Deriving an Analytical Model for Hydro-Magnetic Micro Flow Controller

2008 ◽  
Author(s):  
Mahdi Esmaily Moghadam ◽  
Mohammad Behshad Shafii
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Magnetic Particles ◽  
Switching Time ◽  
Critical Factor ◽  
Pressure Head ◽  
Experimental Results ◽  
Working Fluid ◽  
Effective Parameters ◽  
Flow Controller

Fluid control, namely pumping and valving, is a critical factor in the performance of micro-fluidic systems. In recent years a variety of micro-fluidic systems are developed for the purpose of miniaturizing fluid handling, and chemical analysis to develop Lab On a Chip (LOC) technology. The mentioned facts resulted in design and fabrication of a novel hydro-magnetic flow controller. The idea behind this device is that magnetic particles, mixed and dispersed in a carrier liquid, can be accumulated in the form of a piston. Depending upon dragging speed of these pistons, which itself is a function of switching time, this device can be used to either increase (pumping) or decrease (valving) the flow rate. The valving characteristic of the setup, which occurs at higher switching times, was concurrent with regular forming of pistons in micro-tube. Experimental results in this part show a meaningful trend for the flow rate changes versus effective parameters of the flow. Considering this fact, lead us to propose a mathematical (analytical) model, which is a function of concerning parameters. Pressure head difference, concentration, material of particles, switching time, working fluid and, switching mode, depending on their complexity, have been introduced into the mathematical model, completely theoretically or semi-experimentally. The equations were derived based on the recognition of the leakage flow through the formed pistons and the pumped flow after each switching. The model was validated by the experimental results for nickel particles of less than 10μ in diameter and 0.5 gNi/100ccH2O concentration in water for a defined pressure head in a pressure driven flow setup.

Investigation of Switching Time and Pressure Head Effects on Hydro Magnetic Micro-Pump and Flow Controller

2008 ◽  
Author(s):  
Mahdi Esmaily Moghadam ◽  
Mohammad Behshad Shafii
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Flow Rate ◽  
Switching Time ◽  
Pressure Head ◽  
Forming Process ◽  
Carrier Fluid ◽  
Micro Pump ◽  
Flow Controller ◽  
Switching Mode

The significant importance of micro-scaled devices in medicine, lab-on-a-chip, and etc resulted in a vast variety of researches. The idea behind the novel hydro magnetic micropump and flow controller is that ferromagnetic particles, mixed and dispersed in a carrier fluid, can be accumulated and retained at specific sites to form pistons in a micro-tube using some external magnetic field sources along the micro-tube. This external magnetic field is related to some solenoids, which are turned on and off alternatively. Depending upon dragging speed of these pistons, which itself is a function of switching time, this device can be used to either increase (pumping) or decrease (valving) the flow rate of the carrier fluid. In this research the observations of pistons forming process and the related phenomena were investigated for different switching times in a pressure driven flow setup. In the first part of the experiments, the variation of flow rate versus switching time was investigated with nickel particles of less than 10 micron in diameter and (0.25gNi)/(100ccH2O) concentration in water at the optimum switching mode. In the next part, keeping all the parameters fixed, the effect of the pressure head variation on the flow rate was inspected.

A Novel Hydro Magnetic Micro-Pump and Flow Controller

2008 ◽  
Author(s):  
Ehsan Alavi Dehkordi ◽  
Mahdi Esmaily Moghadam ◽  
Mohammad Behshad Shafii
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Switching Time ◽  
Characteristic Curve ◽  
Pressure Head ◽  
Working Fluid ◽  
Field Variation ◽  
Micro Pump ◽  
Switching Mode

In order to deal with the limitations of micro-pumps and micro-valves and meet the advantages of magnetic systems a novel plan is described here. The idea behind the plan is that magnetic particles, mixed and dispersed in a carrier liquid, can be accumulated and retained at specific sites to form pistons in a micro-tube using some external magnetic field sources along the tube. In other words, using some solenoids and switching them on and off, in a specific order and period, causes the desired external magnetic field variation through the tube. Changing the period and the mode of activation and deactivation of the solenoids, which are called switching time and switching mode, respectively, flow can either be pumped or controlled. It is to note that, if it is required, ferro-magnetic particles can be extracted and recharged to the flow. In this research a pressure driven setup has been fabricated to make the above idea feasible to execute. The effect of the working fluid, switching time, and different concentrations on the flow rate were investigated. The experimental results corresponded to an optimum switching mode for nickel particle of diameter less than 10 microns for a constant pressure head. In order to obtain both pumping and valving characteristics of the setup, switching time was varied from 0.01 s to 5.0 s. The graphs obtained from the experiments show that best pumping performance of the setup occurred at an optimum switching time and switching mode. In addition, concentration was an important factor that affected both pumping and valving characteristics of the setup. Also, due to the differences that exist between properties of water and ethanol, changing the working fluid to ethanol resulted in a different characteristic curve.

Study Electromagnetic Pump Based on Ionic Liquids

2013 ◽  
Vol 437 ◽  
pp. 540-543
Author(s):  
Jing Wan ◽  
Zhi Bo Wang ◽  
Xiao Tao Zhou ◽  
Yu Mei Zhang ◽  
Su Hua Chen ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Magnetic Flux ◽  
Flux Density ◽  
Flow Rate ◽  
Single Phase ◽  
Pressure Head ◽  
Experimental Results ◽  
Magnetic Flux Density ◽  
Electromagnetic Pump

Ionic liquids are rising materials with unique excellence. Here the electromagnetic pump based on ionic liquids are presented. The pressure head difference is 3.2mm at 15 VDC and 0.4T. The flow rate is 8.6μl/s at 8VDC and 128μl/s at 21VDC when the magnetic flux density is 0.4T. The performances obtained theoretically in single phase are compared with the experimental results.

scholarly journals Generalized analytical model based on harmonic coupling for hybrid plasmonic modes: comparison with numerical and experimental results

2015 ◽  
Vol 23 (21) ◽  
pp. 27376 ◽  
Author(s):  
Mitradeep Sarkar ◽  
Jean-François Bryche ◽  
Julien Moreau ◽  
Mondher Besbes ◽  
Grégory Barbillon ◽  
...  
Keyword(s):  
Analytical Model ◽  
Experimental Results ◽  
Model Based

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): sensitivity analysis on the Newberry volcanic setting

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hannah R. Doran ◽  
Theo Renaud ◽  
Gioia Falcone ◽  
Lehua Pan ◽  
Patrick G. Verdin
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Energy Flow ◽  
Closed Loop ◽  
Working Fluid ◽  
Valuable Insight ◽  
Deep Borehole

AbstractAlternative (unconventional) deep geothermal designs are needed to provide a secure and efficient geothermal energy supply. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as the working fluid mass flow rate, the casing and cement thermal properties, and the wellbore radii dimensions. The results conclude the highest energy flow rate to be 1.5 MW, after an annulus radii increase and an imposed mass flow rate of 5 kg/s. At 3 kg/s, the DBHE yielded an energy flow rate a factor of 3.5 lower than the NWG 55-29 conventional design. Despite this loss, the sensitivity analysis allows an assessment of the key thermodynamics within the wellbore and provides a valuable insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of subcritical conditions, and could aid the development of unconventional designs within future EGS work like the Newberry Deep Drilling Project (NDDP). Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems to support EGS projects that could extend to deeper depths.

scholarly journals Improving Output Performance of a Resonant Piezoelectric Pump by Adding Proof Masses to a U-Shaped Piezoelectric Resonator

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 500
Author(s):  
Jian Chen ◽  
Wenzhi Gao ◽  
Changhai Liu ◽  
Liangguo He ◽  
Yishan Zeng
Keyword(s):  
Flow Rate ◽  
Maximum Flow ◽  
Working Fluid ◽  
Driving Voltage ◽  
Piezoelectric Resonator ◽  
Piezoelectric Pump ◽  
Compact Structure ◽  
Output Performance ◽  
Volume Efficiency ◽  
Working Efficiency

This study proposes the improvement of the output performance of a resonant piezoelectric pump by adding proof masses to the free ends of the prongs of a U-shaped piezoelectric resonator. Simulation analyses show that the out-of-phase resonant frequency of the developed resonator can be tuned more efficiently within a more compact structure to the optimal operating frequency of the check valves by adjusting the thickness of the proof masses, which ensures that both the resonator and the check valves can operate at the best condition in a piezoelectric pump. A separable prototype piezoelectric pump composed of the proposed resonator and two diaphragm pumps was designed and fabricated with outline dimensions of 30 mm × 37 mm × 54 mm. Experimental results demonstrate remarkable improvements in the output performance and working efficiency of the piezoelectric pump. With the working fluid of liquid water and under a sinusoidal driving voltage of 298.5 Vpp, the miniature pump can achieve the maximum flow rate of 2258.9 mL/min with the highest volume efficiency of 77.1% and power consumption of 2.12 W under zero backpressure at 311/312 Hz, and the highest backpressure of 157.3 kPa under zero flow rate at 383 Hz.

Convective Losses From Cavity Solar Receivers—Comparisons Between Analytical Predictions and Experimental Results

1983 ◽  
Vol 105 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. M. Clausing
Keyword(s):  
Experimental Data ◽  
Experimental Evidence ◽  
Analytical Model ◽  
Excellent Agreement ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Refined Model ◽  
Wall Area

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent agreement is obtained, and the important mechanisms are more clearly delineated.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

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