Numerical Optimization of Extended Heat Transfer Surfaces and Compact Heat Exchangers

Author(s):  
Boris Abramzon
2005 ◽  
Author(s):  
D. K. Tafti

The paper describes two- and three-dimensional computer simulations which are used to study fundamental flow and thermal phenomena in multilouvered fins used for air-side heat transfer enhancement in compact heat exchangers. Results pertaining to flow transition, thermal wake interference, and fintube junction effects are presented. It is shown that a Reynolds number based on flow path rather than louver pitch is more appropriate in defining the onset of transition, and characteristic frequencies in the louver bank scale better with a global length scale such as fin pitch than with louver pitch or thickness. With the aid of computer experiments, the effect of thermal wakes is quantified on the heat capacity of the fin as well as the heat transfer coefficient, and it is established that experiments which neglect accounting for thermal wakes can introduce large errors in the measurement of heat transfer coefficients. Further, it is shown that the geometry of the louver in the vicinity of the tube surface has a large effect on tube heat transfer and can have a substantial impact on the overall heat capacity.


1988 ◽  
Vol 41 (9) ◽  
pp. 321-364 ◽  
Author(s):  
Allan D. Kraus

The extended surface literature from 1922 to 1987 is reviewed. The review begins with the classic NACA report of Harper and Brown published in 1922 and concludes with the works of Marto, Wanniarachchi, Rose, Mitrou, and Razelos published in 1986. A section entitled “The Beginnings” traces the accomplishments of the pioneers and it covers the period from 1922 to 1945 which coincides with the publication of Gardner’s landmark paper. At this point, a chronological approach is abandoned in favor of a categorization into topical areas. These are the elimination of the Murray–Gardner assumptions, boiling and condensation, experimental endeavors, compact heat exchangers, internally finned configurations, numerical analyses, optimizations, analyses of finned arrays, and additional topics including the use of extended surface to augment heat transfer, heat transfer in electrical and electronic equipment, purely mathematical techniques, and heat and mass transfer.


2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Robert J. Moffat ◽  
John K. Eaton ◽  
Andrew Onstad

Metallic and graphitic open-cell foams are being used or proposed as extended surfaces (fins) in heat sinks for electronic cooling and compact heat exchangers for aircraft applications. Three parameters must be known to calculate the heat transfer performance of a foam-fin: the product hmAc* as a function of flow-rate (the convective conductance per unit volume), the product ksAk* (the effective conductive conductance as a fin), and Rbond (the effective thermal resistance between the foam and the surface to which it is attached). This paper describes a new test method, which, in conjunction with an older well established type of test, allows all three parameters to be measured using one specimen.


1978 ◽  
Vol 100 (2) ◽  
pp. 177-179 ◽  
Author(s):  
R. K. Shah

Laminar hydrodynamic entry length solutions for circular and noncircular ducts are essential in proper design of compact heat exchangers and other heat transfer and fluid flow devices. A closed form equation has been proposed to present these solutions for the circular tube, parallel plates, rectangular, equilateral triangular, and concentric annular ducts. The necessary constants are evaluated and it is shown that the proposed correlation predicts the apparent friction factors within ± 2.4 percent.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6056
Author(s):  
Gaoliang Liao ◽  
Zhizhou Li ◽  
Feng Zhang ◽  
Lijun Liu ◽  
Jiaqiang E

Heat exchangers play an important role in power, the chemical industry, petroleum, food and many other industrial productions, while compact heat exchangers are more favored in industrial applications due to their high thermal efficiency and small size. This paper summarizes the research status of different types of compact heat exchangers, especially the research results of heat transfer and pressure drop of printed circuit heat exchangers, so that researchers can have an overall understanding of the development of compact heat exchangers and get the required information quickly. In addition, this paper summarizes and analyzes several main working fluids selected in compact heat exchangers, and puts forward some discussions and suggestions on the selection of working fluids. Finally, according to the existing published literature, the performance evaluation indexes of compact heat exchangers are summarized and compared, which is convenient for developers and researchers to better grasp the design direction.


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