Numerical investigation of heat transfer and erosion characteristics for H-type finned oval tube with longitudinal vortex generators and dimples

Zhao, Xin‐Huai; Tang, G.H.; Ma, Xurui; Jin, Y.; Tao, Wen‐Quan

doi:10.1016/j.apenergy.2014.04.033

Cited by 69 publications

(7 citation statements)

References 39 publications

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“…A similar study with dimples and protrusions in microchannels using Al 2 O 3 ‐Water nanofluids was conducted by Li and colleagues, Dimpled vortex generators in lattice cooling channels showed superior heat transfer capabilities due to increases in surface area . Several other similar studies on enhanced tubes with dimples in channels and tubes were performed by various researchers as reported in the literature …”

Section: Introductionmentioning

confidence: 59%

“…20 Several other similar studies on enhanced tubes with dimples in channels and tubes were performed by various researchers as reported in the literature. [21][22][23][24][25][26] At this stage, it is important to study heat transfer behavior with different spacings between the tubes, because no such study has yet been performed. Hence, with this motivation, an experimental study is reported in this article to address the heat transfer enhancement at different spacings of the tubes.…”

Section: Introductionmentioning

confidence: 99%

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Heat transfer analysis of plain and dimpled tubes with different spacings

Afzal

A.D²,

Javad

et al. 2017

Heat Trans. Asian Res.

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Heat transfer enhancement by modifying the surface of tubes is commonly practiced throughout the world. Grooves, dimples, flutes or corrugations are placed inside and outside the surface of tubes and channels for enhancement. In this article, a novel method for heat transfer enhancement by varying the spacing between the tubes is reported. A comparison is made between the heat transfer performance of plain tubes and dimpled tubes at different spacings. For analysis, an experimental setup is fabricated and assembled. The flow is externally forced laminar flow of air over a hot tube maintained at constant temperature. Four different velocities of air 0.4, 0.6, 0.8, and 1.0 m/s are considered in this study. Tube surface temperature, heat transfer coefficient, heat transfer rate and Nusselt number are the parameters studied to analyze the thermal behavior of tubes at different spacings of 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 cm. From the experimental investigation it is found that, apart from heat transfer enhancement by providing dimples on the tube surfaces, there is an optimal spacing between the tubes after which no further improvement is obtained. In this study, 3.0 cm is found to be the optimal spacing for both plain and dimpled tubes. However, the percentage value of heat transfer enhancement is greater with optimal spacing and for all velocities of air in dimpled tubes.

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Section: Introductionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Heat transfer analysis of plain and dimpled tubes with different spacings

Afzal

A.D²,

Javad

et al. 2017

Heat Trans. Asian Res.

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“…Though generally, k-ѡ shear stress transport (SST) formulation are used for simulating low Reynolds number flows, many researchers use k-ϵ models with different wall treatments as this requires less computation time and resources. Further, it is also found that the RNG k-ϵ model and realizable k-ϵ model provide accurate results in numerical simulations (Zhao et al [7]). They found that the RNG k-ϵ model aligned nicely with their experimental data.…”

Section: Governing Equations and Turbulence Solvermentioning

confidence: 94%

Airside Performance of H-Type Finned Tube Banks with Surface Modifications

et al. 2019

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The present study numerically investigates some novel modifications to augment the performance of the H-type finned tube banks, which are widely used in waste heat recovery in industries. The imposed modifications upon the original H-type finned tube banks include the following: (1) Design 1 contains some triangular cuts at the edge of the original rectangular fin; (2) Design 2 modifies the original rectangular geometry into a trapezoid shape; (3) Design 3 renders the original rectangular cross-section fin thickness into trapezoid cross-section; and (4) Design 4 changes the original rectangular shape into a circular shape. Based on the simulations, it is found that Design 1 shows barely any improvements in the heat transfer performance and surface area reduction. Design 2 can provide some weight saving and surface area reduction at a slightly inferior heat transfer performance. Design 3 can offer up to 14% improvements in the overall heat transfer performance without any pumping power penalty. Yet, Design 4 provides the maximum weight saving as compared to the original reference case. With 3–9% lesser surface area than the reference case, Design 4 still offers marginally higher heat transfer performance.

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“…Tian et al [53] performed an investigation on the fluid flow and heat transfer characteristics resulting applying winglet VGs in a wavy FTHE. Zhao et al [54] performed numerical simulations to investigate the heat transfer and flow characteristics for H-type finned elliptical tubes with VGs and dimples. Lemouedda et al [55] and Zeng et al [56] optimized an FTHE with winglet VGs by a genetic algorithm (NSGA II) and the Taguchi method, respectively.…”

Section: Introductionmentioning

confidence: 99%