Radiation in boundary layer flow of an absorbing, emmiting and anisotropically scattering fluid

Krishnaprakas, C. K.; Narayana, K. Badari; Dutta, Pradip

doi:10.1108/09615530010338204

Cited by 5 publications

(2 citation statements)

References 4 publications

(3 reference statements)

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“…A few studies have addressed the coupling of convection with thermal radiation. Krishnaprakas et al (2000) have studied the radiation in boundary layer flow of an absorbing, emitting and anisotropically scattering fluid. Tan and Howell (1991) have solved the combined radiation and natural convection for a two-dimension differential heated cavity problem with radiatively participating medium and concluded that the bulk temperature of the fluid increases and a significant change in flow and temperature distribution noticed in presence of participating media radiation.…”

Section: Nomenclaturementioning

confidence: 99%

Coupled magneto-buoyant convection and radiation in an inclined enclosure

Jena

Mahapatra²,

Sarkar³

2013

International Journal of Numerical Methods for Heat &Amp; Fluid Flow

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Purpose – The current study aims to address the interaction between participating media radiation with thermo-gravitational convection of an electrically conducting fluid enclosed within a tilted enclosure under an externally imposed time-independent uniform magnetic field. Design/methodology/approach – The differentially heated boundaries of the tilted enclosure are considered to be diffuse, gray and the enclosed fluid is assumed to be absorbing, emitting and isotropically scattering. The Navier-Stokes equations, meant for magneto convection are solved using modified MAC method. Gradient dependent consistent hybrid upwind scheme of second order is used for discretization of the convective terms. Discrete ordinate method, with S8 approximation, is used to model radiative transport equation in the presence of radiatively active medium. Findings – Effect of uniform magnetic field with different magnitudes and orientations of cavity has been numerically simulated. The effect of participating media radiation has been investigated for different optical thicknesses, emissivities, scattering albedos and Planks number. The results are provided in both graphical and tabular forms. The flow lines, isotherms bring clarity in the understanding of flow behaviour and heat transfer characteristics. Originality/value – Despite the idealized nature, the present study is quite essential to understand the cumbersome physics of realistic problem.

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Section: Nomenclaturementioning

confidence: 99%

Coupled magneto-buoyant convection and radiation in an inclined enclosure

Jena

Mahapatra²,

Sarkar³

2013

International Journal of Numerical Methods for Heat &Amp; Fluid Flow

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“…Studies have shown that radiative heat flux is significant compared to the convective heat flux in flows with temperature greater than 1,000 K (Rolin et al 1981;Kim and Baek 1996;Chen 1997;Krishnaprakas et al 2000;Ko and Anand 2008). The wavelength of radiation emitted by the hot fluid depends on the type and the temperature of the fluid.…”

Section: Introductionmentioning

confidence: 96%

Analysis of a nano-porous multi-layer film for thermal radiation barrier coatings

2011

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A highly reflective thermal radiation barrier coating (TRBC) made of a multi-layer film is studied for high temperature applications. The multi-layer film with a periodic microstructure consisting of cylindrical nanopores acts a photonic band gap (PBG) crystal. The coating is constructed such that pores are arranged periodically along the in-plane directions and axes of the pores are parallel to the thickness direction. The pore diameter is varied periodically through the thickness to form a multilayer film of alternating low and high porosities. The primary motivation behind considering this microstructure is that it can be fabricated from aluminum dioxide, which remains stable at high temperatures. The reflectivity of a single layer with uniform porosity is computed by numerically solving Maxwell's equations, by considering both the microstructure explicitly and a homogenized layer to gain insights into the effect of pore size on the reflectivity of the nano-porous layer. Based on the study of the single layer, two microstructures with different arrangements of pores are designed to exploit the effect of microstructure to widen the band gap of the PBG crystal and to increase the reflectivity of the TRBC. Results of numerical simulations reveal that a wider band gap and higher reflectivity can be achieved by making the interpore distance of alternate layers of the multi-layer film comparable to the wavelength of the incident thermal radiation. A TRBC, which is made of a microstructure with a wider band gap and has increased reflectivity, will reflect a greater amount of incident heat energy over a wider range of frequencies.

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