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Thermal/fluid characteristics of cylindrical-filament open-cell box-lattice structures as heat exchanger surfacesBalantrapu, Kiran. January 2006 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2006. / "May 2006." Includes bibliographical references (leaves 46-48). Online version available on the World Wide Web.
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Thermal performance of plain-weave screen as a heat exchanger surface in parallel plate free convectionSoma Shekar, Sidigonde. January 2004 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2004. / "December 2004." Includes bibliographical references (leaves 43-46). Online version available on the World Wide Web.
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An experimental study of co-flow ammonia-water desorption in an oil-heated, microscale, fractal-like branching heat exchangerMouchka, Gregory A. 24 March 2006 (has links)
An experimental study was performed in which an ammonia-water solution
was desorbed within a branching fractal-like microchannel array. The solution entered
in the center of a disk, and flowed out radially until discharging in to a gravity-driven
separation chamber. Heat was added to the ammonia-water through a thin wall, above
which flowed heat transfer oil in a separate branching fractal-like microchannel array.
Such arrays have been shown to utilize the increased heat transfer coefficients seen in
parallel channel arrays; however, they do so with a lower pressure drop.
An experimental flow loop consisting of ammonia-water and heat transfer oil
sub-loops was instrumented along with a test manifold for global measurements to be
taken. Temperature, pressure, density and mass flow rate measurements permitted
calculation of desorption and heat transfer characteristics. Parameters included oil
mass flow rate, oil inlet temperature, and strong solution flow rate, while strong
solution concentration, temperature, and weak solution pressure were kept constant.
The desorber was assumed to achieve equilibrium conditions between the
vapor and weak solution in the separation chamber. The exit plenum was large and
acted as a flash chamber, making the assumption reasonable. The vapor mass fraction
was determined from knowledge of the weak solution saturation temperature.
Heat exchanger analyses (LMTD and ε-NTU) were done to determine the heat
transfer characteristics of the desorber. Calculated values of UA are shown to be as
high as 5.0 W/K, and desorber heat duties were measured as high as 334 W. Strong
solution, at 0.30 mass fraction, was desorbed into weak solution and vapor with
concentrations ranging from 0.734 to 0.964. Circulation ratios, defined as strong
solution mass flow rate per unit desorbed vapor mass flow rate, varied in this study
from 3.4 to 20.
A method for specifying desorber operating conditions is described, in which a
minimum desorber heat input per unit vapor flow rate is determined at an optimum
circulation ratio. A description of how the circulation ratio behaves as a function of
strong solution mass flow rate, oil flow rate, and the maximum temperature difference
between oil and ammonia-water solution is shown. / Graduation date: 2006
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Characterization of the Advanced Plant Experiment (APEX) passive residual heat removal system heat exchangerStevens, Owen L. 07 June 1996 (has links)
The Oregon State University (OSU) Radiation Center (RC) is the location of a one
quarter scale model of the Westinghouse Electric Corporation advanced light-water
nuclear reactor design called the AP-600. The full scale AP-600 is a 600 megawatt electric
nuclear power plant that incorporates unique passive systems to perform the safety
functions currently required of all existing nuclear power plants. Passive safety refers to
a system's ability to perform its desired function using natural forces such as gravity and
natural circulation. This reduces the reliance on active systems to assure plant safety.
The Advanced Plant Experiment (APEX) at the OSU RC is an electrically heated
simulation of the AP-600 that includes the Nuclear Steam Supply System (NSSS) and all
of the passive safety systems. The APEX facility was funded by the United States
Department of Energy and the Westinghouse Electric Corporation. The facility was built
to perform the long term cooling tests necessary for design certification of the AP-600.
The data taken will be used to benchmark the thermal hydraulic computer codes applied
in the design certification process and to better understand the phenomena involved in the
full scale AP-600.
This paper presents the analysis of the Passive Residual Heat Removal System
(PRHR) and in particular the PRHR's "c"-shaped heat exchanger (PRHR Hx). This paper
includes analysis and modeling of the PRHR Hx including: hydraulic flow parameters, heat rejection capability, an empirical correlation for determining pressure drop, and an examination of the flow phenomena that occurs in the tank in which the heat exchanger is installed. / Graduation date: 1997
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The influence of cross-winds on the performance of natural draft dry-cooling towers /Du Preez, Abraham Francois. January 1992 (has links)
Dissertation (Ph. D.)--University of Stellenbosch, 1992. / Bibliography. Also available via the Internet.
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Fouling characteristics of a desalted crude oilLin, Dah-cheng 24 August 1990 (has links)
The fouling characteristics of a desalted crude oil were investigated in a systematic
investigation. There are two main parts in this study, the dry bulk tests (dehydrated crude
oil) and the wet bulk tests (to which desalter brine was added). Three barrels of desalted
crude oil provided by Amoco Oil Company were studied.
For the dry bulk tests, no brine was added to the crude oil. The effects of fluid
velocity and surface temperature on fouling were investigated. The higher the surface
temperature the greater the fouling was observed. Fouling decreased with an increase of
fluid velocity. Fluid velocity had a stronger effect on fouling at low surface temperatures
than at high surface temperatures. It was also observed that the fouling behavior of crude
oil depended on small difference in composition. The threshold surface temperatures for
the initiation of fouling were 400-450 °F (3.0 ft/sec), 525-550 °F (5.5 ft/sec), 550-600
°F (8.0 ft/sec) and about 600 °F (10.0 ft/sec) for Barrel No. 2 and Barrel No. 3. For
Barrel No. 1 however, the threshold surface temperatures were about 550 °F (3.0 ft/sec)
and 600 °F (5.5 ft/sec).
For the wet bulk tests, a certain amount desalter brine (weight percentage = 0.8%)
was added to the crude oil for each run. The effects of fluid velocity, surface temperature
and the presence of brine on fouling were investigated. Higher surface temperature
enhanced fouling considerably. Fouling was reduced as fluid velocity was increased. It
was shown that brine had a strong effect on fouling. No fouling occurred for velocities of
5.5 and 8.0 ft/sec at a surface temperature of 350 °F which was a condition for which an
aqueous phase was present and the salt remained in solution. Significant fouling occurred
for velocities of 5.5 and 8.0 ft/sec at a surface temperature operated at a low 400 °F (Tb =
300 °F) which was a condition for which the aqueous phase at the heat transfer surface was
dissolved or boiled to extinction and the salt was deposited on the heat transfer surface. / Graduation date: 1991
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An analysis of water for water-side fouling potential inside smooth and augmented copper alloy condenser tubes in cooling tower water applicationsTubman, Ian McCrea. January 2003 (has links)
Thesis (M.S.)--Mississippi State University. Department of Mechanical Engineering. / Title from title screen. Includes bibliographical references.
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Thermoacoustic heat pumping study : experimental and numerical approaches /Duthil, Eric Patxi. January 2003 (has links)
Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 122-129). Also available in electronic version. Access restricted to campus users.
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Numerical analysis of the performance of staggered pin-fin micro heat exchangers /Choo, Jui Sheng. January 2003 (has links) (PDF)
Thesis (M.S. in Engineering Science)--Naval Postgraduate School, December 2003. / Thesis advisor(s): Ashok Gopinath. Includes bibliographical references (p. 83-84). Also available online.
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Dynamic analysis of triple heat exchangers by the finite element method袁大偉, Yuen, Da-wai, David. January 1989 (has links)
published_or_final_version / Mechanical Engineering / Master / Master of Philosophy
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