In order to estimate wind turbine residL2;characteristics
in the presence of atmospheric turbulence, the important atmospheric
sources for the force excitations felt by the wind turbine system
must be identified and characterized. The goal of this research
is to develop the wind turbulence input model for horizontal axis
wind turbines....
An experimental study was made of the average and turbulent
wind characteristics of the flow over a model of a coastal headland.
The scale of the model was 300:1, corresponding to a prototype size
of 500 m.
The data for validation of the model study was obtained from
instruments mounted...
The volumetric receiver is an advanced solar central receiver
concept designed to produce high temperature air. This document
presents the results of a heat transfer and performance evaluation of
the volumetric receiver concept.
The volumetric receiver consists of an array of ceramic fins or
fibers arranged in concentric rows around...
Hydrodynamic effects play important roles in fluidized bed
combustion processes. Since the motion of "bubbles" is an important
influence on fluidized bed heat transfer, a better understanding of their
behavior is necessary for improving the design of fluidized bed boilers.
Using a two-dimensional bed, silica sand particles were fluidized with...
The equations of motion of an elastic cable suspended in a
viscous medium from two arbitrary points are derived. These are
then linearized for the undamped, inextensible case, and it is found
that the equations describing the in-plane motion of the cable are
then independent of the equation describing the...
The second law of thermodynamics, through the exergy
concept, allows us to quantify and rationally cost the
consumption of exergy (irreversibility) used to drive the
heat exchange process and the effluent losses of exergy in
a heat exchanger For systems with a network of heat
exchangers, the exergy concept recognizes...
Development of variable speed horizontal axis wind turbines has resulted in a need for an analysis code with a rotor speed degree-of-freedom. This study develops a five degree-of-freedom time domain computer code that evaluates blade and rotor, mean and cyclic loads with nonlinear aerodynamics together with atmospheric turbulence as a...
An important element in rector safety and fuel performance assessments is the efficient calculation of the time dependent temperature profiles within reactor fuel pins. Because the fuel pins have temperature dependent thermal properties, the governing partial differential equations are nonlinear. Traditionally, finite difference or finite element methods have been used...
This paper deals with the thermal decompositon of
wood slabs under fire conditions. The partial differential
equation is solved numerically by the use of an implicit
finite difference method. Wood is treated as two
components, Lignin and Hemicellulose on one side, and
Cellulose on the other side. The chemical reactions...
Only very recently has modern technology been applied
to the design of the tennis racket. In fact, the tennis
player of a few hundred years ago would easily recognize
today's racket. Although the literature reveals a surprising
number of studies on racket mechanics, little work has been
reported on the...
Polymeric composites exhibit time-dependent behavior, which raises a concern
about their long term durability and leads to a viscoelastic study of these materials.
Linear viscoelastic analysis has been found to be inadequate because many polymers
exhibit nonlinear viscoelastic behavior. Classical laminate theory is commonly used in
the study of laminated...
Freezing is one of the important technologies for preservation of foods.
In this project, using surimi as a food model, thermophysical properties of frozen
foods were evaluated and the freezing process was simulated using a finite
element package.
To measure temperature-dependent thermal conductivity, a line-source
probe system was used. Effects...
A thermodynamic analysis of forced geoheat recovery from aquifers
has been accomplished. The system investigated consists of a single
recharging-discharging well pair, in a horizontally extensive aquifer,
with either power generation or space heating as surface applications.
The space heating systems investigated are (i)direct heating, (ii)heat
pumps and (iii)a combination...
This thesis is concerned with designing and simulating waste
energy retrieval systems from large transformers to provide heating and
cooling of a control house. The transformer selected is Transformer
Bank One at the Ross Substation in the BPA system. The unit is an
ASEA 250 MVA transformer with forced oil,...
The thermal contact conductance (TCC) between two machined pieces of stainless steel was studied. A guarded hot plate thermal conductivity test fixture was designed and built for the experiment. Factors investigated included the contact pressure, surface roughness, interface material and average test temperature. The contact pressure at the interface ranged...
A phase sensitive measurement technique that permits the simultaneous determination
of two independent thermal properties of thin dielectric films is presented. Applying the technique results in a film's thermal diffusivity and effusivity, from which the thermal conductivity and specific heat can be calculated. The technique involves measuring a specimen's front...
"Piping Design and Engineering" first published in 1963 by
Grinnell, Co. is widely used by engineers to perform approximate
thermal stress analysis of high-temperature piping systems. The
text consists of numerical constants to calculate end reactions and
maximum bending stresses in a variety of piping configurations from
known properties of...
A study was conducted to determine what effects the type of
pollutants, storage conditions, storage time, and method of sample
conditioning have on the reported weight of an air pollutant collected
by filtration. Samples were collected from a refuse dump, an arc
furnace smelting nickel ore, and a rotary kiln...
This study determined the independent effects of various homogenization cycles and
precipitation treatments on the elevated temperature workability and the final ambient
temperature mechanical properties of AA2024 aluminum alloy and on the T3 tensile
properties of 2014 aluminum alloy as well as T6 tensile properties of 2618 and 2618 (Curich)...
An experimental investigation has been performed to determine the
forced convection heat transfer due to three-dimensional air flow over
a flat plate as a function of angle of attack and free stream velocity.
The experimental method employed a transient thermal technique and
placed the convecting surface next to the exhaust...
Samples of commercial purity titanium were heat treated above the
beta transformation temperature and within the two phase alpha-beta
phase field, followed by cooling at varying rates. Testing of the
samples in tension and by instrumented impact indicated that some
strengthening could be imparted by these heat treatments, although at...
A system which allows the computer to capture sketches
made by a mechanical designer is described. The system not
only recognizes basic features as they are sketched, but it
also reasons the spatial relationships between features and
builds a high level abstract representation (feature model)
of the artifact. The temporal...
Laser ultrasonics can be used to nondestructively evaluate structures to determine the existence and location of surface and interior flaws. The goal of this research was to determine if laser ultrasonic techniques can be applied to the inspection of aluminum plate. titanium tubes, and large welded plate structures. The research...
This dissertation investigates by means of computer simulation the potential of a
Band Variable-Inertia Flywheel (BVIF) to store energy for an urban transit bus.
Replacing both a fixed-inertia flywheel (FIF) and a continuously variable transmission
(CVT), the Band Variable-Inertia Flywheel is capable of accelerating a vehicle
from rest to a...
Effective combustion of waste fuels requires an
understanding of the fuels characteristics. Gaseous and
particulate emissions, ash residues and combustion
properties are of interest to many; those that produce and
sell heating units, utilities interested in using the fuels
for power generation, regulatory agencies, municipalities
needing to solve a disposal...
When trace quantities of an alkali element are added to a flame,
its optical and electrical properties change significantly. Addition of
alkali seed to both premixed and diffusion flames has been used in the
development of two new techniques, one for flame temperature measurement
and the other for enhanced mixing....
The objective of this work was to develop a method for determining stochastic loads on horizontal axis wind turbine blades. Stochastic loads caused by wind turbulence are a major consideration in designing for long life, cost effective wind turbines. The rotor blades are of particular concern because the blades are...
The purpose of this study is to provide the necessary technical
background and data for the development of a suspension system for a
recumbent bicycle. For this reason, the customer requirements-design
criteria for the development of the suspension system were set, and several
static and dynamic tests were conducted on...
In the mid 1930's the Diesel engine, which formerly was used only as a large, low-speed machine, was developed into a smaller
high-speed engine for use in trucks, busses, and tractors. Along
with these changes in mechanical design came many problems, of
which a major one was lubrication. Because ordinary...
During the operation of phase-change ink-jet printers a bubble formation
phenomenon often occurs. These bubbles are detrimental to the operation of
the printer and substantial efforts are made to remove them. The objective of
this research was 1: to develop a fundamental understanding of how bubble or
void formation occurs...
A calorimeter capable of measuring the heat capacity of 1 mg size samples from
4.2 to greater than 100 K has been designed, constructed, and tested. The sample is
bonded to the end of a 0.002 inch diameter, 0.5 cm long chromel-constantan
thermocouple (type E) and heated optically with a...
The sketching software developed in this thesis, is aimed to serve as an intelligent design tool for the conceptual design stage of the mechanical design process. This sketching software, Sketch Pad for Windows, closely mimics the traditional paper-and-pencil sketching environment by allowing the user to sketch freely on the computer...
A comparative study of three six-axis force sensors selected after an extensive literature survey is presented. A sensor to measure ground contact force at each foot of a walking machine is recommended.
Principles of force sensing are reviewed and characteristics of sensing elements are discussed. Results of simulation of three...
This thesis is concerned with simulating two forms of energy retrieval.
Standard computer programs are routinely used to simulate
such energy systems. However, the accuracy of these simulations is
not well documented. The main objective of the work presented here is
to evaluate the validity of this type of simulation...