Numerical Analysis Of Fluid Flow Research Articles

Numerical Analysis of Fluid Flow Around Ship Hulls Using STAR-CCM+ with Verification Results

Numerical Analysis of Fluid Flow Around Ship Hulls Using STAR-CCM+ with Verification Results

Numerical Analysis of Fluid Flow and Heat Transfer Characteristics of Novel Microchannel Heat Sink

Microchannel heat sinks have gained prominence in the field of thermal management, offering compact and efficient solutions for dissipating heat flux from high performance electronic devices. Escalating heat flux in modern electronic devices, such as those found in telecommunication equipment, industrial automation equipment, solar devices, and data centre servers has driven the continuous development of microchannel heat sink to achieve efficient thermal management. The critical challenge in thermal management for these devices is to develop a microchannel that enhances heat transfer performance and minimises pressure drop. Heat transfer and pressure drop are two competing factors that determine the practicability of the design for real world application. Improvement in heat transfer performance usually results in an increase in pressure drop and pumping power. This study addresses the challenges of designing microchannel through comprehensive numerical analysis of fluid flow and heat transfer characteristics of a novel design that combines ribs, secondary channels, and tertiary channels. The numerical results showed that the novel microchannel design achieves a favourable balance between heat transfer and pressure drop, demonstrating its potential to be used in application where high heat transfer and efficiency are paramount. To assess the performance of the microchannels, thermal resistance, a measure of system’s resistance to heat transfer is used. At the same pumping power, thermal resistance in the new design is consistently lower compared to other designs.

A numerical analysis of fluid flow and heat transfer between two rotating disks with induced porous medium

In this article, fluid flow between rotating disks is a fundamental topic in fluid dynamics and has various practical applications in engineering and technology. The primary motivation for studying fluid flow between two rotating disk includes its applications in heat exchanger design, generating energy, designing aircraft components like helicopter blades, propellers, wind turbine rotors, fluid pumping, stirring, etc. Authors have considered radially stretching and rotating disks simultaneously under the spiraling motion of a couple stress fluid. This type of motion is developed by radial stretching in addition to the disk’s uniform rotation. This study gives information about the effect of various physical parameters on radial, tangential velocities, and temperature profiles. The similarity transformation resulted in coupled nonlinear ordinary differential equations from the constitutive flow rules of nonlinear partial differential equations. For getting numerical solutions, the authors have used the in-build NDSolve command in MATHEMATICA software, which uses the finite difference method for discretizing and solving differential equations. The outcomes of the above study depict how the fluid flow pattern between the rotating disks is affected by Darcy’s parameter, and other parameters, like Prandtl number, rotation parameter, stretching parameter, couple stress parameter, etc. on the flow, have been thoroughly analyzed, with the physical relevance illustrated. Radial and tangential velocity profiles decrease whenever the Darcy parameter increases. An increase in rotation parameter enhances the radial and tangential velocity due to rotation of the disks.

Numerical Analysis of Fluid Flow and Powder Transport Characteristics of RH-Degasser Ladle Bottom Powder Injection (RH-PBI) Process

Numerical Analysis of Fluid Flow and Powder Transport Characteristics of RH-Degasser Ladle Bottom Powder Injection (RH-PBI) Process

Fluid flow characteristics and heat transfer performance in microchannel heat sinks: A review

The hydraulic and thermal characteristics of fluid flow in microchannels have advanced applications for the thermal management of electronic devices. There has been a wide development in the field of research concerning experimental procedures as well as numerical analysis of fluid flow in microchannels over the past decade. This article provides an overview of overall experimental and numerical studies in recent years to obtain clear understanding of various parameters affecting the fluid flow and heat transfer performance in microchannels. Furthermore, the article will come in handy for the researchers and scientists dealing with the basic correlations and some dimensionless parameters governing the hydrodynamic as well as thermic behavior of fluid flow in microchannels. This article underlines the recent studies on nanofluids in this specific area; additionally, it has encapsulated the influence on thermal performance by numerous designs of MCHS such as fins, ribs, etc. The latest research has revealed that there is a little agreement over the literature provided by experimental and theoretical analyses. Eventually, the conclusions drawn from this study and future prospective of research in this area have been thoroughly discussed.

Numerical Investigation on Characteristics of Fluid Flow Over Cavity in a Parallel Channel at Low Reynolds Numbers

The database management output system is interesting and available in the numerical analysis of fluid flow, especially for a fluid flowing past a cavity inside a channel. The aim of the current study is to investigate numerical simulations characteristic of fluid flowing over a cavity in a parallel channel at low Reynolds numbers and to predict reduced energy. Computer Fluid Dynamic (CFD) is utilized to solve two-dimensional low Reynolds Navier-Stoke equations with support from Gambit software, which incorporates a simulation modelling suite in the meshing model. The numerical simulations were carried out by fluid such as water for the Reynolds numbers of 50 and 1000 and for cavity aspect ratio, W/H, of 1/3, 1/2, 1, 2, and 3. The normal mean velocity input is unity. This investigation indicated that changing cavities aspect ratio influences vortex flow significantly. Besides, the study found that the aspect ratio of cavities and Reynolds numbers influence total pressure and temperature output significantly and are important for most fluid dynamic problems. Finally, the optimal reduced pressure in a channel and optimal design cavities geometries yield better results.

A Numerical Analysis of Fluid Flow and Torque for Hydropower Pelton Turbine Performance Using Computational Fluid Dynamics

The difficulty of delivering electrical power to rural areas motivated the researchers to explore more accessible power sources. Hydropower is considered a desirable option due to its sustainability and lower costs. Pelton turbines have been widely used in hydropower plants because of their low installation and maintenance costs. This study provides a computational fluid dynamics (CFD) model for Pelton turbine performance under various flow conditions. The model is based on the conservation of mass principle, Newton’s second law, and the first law of thermodynamics. It is used to predict the torque produced by a turbine at different rotational speeds. Previously published experimental results for the same turbine geometry and flow parameters were used to validate the model’s predictions. Validation revealed that the model can reproduce the experimental results. This provides the required robustness for its use as a tool for turbine design and modification.

A numerical analysis of fluid flow and heat transfer in wavy and curved wavy channels

In this paper, a curved wavy channel was proposed to further enhance the thermal performance of the conventional wavy channel. A three-dimensional model of the curved wavy channel was established with defining the overall curvature. The flow behavior and heat transfer in the wavy and curved wavy channels were numerically investigated under various wave amplitudes. The mechanism behind the observed phenomena was revealed by analyzing the synergy between velocity and temperature fields. The results indicated that the Nusselt numbers in curved wavy channels with amplitudes of 0.40 mm and 0.80 mm can be raised by 44.3% and 15.3% compared to those in conventional wavy channels. The parametric study showed that the flow resistance is more sensitive to the wavelength. For a given amplitude, curved wavy channels always show a better field synergy than conventional wavy channels. In addition, an inferior field synergy was observed near the suction side in both types of wavy channels, which indicates that the purposive improvement needs to apply to these locations. This study also found that the field synergy angle has limitations in characterizing the heat transfer intensity in the channel with small wavelengths. This is because that extremely chaotic flow patterns caused by small wavelengths result in a negative dot product of temperature gradient and velocity over a large area.

High-resolution microscopy assisted mechanical modeling of ultrafine electrospun network

This paper demonstrates a novel hi-resolution microscopy-assisted computational approach to mechanical modeling of ultrafine electrospun networks (ESN). Morphological data extracted from X-ray microtomography (μCT) of ESN made of poly(lactic-co-glycolic acid) (PLGA), supplemented by data acquired from the nanoscale flexural test of a single fiber, was used to create a volumetric finite element (FE) model of the investigated ESN. The results of the carried-out FE simulation have been successfully validated against the results of the quasi-static tensile test. The accuracy and the reliability of the μCT-based ESN geometry have been proved by the comparison with the scanning electron microscopy (SEM) data and by the numerical analysis of fluid flow across the rendered ESN structure. The designed methodology enables the analysis of potential factors affecting the mechanical properties of electrospun structures made of aliphatic polyesters, like the depth of fiber fusion, the ESN geometric inaccuracies, and the fiber diameter distribution. Moreover, in the study, the novel experimental setup enabling for single fiber AFM flexural test was proposed, assuming deposition of fibers directly on polystyrene (PS) substrate containing crater-like wells. Additionally, the presented study contains the numerical analysis of the effect of the substrate stiffness on the results of the three-point bending test of a single fiber.

Application of Taguchi method in the numerical analysis of fluid flow and heat transfer around a flat tube with various axial ratios

In this paper, the behavior of airflow over flat and circular tubes is investigated in terms of aerodynamics and heat transfer simultaneously to determine the most effective factors and their optimum levels. Three types of flat tubes, with axial ratios of 1.5, 2, and 2.5, are considered in comparison with circular tubes. Two boundary conditions of constant temperature and constant heat flux are applied on the tube wall. By using the Taguchi method and analysis of variance (ANOVA), the L16 array is investigated statistically. The drag force coefficient, the Nusselt number, and the thermal-hydraulic performance are calculated, as well as the optimal values and contributions of design variables. The results show that, while the axial ratio has a major effect on the drag force, it has little impact on the rate of heat transfer, and the tube wall boundary condition would be more effective. However, the axial ratio of the tube has the greatest impact on thermal-hydraulic performance. In terms of flow behavior, the vortex shedding phenomenon is eliminated in most cases of flat tubes. By utilizing the Taguchi method and statistical analysis, the volume of calculations is reduced by 50% without considering the reduction of data analysis time.

Numerical Analysis of Fluid Flow and Heat Transfer by Means of a Unified Model in a Direct Current Electric Arc Furnace

Herein, a unified 2D axially symmetric model coupling the plasma arc and molten bath in a direct current electric arc furnace is established, with the physical phenomena at the plasma arc/molten bath interface to be confronted by the “local thermodynamic equilibrium diffusion approximation” method. After ensuring model validation and grid independence test, the fluid flow and heat transfer processes are analyzed. The numerical investigation reveals that in terms of the relative importance of driving forces in the molten bath, an anticlockwise eddy is formed at the molten bath center driven by electromagnetic force, whereas a clockwise eddy is formed near the lateral part of the molten bath driven by buoyancy force. Regarding the distribution of heat flux, the convection–conduction and radiation heat govern the rate of heat transfer from the plasma arc to the molten bath. In addition, for larger arc current, higher arc power in the plasma arc region and higher heating rates in the molten bath are obtained when the arc length is held constant; for shorter arc length, lower arc power in the plasma arc region but higher heat transfer efficiency in the molten bath is attained when the arc current is held constant.

Experimental and Numerical Analysis of Fluid Flow in Microfibers

The flow in small geometries is of interest in applications like bioanalysis systems, micro-valves and flow through porous media. The flow generally straight- forward to predict since the flow is stratified and so the geometries are clear-cut. However, once it involves flow through twin scale porous media, the flow gets harder to predict. The flow-through porous media are usually applied to areas like composites manufacturing, paper making and drying of ore pellets. The aim of this paper is to check flows in small geometries with numerical and experimental ways to realize an enlarged understanding of porous media flow. The optical technique best fitted to this sort of geometries is micro image velocimetry (μ-PIV) and numerical calculations are done with computational fluid dynamics (CFD). μ-PIV is employed to analyze the flow in channels with one fiber and with fiber arrays of various patterns and densities. The impact consistency has on flow fields in channels is investigated with CFD.

Numerical Analysis of Fluid Flow and Heat Transfer in Micro-Channel Heat Sinks with Double-Layered Complex Structure.

Micro-channel heat sink (MCHS) has been extensively used in various electronic cooling fields. Double-layered MCHS, or DL-MCHS, is regarded as one effective technique for high-heat-flux transfer and is expected to meet the ever-increasing heat load requirement of future electronic device generations. In order to improve the cooling capacity, two new types of the MCHS, with a double-layered matrix structure (DL-M) and double-layered interlinked matrix structure (DL-IM) are proposed and investigated numerically. The two designs are compared with the traditional double-layered rectangular structure (DL-R) and the double-layered triangular structure (DL-T). Different properties of the heat sink are investigated to assess the overall heat transfer performance, for which coolant flow and heat transfer are both evaluated. The numerical results reveal that the periodical slot subchannel in the matrix has a significant effect on fluid flow for heat transfer. In comparison to the DL-R and the DL-T, the DL-M and DL-IM realize a much lower pressure drop and temperature rise at the base surface and also have higher Nusselt number and secondary flow intensity, therefore, manifesting better overall thermal performance. In the DL-M and DL-IM, the coolant flows along the periodical subchannel in one layer and is redirected into the second layer with vortices being induced. The vortices promote the coolant mixing and enhance the mass and heat transfer. These geometric design strategies can provide references for wide heat sink applications.

Reactivation of natural fractures network by hydraulic fracturing

Modelling the process of induced fracture initiation, propagation and interaction with natural fractures is a very challenged task. Significant progress has been made in recent years in the development of complex fracture models to address the needs for more suitable design tools than the conventional planar fracture models. However, some aspects of this complex process are not still fully understood in terms of their impact or importance to the overall fracture geometry, or the complexity of simulating them is beyond the current modelling capabilities or requires computation effort that is not practical for engineering purpose. A technique that has been developed to represent the process of fracture propagation is the Continuous Approximation of Strong Discontinuities, which introduces a special kinematics, capable of representing the process of degradation of the material. One way to implement this approximation is to introduce the effects of a very narrow band of localized deformations within the existing finite elements. In this paper was used a finite element procedure that performs numerical analysis of fluid flow in a deformable porous media in a fully coupled scheme. In this analysis the propagation of the hydraulic fracture occurs specially along the pathway of the natural fractures, due to their lower tensile strength and greater permeability.

Numerical Analysis of Fluid Flow on Wall Cylinder Circular with K-ε Modeling for a High Reynolds Rate

This study discusses the numerical study of two-dimensional analysis of flow through circular cylinders. The original physical information entered in the equation governing most of the modeling is transferred into a numerical solution. Fluid flow on two-dimensional circular cylinder wall using high Reynolds k-ε modeling (Re = 106), Here we will do 3 modeling first oder upwind, second order upwind and third order MUSCL by using k-ε standard. The general procedure for this research is formulated in detail for allocations in the dynamic analysis of fluid computing. The results of this study suggest that MUSCL's third order modeling gives more accurate results better than other models.

Numerical Analysis of Fluid Flow and Heat Transfer in Wavy and Hybrid-Slit-Wavy Fin-and-Tube Heat Exchangers

This numerical study pertains to characterizing flow and heat transfer interactions for an interrupted fin design with wavy profile in a compact tube-and-fin heat exchanger. Sinusoidal wavy fin is combined with slit fins to investigate thermal-hydraulic performance relative to an uninterrupted fin design. This fin is referred to as hybrid-slit-wavy (HSW) in this work. Commercial computational fluid dynamics (CFD) software is used for 3D numerical solution of the complete Navier–Stokes and energy equations in the heat exchanger to study flow physics and predict performance. The modeling approach is first validated with available test data from the literature on a wavy (herringbone profile) fin heat exchanger. The predicted friction factor was within 12% and the Colburn j-factor was within 7% of the reported test data over a Reynolds number range of 350 to 6500. In the case of the HSW fin, it was found that the air-side heat transfer is enhanced by about 20% to 39% relative to the baseline uninterrupted fin with an associated pressure drop penalty of 20% to 38%. The area goodness factors of the HSW fins are up to 4% higher compared to the wavy fins at various operating conditions, indicative of favorable tradeoff.

Permeability determination in tight rock sample using novel method based on partial slip modelling and X-ray tomography data

Purpose The purpose of the paper was the application of computational fluid dynamics (CFD) techniques in fluid flow using Maxwell’s equation for partial slip modelling, estimating the flow parameters, and selecting tangential momentum accommodation coefficient (TMAC) for tight rock samples in permeability calculations. Design/methodology/approach The paper presents a numerical analysis of fluid flow in a low-porosity rock sample by using CFD. Modelling results allowed to determine mass flow rates in a rock sample and to calculate permeability values using a modified Darcy’s equation. Three-dimensional (3D) geometrical model of rock sample generated using computed X-ray tomography was used in the analysis. Steady-state calculations were carried out for defined boundary conditions in the form of pressure drop. The simulations were applied taking into account the slip phenomenon described by Maxwell’s slip model and TMAC. Findings Values of permeability were calculated for different values of TMAC, which vary from 0 to 1. Results in the form of gas mass flow rates were compared with the measured value of permeability for rock sample, which confirmed the high accuracy of the presented model. Practical implications Calculations of fluid flow in porous media using CFD can be used to determine rock samples’ permeability. In slip flow regime, Maxwell’s slip model can be applied and the empirical value of TMAC can be properly estimated. Originality/value This paper presents the usage of CFD, Maxwell’s equation for partial slip modelling, in fluid flow mechanism for tight rock samples. 3D geometric models were generated using created pre-processor (poROSE software) and applied in the raw form for simulation.

Numerical analysis of heat transfer in air-water heat exchanger with microchannel coil

This paper presents numerical analysis of fluid flow and heat transfer in the heat exchanger with microchannel coil (MCHX). In accordance with previously published experimental results, 3D mathematical model has been defined and appropriate numerical simulation of heat transfer has been performed. Geometry and working parameters of cross-flow air-water heat exchanger with microchannel coil, installed in an open circuit wind tunnel and used in experimental investigations, have been applied in numerical analysis in order to validate the mathematical model. 3D model with air and water fluid flow and heat transfer domains has been used, as it gives more precise results compared to models that assume constant temperatures or constant heat fluxes on the pipe walls. Developed model comprised full length of air and water flows in the heat exchanger. Due to limitations of computational capacity, domain has been divided in multiple computational blocks in the water flow direction and then solved successively using CFD solver Fluent. Good agreement between experimentally measured and numerically calculated results has been obtained. The influence of various working parameters on heat transfer in air-water heat exchanger has been studied numerically, followed with discussion and final conclusions.

Numerical Analysis of Fluid Flow on Cross Flow and Kaplan Turbine Prototype

Based on previous research conducted by Purwantono about the utilization of exhaust flow from a conventional cross-flow turbine prototype that was used as an inlet of tubin Kaplan [1]. This research was carried out to see how the exhaust flow velocity of each tubin before and after was combined into one combination turbine. This numerical based study uses the Ansys 18.0 application by inputting a 3D design from a conventional turbine prototype which was used as the material for this study. The results obtained in this study show the average of outlet velocity in the Kaplan turbine that uses a velocity outlet from a cross flow turbine of 0.3 m / s greater when it is combined, which is 8.33 m / s and after being combined to 0.38 m / s. The results of this study are expected to contribute to the development of conventional turbines later

Local non-vuggy modeling and relations among porosity, permeability and preferential flow for vuggy carbonates

It is challenging to predict the permeability of a vuggy carbonate based on a bulk porosity indicator such as the effective porosity obtained by helium porosimetry. The primary reason is that heterogeneity in the local porosity distribution within the rock may cause nonuniform fluid flow or preferential flow due to the large amount of hydraulically ineffective pore spaces. Here we present the results of a new X-ray computed tomography (CT) based numerical fluid-flow analysis for various types of vuggy carbonate samples, together with experimental visualization of the flow paths within some samples. To numerically analyze the preferential flow, the samples are modeled as aggregates of submillimeter-scale non-vuggy carbonates with different porosities for which the widely-used Lucia bulk porosity-permeability relations of non-vuggy carbonate rock are applied (local non-vuggy modeling). The local porosity distribution is estimated using X-ray computed tomography of the samples. The local permeability distribution is then estimated based on the local porosity distribution, and a single-phase Darcy flow simulation is performed. This provides the bulk porosity and permeability and the preferential flow within the samples, which are consistent with experimentally measured values and visualized flow paths. Both lognormal and normal distributions of local porosity are identified. Preferential flow is associated with a lognormal distribution, and the geometric standard deviation is related to the degree of preferential flow. We show that, in the case of a normal local porosity distribution, the bulk permeability can be predicted based on a bulk porosity indicator such as the effective porosity measured using helium porosimetry. Additionally, we show that in the case of a lognormal local porosity distribution, the permeability is a function of the geometric mean and the geometric standard deviation of the distribution. This new method will contribute to better evaluation and modeling of vuggy carbonate reservoirs/aquifers for hydrocarbon production, carbon storage, and water resource conservation.