Author: Islam RamadanPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Experimental Investigation of the Oscillating Flow Dynamics at the Exit of Regenerator Meshes with Different Configurations
Author: Islam RamadanSimulation Study of Fluid Flow in Wire Mesh Regenerator
Author: Kuttum Pavan KumarPublisher:
ISBN:
Category :
Languages : en
Pages : 122
Book Description
In this study, the pressure drops and friction factor characteristics of the Stirling engine regenerator were experimentally and numerically studied. The Stirling regenerator test bench is designed to analyze and evaluate different wire mesh regenerators' pressure drop characteristics under steady-state flow conditions. At the same time, 3-D numerical simulations are performed to numerically characterize the pressure loss inside the wire mesh regenerator under different porosity and flow boundary conditions. In the experiment, three stainless steel Meshes of #300 Mesh, #400 Mesh, #500 Mesh and a hybrid mesh of #300/400/500 and #500/400/300 mesh of 5 mm diameter and a length of 45 mm were fabricated. The steady flow test bench comprises a helium gas tank, rotameter, two pressure transducers, and a specially designed module that houses the porous structure sample. The goal is to measure the hydrodynamic properties of the regenerator during the single flow experiment. In addition, pressure drop and friction factor correlation were calculated for the set of regenerator wire mesh. For different configurations of wire mesh regenerators, the numerical research uses a finite volume method on CFD (computational fluid dynamics) models. The conventional two-parameter Ergun is obtained from the pressure drop and Reynolds number equations, and it may be confidently applied in an identical porous media for future regenerator flow.
Experimental Investigation of an Oscillating Flow Generator
Author: Cogan S. SemlerPublisher:
ISBN:
Category : Hydrodynamics
Languages : en
Pages : 47
Book Description
The objective of this project was to construct and test a device that can transform fluid flow into the continuous oscillatory linear motion of a hydro/airfoil. This device may be used to generate power from a renewable energy source such as tidal flow or wind power. The device was constructed in the NPS machine shop. It consisted of a flat plate that is mounted on two rail guides such that it can execute a linear back-and-forth motion. The blade oscillation is flow induced due to the lift and the moment generated on the flat plate in such a way that the plate reverses direction at the stroke endpoints without active control. Tests in two water channels and one towing tank showed that flow-induced blade oscillation could be achieved for certain combinations of flow speed, blade size and pitch axis location. It is concluded that additional testing is warranted to further develop and gain understanding of this technology and its possible application to renewable power generation.
An Experimental Investigation of Multiple Time Dependent Modes in Taylor-Couette Flow
Author: Nabil Ahmed Shawki El-MinshawyPublisher:
ISBN:
Category :
Languages : en
Pages : 470
Book Description
An Experimental Investigation of Bubble-driven Two-phase Flow
Author: Karen L. BurchExperimental Investigation of a Constant-area Two-phase Flow Ejector
Author: Joseph A. BrayAn Experimental Investigation of the Reverse Flow Boundary Layer Over an Upstream Moving Belt
Author: Vishwambhar Nath PandeyPublisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 79
Book Description
A Study of the Impact of Mesh Configuration on Three-dimensional Fluidized Bed Simulations
Author: Anthony NaccaratoPublisher:
ISBN:
Category : Computational fluid dynamics
Languages : en
Pages : 26
Book Description
The objective of this work is to study the influence of computational grid on the accuracy and efficiency of fluidized bed simulations. Due to their enhanced mixing and heat transfer characteristics, fluidized bed systems have gained attention in a wide range of industrial applications, including power generation, fuel synthesis and pharmaceuticals. Traditionally these systems are developed through extensive experimental work. Laboratory-scale prototypes often exhibit different flow characteristics than industrial-scale systems, making design and optimization even more difficult and costly. As a result, computational fluid dynamics (CFD) has become a useful tool for design and optimization of these systems. An important issue in CFD analysis of gas-solid flows in fluidized beds is the influence of mesh on the results. The present study focuses on analyzing the reliability of fluidized bed simulations as affected by mesh configuration and resolution. Several approaches to constructing the computational grid are discussed and the influence of mesh configuration on simulation performance and accuracy is demonstrated. Given its capacity to handle both structured and unstructured grids, cases are simulated via the open-source platform OpenFOAM. The accuracy of the predictions given by OpenFOAM are validated against experimental data and compared with results from MFiX, the National Energy Technology Laboratory CFD platform. Grid resolution studies are performed, and the computational performance of various grid arrangements are evaluated.
Numerical Simulation of Bubbles and Drops in Complex Geometries by Using Dynamic Meshes
Author: Enrique Gutiérrez ÁlvarezPublisher:
ISBN:
Category :
Languages : en
Pages : 184
Book Description
CFD techniques are important tools for the study of multiphase flows, because most of the physical phenomena of these flows often happen on space and time scales where experimental methodologies are impossible in practice. Notwithstanding, numerical approaches are limited by the computational power of the present computers. In this sense, small improvements in the efficiency of the simulations can make the difference between an approachable problem and an unapproachable one. The proposal of this doctoral thesis is focused on developing numerical algorithms to optimize the simulations of multiphase solvers based on single fluids formulations, applied on three-dimensional unstructured meshes, in the context of a finite-volume discretization. In particular, the methods developed in the context of this PhD thesis use a conservative level set technique to deal with the multiphase domain. The work has been organized in five chapters and four appendices. The first chapter constitutes an introduction to the multiphase flows and the different approaches used to study them. The core work of the of this PhD thesis is explained throughout chapters two, three, and four. In those chapters, the improvements performed on the multiphase DNS techniques are addressed in detail, providing results comparisons and discussions on the obtained outcomes. After developing the main ideas of the thesis, a final concluding chapter is presented, summarizing the main findings of this research, and pointing out some future work. Finally, the appendices includes some material that can be useful to understand in depth some specific parts of the thesis but, conversely, they are not essential to follow the main thread. As said before, the core work of this thesis is presented throughout chapters two, three and four. In chapter two, four domain optimization methods are formulated and tested. By using these techniques, small domains can be used in rising bubble simulations, thus saving computational resources. These methods have been implemented in a conservative level set framework. Some of these methods require the use of open boundaries. Therefore, a careful treatment of both inflow and outflow boundaries has been carried out. This includes the development of a new outflow boundary condition as a variation of the classical convective outflow. At this point, a study about the sizing of the computational domain has been conducted, paying special attention to the placement of the inflow and outflow boundaries. Additionally, once the methods are formulated, several validation cases are run to discuss the applicability and robustness of each method. The third chapter present a physical study of a challenging problem: the Taylor bubble. By using the most promising technique from those presented in the previous chapter (i.e. the moving mesh method), the problem of an elongated bubble rising in stagnant liquid is addressed here. A transient study on the velocity field of the problem is provided. Moreover, the study also includes sensitivity analyses with respect to the initial shape of the bubble, the initial volume of the bubble, the flow regime and the inclination of the channel. Chapter number four presents an extension of the developed method to simulate bubbles and drops evolving in complex geometries. The use of an immersed boundary method allows to deal with intricate geometries and to reproduce internal boundaries within an ALE framework. The resulting method is capable of dealing with full unstructured meshes. Different problems are studied here to assert the proposed formulation, both involving constricting and non-constricting geometries. In particular, the following problems are addressed: a 2D gravity-driven bubble interacting with a highly-inclined plane, a 2D gravity-driven Taylor bubble turning into a curved channel, the 3D passage of a drop through a periodically constricted channel, and the impingement of a 3D drop on a flat plate.
Experimental Investigation of Hydrodynamic Stability of Poiseuille Flow to a Three Dimensional Disturbance
Author: Suruliappan RajamanickamPublisher:
ISBN:
Category : Laminar flow
Languages : en
Pages : 152
Book Description