Spelling suggestions: "subject:"heat convection, batural"" "subject:"heat convection, featural""
1 |
Laminar natural convection in vertical tubes with one end open to a large reservoirWu, Yissu 10 March 1995 (has links)
Graduation date: 1995
|
2 |
Stability analysis on single-phase natural circulation in Argonne Lead Loop FacilityTang, Hong 28 June 2002 (has links)
Natural convection provides a means for circulating fluids without the use of
pumps. This type of system is of great interest for a wide variety of applications,
including solar heaters, process industry, and nuclear reactors. Natural
convection will play a vital role in the area of passive safety and reliability,
particularly for the development of Generation IV nuclear energy systems.
This study mainly focuses on the linear stability analysis of asymmetrically
heated/cooled natural convection loops with large temperature variations across
the heated core. The study targets the Argonne Lead Loop Facility (ALLF), a
concept for an experiment loop to support the development of the Secure
Transportable Autonomous Reactor-Liquid Metal (STAR-LM) at Argonne
National Laboratory, using lead-bismuth eutectic (LBE) as the primary reactor
coolant.
A one-dimensional linear stability analysis is performed and the Nyquist
criterion is employed to find the linear stability boundary of both forward and
backward circulations. It was found that the natural circulations could be linearly
unstable in a high Reynolds number region. Increasing loop friction makes a
forward circulation more stable, but destabilizes the corresponding backward
circulation under the same heating/cooling conditions. The preliminary results suggest that as the Peclet number decreases, the forward circulation is prone to
become unstable while the backward circulation is prone to remain stable. / Graduation date: 2003
|
3 |
The manipulation of instabilities in a natural convection boundary layer along a heated, inclined plateTrautman, Mark A. 12 1900 (has links)
No description available.
|
4 |
Fully developed laminar natural convection in a vertical parallel plate channel with symmetric uniform wall temperatureWillie, Robert H. 07 June 1996 (has links)
Described in this thesis is an investigation of the fully developed natural convection
heat transfer in a vertical channel formed by two infinitely wide parallel plates
maintained at a uniform wall temperature. Closed-form solutions for the velocity
and temperature profiles are developed along with local and averaged Nusselt
numbers. The local Nusselt number based on bulk temperature is found to be 3.77.
This result is an analog corresponding to 7.60 for fully developed laminar forced
convection in a parallel plate channel with uniform wall temperature boundary
condition. The local Nusselt number based on the ambient temperature is deduced
as a function of flowwise location. Results are compared with existing numerical
and experimental data to find good agreement. / Graduation date: 1997
|
5 |
Laminar natural convection within long vertical uniformly heated parallel-plate channels and circular tubesVorayos, Nat 27 June 2000 (has links)
The problem of simple mathematical models of laminar natural convective
flow within a long vertical parallel-plate channels and circular tubes kept at
uniformly heated walls is revisited to seek a clear physical understanding of heat
transfer mechanisms. A series solution method to analyze the fully developed flow
and an integral solution method to analyze the developing flow are used. Chapters
3, 4, and 5 of this dissertation constitute a series of three-paper manuscripts for
submission to archival journals.
The channels and circular tubes considered here are assumed to be
sufficiently long to yield a fully developed flow thermally as well as
hydrodynamically before the exit is encountered. In such fully developed flow
situation, the fluid mass flow rate naturally induced into the channel due to
buoyancy is found to be a function of the wall heating condition. The predicted
average Nusselt number as a function of GrPrD/L not only agrees with the existing
literature but also is found to be in a functional form comparable to that proposed
by Elenbaas (1942 a and b). Our results show that, in spite of being driven by
buoyancy (rather than by a pump or a blower), the flow and heat transfer
characteristics in the fully developed regime are essentially the same as those of
fully developed laminar forced convection in which the flow is externally driven.
This observation is confirmed to be valid also in the study (Chapter 5) of
laminar natural convection in the developing (entrance) region within a long
vertical parallel-plate channel and circular tube. The mass flow rate, which has to
remain invariant with axial location even in the entry region, is determined by the
flow in the fully developed region. This is the same mechanism involved in forced
convection in which the fluid outside the developing boundary layers (i.e. the core
flow) is forced to accelerate in the entrance region. The entrance length of channel
natural convection is also discovered to be about the same as that in forced
convection. / Graduation date: 2001
|
6 |
Natural convection cooling of vertical plates in an enclosure : a numerical simulationDestremau, Axel 07 November 1991 (has links)
Graduation date: 1992
|
7 |
Turbulent plumes generated by a horizontal area source of buoyancyChaengbamrung, Apichart. January 2005 (has links)
Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: leaf 232-245.
|
8 |
A spectral method determination of the first critical Rayleigh number for a low-Prandtl number crystal melt in a cylindrical containerDietz, Charles Miller 06 October 2009 (has links)
The onset of laminar Rayleigh-Bénard convection is investigated for a low-Prandtl number liquid metal in a cylindrical container. All surfaces are considered to be solid and no-slip. Two cases are considered for the thermal boundary conditions at the side wall: conducting and insulated surfaces. A Chebyshev Galerkin spectral model is used to reduce the governing Boussinesq system to a first-order system of ordinary differential equations. A local stability analysis using the linearized system determines the first critical Rayleigh number. The results are compared with experimental data and a numerical study. / Master of Science
|
9 |
Numerical analysis of liquid cooling by natural convection for heated protusions simulating vertical plate-mounted electronic components facing an opposing platePark, Sung-kwan 12 March 1993 (has links)
Graduation date: 1993
|
10 |
Utilizing Free Convection in the Design of a Gravity Driven Flow BatteryMohr, Robert Charles January 2023 (has links)
As the cost of variable renewable energy resources like wind and solar decline rapidly the major barrier to decarbonization of the electrical grid becomes that of energy storage. Current storage technologies are much too expensive to justify widespread adoption and it is unclear what type of technology is even capable of fulfilling this role. Flow batteries are an often proposed technological solution to this problem but they are plagued by high cost and reliability issues due to the expensive and complex balance of plant included in the system design.
In this work a new design for a gravity driven flow battery is explored which is capable of drastically lowering the cost of flow batteries by removing the pumps and membranes and replacing their function with density stratification and flow driven by the density change of the electrode reactions. A design for a zinc-bromine battery which makes use of this free convection during operation is explored. The system is studied through construction of prototype cells, exploration of key design variables, and a techno-economic analysis of the technology is performed showing cost viability. The free convection phenomenon which underlies the battery operation is expanded upon by connecting non-dimensional correlations in heat transfer with electrochemical transport equations in order to create predictive understanding of flow behavior based on system composition. This correlative understanding is used to construct a model of a zinc-bromine gravity driven flow battery. This model shows results which align with experimental data and gives insight into the complex transport dynamics of the system.
|
Page generated in 0.0747 seconds