as the flow rate increased. This indicates that the flow rate affects plant growth by influencing the nutrient uptake, and an increase in the flow rate can aid in improving nutrient use efficiency. In hydroponics, regulating the flow rate at a reasonable volume is recommended to increase yield by enhancing nutrient use efficiency, but too intensive a flow rate may cause excessive physical stimulation to plants and inhibit their growth. Therefore, it is important to choose an appropriate substrate flow rate for optimal hydroponics production.

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6602
Lili Qian ◽  
Jun Ni ◽  
Zhiyang Xu ◽  
Bin Yu ◽  
Shuang Wang ◽  

Hydrothermal liquefaction can directly and efficiently convert wet biomass into biocrude with a high heating value. We developed a continuous hydrothermal liquefaction model via Aspen Plus to explore the effects of moisture content of Chlorella, reaction pressure and temperature on thermodynamic equilibrium yields, and energy recoveries of biocrude. We also compared the simulated biocrude yield and energy recoveries with experiment values in literature. Furthermore, vertical and horizontal transportation characteristics of insoluble solids in Chlorella were analyzed to determine the critical diameters that could avoid the plugging of the reactor at different flow rates. The results showed that the optimum moisture content, reaction pressure, and reaction temperature were 70–90 wt%, 20 MPa, and 250–350 °C, respectively. At a thermodynamic equilibrium state, the yield and the energy recovery of biocrude could be higher than 56 wt% and 96%, respectively. When the capacity of the hydrothermal liquefaction system changed from 100 to 1000 kg·h−1, the critical diameter of the reactor increased from 9 to 25 mm.

2021 ◽  
Vol 13 (20) ◽  
pp. 11295
Ali Babaeebazaz ◽  
Shiva Gorjian ◽  
Majid Amidpour

In this study, a small-scale two-stage multi-stage flash (MSF) desalination unit equipped with a vacuum pump and a solar parabolic collector (PDC) with a conical cavity receiver were integrated. To eliminate the need for heat exchangers, a water circulation circuit was designed in a way that the saline feedwater could directly flow through the receiver of the PDC. The system’s performance was examined during six days in July 2020, from 10:00 a.m. to 3:00 p.m., under two distinct scenarios of the MSF desalination operation under the vacuum (−10 kPa) and atmospheric pressure by considering three saline feedwater water flow rates of 0.7, 1 and 1.3 L/min. Furthermore, the performance of the solar PDC-MSF desalination plant was evaluated by conducting energy and exergy analyses. The results indicated that the intensity of solar radiation, which directly affects the top brine temperature (TBT), and the values of the saline feedwater flow rate have the most impact on productivity. The maximum productivity of 3.22 L per 5 h in a day was obtained when the temperature and saline feedwater flow rate were 94.25 °C (at the maximum solar radiation of 1015.3 W/m2) and 0.7 L/min, respectively, and the MSF was under vacuum pressure. Additionally, it was found that increasing the feedwater flow rate from 0.7 to 1.3 L/min reduces distillate production by 76.4% while applying the vacuum improves the productivity by about 34% at feedwater flow rate of 0.7 L/min. The exergy efficiency of the MSF unit was obtained as 0.07% with the highest share of exergy destruction in stages. The quality parameters of the produced distillate including pH, TDS, EC and DO were measured, ensuring they lie within the standard range for drinking water. Moreover, the cost of freshwater produced by the MSF plant varied from 37 US$/m3 to 1.5 US$/m3 when the treatment capacity increased to 8000 L/day.

2021 ◽  
Kelsey N Sommer ◽  
Mohammad Mahdi Shiraz Bhurwani ◽  
Vijay Iyer ◽  
Ciprian N Ionita

Abstract Background3D printing (3DP) used to replicate the geometry of normal and abnormal vascular pathologies has been demonstrated in many publications; however, reproduction of hemodynamic changes due to physical activities, such as rest versus moderate exercise, need to be investigated. We developed a new design for patient specific coronary phantoms, which allow adjustable physiological variables such as coronary distal resistance and coronary compliance in patients with coronary artery disease. The new design was tested in precise benchtop experiments and compared with a theoretical Windkessel electrical circuit equivalent, that models coronary flow and pressure using arterial resistance and compliance. MethodsFive phantoms from patients who underwent clinically indicated elective invasive coronary angiography were built from CCTA scans using multi-material 3D printing. Each phantom was used in a controlled flow system where patient specific flow conditions were simulated by a programmable cardiac pump. To simulate the arteriole and capillary beds flow resistance and the compliance for various physical activities, we designed a three-chamber outlet system which controls the outflow dynamics of each coronary tree. Benchtop pressure measurements were recorded using sensors embedded in each of the main coronary arteries. Using the Windkessel model, patient specific flow equivalent electrical circuit models were designed for each coronary tree branch, and flow in each artery was determined for known inflow conditions. Local flow resistances were calculated through Poiseuille’s Law derived from the radii and lengths of the coronary arteries using CT angiography based multi-planar reconstructions. The coronary stenosis flow rates from the benchtop and the electrical models were compared to the localized flow rates calculated from invasive pressure measurements recorded in the angio-suites. ResultsThe average Pearson correlations of the localized flow rates at the location of the stenosis between each of the models (Benchtop/Electrical, Benchtop/Angio, Electrical/Angio) are 0.970, 0.981, and 0.958 respectively. Conclusions3D printed coronary phantoms can be used to replicate the human arterial anatomy as well as blood flow conditions. It displays high levels of correlation when compared to hemodynamics calculated in electrically-equivalent coronary Windkessel models as well as invasive angio-suite pressure measurements.

2021 ◽  
Aliaksei Sottsau ◽  
Ramir Akbashev ◽  
Alexandr Peratsiahin ◽  
Vadim Garnaev

Abstract An innovative technology for determining the water cut in well products (without preliminary separation into liquid and gas fractions) uses the results of electrical impedance measurements and its dependence on the alternating current frequency. Water cut meter's sensor includes measuring and current electrodes, between which there is a well's multiphase flow. Imaginary and real components of the impedance quantitatively describe the component composition of the studied oil and gas-water mixtures. In this process, machine learning methods and developed algorithms for features extraction are used. Depending on the type of emulsion, two independent sensors are used in the oil pipeline, one of which measures in a direct emulsion, the other in an inverse emulsion. Tests of the described water cut meter on flow loops in the Russian Federation and in the Netherlands, as well as studies of well flows in oil production facilities in the Russian Federation and the Kingdom of Saudi Arabia, have shown high measurement accuracy in the full range of water cut, with high gas content, as well as at high salinity and in a wide range of flow rates. To do so, modern methods of data classification based on neural networks and regression modeling implemented using machine learning are employed. It was found that the flow rates of liquid and gas do not affect the results of measuring the water cut due to the high frequency of the impedance measurements - up to 100 thousand measurements per second. Use of in-line multiphase water cut meter makes it possible to apply intelligent methods of processing field information and accumulate statistical data for each well, as a big data element for predicting and modeling in-situ processes. It will also allow to introduce promising production processes aimed at increasing oil production and monitoring the baseline indicators of the well. Novelty of the presented technology: Solution of the problem of high-speed determination of water cut in a multiphase flow without preliminary separation using impedance metering. Creation of mathematical models of multiphase flow and methods for determining the type of flow and the type of emulsion. Machine learning methods and neural networks employment for high-speed analysis of flow changes. Development, successful testing and implementation of an affordable multiphase water cut meter of our own design, which has no analogs in industrial applications.

2021 ◽  
Sascha Müller ◽  
Jacek Fiutowski ◽  
Horst-Günter Rubahn ◽  
Nicole Rita Posth

The fate and transport characteristics of nanoplastic (NP) through different environmental systems is largely governed by physio-chemical processes and their specific interaction with environmental constituents (i.e., minerals, dissolved species, suspended particles). A hydrodynamic component present in almost all terrestrial and marine aqueous environments impact the physio-chemical processes micron-scale is largely overlooked in NP transport studies. Therefore, we tested the interaction behavior of nanosized plastic polystyrene particles of various coatings in the presence of minerals abundant in the Earth crust within a hydrodynamic continuum representing flow rates from groundwater to surface water systems. Our batch experiments show that particle-mineral adsorption is largely driven by the magnitude of opposite charge configurations, which is either produced by mineral type or specific nanoplastic surface coating. Zetapotential serves as a good predictor of adsorption between uncoated and carboxyl-coated polystyrene with minerals. It fails, however, to predict adsorption behavior between NH2 coated polystyrene and apatite or feldspars, due to the more complex and varying compositions of these minerals. Incorporating the hydrodynamic force component into the particle- mineral interaction scheme reproduces those adsorption trends at slow flowrates of 1e-04 m/d. However, increasing flow rates by a factor of 100 modifies charge-driven adsorption between minerals and plastics. This study highlights the unabating importance of hydrodynamic conditions when predicting nanoplastic transport in different subsurface environments, and has implications for nanoplastic behavior in both terrestrial and marine aqueous environments.

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6543
Mieczysław Dzierzgowski

Laboratory measurements and analyses conducted in a wide range of changes of water temperature and mass flow rate for different types of radiators allowed to provides limitations and assessment of the current radiators heat transfer model according to EN 442. The inaccuracy to determinate the radiator heat output according to EN 442, in case of low water mass flow rates may achieve up to 22.3% A revised New Extended Heat Transfer Model in Radiators NEHTMiRmd is general and suitable for different types of radiators both new radiators and radiators existing after a certain period of operation is presented. The NEHTMiRmd with very high accuracy describes the heat transfer processes not only in the nominal conditions—in which the radiators are designed, but what is particularly important also in operating conditions when the radiators water mass flow differ significantly from the nominal value and at the same time the supply temperature changes in the whole range radiators operating during the heating season. In order to prove that the presented new model NEHTMiRmd is general, the article presents numerous calculation examples for various types of radiators currently used. Achieved the high compatibility of the results of the simulation calculations with the measurement results for different types of radiators: iron elements (not ribbed), plate radiators (medium degree ribbed), convectors (high degree ribbed) in a very wide range of changes in the water mass flow rates and the supply temperature indicates that a verified NEHTMiRmd can also be used in designing and simulating calculations of the central heating installations, for the rational conversion of existing installations and district heating systems into low temperature energy efficient systems as well as to directly determine the actual energy efficiency, also to improve the indications of the heat cost allocators. In addition, it may form the basis for the future modification of the European Standards for radiator testing.

2021 ◽  
Anatoliy Andreevich Isaev ◽  
Rustem Shafagatovich Takhautdinov ◽  
Vladimir Ivanovich Malykhin ◽  
Almaz Amirzyanovich Sharifullin

Abstract This paper presents a set of activities to reduce water cut and develop a technical solution to measure water cut: measurement of watercut, flow rates and gas-oil ratio of a well output using a mobile unit. tracer tests and conformance control operations - watercut of reacting wells within Bashkirian stage decreased by 16,6% after those operations were performed. water flow control, flow deviation and remedying production casing damages made it possible to reduce extraction of produced water and, accordingly, the cost of oil production. development of Liquid Phase Separation Device enabled alternate delivery of oil and water to the intake of downhole pump.

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