Numerical simulation of conjugate heat transfer and surface radiative heat transfer using the P 1 thermal radiation model: Parametric study in benchmark cases.

• A parametric investigation of radiative heat transfer is carried out, including the effects of conjugate heattransfer between fluid and solid media. The thermal radiation is simulated using the P1 -model. Thenumerical model and the thermal coupling strategy, suitable for a transient solver, is described. Suchnumerical coupling requires that the radiative equation is solved several times at each iteration; hence,the computational cost of the radiative model is a crucial issue. The P1 -model is adopted because of itsparticularly fast computation. First, a collection of benchmark cases is presented and used to carefullyvalidate the radiation model against literature results and to analyse the model prediction limits.Despite the simplicity of the model, it satisfactorily reproduces the thermal radiation effects. Some lackof accuracy is identified in particular cases. Second, a number of benchmark cases are described andadopted to investigate fluid–solid thermal interaction in the presence of radiation. Three cases aredesigned, to couple radiation with: pure conduction, conduction and forced convection, conductionand natural convection. In all the cases, the surface radiative heat transfer strongly influences the systemthermodynamics, leading to a significant increase of the fluid–solid interface temperature. The main non-dimensional numbers, related to the mutual influence of the different heat transfer modes, are intro-duced and employed in the analyses. A new conduction-radiation parameter is derived in order to studythe conductive boundary layer in absence of convective heat transfer.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Nyckelord

P1 -model

Thermal radiation

Conjugate heat transfer

Surface radiative heat transfer

Thermal coupling

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