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For a heat exchanger to be manufactured, a series
of materials processing steps must be executed.
Intricate designs and increasingly tight manufacturing
conditions may not necessarily be in full accord.
In such cases, serious problems in manufacturing
may prevent a designer from getting the most of
its product, or may lead to failing altogether.
A number of issues related to such problems have
been considered within the program instituted
at the UK Center for Manufacturing and under the
guidance of Dr. D.P. Sekulic. Two such R&D
problems are as follows:
1. Modeling of the transient 3D behavior of a
compact heat exchanger during manufacturing
2. Thermal integrity of fin-tube bonds for multilouver
fin - extruded microchannel tube configuration
1. Modeling of the transient 3D behavior of a
compact heat exchanger during manufacturing
The
following caption refers to an illustration(s)
on the
graphic version
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| The sequence of instantaneous
temperature fields in a compact heat exchanger
core (source: Sekulic, D.P., Salazar, A.,
Gao, F., Rosen, J.S., and Hutchins, H.F.,
Local
Transient Behavior of a Compact Heat Exchanger
Core During Brazing, Int. Journal of
Heat Exchangers, Vol. 4 (2003) pp. 91-108.
A segment of an assembly (multilouver fins
and extruded tubes) indicates the locations
of thermocouples installed on a sample during
brazing - data presented in the attached graphs.)
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following caption refers to an illustration(s)
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Temperature history during manufacturing
by brazing and the deviations of predicted and measured
temperatures at listed locations (Sekulic, D.P.,
Salazar, A.J., Gao, F., Rosen, J.S., and Hutchins,
H.F. Experimental Heat Transfer, Fluid Mechanics,
and Thermodynamics 2001, Vol. 1, Edited by G.P.
Celata, P.Di. Marco, A. Goulas, and A. Mariani,
Edizioni ETS, Pisa, 2001 pp. 803-808.)
2. Thermal integrity of fin-tube bonds of a multilouver
fin-extruded microchannel tube configuration
The
following caption refers to an illustration(s)
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A selection of fin-tube joints from
actual heat exchanger. Notice poor and/or pathological
joints (source: H. Zhao, A. J. Salazar, D. P. Sekulic,
Influence of topological characteristics of a brazed
joint formation on joint thermal integrity, ASME-IMECE
2003, Washington D.C., November 2003.)
The
following caption refers to an illustration(s)
on the
graphic version
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A designer assumes that all the joints in a real
heat exchanger are characterized by a selected fin
efficiency. In an actual heat exchanger, this is
far from being true. In the following plot, a distribution
of evaluated fin efficiency in an actual heat exchanger
has been presented and contact resistances modeled.
Very few fin-tube joints have the prescribed thermal
integrity. (Source: H. Zhao, A. J. Salazar, D. P.
Sekulic, Influence of topological characteristics
of a brazed joint formation on joint thermal integrity,
ASME-IMECE 2003, Washington D.C., November 2003.)
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