Comprehensive study of heat transfer enhancement in tubular heat exchangers

Kalinin, E. K.; Dreitser, G. A.; Paramonov, N. V.; Myakochin, A. S.; Тихонов, А. И.; Zakirov, S. G.; Levin, Eugene; Yanovsky, L. S.

doi:10.1016/0894-1777(91)90073-z

Cited by 13 publications

(1 citation statement)

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“…A comprehensive study on heat transfer enhancement of tubular heat exchangers with dimpled tubes was performed by Kalinin et al [17]. Dimpled and helical tubes for compact heat exchangers have been investigated by Giovannini et al [18].…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer and Friction Characteristics for Turbulent Flow of Dimpled Tubes

Wang

et al. 2009

Chem Eng & Technol

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The hydrodynamic and heat transfer characteristics of dimpled tubes with different arrangements were investigated in this paper. The dimples on the tube are outward-facing, raised, with aligned and staggered arrangements. The experiments were carried out in counter-current flow patterns with cold air along the tube inside and hot water around the outside of the tube. The Reynolds numbers of air flow were in the range of 1.6·10 4 to 5.4·10 4 . By comparing the performances among three tubes (smooth tube, dimpled tube with aligned arrangement, and dimpled tube with staggered arrangement), we could find that the dimpled tubes enhanced the Nusselt number by about 18.6∼22.7 %, while the friction factors of the dimpled tubes increased by 18.6∼25.9 % for the aligned arrangement and by 14.3∼29.8 % for the staggered arrangement. The test results also showed that different dimple arrangements have very little effect, which is always within 5 %. By the integrated performance evaluation of (Nu a /Nu s )/(f a /f s ) 1/3 , the maximum of the heat transfer enhancement with the same friction penalty, about 19 %, could be achieved by optimization of the dimpled-tube design.

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Section: Introductionmentioning

confidence: 99%

Heat Transfer and Friction Characteristics for Turbulent Flow of Dimpled Tubes

Wang

et al. 2009

Chem Eng & Technol

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Evaluation of hydraulic thermal flow and heat performance augmentation in a 3D tube fitted with varying concavity dimple turbulator configurations

Al‐Haidari,

Al‐Obaidi

2024

Heat Trans

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Enhanced pipe surfaces offer greater heat transfer enhancement due to increased turbulence levels, leading to improved heat exchange performance. This study combines numerical simulations and experimental work to identify the best geometric design of enhanced tubes for thermal–hydraulic performance, flow structure, and pressure drop, and the simulations are validated with experimental data. Water is a working fluid with Reynolds numbers ranging from 4000 to 15,000, q = 25,500 W/m2, and an inlet temperature of 298 K with constant fluid property, steady state, and no‐slip condition. The three‐dimensional steady incompressible turbulent flow in the concavity dimpled shape‐enhanced tubes is numerically studied. This research found that pipes with a concave shape transfer heat most effectively. The overall heat transfer is significantly influenced by the shape of the dimples, their arrangement in rings, the size of these rings, and the number of rings. However, the number of cylindrical dimples does not seem to impact heat transfer much. The increase in heat transfer performance was by 9.8%–61% for dimple rings = 2ring performed best compared with a smooth pipe and by 8.21%–38.49% at the effect of ring numbers as grouping, also the dimple ring diameters by 5%–38% and by 7%–39% at dimple numbers. The performance evaluation factor (PEF) assesses overall performance by considering both the pressure drop penalty and improved heat transfer. The optimal configuration achieving the highest performance (PEF = 1.295) at a flow rate (Re) of 4000 involves a single dimple ring with a 2‐mm diameter, spaced 10‐mm apart, containing four dimples. Furthermore, discussing the different parameters of thermal and hydraulic performances to obtain the best thermal performance, and increasing the number and size of dimples gives a better guide for engineering to obtain better thermohydraulic performances for heat exchangers.

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