Local Heat Transfer Measurement and Numerical Analysis in the Ventilated Disc Brake with Semi-Cylindrical Grooves

Abstract The steady-state experiment using liquid crystal thermography has been conducted for the analysis of Nusselt number distribution over the absorber surface of solar air heater duct having a gap with the staggered arrangement in inclined rib geometry to recuperate its thermal performance. The heat transfer experiment is performed with uniform heat flux and thermo-chromic liquid crystal is utilized to show the temperature distribution profile over the ribbed surfaces of the rectangular duct of aspect ratio of 5. The colored pattern image of TLCs was acquired using a 3CCD camera and exported to a TIFF file format using frame grabbing SOFTWARE SAPERALT which was further processed to get HSI values. The flow parameters considered in this present investigation are Re, d/W, and g/e varied from 4000-12500,0.15-0.45 and 1-4 respectively. Experiments has been performed with fixed P/e, r/e, p′/P, a and e/Dh of 10, 2, 0.6, 60° and 0.0303 respectively. The influence of relative gap position and relative gap width on flow pattern has been analyzed. The maximum augmentation in Nu and f over the smooth duct was obtained as 4.01 and 4.28 times respectively at the optimum value of d/W = 0.35 and g/e = 2 under similar flow conditions. The maximum value of THPP obtained at d/W & g/e of 0.35 & 2 respectively and Reynolds number of 12445.

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Numerical Analysis of Local Heat Transfer From a Flat Plate to a Pair of Circular Air Impingining Jets

Heat Transfer, Volume 2 ◽

10.1115/imece2004-61950 ◽

2004 ◽

Author(s):

X. Terry Yan ◽

Yavaraj Saravanan

Keyword(s):

Heat Transfer ◽

Numerical Analysis ◽

Flat Plate ◽

Three Dimensional ◽

Turbulence Models ◽

Local Heat Transfer ◽

Local Heat ◽

Impinging Jets ◽

Transfer Coefficients ◽

Heat Transfer Coefficients

Local heat transfer from a flat plate to a pair of circular air impinging jets is investigated numerically. A pair of impinging jets from fully-developed pipe flows are used for the numerical simulations. The Reynolds Averaged Navier-Stokes equations(RANS) and energy equation are solved for the three dimensional flow. Eddy-viscocity based turbulence models, RNG k-epsilon and V2F models, are used. Hybrid meshes are used for the three dimensional flows and mesh independent solutions are obtained. The flow Reynolds number, which is based on the jet diameter, is kept at 23,000. In the analysis, local heat transfer coefficients are obtained for the jet-to-plate distance, L/D, ranging from 2 to 10 and the jet-to-jet spacing, S/D, in the range of 1.75 to 7.0. Both local and average heat transfer coefficients are evaluated and compared with available experimental data under same flow conditions. The effect of using different turbulence models in the numerical analysis is evaluated and the selection of proper turbulence models under such a flow condition is suggested.

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Experimental Study on Convective Heat Transfer of Radial Air Flow in Rotating Multi-Channels

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration ◽

10.1115/95-gt-060 ◽

1995 ◽

Author(s):

G. J. Hwang ◽

C. R. Kuo ◽

C. Y. Chang

Keyword(s):

Heat Transfer ◽

Experimental Study ◽

Convective Heat Transfer ◽

Convective Heat ◽

Air Flow ◽

Local Heat Transfer ◽

Local Heat ◽

Cross Sectional ◽

Transfer Measurement ◽

Single Flow

Experimental study on the convective heat transfer of radial air flow in rotating multi-channels was performed. Three sets of test sections, one single-flow passage, one nine-flow passages and one twenty-five-flow passages with the same cross sectional area of 9π mm2, were applied to the experiments. The test section was formed by rectangular blocks of aluminum alloy with circular flow passages. Between two adjacent blocks, a Bakelite board of 1 mm thickness was placed to separate axial wall heat conduction for local heat transfer measurement. The parameters involved are the Reynolds number Re, the Rotation number Ro, the Buoyancy parameter Gr/Re2, and the ratio of the heat transfer area Ap/Ac. The heat transfer results of radially rotating circular ducts based on per-passage and per-system were obtained.

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Local Heat Transfer Measurements and Numerical Analysis in the Cooling Passage of the Ventilated Disc Brake with Semi-Cylindrically Grooved Surface

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.1305 ◽

2006 ◽

Vol 326-328 ◽

pp. 1305-1308 ◽

Cited By ~ 1

Author(s):

Dae Hee Lee ◽

Chang Yul Lim ◽

Kyoung Ill Yoon ◽

Man Sig Kim ◽

Moon Kyoung Kim ◽

...

Keyword(s):

Heat Transfer ◽

Flat Surface ◽

Numerical Technique ◽

Local Heat Transfer ◽

Groove Depth ◽

Local Heat ◽

Disc Brake ◽

Flux Boundary Condition ◽

Grooved Surface ◽

Cooling Passage

The local heat transfer measurements in the cooling flow passage having both flat surface and semi-cylindrically grooved surface geometries inside the automobile disc brake were made. A uniform wall heat flux boundary condition on both surface geometries was created using gold film Intrex. Liquid crystal was used to measure the surface temperature. The experiments were made at Reynolds number (based on the hydraulic diameter of the rectangular duct) of Re=23,000, groove pitch-to-width (P/D) from 3 to 7, and groove depth-to-width (H/D) from 0.15 to 0.2. The results show that the magnitudes in the average Nusselt number on the grooved surface are maximum 92.8% higher than those on the flat surface without groove. A computer program utilizing the coupled FEM numerical technique that can predict the temperature distributions on the disc brake to analyze the thermal deformation has been developed.

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