Fluid In Tank Research Articles

Design of a Template-Based Electrophoretically Assisted Micro-Ultrasonic Machining Micro-Channel Machine Tool and Its Machining Experiment.

In order to achieve the high-precision and high-efficiency machining of micro-channels for hard and brittle materials, the authors innovatively proposed a new technology called template-based electrophoretically assisted micro-ultrasonic machining (TBEPAMUSM). This technology transfers the micro-channel shape punch-pin to the workpiece material through micro-ultrasonic machining to form a micro-channel. At the same time, it uses the electrophoretic properties of ultra-fine abrasive particles to ensure the existence of abrasive particles in the machining area by applying a DC electric field. According to the new technology machining principle, a machine tool of TBEPAMUSM was designed and developed. The machine tool hardware adopts a C-shaped structure, including a marble platform, an ultrasonic vibration system, a micro three-dimensional motion platform, a working fluid tank, and a pressure sensor. The machine tool intelligent control system is developed based on LabVIEW, including the initialization module, fast positioning module, constant force tool setting module, constant force control machining module, and real-time coordinate display module. Micro-channels with different structures are machined on single-crystal silicon and soda-lime glass using the designed machine tool and the developed control system. The results show that: when electrophoresis assistance is applied in machining, the edge chipping phenomenon of the micro-channel is significantly reduced, the surface roughness is reduced by about 20%, and the machining efficiency is increased by about 4%.

The Impact of Gas-Liquid Dispersed Flow on Heat Exchanger Performance with Improvement Using CuO Nanofluid

Both the air-water dispersion coefficient and the air-nanofluid (CuO) dispersion coefficient were studied and measured in a double-pipe heat exchanger. Pumping air into a tank fitted with a Rushton turbulent impeller resulted in gas-liquid dispersion. In order to test the effects of varying operating conditions on the air-water and air-nanofluid dispersions, they were heated and pumped into the tube of a double-pipe heat exchanger. Reynolds numbers of Rec= 4750-13100 on the shell side and Reh=19900-64000 on the tube side were used to get the total heat transfer coefficient (Uo). The dispersion in the hot fluid tank was achieved by combining the two-phase fluids using a Rushton turbine impeller. It was discovered that the conscious phase saw a significant drop in the heat transfer coefficient when the air bubbles dissipated. Because the impeller's agitation speed affects the rate at which air bubbles are broken, the heat transfer coefficient in the case of dispersion rises as Reh and Rec rise. For all examined parameter values, CuO nanofluid showed significant heat transfer improvement. The heat transfer rate of gas-liquid dispersion increases by nanofluid by as much as 135.5% compared to gas-liquid dispersion which is considered the first attempt for heat transfer enhancement of two phase flow (gas-liquid dispersion) using Nano fluid.

Analysis and mitigation of spatial integration errors for the material point method

SummaryThe material point method (MPM) is a robust numerical simulation approach for continuum mechanics problems involving large material deformations coupled to changing surface topographies. These types of problems are present in many different engineering contexts, from understanding the failure processes of earthen slopes to predicting the strengths and failure mechanisms of body armor to modeling the impact forces of waves in fluid tanks. By using a set of persistent material point tracers to follow the motion and deformation of the continuum material while solving the equations of motion on a static simulation grid, the MPM avoids several shortcomings of more traditional numerical approaches including blurring of material surfaces — as in Eulerian finite element or finite volume methods (FEMs or FVMs) — and mesh tangling — as in Lagrangian FEMs. Despite its robustness, MPM is known to develop significant numerical errors: namely, (i) the particle ringing instability and (ii) solution dependent discretization and integration errors. In this work, we present an analysis of local‐in‐time, spatial integration errors in the MPM and several techniques designed to mitigate these errors. Error mitigation approaches previously described in the literature are compared to a new method we propose for problems involving very large material deformations. The proposed method is shown to offer substantial improvement over standard MPM for simulations of fluid‐like materials without requiring significant augmentation of existing MPM frameworks.

Investigations on performance of single-phase immersion cooling system

Cooling of data centers is crucial from the point of view of energy consumption and zero downtime of data centers. The present study examines the heat transfer behavior for a single-phase immersion cooling system for dielectric fluid (FC40) and dielectric oil (PAO-6) in a 1 U server. Thermal resistance and the temperature of the server are considered to study the system's thermal performance at various system parameters. Parameters varied are inlet/outlet configuration, bypass of the fluid (a gap between the heat sink and the fluid tank), imposed suction fans, fin pitch of the heat sink, fluid flowrate, fluid inlet temperature, and heat load. T-type configuration of inlet/outlet outperforms Z-type configuration. The performance of the system is reduced monotonically with the increase in the gap spacing between the heat sink and tank due to the increased bypass of fluid. The suction created downstream of the heat sink by deploying two fans in series improves the performance appreciably. The effect of the fin pitch of the heat sink on the performance of the system is different for both fluids. For PAO-6, the fin pitch of 2.2 mm yields better performance than the dense pitch of 1.2 mm whereas FC-40 shows the opposite trend. Thermal resistance considerably decreases for PAO-6 with an increase in fluid flowrate from 1 to 3 LPM. Thermal resistance decreases whereas the temperature of the server increases when the fluid inlet temperature increases from 15 to 35 °C. A similar effect is reported when the heat load is increased from 200 to 600 W. Numerical investigations are also carried out for studying to explain the flow field and temperature distribution in case of bypass of fluid.

Out-of-Plane Compression Behaviour of Aluminum Alloy Large-Scale Super-Stub Honeycomb Cellular Structures.

The out-of-plane compression behaviour of 6061-T6 aluminum alloy super-stub honeycomb cellular structures without and with friction stir welding (FSW) facesheets are presented in this paper. A total of twelve axially compressed experiments on large-scale specimens, six with square hollow section (SHS) cores and six with hexagonal hollow section (HHS) cores, were conducted, with failure modes, ultimate resistances and axial load-end shortening curves analysed. The accuracy of finite element (FE) models was validated in accordance with test results. The numerical data obtained from extensive parametric analyses combined with test data were subsequently used to evaluate the applicability of existing design rules in Chinese, European and American aluminium alloy specifications. The results showed that the three specifications generally yielded very conservative predictions for the out-of-plane compression resistances of SHS and HHS super-stub honeycomb cores without and with FSW facesheets by about 30-37%. Design recommendations on the cross-section effective thickness are finally proposed and shown to provide much more accurate and consistent predictions than current design methods. The research results are beneficial to the application and development of large-scale super-stub honeycomb structures in structural engineering, such as the helicopter landing platforms, the base of fluid and gas tanks and ship decks.

A quasi-two-dimensional fluid experimental apparatus based on tank-in-tank configuration.

The fluid tank is an essential facility for experimental research on fluid mechanics. However, owing to the hydrostatic fluid pressure, a fine uniformity of the narrow channel is difficult to be maintained in a tall narrow-channel tank. To address this issue, we proposed a quasi-two-dimensional fluid experimental apparatus based on a "tank-in-tank" configuration and built with an outer tank and an inner tank. The outer tank was cuboid-shaped and used to load the fluid medium, while the inner tank, consisting of two parallel glass plates, was embedded into the outer tank and served as the experimental channel. The hydrostatic pressure acting on the channel was balanced so that a high level of uniformity was maintained over the whole channel. The available height and width of the channel were 2800 and 1500mm, respectively, while its gap distance could be adaptive from 0 to 120mm. Experimental research on motion characteristics of circular disks falling in the quasi-2D channel was implemented to investigate the effects of the falling environment and disk geometry. Four distinct falling types were observed, and the wake flow fields of the falling disks were visualized. The Reynolds numbers of falling disks ranged from 400 to 63 000 presently. Chaotic motion and regular motion were demarcated at Re ≈ 30 000. An analytical model was established to predict the final average falling velocity and Reynolds number. Finally, potential directions for future research and improvements to the apparatus were suggested.

Experimental investigation of fountains in homogeneous fluid with coexistent temperature and concentration effects using PIV/PLIF

Fountains formed due to the injection into homogeneous fluids with the combined effect of temperature and concentration occur widely in nature and in environmental improvement and industrial applications such as brine water discharge, living sewage disposal, release of waste hot gases into the atmosphere from chimneys, solar desalination discharge, and sewage wastewater discharge for agriculture irrigation. In this study, the behavior of round fountains with salt water as a homogeneous ambient fluid in a transparent glass tank over 0.25 ≤ FrT ≤ 2.0, 0 ≤ N ≤ 5.0, and 47 ≤ Re ≤ 824 was studied using particle image velocimetry/planar laser-induced fluorescence (PIV/PLIF). The recorded PIV/PLIF images provide a better understanding of the transient behavior and intrinsic laws of buoyant jets in an ambient fluid and optimally use their transport mechanisms and entrainment characteristics in environmental improvement and industrial applications. Scaling for the initial maximum fountain height at the development stage, the obtained scaling correlation from the experimental results is consistent with previous results from direct numerical simulation results.

The structure of viscous liquid internal flows in tanks with damping baffles

Modern moving objects containing large volumes of liquid need to ensure stability on the movement trajectory, reliability of control during maneuvers, as well as the ability to predict and prevent extreme movement conditions. The presented article provides review materials devoted to the research results into inertial flows of viscous incompressible fluid in tanks with internal damping baffles. In order to exert force on resonant excitations from the liquid side and to compensate for the instabilities of moving objects, the analysis and design of rational structures of influence means on currents is carried out. Among the most effective means of damping should be noted rigid internal baffles of various designs installed in tanks in the most likely areas where instabilities and sources of excitation of resonant fluid movements may occur. Flat rigid partitions, profiled permeable damping surfaces, perforated and retaining elements, enslavers of liquid due to surface tension forces, etc., require comprehensive and detailed study and analysis.

Free vibration analysis of an auxetic honeycomb sandwich plate placed at the wall of a fluid tank

This paper presents a parametric investigation of the free vibration characteristics of an auxetic honeycomb sandwich plate mounted at the wall of a liquid tank. Frostig's second model is utilized in the core, while first-order shear deformation theory (FSDT) is applied to the face sheets. The honeycomb core is homogenized using one of the newest revised models (Tornabene's model), and the fluid is assumed to be ideal. The governing equations of motion are derived using Hamilton's principle and solved using the Galerkin method. Present solution method, honeycomb core homogenization formula, and mathematical framework for the fluid-sandwich plate interaction are verified using 3D Finite Element Analysis (FEA). Finally, the wet fundamental frequency is investigated with geometric parameters such as the ratio of tank dimensions to the plate length, fluid height from the plate's bottom edge, plate location at the tank wall, and honeycomb cell geometry. According to the results of this study, the thickness of the face sheet and the cell wall enhance the wet fundamental frequency, while the cell aspect ratio decreases it.

Evaluating the dynamic behaviour of wind-powered compression refrigeration cycle integrated with an ice storage tank for air conditioning application

Looking for an alternative renewable energy source to meet the energy demand of refrigeration and air conditioning systems has been a matter of high priority. The current study proposes a wind-powered compression refrigeration cycle integrated with an ice storage tank in order to meet the cooling demand of a building. An educational building in Zabol, a city in the southeast of Iran, is selected as a case study. A comprehensive model based on energy and exergy analyses is carried out for all components to investigate their performance. The effects of design parameters are evaluated through the parametric study. The results show that the refrigeration production has less dependency to the evaporator temperature compared the other parameters such as wind speed. A dynamic behaviour study indicates that the proposed system daily coefficient of performance has grown 17 % compared to the conventional cycle. Also, in the maximum required cooling demand hour, COP has ascended significantly. The maximum storage refrigeration inside the ice tank is about 46 % of total refrigeration production occurring at 4 AM, while the maximum consumption of stored refrigeration from the ice tank is about 87 %, happening at 4 PM. At the end of the design day, 5 % of tank fluid mass remains in the solid state. The 48 % of total energy passing through the system in work and heat shapes from various equipment destroyed via exergy destruction. The wind turbine (27.8 % of total weight) and the ice storage tank (23.14 % of total weight) have the maximum exergy destruction, respectively.

Analysis of heat transfer from a local heat source at cryogenic temperatures

Understanding the dispersion of heat around a cryogenic fluid tank, specifically the interaction between the cryogenic fluid and the tank wall is critical in the analysis of long duration cryogen storage in microgravity. The heat transfer interaction between a cryogenic storage tank and heat sources from external spacecraft structures is also one of the many factors that determine how much heat enters a tank. Recent flight experiments with two-phase fluids have indicated that local concentrations of heat input (also known as “hot spots”) can cause unwanted affects including local boiling. Computational fluid dynamic (CFD) models can provide a detailed assessment of the heat transfer occurring across a cryogenic storage system. However, CFD modeling takes time to construct and run. A simpler approach that can act as initial guidance for later CFD modeling analyzes external “hot spots” as point or finite heat sources. A radial, finite element network or a local direct solution can effectively estimate the heat spread across a cryogenic storage tank by calculating the temperature and heat load as a function of distance from the heat source. This calculation accounts for the convective heat transfer between the cryogenic fluid and storage tank surface. Similar approaches can be used to determine the effectiveness of cooling from a cryocooler as a finite, local heat sink. This approach allows for quick approximations of the thermal map across a cryogenic tank as well as sensitivity analysis under a wide range of design parameters including gravitational fields as implied through natural convection coefficients.

Numerical investigation of surface evaporation and thermocapillarity effects on natural convection within a contained fluid in cryogenic tank

Quantification of liquefied gas surface evaporation in partially filled cryogenic tank is important in both design process and operations control later. This paper focuses on effects of external heat leaks on the surface evaporation and the natural convection of a liquefied gas contained in cryogenic cylindrical tank with consideration of thermocapillarity. The evaporation mass flow rate is assumed negligible; however, the absorbed heat during the process is considered and defined according the Hashemi-Wesson model. The physical problem was formulated in dimensionless form, and then solved numerically using finite volume procedure. The external heat leaks and the surface evaporation heat flux were quantified by means of Nusselt number. Several simulations have been conducted based on the Rayleigh number (10+4 ≤ Ra ≤ 10+5), Marangoni number (0 ≤ Ma ≤ 2000) and the cavity aspect ratio (0.5 ≤ AR ≤ 2). Results showed that as Ra increases, the heat transfer rate from wall to fluid increases as well as the evaporation rate. Large value of Ma can reduce the surface evaporation heat flux up to 5% due to thermocapillary flow. High filling level reduces surface evaporation up to 42% for AR = 0.5, whereas low filling level promotes it to 46% for AR = 1.5, with respect to AR = 1. Free surface and side wall Nusselt numbers are strongly dependent on Ra, Ma and AR, and both have been correlated in simple formulas within engineering tolerance ±5%.

Effect of gas injection mass flow rates on the thermal behavior in a cryogenic fuel storage tank

Large scale using of liquid hydrogen and liquid oxygen on energy engineering, chemical engineering and petrochemical industries, bring a series of non-equilibrium thermal behaviors within fuel storage tanks. Accurate simulation on the thermal behavior in cryogenic fuel storage tanks is therefore a critical issue to improve the operation safety. In the present study, a 2-dimensional numerical model is developed to predict the active pressurization process and fluid thermal stratification in an aerospace fuel storage tank. Both external heat penetration and heat exchange occurring at the interface are accounted for in detail. The volume of fluid method is adopted to predict the thermal physical process with high-temperature gas injected into the tank. The effect of the gas injection mass flow rate on the tank pressure, the interface phase change, and the fluid temperature distribution are investigated respectively. Finally, some valuable conclusions are obtained. The present study may supply some technique references for the design of the pressurization system. • Tank pressurization and fluid temperature distribution are investigated. • The pressure rise rate increases with the gas injection mass flow rate. • Serious liquid evaporation occurs in the initial pressurization period. • Vapor condensation increases with time and gas injection mass rate. • The penetration depth of thermal capacity experiences increases with time.

Variational domain decomposition scheme for linear Stokes-Joukowski potentials of fluid in baffled tanks

Variational domain decomposition scheme for linear Stokes-Joukowski potentials of fluid in baffled tanks

Selective withdrawal of a three-layer viscous fluid

Two dimensional, selective withdrawal of a three-layer fluid in a rectangular tank is considered. Each fluid is viscous, weakly compressible and miscible. The lowermost, heaviest fluid flows with constant speed out through line sinks located on the base and lower side walls of the tank. The uppermost and lightest fluid recharges the tank via line sources located along the top and on the upper side walls at a rate that matches the outward flux. If the line sinks are turned on suddenly, the interfaces between the fluids are drawn downward at different rates; this disparity arises due to the fact that the wave configurations that propagate along the two interfaces are not the same. Density and vorticity contours are presented and used to determine the time at which the middle transition layer of fluid begins to be withdrawn from the tank; at this point the rate of extraction of the most dense fluid is its greatest. Inviscid linearised interfaces are calculated which serve as checks on the early stage evolution of the full nonlinear model.

Theoretical and experimental investigation of a bi-stable piezoelectric energy harvester incorporating fluid-induced vibration

Vibration-based piezoelectric energy harvesting has potential applications in the effective energy supply for sensors and communication devices. To address the need to increase the levels of harvested energy and adjust the low-frequency bandwidth, we design a bi-stable piezoelectric energy harvester (BS-PEH) incorporating fluid-induced vibration, which only needs to simply modify equipment that exists fluid tank. A theoretical model based on fluid equivalence is established to construct the dynamic equation and electromechanical coupling equations of the proposed BS-PEH. Experimental results investigate the validity of the theoretical model, and the comparison with the existing literature also shows the superiority in power density. Then the sensitivity of the averaged power to uncertain resistive load is given and analyzed, and the improvement of energy harvesting capacity by bi-stable structure is discussed. Subsequently, the parametric study for design parameters reveals the influence of each parameter on the output characteristics of BS-PEH and gives the configuration of optimizing energy harvesting. Moreover, the proposed BS-PEH is easy to design, and a higher energy harvesting efficiency can be achieved by simply changing the accessories, in which modifying the slider mass can make the output power reach 81mW.

Numerical Simulation of Strongly Coupled Liquid Fluids in Tanks inside of Floating Body and its Motions with Incoming Lateral Regular Waves

Numerical Simulation of Strongly Coupled Liquid Fluids in Tanks inside of Floating Body and its Motions with Incoming Lateral Regular Waves

PID Power Controller to a Setpoint of Fluid Level Height in a Reservoir for Unattended Human Monitoring

This paper provides a novel approach of a power control system of a fluid tank pump to reach a specific setpoint of fluid level height. The system enables users to fill a tank to any desired height within a chosen time interval. The system is equipped with a timer that allows the user to fill the tank to the desired level within the desired time. The system is based on utilizing a Proportional Integral and Derivative (PID) controller to adjust the pump's power to satisfy the us-er-defined setups (time and fluid level height). This approach has the potential to be applied for domestic purposes for unattended human monitoring. This approach has been demonstrated using LabVIEW coding to apply the fluid and hydrodynamic design and control principles. The results have illustrated the code's capability to achieve the desired tank fluid level height for a variable range of fluid level height setpoints and time intervals

A Review of SPH Techniques for Hydrodynamic Simulations of Ocean Energy Devices

This article is dedicated to providing a detailed review concerning the SPH-based hydrodynamic simulations for ocean energy devices (OEDs). Attention is particularly focused on three topics that are tightly related to the concerning field, covering (1) SPH-based numerical fluid tanks, (2) multi-physics SPH techniques towards simulating OEDs, and finally (3) computational efficiency and capacity. In addition, the striking challenges of the SPH method with respect to simulating OEDs are elaborated, and the future prospects of the SPH method for the concerning topics are also provided.

A Preliminary Study On The Inclination And Shape Of Jets Issuing From An Orifice In The Lateral Wall Of A Pipe

The topic of the behaviour of jets issuing from an orifice in the lateral wall of a pipe is of interest in many engineering fields, such as sea discharges of pollutants via submerged pipes, diffusers to mix different fluids in tanks and reactors, leakage in industrial and civil pipelines, etc. Most of the previous researches focuses on the pressure loss across the orifice, without taking into account the modification of the internal flow and, most important, the direction and shape of the jet issuing from the outlet: as a matter of fact, this is usually considered perpendicular to the axis of the pipe and axisymmetric. We have investigated these issues in the laboratory via Digital Image Analysis techniques, namely LIF (Laser Induced Fluorescence) to measure concentration fields and FTV (Feature Tracking Velocimetry) to measure velocity fields, varying the ratio of the flow rate of the jet to the flow rate in the pipe before the orifice. Here we present some preliminary results, highlighting how the jet is not always perpendicular to the axis of the pipe nor axisymmetric: the inclination increases and the axisymmetry decreases when the ratio of the flow rates above described decreases.