HEAT TRANSFER BY DIRECTING GAS-LIQUID SPRAY PERPENDICULARLY ON A FLAT SURFACE

AbstractAn unsteady, laminar, mixed convective stagnation point nanofluid flow through a permeable stretching flat surface using internal heat source or sink and partial slip is investigated. The effects of thermophoresis and Brownian motion parameters are revised on the traditional model of nanofluid for which nanofluid particle volume fraction is passively controlled on the boundary. Spectral relaxation method is applied here to solve the non-dimensional conservation equations. The results show the illustration of the impact of skin friction coefficient, different physical parameters, and the heat transfer rate. The nanofluid motion is enhanced with increase in the value of the internal heat sink or source. On the other hand, the rate of heat transfer on the stretching sheet and the skin friction coefficient are reduced by an increase in internal heat generation. This study further shows that the velocity slip increases with decrease in the rate of heat transfer. The outcome results are benchmarked with previously published results.

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A Numerical Study of Turbulent Boundary Layer Flow Over a Flat Surface With a Single Dimple

10.1115/imece2000-1282 ◽

2000 ◽

Author(s):

Mark E. Kithcart ◽

David E. Klett

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Turbulent Boundary Layer ◽

Boundary Layer Flow ◽

Flat Surface ◽

Numerical Study ◽

Heat Transfer Augmentation ◽

Study Results ◽

Turbulent Boundary Layer Flow ◽

Layer Flow

Abstract Turbulent boundary layer flow over a flat surface with a single dimple has been investigated numerically using the FLUENT CFD software package, and compared to an experiment by Ezerskii and Shekhov [1989], which studied the same configuration. The impetus for this work developed as a result of previous studies. Kithcart and Klett [1996], and Afanas’yev and Chudnovskiy [1992], showed that dimpled surfaces enhance heat transfer comparably to surfaces with protrusion roughness elements, but with a much lower drag penalty. However, the actual physical mechanisms involved in this phenomena were only partially known prior this study. Results obtained numerically are in good agreement with the experiment, most notably the confirmation of the existence of a region of enhanced heat transfer created by interaction of the flow with the dimple. In particular, the simulation indicates that heat transfer augmentation is a consequence of the development of a stagnation flow region within the dimple geometry, and the existence of coherent vortical structures which create a periodic flow-field within and immediately downstream of the dimple. This periodicity appears to govern the magnitude of the heat transfer augmentation.

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The study of spray impact on the heated sapphire plate

Journal of Physics Conference Series ◽

10.1088/1742-6596/2119/1/012172 ◽

2021 ◽

Vol 2119 (1) ◽

pp. 012172

Author(s):

T G Gigola ◽

V V Cheverda

Keyword(s):

Heat Transfer ◽

Sapphire Substrate ◽

Substrate Surface ◽

Heated Surface ◽

Local Heat ◽

Heat Fluxes ◽

Transfer Coefficients ◽

Heat Transfer Coefficients ◽

Liquid Spray ◽

Sapphire Plate

Abstract The process of the liquid spray impact on the heated surface is studied experimentally using the IR-transparent sapphire plate method. The spatiotemporal distribution of the temperature field on the sapphire substrate surface during impacting spray is received. The obtained experimental data are an important step in a study of the local characteristics of heat transfer in the areas of the contact lines during liquid spray impact on the heated surface. Further, the local heat fluxes and heat transfer coefficients will be determined by solving the problem of thermal conductivity in the sapphire substrate.

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