Experimental investigations of heat transfer enhancement from rectangular duct roughened by hybrid ribs

Alfarawi, Suliman; Abdel-Moneim, S. A.; Bodalal, Awad

doi:10.1016/j.ijthermalsci.2017.04.017

Cited by 103 publications

(40 citation statements)

References 29 publications

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“…8 and 9. Nu/Nu FD e/Dh = 0.5 t/p = 0.25 (model 4) t/p = 0.33 (model 2) t/p = 0.50 (model 5) e/Dh = 0.047 [9] e/Dh = 0.066 [10] Re•10 5 Re•10 5 Figure 8 presented the distribution of Nu/ Nu (FD) in Models with different t/p vs. Reynolds number, and the data of normal ribbed models in [9,10] were given too. The Nu/Nu (FD) all decreased as Reynolds number increased, the Nu/ Nu (FD) could achieve above 13 as t/p = 0.5 in matrix ribbed channel in this paper, while those of normal ribbed channel only reached lower than 2.5.…”

Section: Resultsmentioning

confidence: 99%

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Experimental investigation of flow and heat transfer characteristics on matrix ribbed channel

et al. 2020

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To simulate the actually situation in turbine blades, and provide useful direct results for turbine blade designers, the parameters are same with the blade. The experiments results show that, in comparison to fully developed flow in a smooth pipe of equivalent hydraulic diameter, the Nusselt number inside the matrix-ribbed rectangular channel is increased up to 5 to 9 times higher, while total pressure drop is enlarged by up to significant magnitude. The Nusselt number ratio increases with t/p and t/e increased. Semi-empirical heat transfer is developed for designing of cooling channel.

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Section: Resultsmentioning

confidence: 99%

“…Alfarawi [9] experimentally investigated heat transfer enhancement from rectangular duct roughened by hybrid ribs, obtained the effect of P/e, and obtained correlations for Nu/ Nu s , f/f s , and (Nu/Nu s )/(f/f s ) 1/3 * . Liou et al [10] investigated the heat transfer enhancement of periodical ribbed channel.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of flow and heat transfer characteristics on matrix ribbed channel

et al. 2020

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“…where the optimum performance index is found at the 1.91 with the reference plate.S. Alfarawi et.al, [7] detremined heat transfer and flow friction for a fully developed turbulent flow in a rectangular duct with its bottom wall ribbed with three different rib geometries such as semi-circular, rectangular and hybrid ribs of the two. The key result of the analysis was the enhancement in the heat transfer is critically influenced by the flow velocity and the turbulence intensity as well as the rib pitch to height ratio (p/e).…”

Section: Introductionmentioning

confidence: 99%

Assessment of Thermal Performance of Non-Conventional Grooved Stepped Shoe Ribs by CFD Technique

Bhosale,

Selokar

2019

IJEAT

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In improvement of the thermal performance there is necessity of the heat transfer augmentation. Heat transfer enhancement can be achieved with enlarged or extended surface, impeded boundary level, augmentation in the turbulence etc. It is desired to keep the size of heat exchanger compact for better working conditions. In the proposed work, we made the Computational Fluid Dynamics (CFD) analysis of the non-conventional type of ribs. In this work the non-conventional Stepped grooved shoe shaped ribs were studied by changing its geometry parameters like rib height (15, 20,22mm), thickness of the rib (4, 5,10 mm), and the ratio between these entities. The numerical analysis was done to study change in rate of heat transfer and pressure drop. The effects of variation in staggered arrangements and truncation gap on thermal performance were also studied. It was observed that providing staggered arrangement with truncation gap of 20 mm gives the optimum value of thermal enhancement factor of 1.33.

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“…They found that the circular ribs THERMAL SCIENCE: Year 2019, Vol. 23,No. 2A, showed the best heat transfer performance at all Reynolds numbers ranging from 500-5000.…”

Section: Introductionmentioning

confidence: 99%

“…The results showed that the perturbation of the semi-cylinder ribs provided the highest heat transfer augmentation. Alfarawi et al [23] investigated the heat transfer and flow friction characteristics in a rectangular duct roughened by semi-circular, rectangular and hybrid of semi-circular and rectangular shapes. It was found that the hybrid ribs provided higher values for the efficiency indices than those of the rectangular and semi-circular ribs cases.…”

Section: Introductionmentioning

confidence: 99%

Particle image velocimetry and proper orthogonal decomposition analysis of the channel flow equipped with cylindrical ribs

Gürlek¹

2017

THERM SCI

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Original scientific paper https://doi.org/10.2298/TSCI170305204GThe characteristics of the flow fields in a rectangular channel equipped with cylindrical ribs were examined through the particle image velocimetry experiments. The mean and turbulence characteristics were presented for three different Reynolds numbers of 2900, 8400, and 15000. In addition, the coherent flow structures were extracted by means of the proper orthogonal decomposition method. The flow field is characterized by a large re-circulation region and a secondary clockwise-rotating corner vortex. The high vorticity, fluctuation velocity and shear stress contours are formed along the free shear layers emanating from the upstream rib. As Reynolds numbers increase, the positive vorticity contours extend downstream and fluctuation velocity and shear stress contours spread out towards the channel wall. The proper orthogonal decomposition results have shown that a horizontally aligned co-rotating vortex pair and a corner vortex are the dominant flow structures for the highest Reynolds number.

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Experimental investigations of heat transfer enhancement from rectangular duct roughened by hybrid ribs

Cited by 103 publications

References 29 publications

Experimental investigation of flow and heat transfer characteristics on matrix ribbed channel

Experimental investigation of flow and heat transfer characteristics on matrix ribbed channel

Assessment of Thermal Performance of Non-Conventional Grooved Stepped Shoe Ribs by CFD Technique

Particle image velocimetry and proper orthogonal decomposition analysis of the channel flow equipped with cylindrical ribs

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