Three-dimensional Flow Analysis Research Articles

Implications of homogeneous–heterogeneous reactions, Hall current, and dissipative radiative heat transfer on MHD Casson fluid flow over a bi-directional stretching sheet

This consideration highlights a numerical analysis of the unsteady three-dimensional flow of a Casson fluid over a stretching surface extending in its plane considering the effects of Hall current, thermal radiation, homogeneous–heterogeneous reactions, viscous dissipations, and an external magnetic field. The fluid flow in the region is developed due to the stretching of the sheet along the two directions in its plane. Two different species are present in the flow region which are taking part in homogeneous and heterogeneous reactions. Fluid velocity, thermal, and mass transportation are expressed mathematically using a set of nonlinear partial differential equations ( PDEs ) along with suitable boundary conditions. By using the appropriate similarity transformations, these equations ( PDEs ) that reflect the mathematical model are transformed into a set of nonlinear ordinary differential equations ( ODEs ) . The transformed equations ( ODEs ) were further solved numerically utilizing the bvp 4 c solver. The comprehensive study regarding the impacts of flow parameters on velocities, temperature, and concentration is also presented with graphs. It is observed that the thermal boundary layer is enhanced with an increment in the Hall current parameter, magnetic parameter, and thermal radiation. Moreover, with an increase in homogeneous-heterogeneous reaction parameters, mass transportation decreases. The physical quantities such as the coefficient of skin friction and coefficient of heat and mass transfer are also obtained numerically. Moreover, an appropriate agreement is obtained on comparing the current results with previously published results.

Numerical Investigation of Single and Double Steps in Planing Hulls

Incorporating steps into a hull reduces the wetted surface, promoting improved hydrodynamic lift and reduced resistance at high speeds, provided that the step is designed appropriately. Traditional hydrodynamics studies rely on scaled model testing in towing tanks, but numerical tools offer a more efficient alternative. This study focused on investigating the hydrodynamic performance of stepped hulls by modifying the parent hull of the Naples Systematic Series (C1). The Computational Fluid Dynamics (CFD) code SIEMENS PLM STAR CCM+ version 2302 was used for simulations, including four different beam Froude numbers (FrB = 1.13, 2.22, 2.56, and 2.96) and a total of 15 hull configurations with single and double steps. By employing a three-dimensional computational analysis of multiphase flow using Dynamic Fluid–Body Interaction (DFBI) and overset mesh, various performance parameters such as resistance coefficient, dimensionless wetted surface, sinkage, and dynamic trim were analyzed. The accuracy of the CFD results was confirmed through comparison with experimental data and grid uncertainty assessment. The study demonstrated that placing a single step near the transom decreased trim and increased resistance and wetted surface. Conversely, positioning a step in the forward section reduced the trim angle at lower step heights but increased trim at higher step heights in single-stepped hulls. The application of these findings contributes to the design optimization of stepped hulls for enhanced performance in high-speed maritime applications.

Many-objective optimization for structural parameters of the fuel cell air compressor based on the Stacking model under multiple operating conditions

As the central element of the cathode air supply system, the centrifugal air compressor is pivotal to the regular and efficient operation of on-board fuel cells. In an attempt to further enhance the overall properties of the air compressor, the computational fluid dynamics (CFD) simulation model and Stacking model are developed and calibrated in this study. On this basis, the Many-Objective Random Walk Gray Wolf Optimizer (MORW-GWO) algorithm is proposed to perform many-objective optimization for compressor structural parameters, and the intrinsic mechanisms of performance improvements are elaborated based on three-dimensional flow analysis. The results indicate that the Stacking model achieves excellent predictive performance and generalization ability through the coupling and mutual error correction of base learners and the meta-learner. The MORW-GWO algorithm demonstrates outstanding many-objective optimization capability, convergence ability and universality. Compared to the original compressor, the optimized air compressor achieves improvements of 2.8%, 2.3%, 9.3% and 16.0% in the pressure ratio, outlet temperature, isentropic efficiency and adiabatic compression work, respectively. Besides, it is found that the internal energy loss, separation loss, friction loss, gas leakage and backflow of the optimized air compressor are reduced through the 3-D flow characteristic analysis. The findings can contribute to the many-objective optimization of compressor structural parameters by giving theoretical guidance, data support and directional evidence.

Three-dimensional numerical investigation of a suspension flow in an eccentric Couette flow geometry

This paper investigates the influence of eccentricity on flow characteristics and particle migration in Couette geometries. The study involves numerical simulations using the recent frame-invariant model developed by Badia et al. [J. Non-Newtonian Fluid Mech. 309, 104904 (2022)]. The study begins with a two-dimensional analysis, focusing first on the Newtonian fluid in order to thoroughly characterize the specific properties of this flow configuration. Next, the impact of eccentricity on particle migration in an isodense suspension is examined by numerical simulations based on the experiments conducted by Subia et al. [J. Fluid Mech. 373, 193–219 (1998)]. Furthermore, the study is extended to include a full three-dimensional analysis of a dense suspension flow in an eccentric Couette geometry based on resuspension experiments conducted by Saint-Michel et al. [Phys. Fluids 31, 103301 (2019)] and D'Ambrosio et al.[J. Fluid Mech. 911, A22 (2021)]. The main objective of the latter study is to investigate the influence of eccentricity on the resuspension height and on the calculation of the particle normal stress in the vertical direction through the volume fraction profile analysis. Our results show that even minimal eccentricity can lead to significant changes compared to the centered case.

Multi-depth focused laser differential interferometer based on chromatic aberration.

A modified version of focused laser differential interferometry (FLDI) is demonstrated with adjacent beam pairs distributed along the optical axis. This feature is accomplished using two different wavelengths of light in the interferometer and accounting for the chromatic aberration of the lenses in the optical setup. It is demonstrated that ray trace calculations can be modified to predict the focal points of each of the two different colored beams, and experiments using a tube jet and a laser-induced blast wave show the instrument still has the expected features of an FLDI as well as continued capability for velocimetry. This modification is in effort to allow FLDI to be used for the analysis of three-dimensional flows, especially if combined with other multi-point variations and targeting high-frequency flow content.

Analyzing Single Peristaltic Wave Behavior in Ureter with Variable Diameters: A Ureterdynamic Study

Ureters are muscular tubes that transport urine from the kidney to the bladder. The peristalsis wave is responsible for carrying urine to the bladder. With the regular appearance of peristalsis, areas with anatomic narrowing junctions are crucial for ureteral diseases. A three-dimensional flow analysis is performed for different time steps to understand the effect of the urine bolus formation and the reflux phenomenon on variable diameter ureters. For the constant and variable diameter ureter, the pressure is obtained behind and in front of the propagating bolus respectively. The peristalsis wave creates the high-velocity of a jet in the neck region of the ureter. The contraction produces the trapping of the bolus leading to adverse flow in the contraction region. By virtue tapering, the high-pressure gradient builds up, leading to high wall shear in the ureter. The main goal is to determine the pressure, velocity, gradient pressure, and shear force on the ureter wall during peristaltic motion. These parameters are very important for clinicians to understand its effect in the unobstructed variable diameter ureter. This article may help to build a medical device for engineers. The physical significance of this information lies in its profound insights into the biomechanics and functionality of the ureters, which are essential components of the human urinary system.

Three-dimensional Analysis of Electromagnetic Nanomaterial Flow and Thermal Variations for Forced Convection

This paper investigates the three-dimensional motion of electromagnetic nanofluid under the influence of heat source/sink, nonlinear heat radiation, magnetic field, and altered Arrhenius equation. Nonlinear stretching in the velocity is considered in the x-direction. Thermophoresis (Nt) and Brownian motion (Nb) are also considered in nanoparticle concentration profiles and temperature analysis. The boundary layer equations are transformed into nonlinear ODEs using suitable similarity transformations. The coupled nonlinear homogeneous system of ordinary differential equations is tackled by the MAPLE software. Non-dimensional system of the equation contains fourteen physical parameters Fr, Nb, M, γ, λ, Rd, δ, Pr, Nt, S, E, Sc, Bi and power index, which are governed by the physical model. Graphs are presented to show the impact of the abovementioned parameters on temperature, concentration and velocity profile. The present study contributes by observing how the aforementioned parameters influence the heat dissipation rate of nanofluids. This study has broad applications in the field of nanofluids like oil production, metal extrusion, heat exchangers, catalytic reactors etc. Also, results for a particular case found good concurrence with earlier work.

Optimization of liquid cooling heat dissipation control strategy for electric vehicle power batteries based on linear time-varying model predictive control

The heat dissipation performance of batteries is crucial for electric vehicles, and unreasonable thermal management strategies may lead to reduced battery efficiency and safety issues. Therefore, this paper proposed an optimization strategy for battery thermal management systems (BTMS) based on linear time-varying model predictive control (LTMPC). To begin, based on the results of three-dimensional thermal flow analysis, a reduced order substitution model for the battery cooling system was established. Next, to address the issue of high computational complexity caused by the nonlinear model in the controller, a linearization method based on staged control was designed. Furthermore, the control parameters were optimized using the particle swarm optimization algorithm. Finally, a BTMS physical model based on SIMSCAPE was established for performance simulation. The performance of the logic threshold controller (LTC), linear model predictive controller (LMPC), and nonlinear model predictive controller (NMPC) was compared and analyzed. LTMPC was found to reduce the average temperature of the battery by up to 2.33 °C and 1.90 °C, and the cumulative temperature difference is reduced by 13.9% and 16.6% compared to LTC and NMPC, respectively. Compared to LMPC, LTMPC reduces thermal management energy consumption by 21.2%.

Aircraft engine nozzle guide vane surface temperature optimization

An optimization method based on the sensitivity of global and local geometric parameters is proposed to improve the cooling efficiency of E3 engine nozzle guide vane. For 29 geometric parameters that affect the vane maximum temperature in the cooling design, the sensitivity ranking of them is firstly obtained by the DOE method. Then the most influential parameters including the diameter or location of the film cooling hole are selected as the optimization variables to decrease the maximum surface temperature of the nozzle guide vane. On this basis, to further reduce the local temperature downstream the pressure side, a new duck-paw type film cooling hole is applied. The duck-paw type film cooling hole was produced with the adjoint method through identifying the sensitivity of the geometric boundary parameters of the film cooling holes. Compared to the cylindrical holes, the duck-paw shaped film cooling hole can greatly improve the cooling efficiency under the same conditions. The duck-paw type film cooling holes are applied to the last two rows of film cooling holes located on the pressure side of nozzle guide vane. Three-dimensional conjugate flow and heat transfer analysis results show that the maximum temperature of the optimized cooling structure vane is reduced by 39K, and the average temperature decreases by nearly 20K.

Enhanced heat transfer in a microchannel with pseudo-roughness induced by Onsager-Wien effect

A three-dimensional numerical analysis of flow and conjugate heat transfer in a microchannel in the presence of the electric-field-induced Onsager–Wien effect is performed. A novel design is proposed to induce a pseudo-roughness effect in the microchannel and thereby increasing the heat transfer. A series of thin plate electrode pairs are flushed along the bottom wall of the microchannel. The electric-field-enhanced dissociation of ions induces the Onsager–Wien effect, and generates small flow vortices near the bottom wall of the channel. These flow vortices with sharp local velocity gradients effectively disrupt the viscous and thermal boundary layers, and thus, introduce a pseudo-roughness effect. This disruption of the boundary layers improves the heat transfer between the channel wall and the working fluid. The thermal and hydraulic performances in the microchannel are quantified as a function of the flow Reynolds number Re and electric Reynolds number ReEL. In general, the performance factor PF is higher when the flow and electric Reynolds numbers are higher. However, the associated pressure drop penalty reduces the PFPF<1 in viscous-effect-dominated flows at Re=250. By contrast, the Onsager–Wien effect increases the PF to a maximum value of 1.26 in inertia-dominated flows at Re=1000 and ReEL=15. A significant heat transfer enhancement is realized, even at a low applied voltage of ∼1 kV. The results of this study indicate that the pseudo-roughness produced by the electric-field-induced Onsager–Wien effect can substantially enhance the heat transfer in a microchannel with a trivial amount of additional power consumption. Results presented in this study will serve as a benchmark to design microchannels with enhanced heat transfer by using active vortex generation based on Onsager-Wien effect.

Three-dimensional computational flow dynamics analysis of free-surface flow in a converging channel

Three-dimensional computational flow dynamics analysis of free-surface flow in a converging channel

Apparent permeability in tight gas reservoirs combining rarefied gas flow in a microtube

In tight gas reservoirs, the major flow channels are composed of micro/nanopores in which the rarefaction effect is prominent and the traditional Darcy law is not appropriate for gas flow. By combining the Maxwell first-order slip boundary condition and Navier–Stokes equations, a three-dimensional (3D) analysis of compressible gas slip flow in a microtube was presented, and the flux rate and pressure variation in the flow direction were discussed. Subsequently, by superimposing the Knudsen diffusion, a gas flux formula applicable to a larger Knudsen number was further proposed and satisfactorily verified by two groups of published experimental data in microtubes or microchannels in the membrane. The results indicate that slip flow and Knudsen diffusion make an important contribution to the total gas flow in the microtube, and their weight increases with an increase in the Knudsen number. By substituting the gas flux formula into Darcy’s law for compressible gas, a new apparent permeability model for tight gas reservoirs was proposed, in which the slippage effect and Knudsen diffusion were synthetically considered. The results indicate that the apparent permeability of tight reservoirs strongly depends on the reservoir pressure and pore-throat radius, and an underestimation value may be predicted by the previously published models. This study provides a case study for evaluating these apparent permeability models, which remains a challenging task in the laboratory.

A Simple Line-Element Model for Three-Dimensional Analysis of Steady Free Surface Flow through Porous Media

Considering the fact that only pores can transport water, pores in the homogeneous control volume are conceptualized as a three-dimensional orthogonal network of line elements, which is in contrast to the continuum hypothesis in traditional numerical approaches. The related flow velocity, hydraulic conductivity and continuity equation equivalent to the continuum model are formulated based on the principle of flow balance. Subsequently, the unified form for flow velocity and continuity equation is established based on the local coordinate system, and a finite line-element method is developed, in which three-dimensional steady free surface flow is reduced to one-dimensional form, and the numerical difficulty is greatly decreased. The proposed line-element model is validated by the good agreements of free surface locations with other methods through steady flow in a rectangular dam and a right trapezoidal dam, respectively. It is found that the proposed line-element model is not heavily dependent on the mesh size and penalty parameter. Steady free surface flow on the left bank abutment slope of the Kajiwa Dam in Southwestern China is further evaluated, and a parabolic variational inequality algorithm based on the continuum model is also employed for comparison. The consistent results indicate that the proposed line-element model can capture the steady free surface flow behavior as well as the continuum-based method. Moreover, the proposed line-element model can rapidly achieve accurate solutions whether for simple examples or for complicated engineering applications.

THREE-DIMENSIONAL NUMERICAL ANALYSIS OF FLOW AND HEAT TRANSFER CHARACTERISTICS OF OIL/GAS TWO-PHASE MIXTURE IN AERO-ENGINE BEARING CHAMBERS OF DIFFERENT STRUCTURES

The change of the outlet number of bearing chambers can change the pressure distribution in the chamber and the action of the air shear force, which has an important influence on oil/gas two-phase flow and heat transfer. In this paper, the flow and heat transfer characteristics in the ventless bearing chamber and the vented bearing chamber were compared and analyzed by numerical simulation. The accuracy of the numerical model was verified by comparison with the experimental data. Three different rotor speeds were selected, and the lubricating oil distribution, the velocity of oil/gas two-phase flow, and the temperature distribution in the bearing chamber were investigated under different numbers of outlets of the bearing chamber. The heat flux and Nusselt number distribution of convective heat transfer between oil/gas two-phase flow and the outer wall at different rotor speeds were analyzed. The results show that the thickness of oil film increases in the ventless bearing chamber with increase of rotor speed, and when air flow is large, it hinders the uniformity of lubricating oil distribution and the increase of the velocity of oil/gas two-phase flow, but it can improve the uniformity of heat transfer. In the vented bearing chamber, the thickness of oil film decreases with increase of rotor speed, and the speed of oil/gas two-phase flow increases greatly, and the entraining effect of air is obvious. The research results can provide a theoretical reference for improving the number and structure of bearing chambers to improve the performance of lubricating oil system.

Unsteady three-dimensional nodal stagnation point flow of polymer-based ternary-hybrid nanofluid past a stretching surface with suction and heat source.

As a result of the many real-world applications that may be derived from understanding stagnation point flow in designing, such as the coolant of nuclear reactors, there has been a great deal of interest in the topic. Consequently, the purpose of this research was to offer a numerical analysis of an unstable three-dimensional (3D) nodal stagnation point flow of polymer-based ternary nanofluid past a stretching surface with mass suction and heat source effects. In order to simplify the underlying partial differential equations, an appropriate similarity transformation is applied to them. This simplifies the ordinary differential equations. The shooting with the Runge-Kutta approach is used by the MATHEMATICA software to do the numerical calculation. Suction, stretching, unsteadiness, heat source, and nanoparticle volume fractions are other elements that play a role in regulating the flow and heat transfer as well as drag force profiles and how they affect the problem. The amount of heat transferred, and the friction coefficient increased in both directions when the suction parameter values were raised. In a ternary-hybrid nanofluid, the overall heat transfer rate decreases as the value of the heat source increases. Variations in the nanoparticles' volume fraction parameter cause an intensification in skin friction in both directions. Expanding the unstable and nanoparticles volume fraction parameters also reduces the Nusselt number. Furthermore, the heat transfer presentation of ternary-hybrid nanofluid has superior to the hybrid nanofluid and the normal nanofluid for the suction parameter. When the results of the current research were compared to those of a study that had already been done and published, they were found to be in good agreement.

Comparative Numerical Analysis of Three-Dimensional Flow in the Opening Process of the Single-Disc Butterfly Valves

Comparative Numerical Analysis of Three-Dimensional Flow in the Opening Process of the Single-Disc Butterfly Valves

Three-dimensional computational analysis of flow over twisted hydrofoils

The hydrofoils are frequently employed in many different industrial applications, including submarines, rudders, ship motion controls, and marine propellers. The flow over hydrofoils has been the subject of various research in the past. The present study reports the effects of varying twist applied symmetrically along the span and the section thickness on the hydrodynamic performance parameters of non-cavitating three-dimensional hydrofoils for a relatively wide range of angles of attack. Twisted, half-twisted and untwisted hydrofoils with NACA0009 and NACA0015 sections are investigated numerically by incompressible non-cavitation model of Reynolds-Averaged Navier-Stokes (RANS) equations with the shear stress transport (SST) k-omega turbulence model. The impact of twisting, section thickness and freestream velocity are studied in terms of the distributions of lift, drag, and pressure coefficients for various angles of attacks −2°<AOA<8° following a series of successful validation processes. Twisted hydrofoils are evaluated for the implications of the altered incoming flow velocity on the hydrofoil performance. The Delft Twist-11 hydrofoil, which has been used as a benchmark geometry in the literature, are employed for validation investigations. The purpose of the study is to identify which of the hydrofoils under investigation (twisted, half-twisted, untwisted) has a higher lift force and efficiency, and whose application would be more suitable for a particular angle of attack. In particular, the twisted NACA0009 provides the highest lift and the highest efficiency in the range of −2°<AOA<2° compared to half-twisted and untwisted cases. From AOA = 2°–5°, half-twisted NACA0009 provides the maximum efficiency; at later angles, untwisted NACA0009 performs better. Additionally, the lift force is not much affected by the rise in Reynolds number of flows around twisted hydrofoils, while the drag coefficient significantly decreases.

Optimization of Material-Specific Parameters for Accurate Foaming Flow Analysis

In recent years, various models of polyurethane foam have been modeled using CAE analysis. Material properties are important for accurate modeling of polyurethane flow. However, it is difficult to measure accurate polyurethane material properties. Therefore, in CAE analysis, materialspecific parameters are incorporated in the density evaluation equation to correlate with the experimental results. However, since there is a little detail on how the material-specific parameters are determined, it is necessary to construct a method for determining the optimum parameters. In this study, we propose the genetic algorithm optimization method (real-coded GA) that can handle complex nonlinearities. In order to verify the validity of real-coded GA, the time-density evaluation empirical equation proposed by Kono et al. (2005) was used to find the optimal parameters for the material-specific parameters. It was possible to obtain optimum material-specific parameters that fit well with the experiment results. Furthermore, a three-dimensional fluid flow analysis was performed by incorporating Kono's empirical formula. The filling flow behavior and the peak height of the foam obtained in the experiment agreed with the CAE analysis results. It was shown that accurate CAE analysis is possible by this method.

Research on Sediment Laden Flow Characteristics in Water Conveyance System

In the long-distance water conveyance channels or pipelines of sediment laden flow, due to the change of the flow discharge, there may be different levels of siltation condition, and regular dredging work needs to be carried out. If the water conveyance channels are an open system, it is easier to dredge, but if it is a pressurized pipeline system, dredging is more difficult. Some water delivery irrigation projects of sediment laden flow could not be promoted due to the unresolved problem of siltation. This paper takes a long-distance gravity flow pipeline system as the research object. The distribution branch pipe on the main pipeline is connected to the downstream reservoir for field irrigation. According to the pipe data, the one-dimensional full pipeline numerical model and the three-dimensional pipe calculation model were established respectively. The flow velocity calculation of main pipeline under the condition of simultaneous irrigation of different numbers of distribution branch pipes, and the distribution of different velocities in the pipe was obtained. At the same time, the three-dimensional unsteady flow analysis was carried out to analyse the flow characteristics and siltation patterns in the main pipeline under different flow discharge. It is helpful to predict the silt phenomenon that may exist in the water pipeline in advance by calculation, and give technical suggestions for the pipeline design.

Numerical study of heat transfer enhancement in twisted clockwise-counterclockwise square ducts

The heat transfer and friction factor for the working fluid, such as airflow through a clockwise (CW)-counter clockwise (CCW) square duct, are numerically investigated. The outer cylinder's walls are subjected to a uniform heat flux, and the duct's walls are kept at a constant temperature. For Reynolds numbers of 100–50000, Prandtl numbers of 0.7, 20, and twist ratios of 16.5, 11.5, 7.5, and 2.5, a three-dimensional analysis of fluid flow within the duct area was done. The results of an experiment with a straight square and twisted square duct are compared to the results of this study. The Nusselt number in this investigation is significantly greater than the results of earlier experimental studies. Up to the Reynolds number value of 3000, the percentage rise in Nusselt numbers is similarly indicated as 58–60% greater than the experimental works. Nusselt number and friction factor correlations are also defined.