scholarly journals Miniature 3D-Printed Centrifugal Pump with Non-Contact Electromagnetic Actuation

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 631
Author(s):  
Luca Joswig ◽  
Michael J. Vellekoop ◽  
Frieder Lucklum
Keyword(s):  
Hydrostatic Pressure ◽  
Flow Rate ◽  
Permanent Magnets ◽  
Maximum Flow ◽  
Electromagnetic Actuation ◽  
Flow Rates ◽  
Output Pressure ◽  
Hall Effect Sensor ◽  
3D Printed ◽  
Dynamic Pump

We present a miniature 3D-printed dynamic pump using the centrifugal operating principle. Dynamic pumps typically yield higher flow rates than displacement pumps at reasonable output pressure. Realizing smaller devices suitable for millifluidic and microfluidic applications brings challenges in terms of design, fabrication and actuation. By using microstereolithography printing we have reduced the overall size to an effective pumping volume of 2.58 mL. The free-moving rotor consists of an impeller and permanent magnets embedded during the printing process, which allow for non-contact electromagnetic actuation. The pump is driven by periodically switching the current through stator coils, controlled by a custom built circuit using a Hall effect sensor. It achieves a maximum flow rate of 124 mL/min and a hydrostatic pressure of up to 2400 Pa.

Cerebrospinal fluid shunts: an experimental comparison of flow rates and pressure values in various commercial systems

1972 ◽  
Vol 37 (6) ◽  
pp. 700-705 ◽  
Author(s):  
John L. Fox ◽  
David C. McCullough ◽  
Robert C. Green
Keyword(s):  
Cerebrospinal Fluid ◽  
Hydrostatic Pressure ◽  
Flow Rate ◽  
Experimental Comparison ◽  
Csf Shunt ◽  
Opening Pressure ◽  
Flow Rates ◽  
Content Type ◽  
Actual Flow ◽  
Closing Pressure

✓ The flow-rate characteristics of selected cerebrospinal fluid (CSF) shunt systems under a constant hydrostatic pressure differential were studied and compared with measurements of the opening pressure (OP) and closing pressure (CP). The usual technique of measuring the CP correlated poorly with actual flow rates. The OP measurement revealed variations from 5 to 600 mm H2O in the hydrostatic pressure actually needed to open the valve. The flow-rate values are important in that some shunt systems will not deliver distilled water at rates significantly in excess of 0.35 ml/min (the probable average normal CSF production rate) at hydrostatic pressure differentials of 150 mm H2O. However, this may not be apparent clinically since much higher hydrostatic pressure differentials are present in the erect patient with a CSF shunt where the ventricular pressure and shunt siphoning pressures are additive.

scholarly journals The efficiency of a membrane bioreactor in drinking water denitrification

2015 ◽  
Vol 21 (2) ◽  
pp. 269-275
Author(s):  
Aleksandra Petrovic ◽  
Marjana Simonic
Keyword(s):  
Drinking Water ◽  
Flow Rate ◽  
Membrane Bioreactor ◽  
Nitrate Removal ◽  
Maximum Flow ◽  
Pilot Scale ◽  
Operational Parameters ◽  
Flow Rates ◽  
Removal Capacity ◽  
Removal Efficiencies

The membrane bioreactor (MBR) system was investigated regarding its nitrate removal capacity from drinking water. The performance of a pilot-scale MBR was tested, depending on the operational parameters, using sucrose as a carbon source. Drinking water from the source was introduced into the reactor in order to study the influence of flow-rate on the nitrate removal and denitrification efficiency of drinking water. The content of the nitrate was around 70 mg/L and the C/N ratio was 3:1. Nitrate removal efficiencies above 90% were obtained by flow-rates lower than 4.8 L/h. The specific denitrification rates varied between 0.02 and 0.16 g/L NO3/ (g/L MLSS?d). The efficiencies and nitrate removal were noticeably affected by the flow-rate and hydraulic retention times. At the maximum flow-rate of 10.2 L/h still 68% of the nitrate had been removed, whilst the highest specific denitrification rate was achieved at 0.2738 g/L NO3/ (g/L) MLSS?d). The maximum reactor removal capacity was calculated at 8.75 g NO3/m3?h.

Design and Fabrication of PDMS/PMMA-Based Rotary Micropump

2016 ◽  
Vol 829 ◽  
pp. 29-34 ◽  
Author(s):  
Lung Ming Fu ◽  
Wen Teng Wang ◽  
Chia Yen Lee
Keyword(s):  
Flow Rate ◽  
Rotational Velocity ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Engine Oil ◽  
Working Fluid ◽  
Flow Rates ◽  
Peristaltic Pumping ◽  
Velocity Flow ◽  
Pdms Microchannel

A novel micropump is proposed comprising a PMMA-based rotor, a circular PDMS micro-chamber, and a semi-circular PDMS microchannel connecting the inlet and outlet reservoirs as the rotor spins, a plug of sample fluid is trapped within the microchannel between neighboring blades of the rotor and is driven through the channel toward the outlet. Meanwhile, the rotors periodically compress and release the inlet and outlet regions of the microchannel. Thus, as the rotor turns, one plug of sample fluid is drawn into the microchannel as another is ejected into the outlet reservoir. In other words, a peristaltic pumping effect is achieved. It is shown that the flow rate in the proposed device can be controlled simply by adjusting the rotational velocity of the rotor. A maximum flow rate of 1.22 ml/min is obtained given de-ionized water as the working fluid and a rotational velocity of 232 rpm. Moreover, given the same rotational velocity, flow rates of 0.724 ml/min and 0.336 ml/min are obtained for salad oil and engine oil, respectively.

scholarly journals High Flow-Rate Sample Loading in Large Volume Whole Water Organic Trace Analysis Using Positive Pressure and Finely Ground Sand as a SPE-Column In-Line Filter

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1426
Author(s):  
Ola Svahn ◽  
Erland Björklund
Keyword(s):  
Physicochemical Properties ◽  
Flow Rate ◽  
Solid Phase ◽  
Pure Water ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Positive Pressure ◽  
Flow Rates ◽  
Relative Standard ◽  
Whole Water

By using an innovative, positive pressure sample loading technique in combination with an in-line filter of finely ground sand the bottleneck of solid phase extraction (SPE) can be reduced. Recently published work by us has shown the proof of concept of the technique. In this work, emphasis is put on the SPE flow rate and method validation for 26 compounds of emerging environmental concern, mainly from the 1st and 2nd EU Watch List, with various physicochemical properties. The mean absolute recoveries in % and relative standard deviations (RSD) in % for the investigated compounds from spiked pure water samples at the three investigated flow rates of 10, 20, and 40 mL/min were 63.2% (3.2%), 66.9% (3.3%), and 69.0% (4.0%), respectively. All three flow rates produced highly repeatable results, and this allowed a flow rate increase of up to 40 mL/min for a 200 mg, 6 mL, reversed phase SPE cartridge without compromising the recoveries. This figure is more than four times the maximum flow rate recommended by manufacturers. It was indicated that some compounds, especially pronounced for the investigated macrolide molecules, might suffer when long contact times with the sample glass bottle occurs. A reduced contact time somewhat decreases this complication. A very good repeatability also held true for experiments on both spiked matrix-rich pond water (high and low concentrations) and recipient waters (river and wastewater) applying 40 mL/min. This work has shown that, for a large number of compounds of widely differing physicochemical properties, there is a generous flow rate window from 10 to 40 mL/min where sample loading can be conducted. A sample volume of 0.5 L, which at the recommended maximum flow rate speed of 10 mL/min, would previously take 50 min, can now be processed in 12 min using a flow rate of 40 mL/min. This saves 38 min per processed sample. This low-cost technology allows the sample to be transferred to the SPE-column, closer to the sample location and by the person taking the sample. This further means that only the sample cartridge would need to be sent to the laboratory, instead of the whole water sample, like today’s procedure.

Thermal Performance of High-Flow Single-Phase Liquid-Cooled Heat Sinks

2012 ◽  
Author(s):  
Ildar F. Akhmadullin ◽  
Randall D. Manteufel ◽  
Christopher Greene
Keyword(s):  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Removal ◽  
Internal Flow ◽  
Maximum Flow ◽  
High Flow ◽  
Repeated Measurements ◽  
Heat Sinks ◽  
Flow Rates

Experimental measurements are reported for high-flow liquid-cooled heat sinks designed for cooling electronics components such as a CPU. The flow rate is up to 2 GPM with internal flow passage length scales on the order of 0.1 to 1.0 mm in the primary heat transfer region. Of the designs tested, three achieved maximum flow rates with pressure drops of less than 1.5 psi. Two have lower maximum flow rates because of higher internal flow resistance. In the experiments, particular attention is given to sources of experimental uncertainty and the propagation of uncertainty through the calculations to reported thermal resistance, R (°C/W). Analysis includes bias and precision errors for direct measurement of temperature, flow rate, and pressure drop. Additionally, a separate thermocouple calibration test is reported to establish measurement uncertainties for the system. Main emphasis is made to the error propagation in thermal resistance calculations of each heat sink and measurement of heat removal rate from the CPU. Data is used to determine the standard error for R which ranges up to about 0.05 °C/W with the maximum for one heat sink up to 0.07 °C/W. Averaging of repeated measurements at the same flow rate without accounting for the range of the original data will result in lower uncertainties in the reported results.

Improved Flow Rate in Electro-Osmotic Micropumps for Combinations of Substrates and Different Liquids With and Without Nanoparticles

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Marwan F. Al-Rjoub ◽  
Ajit K. Roy ◽  
Sabyasachi Ganguli ◽  
Rupak K. Banerjee
Keyword(s):  
Heat Transfer ◽  
Zeta Potential ◽  
Thermal Management ◽  
Flow Rate ◽  
Maximum Flow ◽  
Enhanced Heat Transfer ◽  
Flow Rates ◽  
Current Leakage ◽  
Different Types ◽  
Electro Osmotic Flow

A new design for an electro-osmotic flow (EOF) driven micropump was fabricated. Considering thermal management applications, three different types of micropumps were tested using multiple liquids. The micropumps were fabricated from a combination of materials, which included: silicon-polydimethylsiloxane (Si-PDMS), Glass-PDMS, or PDMS-PDMS. The flow rates of the micropumps were experimentally and numerically assessed. Different combinations of materials and liquids resulted in variable values of zeta-potential. The ranges of zeta-potential for Si-PDMS, Glass-PDMS, and PDMS-PDMS were −42.5–−50.7 mV, −76.0–−88.2 mV, and −76.0–−103.0 mV, respectively. The flow rates of the micropumps were proportional to their zeta-potential values. In particular, flow rate values were found to be linearly proportional to the applied voltages below 500 V. A maximum flow rate of 75.9 μL/min was achieved for the Glass-PDMS micropump at 1 kV. At higher voltages nonlinearity and reduction in flow rate occurred due to Joule heating and the axial electro-osmotic current leakage through the silicon substrate. The fabricated micropumps could deliver flow rates, which were orders of magnitude higher compared to the previously reported values for similar size micropumps. It is expected that such an increase in flow rate, particularly in the case of the Si-PDMS micropump, would lead to enhanced heat transfer for microchip cooling applications as well as for applications involving micrototal analysis systems (μTAS).

scholarly journals Synchronized coupling of thermal mass and buoyancy ventilation: wood versus concrete

2021 ◽  
Vol 2042 (1) ◽  
pp. 012152
Author(s):  
L Barrett ◽  
J Jeong ◽  
R Price ◽  
C Subasic ◽  
S Asselin ◽  
...  
Keyword(s):  
Surface Area ◽  
Flow Rate ◽  
Maximum Flow ◽  
Thermal Mass ◽  
Reasonable Accuracy ◽  
Flow Rates ◽  
Early Design

Abstract This study describes an experiment that validates scaling rules for the design of thermal mass, coupled with buoyancy ventilation, suggesting that wood can perform as well as concrete if these rules are respected. The scaling rules potentially offer a shortcut for early design, showing how to tune the interior temperature and rate of buoyancy ventilation by adjusting the thickness and surface area of an internal thermal mass. A pair of test chambers (H~1m), comparing wood and concrete internal thermal masses, were located in Alabama, USA and Montreal, Canada, and left outside in sun- and-wind-sheltered environments for consecutive months. The thermal mass thicknesses were optimized so the chambers would maintain similar interior temperatures and airflow rates. The scaling rules predicted the behavior of the chambers with reasonable accuracy and both the concrete and wood thermal masses performed equivalently. For instance, the test chambers in Alabama were both designed to damp the maximum exterior temperature by a factor 1-1/Ai ≈ 0.7 and produce a maximum ventilation flow rate of Q ≈ 0.37 l/s. The measured damping was 1-1/Ai = 0.81±0.1 and 1-1/Ai = 0.81±0.13 for the concrete and wood chambers, respectively, while the maximum flow rates were 0.374±0.03 and 0.36±0.04 l/s, respectively.

Model Calculations on Micropump Using Reciprocating Motion of Magnetic Material Ball

2014 ◽  
Author(s):  
Hiroshige Kumamaru ◽  
Hayata Fujiwara ◽  
Yoshihisa Nomura ◽  
Kazuhiro Itoh
Keyword(s):  
Experimental Data ◽  
Magnetic Material ◽  
Flow Rate ◽  
Maximum Flow ◽  
Outer Diameter ◽  
Reciprocating Motion ◽  
Model Calculations ◽  
Flow Rates ◽  
Pump Head ◽  
Inner Diameter

The authors are developing a micropump which combines reciprocating motion of a magnetic material ball in a pumping channel and four passive check valves. An additional experiment has been performed for one combination of the ball outer diameter and the channel inner diameter, and results of this experiment are presented in this paper. Including the previous experiments performed by the authors, the maximum pump head of ∼620 mm and the maximum flow rate of ∼7.5 mL/min have been obtained in the present micropump. Also, in this study, model calculations have been performed in order to predict the pump performance, i.e. the relation between pump head and flow rate. Calculated flow rates agree well with experimental data for larger gaps between the ball outer diameter and the pumping-channel inner diameter; however, calculated flow rates are larger than the experimental data for smaller gaps. Therefore, it is necessary to improve the calculation models, in particular by calculating leak flow rate in the pumping channel as a flow through a nozzle instead of that through an orifice.

Effect on Inlet Vent Porosity on Fan Characteristic Performance for Electronics Cooling

2009 ◽  
Author(s):  
Takashi Fukue ◽  
Katsuhiro Koizumi ◽  
Masaru Ishizuka ◽  
Shinji Nakagawa
Keyword(s):  
Flow Rate ◽  
Perforated Plate ◽  
Electronics Cooling ◽  
Maximum Flow ◽  
Flow Area ◽  
Flow Rates ◽  
Fan Performance ◽  
Performance Metric ◽  
Cooling Fans ◽  
The Relationship

Critical fan performance metric such as characteristic output curves and maximum flow rates are affected by various environmental conditions where cooling fans are installed. This paper describes the relationship between the fan performance and configuration factors such as the flow inlet porosity of electronic enclosure, the flow obstacles which imitate high-density packages and narrow flow area configurations. We installed a test enclosure in front of a test fan and measured P-Q curves of the test fan, which were operated in the enclosure. The experiments, it was observed that the pressure difference was increased in the enclosure by the effects of a wall. We installed a perforated plate in front of the fan as an obstacle and investigated how this changed the P-Q curve. In general, addition of the perforated plate in front of the fan decreased the characteristic output of the fan. On the other hand, the flow rate by the fan supply was decreased by the existence of the narrow inlet or obstacles. When an opening area in front of a fan became smaller than double of the fan flow area, the flow rate was significantly decreased. In addition, it was observed that the maximum flow rate depended on the opening area ratio. Finally, a model for predicting flow rates decreases by the enclosure inlet and obstacles was proposed.

scholarly journals Theoretical and Experimental Analysis of Operating Conditions of a Circular Flap Gate for an Automatic Upstream Water Level Control

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2576
Author(s):  
Janusz Kubrak ◽  
Elżbieta Kubrak ◽  
Edmund Kaca ◽  
Adam Kiczko ◽  
Michał Kubrak
Keyword(s):  
Water Level ◽  
Flow Rate ◽  
Water Depth ◽  
Maximum Flow ◽  
Operating Conditions ◽  
Drainage Ditches ◽  
Level Control ◽  
Flow Rates ◽  
Water Head ◽  
Open Position

This article introduces a flow controller for an upstream water head designed for pipe culverts used in drainage ditches or wells. The regulator is applicable to water flow rates in the range of Qmin < Q < Qmax and the water depth H0, exceeding which causes the gate to open. Qmin flow denotes the minimum flow rate that allows water to accumulate upstream of the controller. Above the maximum flow rate Qmax, the gate remains in the open position. In the present study, the position of the regulator’s gate axis was related to the water depth H0 in front of the device. Derived dependencies were verified in hydraulic experiments. The results confirmed the regulator’s usefulness for controlling the water level.

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