Mechanical Engineering Commons^™

Numerical Simulation Of The Heat Leakage At The Gasket Region Of Domestic Refrigerators, Feng Gao

All Theses

Computational Fluid Dynamics (CFD) simulations are performed to investigate the heat loss at the gasket of a standard over/under domestic refrigerator. The study numerically simulates a unique experimental test cell with only the gasket region exposed to the ambient environment and other parts protected by insulation (see picture below). The test cell is cubic with an interior cavity having dimensions 2' x 2' x 2' within which a heating element is placed to create a specified temperature difference. A matching set of door and side panels exposes a 2' width of the gasket region to heat transfer with the surroundings. …

Cfd Simulation Of The Flow Around Nrel Phase Vi Wind Turbine, Yang Song

Masters Theses

The simulation of the turbulent and potentially separating flow around a rotating, twisted, and tapered airfoil is a challenging task for CFD simulations. This thesis describes CFD simulations of the NREL Phase VI turbine that was experimentally characterized in the 24.4m X 36.6m NREL/NASA Ames wind tunnel. All computations in this research are performed on the experimental base configuration of 0^o yaw angle, 3^o tip pitch angle, and a rotation rate of 72 rpm. The significance of specific mesh resolution regions to the accuracy of the CFD prediction is discussed. The ability of CFD to capture bulk quantities, …

Evaluation Of The Performance Of Various Turbulence Models For Accurate Numerical Simulation Of A 2d Slot Nozzle Ejector, Colin Graham

McKelvey School of Engineering Theses & Dissertations

With the development over the last several decades, accurate Computational Fluid Dynamics (CFD) modeling has now become an essential part in the analysis and design of various industrial products where the fluid flow plays an important role. The goal of this thesis is to apply the CFD technology to the analysis of a 2D slot nozzle ejector which has application in Short Take-off and Landing (STOL) aircraft and other future aerospace vehicles. In the nozzle-ejector configuration, the high speed air flow from the nozzle entrains the ambient air into a mixing chamber (ejector) as a means to create additional thrust …

Cfd Simulation Of The Thermal Performance Of A Parallel Counter-Parallel Flow Heat Exchanger For The Treatment Of Hypothermia, Alex Heller

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hypothermia is a life-threatening condition. Currently, active warming methods are the most effective treatment for dysthermic patients. The aim of this study is to investigate the use of computational fluid dynamics (CFD) in evaluating the thermal performance of a parallel/counter-parallel flow heat exchanger used as part of a fluid warmer to treat Hypothermia. The 3D model of the heat exchanger is divided into three regions; Infusate (fluid to be heated), Hot Water (heating fluid), and a Solid Region (wall). At the end of the heat exchanger, an elbow section is used to create the counter-parallel flow arrangement specific to this …

A Study Of The Development Of An Analytical Wall Function For Large Eddy Simulation Of Turbulent Channel And Rectangular Duct Flow, Takahiko Hasegawa

Theses and Dissertations

This paper reports computational work of three-dimensional channel turbulent flow and rectangular duct flow with the Analytical Wall Function (AWF). The main purpose of this study is to establish and validate the new modeling of AWF for Large Eddy Simulation (LES-AWF). In order to compare the performance of the new modeling of LES-AWF, the conventional LES-AWF and Wall-resolved LES are applied. The new LES-AWF showed improvements of flow prediction in both of three-dimensional channel flow and rectangular duct flow, although the improvement in rectangular duct is relatively minor.

A Cfd Assisted Control System Design For Supercritical Water Cooled Reactor, Rohit V. Maitri

Electronic Thesis and Dissertation Repository

In this study, the methodology to construct a control system based on computational fluid dynamics (CFD) simulations is developed for supercritical water cooled reactor (SCWR). The CFD model using Reynolds Stress Model (RSM) and k-w SST model is validated with the experimental cases of steady state and vertically up flowing supercritical water in circular tubes for normal heat transfer and deteriorated heat transfer (DHT) cases. This model is extended to simulate the transient thermal-hydraulic behaviour of supercritical fluid flow and heat transfer, and the results are also compared with the 1-D numerical model, THRUST. The DHT phenomenon is investigated using …

High Fidelity Time Accurate Cfd Analysis Of A Multi-Stage Turbofan At Various Operating Points In Distorted Inflow, David Bruce Weston

Theses and Dissertations

Inlet distortion is an important consideration in fan performance. Distortion can be caused through flight conditions and airframe-engine interfaces. The focus of this paper is a series of high-fidelity time accurate Computational Fluid Dynamics (CFD) simulations of a multistage fan. These investigate distortion transfer and generation as well as the underlying flow physics of these phenomena under different operating conditions. The simulations are performed on the full annulus of a 3 stage fan. The code used to carry out these simulations is a modified version of OVERFLOW 2.2 developed as part of the Computational Research and Engineering Acquisition Tools and …

Validation Of A Modified Version Of Overflow 2.2 For Use With Turbomachinery Under Clean And Total Pressure Distorted Conditions And A Study Of Blade Loading In Distortion, Matthew L. Marshall

Theses and Dissertations

Inlet distortion is an important consideration in fan performance. Distortion can be generated through flight conditions and airframe-engine interfaces. The focus of this paper is a series of high-fidelity, time-accurate Computational Fluid Dynamics (CFD) simulations of a multistage fan, investigating distortion transfer, distortion generation, and the underlying flow physics under different operating conditions. The simulations are full annulus and include 3 stages and the inlet guide vane (IGV). The code used to carry out these simulations is a modified version of Overflow2.2 that was developed as part of the Computational Research and Engineering Acquisition Tools and Environment (CREATE) program. The …

Simulations And Measurements Of Fuel Film Using Refractive Index Matching Method, Fengkun Wang

Wayne State University Theses

ABSTRACT

SIMULATIONS AND MEASUREMENTS OF FUEL FILM USING REFRACTIVE INDEX MATCHING METHOD

by

FENGKUN WANG

APRIL 2014

Advisor: Dr. Ming-Chia Lai

Major: Mechanical Engineering

Degree: Master of Science

Direct Injection (DI) has been known for its improved performance and efficiency in gasoline spark-ignition engines. However, wall wetting is inevitable and the source of UHC and PM. In order to take advantage of the GDI technology, it is important to investigate spray wall interactions in detail.

Numerical and experimental studies are carried out for spray and wall impingements in an optical constant volume vessel. The fuel film was measured spatially and …

Numerical Investigation Of Boiling In A Sealed Tank In Microgravity, Sonya Lynn Hylton

ETD Archive

NASA's missions in space depend on the storage of cryogenic fluids for fuel and for life support. During long-term storage, heat can leak into the cryogenic fluid tanks. Heat leaks can cause evaporation of the liquid, which pressurizes the tank. However, when the tanks are in a microgravity environment, with reduced natural convection, heat leaks can also create superheated regions in the liquid. This may lead to boiling, resulting in much greater pressure rises than evaporation at the interface between the liquid and vapor phases. Models for predicting the pressure rise are needed to aid in developing methods to control …

Characterizing Cryogenic Propellant Flow Behavior Through A Cavitating Venturi In Comparison To Alternative Flow Control Mechanisms, Marjorie Adele Ingle

Open Access Theses & Dissertations

The work detailed is an investigation of the use of a cavitating venturi as both a flow control and metering device. This was achieved through the combination of actual experimentation and numerical modeling of the fluid behavior of both liquid water and liquid methane as it passes through the test article designed, developed, and validated here within this study. The discharge coefficient of the cavitating venturi was determined through weigh flow calibration testing to determine an average mass flow rate. Turbine flow meter flow rate readings were used as a point of comparison and the discharge coefficient was computed. The …

Fluid-Structure Interaction Simulations Of A Flapping Wing Micro Air Vehicle, Alex W. Byrd

Browse all Theses and Dissertations

Interest in micro air vehicles (MAVs) for reconnaissance and surveillance has grown steadily in the last decade. Prototypes are being developed and built with a variety of capabilities, such as the ability to hover and glide. However, the design of these vehicles is hindered by the lack of understanding of the underlying physics; therefore, the design process for MAVs has relied mostly on trial-and-error based production. Fluid-Structure Interaction (FSI) techniques can be used to improve upon the results found in traditional computational fluid dynamics (CFD) simulations. In this thesis, a verification of FSI is first completed, followed by FSI MAV …

Computational And Experimental Study On Vertical Axis Wind Turbine In Search For An Efficient Design, Mohammad M. Bashar

Electronic Theses and Dissertations

Wind alone can fulfill most of the energy requirement of the world by its efficient conversion in to energy. Though Horizontal Axis Wind Turbine (HAWT) is more popular but needs high wind speed to generate energy. On the other hand Vertical Axis Wind Turbine (VAWT) needs low wind speed and can be installed anywhere which are some of the reasons for this research. The main objective of this research is to improve the design and performance of VAWT to make it more attractive, efficient, durable and sustainable. For a VAWT the blades perform the main role to extract energy from …

Cfd Assessment Of Respiratory Drug Delivery Efficiency In Adults And Improvements Using Controlled Condensational Growth, Ross L. Walenga

Theses and Dissertations

Pharmaceutical aerosols provide a number of advantages for treating respiratory diseases that include targeting high doses directly to the lungs and reducing exposure of other organs to the medication, which improve effectiveness and minimize side effects. However, difficulties associated with aerosolized drug delivery to the lungs include drug losses in delivery devices and in the extrathoracic region of human upper airways. Intersubject variability of extrathoracic and thoracic drug deposition is a key issue as well and should be minimized. Improvements to respiratory drug delivery efficiency have been recently proposed by Dr. P. Worth Longest and Dr. Michael Hindle through the …