Heat Transfer, Combustion Commons^™

Distribution Map Of Multi-Walled Carbon Nanotubes In A Refrigerant/Oil Mixture Within A 2.5 Ton Unitary Air-Conditioner, Warren Russell Long

Graduate Theses and Dissertations

In recent years, nanoparticles have received considerable attention as a potential additive to heat transfer fluids (i.e. refrigerant) in order to increase the heat transfer capabilities of these fluids. The potential of carbon nanotubes (CNTs) to exit the compressor, migrate throughout a vapor compression air conditioning system, and possibly foul the components of such a system was experimentally investigated in this research. Six grams of CNTs were dispersed in the polyol ester oil used by a 2.5 ton (8.79 kW) unitary air conditioning system, which was continuously operated for 168 hours. After this time, the unit was shut down and …

Investigation Of Shroud Geometry To Passively Improve Heat Transfer In A Solar Thermal Storage Tank, Matthew Keene Zemler

Doctoral Dissertations and Master's Theses

A shroud and baffle configuration is used to passively increase heat transfer in a thermal store. The shroud and baffle are used to create a vena contracta near the surface of the heat exchanger, which will speed up the flow locally and thereby increasing heat transfer. The goal of this study is to investigate the geometry of the shroud in optimizing heat transfer by locally increasing the velocity near the surface of the heat exchanger. Two-dimensional transient simulations are conducted. The immersed heat exchanger is modeled as an isothermal cylinder, which is situated at the top of a solar thermal …

Design And Simulation Of Passive Thermal Management System For Lithium-Ion Battery Packs On An Unmanned Ground Vehicle, Kevin Kenneth Parsons

Master's Theses

The transient thermal response of a 15-cell, 48 volt, lithium-ion battery pack for an unmanned ground vehicle was simulated with ANSYS Fluent. Heat generation rates and specific heat capacity of a single cell were experimentally measured and used as input to the thermal model. A heat generation load was applied to each battery and natural convection film boundary conditions were applied to the exterior of the enclosure. The buoyancy-driven natural convection inside the enclosure was modeled along with the radiation heat transfer between internal components. The maximum temperature of the batteries reached 65.6 °C after 630 seconds of usage …

Silicon Wafer Temperature Distribution, Daniel Gonzalez, Nathan Jones, Dylan Justice

Mechanical Engineering

Applied Materials is a global company that designs equipment for use in the semiconductor manufacturing industry. The scope of this project covers process chambers used for depositing thin chemical films onto silicon wafers. These processes must take place in particularly specific environments– including extremely low pressures and high temperatures. One challenge engineers face when designing these processes is carefully controlling the thermal behavior of silicon wafers. Typically, behavior is predicted using time consuming and computationally expensive CFD simulations. We have been asked to address this issue with a simpler, faster model which will allow engineers to reduce the total number …

Hepa Filter Evaluation Furnace Control Unit, Matt Gainer, Marc Goupil, Andrew Woolrich

Mechanical Engineering

No abstract provided.

The Design And Testing Of A Solar Autoclave With Broad Spectrum Sterilization Capabilities, Sarah S. Trabia

Honors College Theses

Energy is difficult to come by in developing countries and this interferes with the ability of doctors to provide good healthcare to their patients. Without decent sterilization, patients can become infected and diseases can spread throughout hospitals. This study involves designing a solar autoclave for developing countries that is as efficient as electrical autoclaves. The design is intended to not require any electrical input and to be affordable to those who cannot afford advanced medical equipment. Once the solar autoclave is designed, it will be tested to determine if it can sterilize equipment against a variety of different bacteria, including …

Computational Scheme Guided Design Of A Hybrid Mild Gasifier, You Lu

LSU New Orleans Theses and Dissertations

A mild gasification method has been developed to provide an innovative clean coal technology. The objectives of this study are to (a) incorporate a fixed rate devolatilization model into the existing 2D multiphase reaction model, (b) expand the 2D model to 3D and (c) utilize the improved model to investigate the mild-gasification process and guide modification of the mild-gasifier design. The Eulerain-Eulerian method is employed to calculate both the primary phase (air) and secondary phase (coal particles). The improved 3D simulation model, incorporated with a devolatilization model, has been successfully developed and employed to determine the appropriate draft tube dimensions, …

Phase-Resolved Characterization Of Conical Turbulent Premixed Flames: An Investigation Of Forced Blowoff Dynamics, Sayan Biswas

Master's Theses

Flame dynamics of a bluff body stabilized turbulent premixed flame as it approaches lean blowoff is of interest for practical applications. It is also important to understand the flame behavior under harmonic flow perturbations as it may occur due to acoustically unstable operation of compact combustors. In this study, a harmonically excited conical flame was studied to determine its behavior under strong burning and near blowoff conditions. Chemiluminescence imaging was employed using a Photron high speed camera to characterize the phase resolved flame characteristics for a range of excitation frequencies from 50 to 400 Hz in confined and unconfined geometries. …

Thermal Vacuum Integration For Cal Poly's Space Environments Laboratory, Chelsea Barackman, Steven Jackowski

Aerospace Engineering

The purpose of the senior project is to construct a thermal vacuum by utilizing a preexisting vacuum chamber in the Space Environments Lab, and a donated Advanced Thermal Sciences (ATS) chiller. While a thermal vacuum is already available on campus, building one for the Space Environments Lab would grant undergraduates access to the equipment, allowing a much better understanding of testing methods and procedures in use by the aerospace industry. This paper explains the design and analysis of the thermal vacuum (T-VAC) project as well as the operation and procedures required for the ATS chiller and fill/drain tank. The thermal …

California Olive Ranch Hedger, Tyler Enos, Seth Abbott, David Gamba

Mechanical Engineering

The purpose of this project is to evaluate the problems of the current KCI (Kingsburg Cultivator Incorporated) olive tree hedger in use at California Olive Ranch (COR) in Artois, CA, and then correct these problems which should yield a better performing, more efficient, and reliable machine. These problems include: the hydraulic oil temperature getting too high, the saw blades not having enough horsepower, and poor cutting performance due to operator error as well as terrain variations.

Cryogenic Heat Switch, Daniel Brodkey, Esteban Ruiz, Cristal Vasquez

Mechanical Engineering

A prototype cryogenic heat switch capable of transferring heat at cryogenic temperatures, while decoupling to prevent irreversible heat damage and minimizing parasitic heat loads, is to be developed for the Jet Propulsion Laboratory. Various material properties and cryogenic heat transfer processes will be investigated to determine the best solution for this project. A working proof of concept model will be constructed that may eventually be integrated onto a spacecraft’s passive cooler systems to protect them from the irradiation emitted by the sun, from the albedo of planets, and other malicious heat sources.

Frg Turbojet, Tyler Vitti

Computer Engineering

Members of the Cal Poly SLO campus club FRG work together with students of several different disciplines to build a functional turbojet engine. Engineering approaches include design, fabrication, testing, and computer sensing, control, and integration. The goal of the project is to produce a running turbojet engine monitored and controlled by embedded hardware and specialized PC software. This project is to be used by later groups for further research and development.

An Investigation Of Mist/Air Film Cooling With Application To Gas Turbine Airfoils, Lei Zhao

LSU New Orleans Theses and Dissertations

Film cooling is a cooling technique widely used in high-performance gas turbines

to protect turbine airfoils from being damaged by hot flue gases. Film injection holes are

placed in the body of the airfoil to allow coolant to pass from the internal cavity to the

external surface. The ejection of coolant gas results in a layer or “film” of coolant gas

flowing along the external surface of the airfoil.

In this study, a new cooling scheme, mist/air film cooling is proposed and

investigated through experiments. Small amount of tiny water droplets with an average

diameter about 7 μm (mist) is …

Analysis And Testing Of Heat Transfer Through Honeycomb Panels, Daniel D. Nguyen

Aerospace Engineering

This project attempts to simulate accurately the thermal conductivity of honeycomb panels in the normal direction. Due to the large empty space of the honeycomb core, the thermal radiation mode of heat transfer was modeled along with conduction. Using Newton’s Method to solve for a steady state model of heat moving through the honeycomb panel, the theoretical effective thermal conduction of the honeycomb panel was found, ranging from 1.03 to 1.07 Q/m/K for a heat input of 2.5 W to 11.8 W. An experimental model was designed to test the theoretical results, using a cold plate and a heat plate …

Perceptions Measurement Of Professional Certifications To Augment Buffalo State College Baccalaureate Technology Programs, As A Representative American Postsecondary Educational Institution, Christopher N. Brown

Industrial Technology Theses

The purpose of this study was to assess, measure, and analyze whether voluntary, nationally-recognized professional certification credentials were important to augment technology programs at Buffalo State College (BSC), as a representative postsecondary baccalaureate degree-granting institution offering technology curricula. Six BSC undergraduate technology programs were evaluated within the scope of this study: 1.) Computer Information Systems; 2.) Electrical Engineering, Electronics; 3.) Electrical Engineering, Smart Grid; 4.) Industrial Technology; 5.) Mechanical Engineering; and 6.) Technology Education. This study considered the following three aspects of the problem: a.) postsecondary technology program enrollment and graduation trends; b.) the value/awareness of professional certifications to employers …

Numerical Modeling Of High Temperature Bayonet Heat Exchanger And Decomposer For Decomposition Of Sulfur Trioxide, Vijaisri Nagarajan, Yitung Chen, Tzu-Chen Hung, Qiuwang Wang, Valery Ponyavin

College of Engineering: Graduate Celebration Programs

Motivation

• Hydrogen is an attractive energy carrier in the future energy technology.

• Hydrogen is produced from splitting of water through various process namely electrolysis, photo-electrolysis, photo-biological production and thermochemical water-splitting.

• The aim of this study is to numerically investigate fluid flow, heat transfer and chemical reaction in bayonet high temperature heat exchanger and decomposer.

• Parametric studies are performed to achieve maximum decomposition with less pressure drop.

Latent Heat Thermal Energy Storage With Embedded Heat Pipes For Concentrating Solar Power Applications, Christopher Robak

Master's Theses

An innovative, novel concept of combining heat pipes with latent heat thermal energy storage (LHTES) for concentrating solar power (CSP) applications is explored. The low thermal conductivity of phase change materials (PCMs) used in LHTES presents a design challenge due to slow heat transfer rates during heating and cooling of the material. Heat pipes act to decrease the thermal resistance in the PCM, increasing the overall heat transfer rate sufficiently for use in CSP. First, a laboratory scale experiment is presented to validate the concept of using heat pipes in LHTES to reduce thermal resistance in PCM. A commercial scale …

Computational Models Of Sub-Divided Thermal Energy Storage Tanks Used In Concentrating Solar Power Plants With Parabolic Trough Collectors, Jesus D. Ortega ^, Vinod Kumar *

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Numerical Study Of The Performance Of A Model Scramjet Engine, Ayad Alhumadi

Mechanical & Aerospace Engineering Theses & Dissertations

A computational parametric investigation was conducted to study the effect of variations to several geometric parameters on the performance of a two-dimensional model scramjet engine (square cross section area for 3-D model). Geometric parameters included backstep location, height, and angle and fuel injector angle, diameter, and location. Two- and three-dimensional geometries have been studied, using a finite-volume computational fluid dynamics (CFD) code (FLUENT) with structured grids with sizes between 50,000 and 90,000 cells for the two-dimensional geometry and with structured hexahedral grid sizes between 650,000 and 949,725 cells for the three-dimensional geometry. Otherwise, identical values of program inputs were utilized …

Characterization Of Centrifugally-Loaded Flame Migration For Ultra-Compact Combustors, Kenneth D. Lebay

Theses and Dissertations

The Air Force Research Laboratory (AFRL) has designed an Ultra Compact Combustor (UCC) showing viable merit for significantly reducing gas turbine combustor length making it a viable candidate for implementation as an inter-turbine burner and realization of efficiency benefits from the resulting near constant temperature cycle. This concept uses an off-axis combustor cavity and projects approximately 66% length reduction over a conventional combustor. The annular nature of the cavity creates high angular acceleration levels, on the order of 500-3500 g's, resulting in strong centrifugal and buoyant forces. This unique combination works to significantly reduce the required burn time and subsequently …

Combustion Simulations Using Graphic Processing Units, Mingjie Wang

Master's Theses

Graphic processing units (GPUs) are powerful graphics engines featuring high levels of parallelism and extreme memory bandwidth, which constitute a powerful computing platform to solve complex problems involving chemically reacting flows. In the present study, computer programs for combustion simulations with detailed chemical kinetic mechanisms were compiled in the Compute Unified Device Architecture (CUDA) language for NVIDIA GPU architecture. Ignition processes were simulated under constant pressure and constant volume conditions using an explicit 4^th order Runge-Kutta algorithm for time integration. Sufficiently small time steps were identified with time scale analysis to ensure the integration stability. The program was validated …

Non-Isothermal Cool Flames In Unstirred Static Reactors: A Compressible Model With Global Kinetics, Michael R. Foster, Howard Pearlman

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

A compressible model is developed with kinetics based on the Wang–Mou five-step global kinetic scheme and used to evaluate the temperature, concentration, and velocity fields characteristic of low temperature combustion in unstirred static reactors. This work relaxes the assumption of small exothermicity that enabled prior studies to employ the Boussinesq approximation, valid for cases where BT << 1, i.e., slow reactions and cool flames. In this study, the range of validity of the model is extended to cases with large temperature excursions, including multi-stage ignition. For the weakly exothermic cases considered, including modes of slow reaction and cool flames, the Boussinesq approximation is completely adequate. However, it overpredicts the density change and underpredicts the ignition delay time for high-temperature ignitions. Qualitative comparison with experimental results acquired at microgravity conditions are also discussed.

Numerical Simulation Of Natural Convection In Rectangular Enclosures Of Varying Aspect Ratios And Its Feasibility In Environmental Impact Management Studies, Charles R. Walker

College of Graduate Studies: Theses & Dissertations

Author's abstract: Numerical simulation was used to investigate natural convection in horizontal and vertical enclosures with and without an internal heat source. Natural convection in rectangular enclosures is found in many real-world applications. Included in these applications are the energy efficient design of buildings, operation and safety of nuclear reactors, solar collector design, passive energy storage, heat transfer across multi-pane windows, thermo-electric refrigeration and heating devices, and the design-for-mitigation of optical distortion in large-scale laser systems. Considering all these applications, especially controlling heat transfer in nuclear power plants, knowledge and research results of natural convection in enclosure play a vital …

An Investigation On Cocombustion Behaviors Of Hydrothermally Treated Municipal Solid Waste With Coal Using A Drop-Tube Reactor, Liang Lu, Yuqi Jin, Masato R. Nakamura, Marco J. Castaldi, Kunio Yoshikawa

Publications and Research

This work aims at demonstrating the feasibility of replacing Indonesian coal (INC) with hydrothermally treated municipal solid waste (MSWH) in cocombustion with high ash Indian coal (IC). The combustion efficiencies and emissions (CO, NO) of MSWH, INC and their blends with IC for a series of tests performed under a range of temperatures and air conditions were tested in a drop- tube reactor (DTR). The results showed the following. The combustion efficiency of IC was increased by blending both MSWH and INC and CO emission was reduced with increasing temperature. For NO emission, the blending of MSWH led to the …