Effect Of Fluid Flow Rate Research Articles

Experimental study on the vibration characteristics of fluid–structure coupling in the transition process of flexible bending pipes

The flexible bending pipes with large aspect ratios are more likely to cause large vibrations in the extraction of offshore oil and gas resources, which can accelerate the fatigue damage of the pipes. In order to explore the characteristics of fluid–structure coupling vibration during the transition period after the flexible bending pipe starts to transport fluid, an experimental platform of flexible bending pipes fluid–structure coupling vibration was created. The strain and vibration displacements of the pipe were measured by a resistance strain gauge and a high-speed camera system, respectively. According to the measure results, the largest values of stress and strain both were discovered at the pipe's two ends, and the maximum values of vibration displacement and vibration velocity were found in the middle of the pipe. The phenomenon indicates that the two ends of the pipe are more prone to fatigue damage. Moreover, the dynamic response and dynamic characteristics of the pipeline during the transition process were investigated. In addition, the effects of fluid flow rate, pipe wall thickness and different pipes on the dynamic response and dynamic characteristics of the pipe were also investigated in the present work.

Thermal management analysis of new liquid cooling of a battery system based on phase change material and thermoelectric cooler

The crisis of global warming and environmental pollution has led to the development of electric cars in recent decades. Meanwhile, designing a suitable cooling system for the battery is one of the ways to improve the performance of the electric vehicles. The present work experimentally introduces and examines a new type of liquid cooling system based on the combination of phase change materials (PCM) and thermoelectric cooler (TEC). The battery simulator pack is cooled by water and the heat of water is absorbed by the TEC. In this work, unlike previous works, PCM is used as a passive method to control the temperature of the hot side of the TEC. The effect of fluid flow rate, number and electric power of the TEC as well as the types of the PCM (RT35&RT50) on the system performance have been investigated. In a certain electric power, by changing the number of modules, the voltage is regulated in such a way that the input electric power remains constant. Results showed that increasing flow rate, TECs number and input electrical power decreases the battery pack temperature. However, improvement of the coefficient of performance have a direct relationship with the water flow rate and the TECs number and it is inversely related to the input power. It was also observed that in the same conditions, RT35 keeps the battery pack at a lower temperature than RT50 due to its lower phase change temperature. However, RT35 has higher COPw but lower COPc than RT50. Because the temperature of the battery pack and COP both play a decisive role in designing a cooling system, with the simultaneous application of two limits of TBPS<40℃ and COPw>2, 3TEC/P2 mode exhibits the best performance in the present work with COPc = 6.7, COPw = 2.14 and TBPS = 34.7 ℃.

Fluid flow influences ultrasound-assisted endothelial membrane permeabilization and calcium flux.

The local fluid dynamics experienced by circulating microbubbles vary across different anatomical sites, which can influence ultrasound-mediated therapeutic delivery efficacy. This study aimed to elucidate the effect of fluid flow rate in combination with repeated short-pulse ultrasound on microbubble-mediated endothelial cell permeabilization. Here, a seeded monolayer of human umbilical (HUVEC) or brain endothelial cells (HBEC-5i) was co-perfused with a solution of microbubbles and propidium iodide (PI) at either a flow rate of 5 or 30ml/min. Using an acoustically coupled inverted microscope, cells were exposed to 1MHz ultrasound with 20-cycle bursts, 1ms PRI, and 2s duration at a peak negative pressure of 305kPa to assess the role of flow rate on ultrasound-stimulated endothelial cell permeability, as well as Ca2+ modulation. In addition, the effect of inter-pulse delays (∆t=1s) on the resulting endothelial permeability was investigated. Our results demonstrate that under an identical acoustic stimulus, fast-flowing microbubbles resulted in a statistically significant increase in cell membrane permeability, at least by 2.3-fold, for both endothelial cells. Likewise, there was a substantial difference in intracellular Ca2+ levels between the two examined flow rates. In addition, multiple short pulses rather than a single pulse ultrasound, with an equal number of bursts, significantly elevated endothelial cell permeabilization, at least by 1.4-fold, in response to ultrasound-stimulated microbubbles. This study provides insights into the design of optimal, application-dependent pulsing schemes to improve the effectiveness of ultrasound-mediated local therapeutic delivery.

Investigation of Silica (SiO2) Nano Materials for Increasing Performance of Vehicle Radiator Cooling Systems

This study aims to evaluate the effect of fluid flow rate on the effectiveness of radiator performance by using nanofluid consisting of a mixture of raw water with nano silica (SiO2) particles. The research was initiated by testing the silica material morphologically using a Scanning Electron Microscope (SEM) with the aim of knowing its microstructure. Next, mix the silica nanoparticles (SiO2) with water using a ratio of 0.5%, processed using a magnetic stirrer for 8 hours and precipitated for 24 hours. After being separated from the sediment, the nanofluid was tested for performance using a series of cooling system performance test equipment. A series of test equipment consisting of a radiator, flowmeter, water pump, pipe installation, heater and reservoir tank. Research data collection was carried out at the inlet and outlet temperatures as well as the radiator wall. In this study, variations in fluid flow velocity of 2.5, 4.5, and 6 LPM were carried out. The results showed that the decrease in temperature with the use of a fluid flow rate of 6 LPM was able to dissipate heat well to the environment. The decrease in temperature that occurs is 2.5%. Meanwhile, the lowest average radiator effectiveness value at the lowest speed of 6 LPM is 0.905, the highest at a fluid flow rate of 4.5 is 0.930.

PENINGKATAN PERFORMA RADIATOR KENDARAAN DENGAN NANOFLUID

Abstract This research aims to evaluate the effect of fluid flow rate on the effectiveness of radiator performance by using nanofluid. The research began by making a series of test kits consisting of radiators, flowmeters, pumps, pipes, heaters and fluid reservoirs. The data collection of research was carried out at the temperature of the entrance, wall and exit of the radiator. In this study we did variations in fluid flow speed of 2.5, 4.5, and 6 LPM. The results of the study were able to lower the temperature at the use of fluid flow rate 6 LPM able to dissipate heat into the environment well. The temperature decrease occurred by 2.5%. Meanwhile, the lowest average radiator effectiveness value at the lowest speed at 6 LPM was 0.905 highest at a fluid flow rate of 4.5 of 0.930. Key words: Fluida, effectiveness, radiator

Performance of Radiator with Various Coolant Flow Rate

This research aims to evaluate the effect of fluid flow rate on the effectiveness of radiator performance by using coolant. The research began by making a series of test kits consisting of radiators, flowmeters, pumps, pipes, heaters and coolant reservoirs. The data collection of research was carried out at the temperature of the entrance, wall and exit of the radiator. In this study we did variations in fluid flow speed of 2.5, 4.5, and 6 LPM. The results of the study were able to lower the temperature at the use of fluid flow rate 6 LPM able to dissipate heat into the environment well. The temperature decrease occurred by 2.5%. Meanwhile, the lowest average radiator effectiveness value at the lowest speed at 6 LPM was 0.905 highest at a fluid flow rate of 4.5 of 0.930.

Experimental investigation of particle transport and distribution in a vertical nonplanar fracture

Particle transport in a vertical nonplanar fracture is a typical but poorly understood element in hydraulic fracturing. Particle-fluid flow in a nonplanar fracture with a narrowing width is investigated experimentally by a laboratory-scale slot, and the relevant transport mechanisms are compared with that in the planar slot. The effects of fluid flow rate, particle density, particle size, and particle volume fraction on particle distribution are investigated. The results indicate that the narrowing width complicates the slurry flow and lowers the bed coverage area. The vortex flow appears at the contraction of the cross-section as the bed grows to a threshold height and resuspends more particles further into the slot. An irregular bed with a descending stepped surface is formed due to non-uniform placement. Smaller size sands injected at a high flow rate and a low particle volume fraction build up a smaller bed. Larger and denser particles would reverse the trend. A rational model expressed by four dimensionless numbers is developed by the linear regression method to predict the coverage percentage of the particle bed. The model and experimental results provide directions to quantitatively evaluate the particle transport and distribution in a nonplanar fracture.

Geometry aspect review of the natural circulation system as innovation in passive cooling of nuclear reactor

The passive nuclear reactor cooling system has become a fascinating topic, especially since the nuclear incident in Fukushima Daiichi, Japan. This study proposed to review a natural circulation-based passive cooling system in the geometry aspects of the loop. The numerical review was carried out using COMSOL Multiphysics software to study the geometry effect on the loop’s fluid characteristics. Moreover, related research data to the study of the effect of fluid flow rate on one of the advanced nuclear reactors, namely the Molten Salt Reactor and the effect of loop geometry experimentally, are presented in this study for enrichment purposes. This study clearly showed that geometry aspects need to be considered in designing a natural circulation-based passive cooling system of a nuclear reactor.

Assessment of Solar Dehumidification Systems in a Hot Climate

Solar thermal-powered desiccant dehumidification systems are attracting attention for cooling load-dominated climates. However, their performance varies substantially from place to place depending on climatic conditions, which therefore warrants a tailored design and specification at each geographical location. The current article attempted to investigate the feasibility of extending an existing solar thermal system in a school building in Abu Dhabi to provide dehumidification for the existing air condition system through a desiccant system. The system performance was predicted through a Transient System (TRNSYS) Simulation model to determine the energy savings achieved by the solar-assisted dehumidification system. The current articles determined the effect of fluid flow rate, solar radiation concentration, and heat exchanger effectiveness at the dehumidification of the fresh air as well as energy saved by the proposed system. It was concluded that the system can remove 35% moisture from the air, simultaneously saving 10% of the building’s energy. The system cost and benefit analysis revealed a payback period of 7.5 years, considered slightly higher for an attractive investment in such systems.

Simulation studies on picolitre volume droplets generation and trapping in T-junction microchannels

In this paper, we present simulation studies on the formation of water microdroplets in mineral oil in a T-junction Microfluidics device. We have studied the droplet generation in two different regimes, viz., squeezing and squeezing to dripping transition regime. The effect of fluid flow rates, and surfactant concentration on the droplet generation has been investigated. It is seen that a rise in the concentration of surfactant by 4%, increases the frequency of droplet generation by 16% at the higher capillary number (Ca = 0.02), whereas, there is only a marginal or no change in the case of squeezing regime (Ca = 0.0028–0.008). We have also studied the trapping of the generated microdroplets in microwells. It is observed that the trapping of the droplet is highly influenced by the viscous drag force, droplet length, the surface energy of the droplet, droplet speed, depth of the Well for trapping and alignment of the two plates constituting the device. Our studies reveal that the droplets travelling faster than a critical trapping velocity do not get trapped in the Well. Addition of a surfactant to the mineral oil is seen to lead to a significant reduction in the critical velocity for the droplet trapping. Trapping of droplets travelling at velocities close to the critical velocity for trapping depends strongly on the alignment of the two plats of the Slip-Chip device.

Influence of fluid flow rate on the fouling resistance of calcium sulfate aqueous solution in subcooled flow boiling condition

Fouling is one of the customarily happened, fundamental and expensive problems in heat transfer systems. It causes the reduction in heat transfer performance of the heat exchangers, energy loss and also, damage to the apparatus. Effect of fluid flow rate on the salt deposition was complicated in the previous researches. In this paper, a comprehensive rigorous investigation was performed to make clear the effect of fluid flow rate of calcium sulfate aqueous solution on the heat transfer coefficient and fouling resistance in subcooled flow boiling condition. Large numbers of experiments performed at different flow rates (2.5–11.5 l/min), solution concentrations (1.75–2.20 g/l), fluid bulk temperatures (55–75 °C), and heat fluxes (8–95 kW/m2). Chen model, Gungor and Winterton model, and Kandlikar model approved pure water experimental data. It was found that increasing the heat flux increased the fouling rate and consequently, sharply decreased the heat transfer coefficient. It was also found that increase in the flow rate may cause both increase or decrease of the fouling layer, which depends on the applied heat flux. At low heat fluxes, deposition is mass transfer controlled, and increasing Re enhances the fouling rate while at high heat fluxes the deposition is chemical reaction controlled, and incresing Re decreases the fouling rate.

Effects of fluid flow rate and viscosity on gravel-pack plugging and the optimization of sand-control wells production

Abstract Series of experiments were performed to simulate the invasion of formation sand into and the plugging process of gravel-pack at different viscosities and flowing rates of fluid. Two types of formation sands with the medium size of 0.10 mm and 0.16 mm and the quartz sand and ceramsite of 0.6—1.2 mm were used in the experiments. A new viscosity-velocity index (the product of fluid viscosity and velocity) was put forward to characterize the influencing mechanism and law of physical property and flow condition of formation fluid on gravel-pack plugging, and a new method to optimize the production rate of wells controlling sand production with gravel-packing was proposed. The results show that the permeability of formation sand invaded zone and final permeability of plugged gravel-pack have negative correlations with viscosity and flow velocity of fluid, the higher the flow velocity and viscosity, the lower the permeability of formation sand invaded zone and final permeability of plugged gravel-pack will be. The flow velocity and viscosity of fluid are key factors affecting plugging degree of the gravel zone. The viscosity-velocity index (v-v index) can reflect the flow characteristics of fluid very well and make it easier to analyze the plugging mechanism of gravel zone. For different combinations of fluid viscosity and flow velocity, if the v-v index is the same or close, their impact on the final gravel permeability would be the same or close. With the increase of the v-v index, the permeability of plugged gravel zone decreases first, then the reduction rate slows down till the permeability stabilizes. By optimizing production and increasing production step by step, the optimal working scheme for sand-control well can reduce the damage to gravel-pack zone permeability caused by sand-carrying fluid effectively, and increase well productivity and extend the sand control life.

Modelling bacterial twitching in fluid flows: a CFD-DEM approach

Bacterial habitats are often associated with fluid flow environments. Bacterial twitching is important for initial bacterial colonization and biofilm formation. The existing research about bacteria twitching is largely experimental orientated. There is a lack of models of twitching motility of bacteria in shear flows, which could provide fundamental understanding about how bacterial twitching would be affected by bacteria associated properties such as number of pili and their distribution on the cell body and environmental factors such as flow and surface patterns. In this work, a three-dimensional modelling approach of Computational Fluid Dynamics (CFD) coupled with the Discrete Element Method (DEM) proposed to study bacterial twitching on flat and groove surfaces under shear flow conditions. Rod-shaped bacteria are modelled as groups of spherical particles and Type IV pili attached to bacteria are modelled as dynamic springs which can elongate, retract, attach and detach. The CFD-DEM model of rod-shape bacteria is validated against orbiting of immotile bacteria in shear flows. The effects of fluid flow rate and surface topography on twitching motility are studied. The model can successfully predict upstream twitching motility of rod-shaped bacteria in shear flows. Our model can predict that there would be an optimal range of wall shear stress in which bacterial upstream twitching is most efficient. The results also indicate that when bacteria twitch on groove surfaces, they are likely to accumulate around the downstream side of the groove walls.

Effect of Fluid Flow Rate on Efficacy of Fluid Warmer: An In Vitro Experimental Study.

Introduction In patients who require a massive intraoperative transfusion, cold fluid or blood transfusion can cause hypothermia and potential adverse effects. One method by which to prevent hypothermia in these patients is to warm the intravenous fluid before infusion. The aim of this study was to determine the effect of the fluid flow rate on the efficacy of a fluid warmer. Methods The room air temperature was controlled at 24°C. Normal saline at room temperature was used for the experiment. The fluid was connected to an infusion pump and covered with a heater line, which constantly maintained the temperature at 42°C. The fluid temperature after warming was measured by an insulated thermistor at different fluid flow rates (100, 300, 600, 900, and 1200 mL/h) and compared with the fluid temperature before warming. Effective warming was defined as an outlet fluid temperature of >32°C. Results The room temperature was 23.6°C ± 0.9°C. The fluid temperature before warming was 24.95°C ± 0.5°C. The outlet temperature was significantly higher after warming at all flow rates (p < 0.001). The increases in temperature were 10.9°C ± 0.1°C, 11.5°C ± 0.1°C, 10.2°C ± 0.1°C, 10.1°C ± 0.7°C, and 8.4°C ± 0.2°C at flow rates of 100, 300, 600, 900, and 1200 mL/h, respectively. The changes in temperature among all different flow rates were statistically significant (p < 0.001). The outlet temperature was >32°C at all flow rates. Conclusions The efficacy of fluid warming was inversely associated with the increase in flow rate. The outlet temperature was <42°C at fluid flow rates of 100 to 1200 mL/h. However, all outlet temperatures reached >32°C, indicating effective maintenance of the core body temperature by infusion of warm fluid.

Experimental investigation on heat transfer enhancement for a ferrofluid in a helically coiled pipe under constant magnetic field

This paper experimentally investigates the effects of constant magnetic field on the average Nusselt number variation when the water-based ferrofluid with 1 mass% Fe3O4 nanoparticles flows through a helically coiled pipe with constant wall temperature in various Reynolds numbers. The two-step method has been utilized for ferrofluid preparation. In order to increase the heat transfer coefficient of the system, both active and passive methods are employed simultaneously. Changing the pipe shape to a helical configuration and adding magnetic nanoparticles in the fluid flow are two passive methods, while the active method is the exertion of a magnetic field. The convective heat transfer coefficient and pressure drop are two basic criteria in the evaluation of the results, and the main geometrical parameters are curvature and torsion ratios. The effects of fluid flow rate and the strength of the magnetic fields are also investigated. Applying a 600 G constant magnetic field, the results show the average Nusselt number augmentation of nearly 7%. In constant Reynolds number, the stronger magnetic field of 900 G yields a higher average Nusselt number.

Liquid residence time distribution of multiphase horizontal flow in packed bed milli-channel: Spherical beads versus open cell solid foams

A robust approach to access liquid residence time distribution (RTD) adapted to multiphase flow in porous media is presented. It is tailored to meet specific requirements of small scale systems (centimeter, millimeter or less) with Taylor segmented flow feed. The method involves direct visualization using fluorescence microscopy close to both extremities of a porous packing. Critical image treatment steps and optimization of a versatile discrete model with 4 parameters are detailed and discussed. They allow the precise and rapid determination of RTD curves and their 1st- and 2nd-order moments. The application of the method is successfully illustrated with dense micro-packed beds of sub-millimeter particles and highly porous media like open cell solid foams undergoing a preformed G-L segmented (Taylor) flow. Original results regarding the effect of fluid flowrates and different confined porous media are discussed and lead to a single two-parameter liquid hold up correlation, which is valid for both packings. As usual, RTD broadening is treated as a combination of convective dispersion and mass transfer to a fraction of immobile liquid. The predominant role of mass transfer is underlined with an analysis of characteristic times.

Rate-Based Approach to Cleaning-in-Place

Fouling is a major problem in the food industry. In cases where allergens are involved, excessive cleaning of food processing equipment often takes place to ensure allergen levels are reduced to acceptable levels. Experimental trials were conducted in a pilot scale cleaning rig to assess the effect of fluid flow rate and temperature on the removal rate of milk paste during cleaning-in-place. Conductivity measurements taken during trials were analyzed to produce an equation enabling calculation of the cleaning rate with water temperature, flow rate, initial deposit mass, and time. The rate of cleaning with detergent was also investigated. This methodology produces a rate-based expression for cleaning, which can be applied to other products, and can be used to determine the time when cleaning is complete, the extent of a cleaning process, or when the prerinse should be replaced with a detergent rinse. This prevents overcleaning and therefore reduces the costs associated with overcleaning through energy, mat...

NON-DIMENSIONAL DISTRIBUTION PATTERN ANALYSIS OF PARTICLE TRANSPORTATION IN SIMPLIFIED PIPELINE SYSTEM

Sustainable preservation of pipeline system that deal with particle transportation is more appealing these days. In petroleum industries for instance, sand transported through the pipelines pose serious problems ranging from blockage, corrosion, abrasion and reduction in pipe efficiency to loss of pipe integrity. Accurate four-dimensional simulation that caters the transient effect of the phenomena is used to promote sustainability in design, evaluation and maintenance procedures. This is employed to minimize conventional practices which are costly and inefficient. This work demonstrates the advantages of applying four-dimensional Splitting Fluid-Particle Solver to simulate particle transportation within a simplified pipeline system. Single-phase fluid with solid sphere particles are the assumptions while drift and gravitational forces are taken into account. Effect of fluid flow rate and particle weight alterations are observed within vertical curled and 2-1-2 segmental pipeline. Flow rate variation on multiple inputs shows that proper simulation is essential in order to predict fluid flow behavior prior to pipeline construction. Particle weight variation shows that simulation can lead to better prediction of potential areas of blockage, corrosion, abrasion and other piping system issues. This work proves that four-dimensional simulation can promote sustainability, cost effectiveness and efficiency of pipeline system management.

Numerical Investigation of a Chevron Type Brazed Plate Heat Exchanger

A numerical investigation has been carried out in the present work to study flow characteristics and thermal performance of a chevron type brazed plate heat exchanger (PHE). A local element-by-element analysis utilizing e-NTU method is employed for simulating the heat exchanger. In this approach, Nusselt number is expressed in terms of friction factor which in turn, is given as a function of chevron angle of the heat exchanger. Water has been used as cold and hot fluid. Effect of fluid flow rate and inlet temperatures on the heat duty, overall heat transfer coefficient, fluid outlet temperatures and pressure drop have been studied. When compared with literature results of intermating plate heat exchangers, chevron type plate heat exchanger gives greater heat transfer enhancement, though with increased pressure drop.

Thermal analysis of a high concentration photovoltaic/thermal system

This paper presents a solar photovoltaic/thermal (PV/T) system with triple-junction solar cells. The essential components of the system are a concentrator of high concentration ratio, a PV/T module and a tracking device. Plane-mirrors array structure is applied to the concentrator, which can provide PV/T module with a uniform light intensity distribution and an adjustable concentration ratio. The PV/T module is an integration of triple-junction solar cells and a heat exchange device, where the heat from triple-junction solar cells is collected and transported for thermal applications by fluid passing through. Considering both photovoltaic and thermal conversion, the total solar utilization efficiency is greatly increased. The simulation results show that the thermal conversion efficiency of this high concentration PV/T system in hybrid operation can achieve about 52%, which is approximately in agreement with the experimental result of 48%, meanwhile the theoretical photovoltaic conversion efficiency can reach 26%. The simulation results also reveal the effect of fluid flow rate on the thermal efficiency of high concentration PV/T system, which is quite opposite to that in non-concentration PV/T system.