Water Volumetric Flow Rate Research Articles

Experimental investigation on the performance of a novel dual synthetic jet actuator-based atomization device

A synthetic jet actuator is a zero net mass flux device. In order to improve the compactness of spray cooling system, a novel dual synthetic jet actuator-based atomization device (DSJAA) is proposed and designed. In this atomization system, water is atomized by the oscillating dual synthetic jets instead of high-pressure air source. Moreover, no extra power for supplying water is needed. The effects of driving voltage, driving frequency, fluid volumetric flow rate and spray height are investigated on atomization rate, water droplet size, surface temperature and heat flux. The maximum atomization rate is 3.4 L/h at driving frequency of 700 Hz and driving voltage of 210 V. The dimensionless correlations between the physical properties of dual synthetic jet and the size of water droplet are presented, which provides guideline for the design of a dual synthetic jet actuator-based fluid atomizer. The experimental results show that when the resonance frequency of piezoelectric diaphragm is equal to half the Helmholtz frequency of DSJAA, the atomization performance is the best by setting driving frequency to resonance frequency. The best spray height is equal to the fluid stroke length of DSJAA. The cooling capability is mainly influenced by the Reynolds number of dual synthetic jet and volumetric flow rate of water. A correlation for DSJAA cooling is established. A maximum heat flux of the novel spray cooling method reaches as high as 59 W/cm2 in the experiments.

Two-phase oil/water flow measurement using an Earth’s field nuclear magnetic resonance flow meter

We present a novel multiphase flow metering technique for simultaneous measurement of oil and water volumetric flowrates. An Earth’s field nuclear magnetic resonance (NMR) detection coil is applied to measure free induction decay (FID) signals of two-phase oil/water flows. A dual polarisation technique is introduced utilising an upstream permanent magnet as well as an electromagnetic pre-polarising coil. FID signals with variable pre-polarising conditions are acquired and fit with a model for the NMR fluid signal using a 2D Tikhonov regularisation algorithm, allowing determination of a joint 2D velocity-T1 probability distribution. Appropriate analysis of the measured velocity-T1 distributions allows calculation of individual phase flowrates. The performance of the NMR flow measurement technique is examined for oil/water flows which are visually observed to be in three different flow regimes: stratified flow with mixing, dispersion of oil-in-water and water, and full oil-in-water emulsions. Two-phase flow characteristic features such as velocity slip are examined for each flow regime. Finally the accuracy of the measurement system in each flow regime is validated against in-line rotameter measurements.

Experimental studies on the upward flow characteristics of high-pressure gas and water in small-diameter vertical pipes

Considering the new applications of high-pressure gas pumps in practical engineering, the gas-liquid two-phase flow in small-diameter vertical pipes of the system in this study was tested. The gas volumetric flow rate, water volumetric flow rate, and working efficiency at different submergence height, pressure, and head values were measured. The results revealed that the pressure of high-pressure gas determines the gas consumption of the device and that a linear relationship exists between them. The void fraction of the vertical pipe effectively reflects the mixing of gas and water and affects the pumping capacity of the system. The water volumetric flow rate and working efficiency of the system reach their maximum values simultaneously when the void fraction reaches β0, which is a fixed value. A smaller diameter of the gas inlet pipe d enables the pump water efficiency to reach its peak at a lower pressure. We also present an optimization scheme for the selection of the diameter of vertical pipe D. These findings help facilitate a better understanding of the mechanism of the phase distribution and the interaction of the gas-water phases with each other in small-diameter vertical pipes and provide the basis for experiments to further improve the device performance.

Two-dimensional numerical study of a heat and mass exchanger for a dew-point evaporative cooler

This paper describes a two-dimensional numerical model of heat and mass transfer in a dew-point evaporative cooler that couples the momentum and mass transfer equations with the energy equation using various heat and mass transfer models. The numerical model is validated by experiment results from other studies and is then used to study the impacts of various operating conditions including the inlet volumetric air flow rate, working-to-primary air ratio, inlet water temperature, volumetric water flow rate and the temperature and humidity of the inlet air on the cooling in an improved dew-point evaporative cooler with a corrugated surface heat and mass exchanger.

An experimental study on oil-dispersion baths generated by the Jungebad apparatus

BackgroundSince the very early documentation of medical treatments, bathing is an essential part of almost all traditional medical systems. In this context the oil-dispersion bath, developed in the 1930s by Werner Junge has been developed from anthroposophic medicine. We aimed at analyzing the apparatus, which churns water and essential oils into an oil-water dispersion, by means of an experimental study. Material and MethodsUsing three different oils (rheumatic oil, citrus oil and rosemary oil) oil volumetric flow rate and oil droplet size distribution were examined at three different water volumetric flow rates of 5, 10, and 15 l/min at a constant temperature of 40 °C. Additionally, for the rheumatic oil measurements are taken at three different temperatures, 35, 40, and 45 °C at a constant volumetric flow rate of 10 l/min. Finally results were compared with a manual oil dispersion process. ResultsOil volumetric flow rate increases with increasing water volumetric flow rates. Oil flow rate increases with increasing water temperature. Droplet-size distribution shows an optimal fit with a log-normal distribution for a volumetric flow rate of 5 l/min in all oils applied with citrus and rosemary oil showing a larger mean diameter compared to the rheumatic oil. Comparing the oil droplet size distribution for a traditional oil bath, distributions behaved completely different in comparison to our distributions. Moreover it seemed not possible to create an oil-dispersion with repeatable droplet size distributions whereas the Jungebad apparatus created similar oil dispersions with predictable results, independent of the user. DiscussionThis is the first study to explore the mechanisms of creation of the oil-dispersion bath by means of an experimental set up. Based on these experimental results, a more fundamental theoretical approach should be carried out to complement our findings and to gain deeper insights in the hydrodynamic and droplets forming processes in the Jungebad apparatus.

Pengaruh tebal kaca terhadap kinerja kolektor surya pelat datar dengan menggunakan absorber batu granit

This paper presents the experimental data of the use of granite stone as an absorber of the tested solar colecctor. The purpose of this study is to know the effect of the cover thickness of the collector. Three different thickness of the glass cover of the collector, i.e. 3 mm, 5 mm, and 8 mm, were tested. Three identical collectors were utilized in this current study, and the collectors were placed facing North. The dimension of the granite absorber is 100 cm x 80 cm x 10 cm and the arrangement of the pipes in the collector is parallel with 7 pipes. The water used to remove the heat from the absorber was flowed naturaly due to the gravity. The water volumetric flow rates employed were 300 cc/min, 400 cc/min and 500 cc/min which were measured using a glass volume meter and a stop watch. The research results show that energy come to the absorber (Qin), energy absorbed by the absorber (Quse), and the temperature of water increase with the time. All of them have a peak at around 12.00-14.00 Wita. The thicknes of the glass cover affect the performance of the collectors. The glass cover thickness of 5 mm results in the better performance than that of the two others.

Effect of the gap height of radial gate on the volumetric flow rate in dam

This paper investigates how the variation of gap height of radial gate in scaled down dam would affect the volumetric flow rate. Both fluid/structure interaction (FSI) numerical simulation and experimental works on a scaled-down dam model were conducted, eventually both approaches yield results with discrepancy not exceeding 9.63%. For 10 mm and 12 mm gap, lowest water flow rate is being observed in the Gate 2 compared to Gate 1 and Gate 3. Conversely, the Gate 2 registered highest water flow rate for gate with gap of 8 mm. Generally, it is found that the volumetric flow rate increases along with the increase with the gap height of radial gate. Moreover, the volumetric water flow rate in actual dam also be determined using Reynolds number.

Impact of inclination on single phase heat transfer in a partially filled rotating pipe

Heat transfer in a partially-filled, rotating inclined pipe with water flowing through it is experimentally investigated. The test section is a 1000 mm long stainless steel pipe with 32.8 mm inner diameter and 1.1 mm wall thickness. The outer wall is painted black to improve its emissivity. The outer wall temperature distribution is captured using a thermal camera. Uniform wall heat flux (1405–10784 W/m2), water volumetric flow rate (100–830 ml/min), rotation rate (10–300 RPM) and pipe inclination angle (3° and 6°) are varied to study their influence on the heat transfer coefficient. Local heat transfer coefficient along the length of the partially filled rotating test section is reported. While heat transfer coefficient increases with the increase in wall heat flux, liquid volume flow rate and rotation rate, it decreases with increase in inclination angle. A generalised correlation to predict the average Nusselt number is developed in terms of four dimensionless numbers, viz., the flow Reynolds number to capture the effect of the axial fluid flow, rotation Reynolds number to account for the effect of pipe rotation, flow Froude number to take care of the effect of pipe inclination and dimensionless heat flux to incorporate the effect of wall heat flux on the heat transfer coefficient.

Performance Study of a Cylindrical Parabolic Concentrating Solar Water Heater with Nail Type Twisted Tape Inserts in the Copper Absorber Tube

This paper reports the overall thermal performance of a cylindrical parabolic concentrating solar water heater (CPCSWH) with inserting nail type twisted tape (NTT) in the copper absorber tube for the nail twist pitch ratios, 4.787, 6.914 and 9.042, respectively. The experiments are conducted for a constant volumetric water flow rate and during the time period 9:00 a.m. to 15:00 p.m. The useful heat gain, hourly solar energy collected and hourly solar energy stored in this solar water heater were found to be higher for the nail twist pitch ratio 4.787. The above said parameters were found to be at a peak at noon and observed to follow the path of variation of solar intensity. At the start of the experiment, the value of charging efficiency was observed to be maximum, whereas the maximum values of instantaneous efficiency and overall thermal efficiency were observed at noon. The key finding is that the nail twist pitch ratio enhances the overall thermal performance of the CPCSWH.

Development of a dual optical fiber probe for the hydrodynamic investigation of a horizontal annular drive gas/liquid ejector

A dual-channel optical fiber probe was developed to quantify the bubble characteristics (void fraction, velocity, and bubble size) in a gas–liquid annular ejector system. Water is pumped upstream of the ejector contraction. Since a low pressure region exists downstream in the ejector diffuser, this permits air to be sucked into the flowing liquid by jet pump action and the inlet air volumetric flow rate is measured by a flow meter. Verification of the void fraction (range 0.15–0.5) measured by the optical fiber probe was then possible and deviations were generally around ± 5%. Also, bubble velocity was measured using the optical probe by cross-correlating signals from the two fibers whose tips are separated by a known distance. Alternatively measuring bubble velocity using a particle image velocimetry method provided validation for the optical fiber probe system where a high speed camera was used to capture instantaneous bubble images at time intervals of 0.125ms. Excellent agreement between the velocities using both methods is reported. For bubble size measurements, analyzing the temporal signals from a single probe enabled estimation of the size of a bubble. Bubble sizes measured ranged between 1.5 and 6.0mm and size distributions were constructed for different ejector water volumetric flow rates ranging from 0.0022 to 0.0063m3/s. LabVIEW provided a convenient platform for coding the algorithms for estimating the void fraction, bubble velocity and bubble size. For further comparison, a CFD study of the ejector system was done, and the vertical radial profiles of the void fraction were compared with those obtained by the optical fiber system and these showed good agreement.

INCREASING EXTINGUISHING EFFECT OF WATER MIST BY ELEKTRIFICATION

This paper describes extinguishing experiments to verify the possibility of increasing the fire-extinguishing efficiency of low-, medium- and high-pressure water mist by its charging by the electric field of high DC voltage. The experimental results confirmed the effects of the electrical voltage, the configuration of electrodes (anode, cathode), the volumetric water flow rate, water pressure and the type of mist nozzle. Higher fire-extinguishing effect of electrically-charged water mist was shown by a shorter extinguishing time, a smaller volume of water to extinguish the fire and a higher percentage of successful extinguishing attempts. Benefit: faster and more efficient fire-fighting with a smaller risk of injury of persons and smaller subsequent damage in the protected space.

Imaging water velocity and volume fraction distributions in water continuous multiphase flows using inductive flow tomography and electrical resistance tomography

This paper presents the design and implementation of an inductive flow tomography (IFT) system, employing a multi-electrode electromagnetic flow meter (EMFM) and novel reconstruction techniques, for measuring the local water velocity distribution in water continuous single and multiphase flows. A series of experiments were carried out in vertical-upward and upward-inclined single phase water flows and ‘water continuous’ gas–water and oil–gas–water flows in which the velocity profiles ranged from axisymmetric (single phase and vertical-upward multiphase flows) to highly asymmetric (upward-inclined multiphase flows). Using potential difference measurements obtained from the electrode array of the EMFM, local axial velocity distributions of the continuous water phase were reconstructed using two different IFT reconstruction algorithms denoted RT#1, which assumes that the overall water velocity profile comprises the sum of a series of polynomial velocity components, and RT#2, which is similar to RT#1 but which assumes that the zero’th order velocity component may be replaced by an axisymmetric ‘power law’ velocity distribution. During each experiment, measurement of the local water volume fraction distribution was also made using the well-established technique of electrical resistance tomography (ERT). By integrating the product of the local axial water velocity and the local water volume fraction in the cross section an estimate of the water volumetric flow rate was made which was compared with a reference measurement of the water volumetric flow rate.In vertical upward flows RT#2 was found to give rise to water velocity profiles which are consistent with the previous literature although the profiles obtained in the multiphase flows had relatively higher central velocity peaks than was observed for the single phase profiles. This observation was almost certainly a result of the transfer of axial momentum from the less dense dispersed phases to the water, which occurred preferentially at the pipe centre. For upward inclined multiphase flows RT#1 was found to give rise to water velocity profiles which are more consistent with results in the previous literature than was the case for RT#2—which leads to the tentative conclusion that the upward inclined multiphase flows investigated in the present study did not contain significant axisymmetric velocity components.

Numerical modelling of series-parallel cooling systems in power plant

The paper presents a mathematical model allowing one to study series-parallel hydraulic systems like, e.g., the cooling system of a power boiler's auxiliary devices or a closed cooling system including condensers and cooling towers. The analytical approach is based on a set of non-linear algebraic equations solved using numerical techniques. As a result of the iterative process, a set of volumetric flow rates of water through all the branches of the investigated hydraulic system is obtained. The calculations indicate the influence of changes in the pipeline's geometrical parameters on the total cooling water flow rate in the analysed installation. Such an approach makes it possible to analyse different variants of the modernization of the studied systems, as well as allowing for the indication of its critical elements. Basing on these results, an investor can choose the optimal variant of the reconstruction of the installation from the economic point of view. As examples of such a calculation, two hydraulic installations are described. One is a boiler auxiliary cooling installation including two screw ash coolers. The other is a closed cooling system consisting of cooling towers and condensers.

Experimental study on two-phase flow pressure drop during steam condensation in trapezoidal microchannels

The characteristics of two-phase pressure drop for steam condensation in trapezoidal microchannels with different cross-sectional geometries via novel experimental facility and specific analytical method were investigated in this study. Three types of multi-port trapezoidal microchannels with hydraulic diameter range of 134–166μm and aspect ratio range of 3.1–6.7, were employed. The pressure drop was determined under steam mass flux between 130 and 340kgm−2s−1 accompanied with various cooling water volume flow rate ranging from 20 to 40Lh−1. The results showed that the total frictional, deceleration and contraction pressure drop were more obvious than other local pressure drop. It also presented that not only the steam mass flux, steam quality, cooling water volumetric flow rate and hydraulic diameter but also the aspect ratio had a significant influence on the two-phase frictional pressure drop. The comparison between the experimental data and existing models were finally carried out to verify their predictive accuracy for steam condensing flows in microchannels, and accordingly a modified Friedel model was proposed. The model considering the effect of geometrical parameters of microchannels, the forces acting on fluid and fluid properties, can be available to predict the steam condensing two-phase flow pressure drop multiplier for liquid flowing alone.

Research on heat exchange and control method of the evaporative condenser in the equipment of flax fiber modification

Aiming at improving heat utilization of the evaporative condenser in the equipment of flax fiber modification, we proposed a new method to control the main factors that affect the heat exchange of the evaporative condenser. Firstly, a steady-state mathematical model was developed to evaluate the heat exchange of evaporative condenser after analyzing the heat exchange process of ammonia recovery system in the modification equipment and the thermal mass transfer process of evaporative condenser on details. Then, the thermal load of evaporative condenser was computed and analyzed through the numerical simulation. It is found that the suction pressure of compressor has obvious influence on the thermal load of evaporative condenser. Besides, under the maximum suction pressure, the thermal load is 291.4 kW, and the corresponding air speed and spraying water volumetric flow rate are 2.5 m/s and 12 m3/h, respectively. When the thermal load decreases, the air speed and spraying water volumetric flow rate are adjusted accordingly.

Design of an Air-Sparged Tubular Photocatalytic Reactor for the Degradation of Methylene Blue: Mass-Transfer Limitation Studies

An alternative process for the removal of organic pollutants in aqueous systems is photocatalysis. The challenges hindering its industrial use are electron-hole recombination and mass-transfer limitations. In order to address these problems, the objective of this study is to introduce air by sparging, and design an air-sparged photocatalytic reactor using titanium dioxide immobilized on borosilicate glass. The performance of the reactor on the removal of the model pollutant, methylene blue (MB), was evaluated and compared against the reactor operated without sparging. The effect of mass-transfer limitations on reactor performance was also investigated by regression using a Langmuir-type model equation. The sparged photocatalytic reactor was able to degrade 57% MB in 2 hours, an improvement of 40% compared to no sparging, and is comparable to similar reactors in literature, but with the advantage of using less expensive materials of construction and simpler immobilization technique. Mass-transfer limitation studies showed a good fitting of the initial reaction rate r , with r = 0.1399 Q / (0.6120 + Q ) for the sparged operation, and Q is the volumetric flowrate of water (L/min). The model also shows that the reactor operates near the reaction-limited regime, and that the extent of mass-transfer limitation effects was reduced by the present reactor.

Demulsification of stable emulsions from produced water using a phase separator with inclined parallel arc coalescing plates

A novel and highly efficient oil–water separator equipped with a series of inclined multiple arc coalescence plates is developed and optimized for the removal of stable oil emulsions from produced water. The synthetic high salinity produced water with stable emulsions was prepared by mixing Catenex oil and the emulsifying surfactant (Armac T) with brine water. A series of experiments were performed to evaluate the effects of the arc coalescence plate geometry, produced water volumetric flow rate, influent oil concentration, and treatment temperature on the oil removal efficiency using the developed separator. Optimal coalescence plate arc geometry for maximum oil removal at different operating conditions was determined. Using the optimal coalescence plate arc geometry, strong correlations between oil removal efficiency from produced water, volumetric flow rate, and treatment temperature were established. The results demonstrated that the developed oil–water separator is highly effective in the treatment of stable emulsions in produced waters due to the combined effects of chemical demulsification and oil droplet coalescence.

Improving Biogas Quality through Circulated Water Scrubbing Method

The dependence of human being on fossil fuels has decreased significantly the conventional energy resources. To overcome this problem it is required alternative substitute fuels which are cheap and accessible which biogas is one of the fuels. Nevertheless, the use of biogas has not yet been maximized because of the low calorific value which is produced from the process without purification. The circulated water absorption method is one mean of effective biogas purification. Under this method it is expected to increase the level of methane (CH4) and to reduce both the level of carbon dioxide (CO2) and hydrogen sulfide (H2S). In order to obtain the aim, the research was carried out under variations of water and biogas volumetric flow rate. The results show that the highest quality of biogas produced was under the variation of water volumetric flow rate of 15 lt/min with biogas volumetric flow rate of 1 lt/min which increased the level of methane (CH4) from 59.36 % to 62.8 % and decreased the carbon dioxide (CO2) content from 33.53 % to 26.8 %, and hydrogen sulfide (H2S) from 208.33 to 86 ppm. Lower biogas and water volumetric rates allowed longer contact between biogas molecule and absorbent. This resulted in an opportunity for absorbent more active to dissolve carbon dioxide and hydrogen sulfide in biogas. These compounds then flowed outward of the scrubbing unit along with the absorbent. The research proved that the raw biogas purification by circulated water scrubbing method was an effective mean in enhancing the quality of biogas.

A two-phase flow meter for determining water and solids volumetric flow rates in stratified, inclined solids-in-water flows

This paper describes the design and implementation of a two-phase flow meter which can be used in solids-in-water two phase pipe flows to measure the in-situ volume fraction distributions of both phases, the velocity profiles of both phases and the volumetric flow rates for both phases. The system contains an Impedance Cross Correlation (ICC) device which is used in conjunction with an Electromagnetic Velocity Profiler (EVP). Experimental results were obtained for the water and solids velocity and volume fraction profiles in upward inclined flow at 30° to the vertical, in which highly non-uniform velocity and volume fraction profiles occur.

Design and construction of a secondary electron suppressed Faraday Cup for measurement of beam current in an electrostatics proton accelerator

In this work, design and construction process of a Faraday Cup (FC) for measuring the beam current in a 200keV, 80W electrostatic proton accelerator (ES-200) at Shahid Beheshti University has been presented. After choosing the appropriate material, optimum thickness and dimensions of the FC have been calculated using SRIM, MCNPX and CST Studio package, respectively. Geometrical parameters are optimized to reduce the scape of secondary electrons from the cup. The designed FC has been constructed and installed on the ES-200 accelerator. According to the experimental results, maximum proton current of 400μA±10% has been measured. In addition, the required cooling system has been designed and simulated using ANSYS. Based on the computational results with the water volumetric flow rate of 4×10−5m3s−1, the maximum temperature in the FC would not exceed 320K.