The investigation of groove geometry effect on heat transfer for internally grooved tubes

Bilen, Kadir; Çetin, Murat; Hasan, Gul; Balta, Tuba

doi:10.1016/j.applthermaleng.2008.04.008

Cited by 202 publications

(76 citation statements)

References 31 publications

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“…A theoretical formula to calculate the thickness of laminar film on the crest of grooves was first proposed by Gregorig,6 but the procedure required for design of the groove shape was not reported in their research. Thereafter, much research of filmwise condensation on grooved surfaces has been conducted, and several shapes of grooves, such as triangular, 7 sinusoidal, and rectangular, 8,9 were developed. Mori et al 7 investigated the condensation on triangular, wavy, and flat bottomed grooves with theoretical analysis and experiments.…”

Section: Introductionmentioning

confidence: 99%

“…The calculations were in excellent agreement with the data from Gregorig. 6 Bilen et al 9 performed an experimental study on surface heat transfer for different geometric groove shapes (circular, trapezoidal, and rectangular). Among the grooved tubes, heat transfer enhancement was obtained up to 63% for circular grooves, 58% for trapezoidal grooves, and 47% for rectangular grooves, in comparison with the smooth tube at the highest Reynolds number (Re = 38,000).…”

Section: Introductionmentioning

confidence: 99%

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Numerical study on condensation heat transfer of trapezoid grooved surfaces

Song²,

2016

Advances in Mechanical Engineering

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This article presents a numerical analysis and experimental study on condensation heat transfer and fluid flow for filmwise condensation on trapezoid grooved surfaces. First, a physical model was properly simplified based on some reasonable assumptions. Then, the coupled non-linear governing equations for the mass transfer, fluid flow, and twodimensional thermal conduction were developed. The relationship between z-coordinate and heat transfer was obtained by solving the equations numerically. The influences of groove length and basic angle were discussed. The calculation results showed that the heat flux decreased with increase in groove length, and the decline range also decreased gradually. The calculation results also suggested that the heat flux through groove with a = 60°was lower than the groove with a = 75°at the top of the groove, while the opposite conclusion was obtained at the low parts. The distributions of wall temperature and heat flux on trapezoid groove were also studied systematically. The distribution of surface temperature and heat flux presents obvious lateral inhomogeneity, and the maximum wall temperature and heat flux were both obtained in region II. The thermal resistance of groove with a = 60°was lower but the liquid-discharged ability was better than that of groove with a = 75°. In order to validate the feasibility and reliability of the present analyses and to further investigate the heat transfer performance of trapezoid grooved surfaces, experiments were carried out with three condensing plates including two trapezoid grooved surfaces in different physical dimensions and one smooth surface. The experimental data obtained under various schooling were compared with the calculations, and the experimental results for different condensing plates are all in good agreement with the numerical model, with a maximum deviation less than 15%. Moreover, the trapezoid grooves can enhance the condensation heat transfer by 1.5-2.5 times higher than the smooth surface. The present analyses are feasible and can be used in the parameter design and heat transfer calculation of trapezoid grooved surfaces.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical study on condensation heat transfer of trapezoid grooved surfaces

Song²,

2016

Advances in Mechanical Engineering

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“…The air jet from the air nozzle could act as like a turbulence promoter, such as grooves (13) and dimples (14) on a tube wall and twisted tapes in a tube (14) . Turbulence promoters increase the degree of turbulence intensity and friction factor (14) .…”

Section: Enhancement Of Heat Transfer In Aja Machiningmentioning

confidence: 99%

Air Jet Assisted Machining of Titanium Alloy

Obikawa

Funai

Kamata

2011

JAMDSM

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Titanium alloy has been applied to elements and structures in aerospace engineering, bioengineering, marine engineering, etc. because of its superior properties. However, machining of this alloy is likely to accelerate tool wear, shorten tool life and deteriorate the surface integrity. Therefore, high-speed machining of this alloy has been studied for many years. In this study, finish-turning of Ti-6Al-4V was conducted at higher cutting speeds using a new lubrication method called air jet assisted (AJA) machining, in which not only the cutting fluid but also the jet of compressed air was applied to the cutting zone to extend tool life. The results of cutting experiments using an uncoated cemented carbide tool showed that the air jet toward the tool tip applied to the conventional wet machining was effective to extend the tool life. Finally, cooling mechanism in AJA machining was discussed from a viewpoint of enhancement of the heat transfer coefficient from the cutting tool to the cutting fluid.

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“…There are many geometric shapes of the rib-groove channel which have been studied in the past. The common geometric shapes include rectangular, triangular, square, and circle [3][4]. All these types of rib-groove channels were used in many engineering applications such as cross-flow heat exchanger, gas turbine airfoil cooling design, solar air heater blade cooling system, and gas cooled nuclear reactor [5][6].…”

Section: Introductionmentioning

confidence: 99%