Recent Advances in Heat Transfer Enhancements: A Review Report

Abstract

Different heat transfer enhancers are reviewed. They are (a) fins and microfins, (b) porous media, (c) large particles suspensions, (d) nanofluids, (e) phase-change devices, (f) flexible seals, (g) flexible complex seals, (h) vortex generators, (i) protrusions, and (j) ultra high thermal conductivity composite materials. Most of heat transfer augmentation methods presented in the literature that assists fins and microfins in enhancing heat transfer are reviewed. Among these are using joint-fins, fin roots, fin networks, biconvections, permeable fins, porous fins, capsulated liquid metal fins, and helical microfins. It is found that not much agreement exists between works of the different authors regarding single phase heat transfer augmented with microfins. However, too many works having sufficient agreements have been done in the case of two phase heat transfer augmented with microfins. With respect to nanofluids, there are still many conflicts among the published works about both heat transfer enhancement levels and the corresponding mechanisms of augmentations. The reasons beyond these conflicts are reviewed. In addition, this paper describes flow and heat transfer in porous media as a well-modeled passive enhancement method. It is found that there are very few works which dealt with heat transfer enhancements using systems supported with flexible/flexible-complex seals. Eventually, many recent works related to passive augmentations of heat transfer using vortex generators, protrusions, and ultra high thermal conductivity composite material are reviewed. Finally, theoretical enhancement factors along with many heat transfer correlations are presented in this paper for each enhancer.

Introductory Chapter: Advanced Features and Applications of Heat Exchangers–An Outline

“…A very general review on advances in heat transfer enhancements was performed by Siddique et al [3]. They addressed most usual heat transfer enhancers: fins and microfins, porous media, large particles suspensions, nanofluids, phase-change devices, flexible seals, flexible complex seals, vortex generators, protrusions, and ultra-high thermal conductivity composite materials.…”

Constructal entransy dissipation rate minimization for leaf-like fins

“…(4), (7) and (8), the entransy dissipation rate of the k p vein is (10) According to eqs. (9) and (10), the entransy dissipation rate of the whole elemental leaf-like fin is…”

“…Henceforth, many scholars had done plenty of researches on the fin heat transfer problems [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] based on constructal theory. Bejan and Dan [10] used the analytical method and finite element method to carry out constructal optimization of a tree-shaped fin, and the results showed that the results obtained based on these two methods agreed with each other.…”

Application of the method of fundamental solutions to the analysis of fully developed laminar flow and heat transfer

“…A comprehensive report on recent advances in heat transfer enhancements was presented by Siddique et al (2010), while the classification of heat transfer enhancement techniques was documented by Bergles (1998). The mechanisms of enhancing heat transfer that require external power, dubbed active methods, comprise, for example, application of stirring in the fluid vessels or surface vibration, as presented by Nesis et al (1994).…”