Effect Of Water Flow Rate Research Articles

Parametric study of PEM water electrolyzer performance

AbstractGreen hydrogen can contribute significantly to combating climate change by helping to establish an energy economy that is both sustainable and carbon-free. One pathway to obtaining green hydrogen is by water electrolysis powered by renewable energy. Proton exchange membrane water electrolysis (PEMWE) is a promising option owing to its high current density at high efficiency. Here, we report on experimental results from a parametric investigation of PEMWE. We have examined the effect of water flow rate at 80 °C using a 5 cm2 PEM electrolyzer cell hardware and lab-fabricated membrane electrode assemblies. The results showed that a water flow rate of 0.08 ml cm−2 min−1 was sufficient to meet the water consumption by electrochemical reactions at the anode as well as water depletion by diffusion and electroosmotic drag. We then employed this optimal flow rate to examine the effect of various operating parameters on PEMWE performance and efficiency such as operating temperature, membrane thickness, flow field channel configuration, and porous transport layers as a function of the applied voltage. The results provide useful insights into the operating conditions for optimal PEMWE performance. Graphical abstract

Response surface methodology was used to optimize the defluorination process of steam-enhanced microwave roasting waste cathode carbon

As a typical hazardous solid waste, improper treatment of waste cathode carbon (WCC) will cause great harm to animals and plants and their living environment. In order to make the treatment of WCC more simple, efficient and clean, this paper mainly adopts the method of microwave roasting and introducing water vapor to make the fluoride in WCC melt at high temperature and be absorbed by water vapor. The effects of water flow rate, reaction temperature, reaction time, material particle size and other important factors on the defluorination efficiency of WCC were studied by single factor experiment. In this paper, the response surface method (RSM) was used to obtain and verify the best results of the experiment, and the optimum process conditions of water vapor enhanced microwave roasting WCC defluorination were determined: the reaction temperature was 1100 °C, the reaction time was 2.8 h, and the water flow rate was 3.2 mL·min−1. Under this condition, the defluorination effect of WCC is the best. The predicted value of defluorination efficiency of WCC is 99.85 %, and the actual value is 99.8 %.

The impact of variation in water flow rate and temperature on reliability analysis of run of the river power plants

AbstractA run‐of‐the‐river power plant is a renewable energy source used for electricity production. Its power output depends on the varying water flow rate over time, which can impact the reliability of the electric network. Previous research has not studied the effects of water flow rate and temperature variations on the hazard rate of the plant's components. This paper addresses this gap by investigating the impact of these variations on the reliability of electric networks with run‐of‐the‐river power plants. The analysis considers the hazard rates of the plant's components, incorporating the relationship between hazard rate and temperature based on the Arrhenius law. Parameters such as power output, current, power loss, operating temperature, and hazard rate are calculated for different water flow rates and ambient temperatures. Numerical simulations on a test system are conducted to examine the influence of water flow rate and temperature on the reliability indices of the electric network. The results demonstrate that water flow rate and temperature significantly affect the hazard rates of run‐of‐the‐river power plants. This highlights the need to consider these factors in the reliability analysis of electric networks incorporating these renewable resources.

An investigation into the use of riverine mesocosms to analyse the effect of flow velocity and recipient textiles on forensic fibre persistence studies

Textile fibre evidence can provide important activity level information in criminal cases. To date, very few studies have investigated fibre persistence on fabrics exposed to aquatic conditions, even though items of evidence and victim’s bodies can regularly be found in aquatic environments. This lack of research on whether fibres (and other trace evidence) persist on evidence submerged in water, has shown to impact practice as it is reported that crime scene examiners do not attempt to recover this evidence, due to the belief that it would not be present. The dynamic nature of aquatic environments mean that the studies are difficult to conduct in situ and variables, such as water flow rate are not possible to control and thought to be difficult to monitor. To address these challenges, artificial streams (also known as mesocosms) were employed in this study to investigate the persistence rate of polyester fibres on different fabric types (Woollen/nylon mix carpet, 100% polyester fleece, and 95% polyester/5% elastane sports vest) for a four week exposure time (1, 8, 24, 48, 120, 168, 264, 336, 504 and 672 hrs). The effect of water flow rate on the persistence of fibres was investigated by conducting the experiment with two flow velocities; 'high' (∼2.75 L/s) or 'low' (∼0.7 L/s). Significant differences between textile type were seen at 504 hrs under low flow conditions and 8, 24, 168 and 264 hrs under high flow conditions. When comparing flow velocities, a significant difference was seen at 1 hr exposure for the fleece textile only, indicating that the two flow rates used in this study do not significantly affect fibre persistence. Initial loss rates were highest for the first hour of submergence for the carpet, fleece and sports vest. Fibre persistence rates were highest on the carpet, followed by fleece and then sports vest. Persistence rates remained mostly constant after 24 hrs for all textiles but with redistribution of fibres between textiles being seen after this exposure time. The use of artificial flumes in this study provided a balance between realistic experimentation and a controlled study; key experimental variables could be continously and safely monitored. This study provides the first fibre persistence data in river type environments and proposes a new method for testing persistence in aquatic environments. This approach is not limited to fibres evidence and could be employed for other evidence such as glass, pollen, fingerprints and DNA.

Performance evaluation of a solar desalination-hot water system using heat pipe vacuum tube parabolic trough solar collector – An experimental study with Taguchi analysis

The utilization of renewable energy to generate hot water and distilled water can considerably reduce pollution. This study looked at a hybrid system that used a parabolic-trough heat pipe solar collector to generate hot water while also providing drinking water. The system is constructed in two stages, the first producing distilled water and the second producing hot water. A concave mirror increases the temperature of a vacuum tube heat pipe's evaporator area and the condenser of the heat pipe, which is directly connected to the desalination system's saltwater tank. To improve the amount of drinking water generated and to transfer thermal energy to the hot water generation system, a condenser region at the top of the saltwater tank, as well as multiple heat pipes, were employed. The effect of the water flow rate (200, 300, 400 and 500 ml/min), number of heat pipes (0, 1, 2 and 4), and the filling porous medium (0, 0.3, 0.6 and 0.9 m) of the vacuum tube on the system performance were evaluated. In addition, Taguchi-Based design of experiments was used to determine the effect of independent input parameters on the energy and efficiency of the system. The results showed that the effects of water flow rate, porous medium length, and number of heat pipes on the energy efficiency were approximately 50.89%, 26.53%, and 20.6%, respectively. Furthermore, the cost of distilled water and the cost of hot water were approximately 0.0380 $/L and 1.01 $/m3, respectively. Additionally, the highest daily productivity of the system (4940 ml/day) was obtained with a water flow rate of 200 ml/min, a length of porous media of 0.6 m, and four heat pipes. The CO2 emission reduction based on the environmental and enviroexergoeconomic parameters of the proposed systems ware improved by 37.5% and 268.4%, respectively, resulting in returns of approximately $358.1 and $260.5, respectively.

Operating Parameters Optimization for the Production of Liposomes Loaded with Antibodies Using a Supercritical Fluid-Assisted Process

Encapsulation of antibodies represents a significant advance to protect and deliver these therapeutics in a controlled manner, increasing the stability requested to cover the temporal gap between particle production and their administration. Furthermore, using encapsulation, extracellular, cell surface, and intracellular targets can be reached. This work examines the feasibility of encapsulating mouse IgG isotype control antibodies within phosphatidylcholine-based liposomes using a supercritical fluid-based process called SuperLip (Supercritical-assisted Liposome formation). This process allows a continuous production of both nano- and micrometric liposomes with high encapsulation efficiency working under mild operative conditions. The effect of some operative parameters has been studied on liposome mean diameter, particle size distribution, and antibody entrapment efficiency, comparing these data with those collected working with liposomes obtained by the thin-layer hydration technique. In particular, the effect of water flow rate and of the antibody loading were studied. Antibody-loaded liposomes with mean diameters in the range between 205 and 501 nm have been obtained by using a supercritical fluid-assisted process. High entrapment efficiencies up to 94% have been calculated.

Effects of external injection of deionized water and water with impurities on Water-assisted flares

Water-assisted flares are used on offshore platforms and occasionally at downstream oil and gas facilities to reduce soot and oxides of nitrogen (NOx) emissions and flame luminosity. Typically, water-assisted flares inject water into the flame from outside the flare stack (external injection), and the water often contains high concentrations of impurities. Different configurations of water injection were explored using a range of water flow rates, atomizer angles, and radial displacements from the burner center to understand the effects of water flow rate and location of water entrainment into the flame on emissions. A range of sodium chloride (NaCl) concentrations was also tested as a surrogate species for the impurities contained in the water used at offshore and downstream oil and gas facilities. Flow visualization analysis was carried out, and the water droplet velocity field was used to discuss their motion transitioning from being dominated by their momentum to that of the buoyancy of the combustion products. This study used atmospheric turbulent non-premixed flames on a two-inch circular burner at a constant propane flow rate of 20 standard L/min. It was discovered that the atomizer’s angular displacement plays a significant role in black carbon (BC) and NOxemissions suppression, but the atomizer’s horizontal displacement does not affect NOxemission. Water directed very close to the base of the flame ensured water was present early in the combustion process relative to other external injected configurations and reduced emissions by a greater extent compared to when the water was directed higher in the flame. The buoyancy of the flame affects the velocity of the injected water, helps to redirect its flow in the flame, and increases its mixing with fuel and air. Large amounts of water droplets pass through the flame front and evaporate within the fuel side of the flame envelope. The flame color and luminosity were affected by an increased NaCl concentration and the different configurations of the injected water. Higher NaCl concentration in the water causes an increase in BC emissions and a slight decrease in NOx emissions relative to deionized water. The smaller NaCl concentration in the water does not affect NOxand BC emissions compared to deionized water.

Heat Transfer Analysis of Melting Process over A Horizontal Three Fins Tube With Different Orientations

In this paper, an experimental study was achieved for the melting process of a phase change material around a copper tube with three longitudinal copper fins that placed inside a rectangular plastic container as a horizontally latent thermal energy storage unit (LTESU). A paraffin wax was used as a phase change material (PCM). Some parameters were considerable in this work like the directions of fins at angles of (0°, 30°, 60° and 90°), temperature of the water entering to the finned tube at (55, 65 and 75) °C and the effect of water flow rate inside the finned tube at (7.5, 15 and 22.5) liters / min. The law of energy conservation was used to find the amount of potential energy stored inside paraffin wax by calculating the energy liberated from the hot water entering the system. The results showed that the effect of the temperature of water entering to the system has given increases in the melting with rate of (64.3)% at a temperature of (75) °C compared to the water temperature at (55) ° C. Also the increases in melting rate has reached to (17.5)% at the flow rate (22.5) liters / min compared to the flow rate (7.5) liters / min . The melting has reached to (25.6)% at the angle of (30) degrees compared to the angle of (90) degrees. The results also showed that when using temperature of (55) ° C, water flow rate (7.5) l/min and rotation angle of (30°) that the maximum enhancement ratio in the melting fraction reached to (5.74)% and when using the water temperature (65) degrees and flow rate (15) l/min and the angle of rotation (30°) the maximum enhancement ratio was (11.9)%. When using the incoming water temperature (75) °C and flow rate (22.5) l/min and the angle of rotation at (30°) the maximum enhancement ratio was (12.03)%. The highest percentage of time savings was also reached (12.03%) at the angle of (30°) compared with (90°). Finally, the highest percentage of energy liberated was reached at a water temperature (75) ° C and fin rotation angle (30°) and the flow rate (22.5) l / min was reached (5355) watts.

Effect of water flow rate on properties of zinc oxide thin films prepared using spatial atomic layer deposition

In this study, spatial atomic layer deposition (ALD) system is employed to grow zinc oxide films (ZnO) with diethylzinc and water precursors. The H2O flow rate is varied to investigate its effect on electrical, structural and optical properties of the films. The experimental results show that the low H2O flow rates lead to a lower amount of oxygen vacancies compared to higher flow rates. The x-ray diffraction reveals the stress released and crystalline structure repair at high flow rates. The film deposited at 9 sccm corresponding to the saturation point exhibits the highest electron mobility of 32 cm2V–1s–1 and the lowest resistivity of 0.05 Ω-cm. A deposition mechanism is proposed, where the low H2O flow rate requires multiple ALD cycles to complete oxidation of surface ligands, thereby suppressing the oxygen vacancies formation. High H2O flow rates give rise to better ZnO growth, favoring the oxygen vacancies formation and stress release.

Effects of surfaces and nozzles on hydrodynamic characteristics of water film during spray impingement

The hydrodynamic behaviors during the spray impingement onto a solid surface are greatly different from the single or multiple droplets impingement since the spray is polydisperse and the interaction between droplets is indispensable. The present paper investigated the hydrodynamic characteristics of the water film formed on the different solid surfaces including the radial flow and wave, which characterized the spray impingement to some extent. Experimental results showed that a bulge on the solid surfaces under the pressure-swirl nozzle was observed, and the bulge phenomenon became indistinct with the increase of spray heights. The water film was subdivided into the raised zone, annular zone and free flow zone according to the radial film distribution on the surfaces. The maximum Reynolds number of the radial flow was 1099 and lower than the critical Reynolds number (5 × 105) of the flow along a flat plate, indicating that the radial motion of the water film along the solid surfaces belonged to the laminar flow. The effects of water flow rates and spray heights on the radial flow and wavy characteristics of the water film formed on the PMMA surface were relatively more significant than the polished copper surface. Besides, via comparison, it was found that the fluctuation of the water film produced by the air-atomized nozzle was more dramatic than the pressure-swirl nozzle due to the direct droplet impingement. The experimental findings provide some references for further research on hydrodynamic behaviors of spray impingement.

Effect of Water Flow on Underwater Wet Welded A36 Steel

Underwater wet welding (UWW) combined with the shielded metal arc welding (SMAW) method has proven to be an effective way of permanently joining metals that can be performed in water. This research was conducted to determine the effect of water flow rate on the physical and mechanical properties (tensile, hardness, toughness, and bending effect) of underwater welded bead on A36 steel plate. The control variables used were a welding speed of 4 mm/s, a current of 120 A, electrode E7018 with a diameter of 4 mm, and freshwater. The results show that variations in water flow affected defects, microstructure, and mechanical properties of underwater welds. These defects include spatter, porosity, and undercut, which occur in all underwater welding results. The presence of flow and an increased flow rate causes differences in the microstructure, increased porosity on the weld metal, and undercut on the UWW specimen. An increase in water flow rate causes the acicular ferrite microstructure to appear greater, and the heat-affected zone (HAZ) will form finer grains. The best mechanical properties are achieved by welding with the highest flow rate, with a tensile strength of 534.1 MPa, 3.6% elongation, a Vickers microhardness in the HAZ area of 424 HV, and an impact strength of 1.47 J/mm2.

Experimental Investigation on Improvement of Wet Cooling Tower Efficiency with Diverse Packing Compaction Using ANN-PSO Algorithm

In this study, a numerical and empirical scheme for increasing cooling tower performance is developed by combining the particle swarm optimization (PSO) algorithm with a neural network and considering the packing’s compaction as an effective factor for higher accuracies. An experimental setup is used to analyze the effects of packing compaction on the performance. The neural network is optimized by the PSO algorithm in order to predict the precise temperature difference, efficiency, and outlet temperature, which are functions of air flow rate, water flow rate, inlet water temperature, inlet air temperature, inlet air relative humidity, and packing compaction. The effects of water flow rate, air flow rate, inlet water temperature, and packing compaction on the performance are examined. A new empirical model for the cooling tower performance and efficiency is also developed. Finally, the optimized performance conditions of the cooling tower are obtained by the presented correlations. The results reveal that cooling tower efficiency is increased by increasing the air flow rate, water flow rate, and packing compaction.

Experimental analysis of reverse cycle defrosting and control strategy optimization for transcritical carbon dioxide heat pump water heater

The heating performance of air source transcritical carbon dioxide heat pump will be dramatically reduced with frost formation when operating in cold regions. Although reverse cycle defrosting is widely used, no information is available in the transcritical carbon dioxide system. In this paper, the reverse cycle defrosting was experimentally investigated in a transcritical carbon dioxide heat pump with a microchannel evaporator. The effect of water flow rate, initial water tank temperature, compressor frequency and electronic expansion valve opening are respectively studied, and an optimized control strategy is proposed considering the defrosting time and stability. Results show that thermal energy is considerably affected by water side parameters, and stability is more sensitive to the water temperature and electronic expansion valve opening. With the optimized reverse cycle defrosting, defrosting time and total energy consumption are reduced by 95 s and 21.8% compared with the pre-set basic control strategy, and the total energy consumption is also saved by 38.6% compared with the other defrosting method. The optimized reverse cycle defrosting is verified to be preferable for the transcritical carbon dioxide system, and the presented discussion is beneficial for the application of reverse cycle defrosting in the air-to-water heat pump.

Effects of water flow rate and surface cover plant density on the growth of duckweed (Lemna minor L.)

Globally, agriculture sector is facing unprecedented challenges in producing fertilizers and increasing the amount of fertilizer production without having negative impact on the environment. Thus, the organic fertilizers are needed to be produced as they do not give any damages to the environment. Duckweed plant has a lot of potentials that can be used in the agriculture sector. This plant can breed in approximately 16-48 hours by splitting. The water needs and its breeding speed ability are the basis for conducting this research. The research objective was to determine the effect of water flow rate and surface cover plant density on the growth and yield of duckweed plants. This research was conducted in November–December 2018 in Cangkringan District, Sleman, Special Region of Yogyakarta, Indonesia. The experiment was arranged in a split plot design. The main plot was irrigation water flow rate, consisting of two levels, namely large water flow rate (0.336 L.second-1) and small water flow rate (0.085 L.second-1). The subplot was the density of the duckweed plant surface cover, consisting of 10%, 20%, 40% and 60%. The results of this study indicated there was no effect of water flow rate on the plant growth, yield, and yield quality of duckweed plants. The C/N ratio of the duckweed plants fulfilled the requirement to be used as green manure.

Particle migration and blockage in geothermal reservoirs during water reinjection: Laboratory experiment and reaction kinetic model

Abstract During water reinjection in geothermal reservoirs, the risk of particle migration and blockage is often unavoidable, especially in the reservoirs with high mud content and poor consolidation. In this paper, a series of core flooding experiments using a sand-packed tube were conducted to evaluate the effects of water flow rate, sand grain composition, temperature, and confining pressure on the particle migration and blockage in reservoir. A novel reaction kinetic model was established to describe the process of particle migration and blockage in porous media. The results show that the movable particles in reservoir can be divided into fine particles (size

Extrusion texturization of cricket flour and soy protein isolate: Influence of insect content, extrusion temperature, and moisture-level variation on textural properties.

Due to the increasing global population and unsustainable meat production, the future supply of animal‐derived protein is predicted to be insufficient. Currently, edible insects are considered as a potential and “novel” source of protein in the development of palatable meat analogues. This research used high moisture extrusion cooking (HMEC), at a screw speed of 150 rpm, to produce meat analogues using full‐ or low‐fat cricket flours (CF) and soy protein isolate (SPI). Effects of water flow rate (WFR), cooking temperature (9 and 10 ml/min; 120, 140, and 160°C, respectively), and CF inclusions levels of 0, 15, 30, and 45% were analyzed. Cooking temperature and CF inclusion had a significant effect (p < .05) on both tensile stress in parallel and perpendicular directions, while WFR had no significant effect (p = .3357 and 0.7700), respectively. The tensile stress increased with temperature but decreased with CF inclusion at both WFRs. Comparatively, the tensile stress was stronger at WFR of 9 ml/min than at 10 ml/min; however, the tensile stress in parallel was mostly greater than tensile stress in perpendicular directions. Fibrous meat analogues with high anisotropic indices (AIs) of up to 2.80 were obtained, particularly at WFR of 10 ml/min and at inclusions of 30% low‐fat CF. By controlling HMEC conditions, full‐/low‐fat cricket flours at 15% and 30% inclusions can offer an opportunity to partially substitute SPI in manufacturing of fibrous meat analogues.

Biodosimetric Studies for Ballast Water Treatment

Ultraviolet (UV) reactor for ballast water treatment is investigated in this paper. Experimental and numerical simulations are performed for a base reactor named LBW850e. B. Pumilus is chosen as a challenge organism in the experiments. Simulation is carried out based on the commercial software ANSYS FLUENT with user defined functions implemented. The effects of water flow rate and UV transmittance (UVT) on the UV reactor performance in terms of reduction equivalent dose (RED) are studied. The results show that the increase of water flow rate reduces RED. While RED increases with the increase of UVT. The experimental and simulation results show reasonable agreement with each other. With this achieved, the numerical model developed in the current work can be applied to other reactors.

The Effects of Water Flow Rate On The Air Entrainment Process From Vertical Plunging Water Jet With Downcomer

This study is intended to research the characteristics of bubbles produced by the phenomenon of air entrainment. This phenomenon is used in the Jameson cell, a flotation system used to separate valuable minerals from impurities. This process has proven successful in providing high separation efficiency. However, the characteristics of hydrodynamic bubbles and water entrainment have not been widely described. Research was set up in the form of a water loop consisting of a pump, flow meter, nozzle, downcomer, and water box. Data collection is done by using a digital camera and a high-speed digital video camera with a backlighting system. The resulting image is processed with software to obtain quantitative data. Results indicate that increasing the water flow rate also causes the ratio of air to water to increase (air entrainment).Air Entrainment is natural phenomenon air carried out as a result of a fluid jet stream. Mass transfer deepens penetration because a high jet speed produces bubbles and tends to force those bubbles towards the flow. Increasing the water flow rate will expand the surface roughness to produce more bubbles. Thus, it can be concluded that there are three phenomena that will affect whether or not the discharge will increase the air entrainment process: depth of bubble penetration, area of bubble dispersion, and air entrainment rate.

Sediment delivery of partially-unfrozen loam soil rill by snow/glacier meltwater flow

Erosion of freeze-thaw soil by meltwater from snow/glacier is one of the main erosion types in high altitude or latitude regions. This study aims to experimentally measure soil erosion processes over partially-unfrozen soil slopes in laboratory. The experiments including three slope gradients of 10°, 15°, and 20°, three water flow rates of 1, 2, and 4 L/min (0.06, 0.12, and 0.24 m3/h), and three thawed-soil depths of 1, 2, and 5 cm were conducted to measure sediment concentration and calculate its delivery rate under seven slope lengths of 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, and 6.0 m. The sediment delivery rates from nonfrozen soil slopes under the corresponding slope gradients, flow rates, and slope lengths also were measured as control treatments. Results showed that the sediment delivery rate from both partially-unfrozen and nonfrozen soil slopes increased logarithmically with slope length. The sediment delivery rate from partially-unfrozen soil slope increased with the increased slope gradient and meltwater flow rate significantly, and the effect of water flow rate on it was greater than that of slope gradient. The thawed-soil depth did not significantly affect sediment delivery rate. The sediment delivery rate from a partially-unfrozen loamy soil slope averagely was 11.4% smaller than that from nonfrozen soil slope. This study is helpful to understand the erosion process of thawing-soil by meltwater from snow/glacier.

Heat transfer enhancement in a hybrid PV cell-cooling tower

This research has been conducted with the purpose of finding an innovative and environmentally friendly means of cooling for a photovoltaic (PV) solar cell to overcome the common obstacle that hinders PVs to be widely used. A small scale cooling tower was devised and fabricated that works based on evaporation cooling. To optimize the cooling performance, the effect of water flow rate and wind speed were investigated. The experiments were conducted at three different water flow rates with and without considering wind. The average PV cell temperature and the percentage increase in electrical output regarding the reference state of without cooling at each wind speed were measured. After introducing water to the back of the PV cell, the measured value of surface temperature followed a downward trend with a steep slope at lower flow rates. The results showed a significant rise of 44.83% in PV electrical efficiency at the highest flow rate when there is no wind. However, this enhancement reduced to 21.49% and 19.49% for wind speed of 2 m/s and 3.5 m/s, respectively. The net evaporation rate was also calculated for each case to explain the reasons for the observed trends. Finally the feasibility study of the cooling system was conducted and it was found that the proposed cooling system was efficient and practical.