Photon Monte Carlo Simulation for Radiative Transfer in Gaseous Media Represented by Discrete Particle Fields

Abstract

Monte Carlo ray-tracing schemes have been developed for the evaluation of radiative heat transfer for problems, in which the participating medium is represented by discrete point masses, such as the flow field and scalar fields in PDF Monte Carlo methods frequently used in combustion modeling. Photon ray tracing in such cases requires that an optical thickness is assigned to each of the point masses. Two approaches are dis-cussed, the point particle model (PPM), in which the shape of particle is not specified, and the spherical particle model (SPM) in which particles are assumed to be spheres with specified radiation properties across their volumes. Another issue for ray tracing in particle fields is the influence region of a ray. Two ways of modeling a ray are proposed. In the first, each ray is treated as a standard volume-less line. In the other approach, the ray is assigned a small solid angle, and is thus treated as a cone with a decaying influence function away from its centerline. Based on these models, three different inter-action schemes between rays and particles are proposed, i.e., line-SPM, cone-PPM and cone-SPM methods, and are compared employing several test problems. DOI: 10.1115/1.2345431

IHT: Tools for Computing Insolation Absorption by Particle Laden Flows

“…As pointed out by Wang and Modest [6], line rays and point particles can not intersect in practice. The formulation used here is that line rays are checked for intersection against spheres of radius r eff , where the effective radius is a problem-specific parameter.…”

“…Well suited for insola tion absorption computations, it is also has potential applications in combustion (sooting flames), biomass gasifica tion processes and similar processes. The algorithm is based on the the "Photon Monte Carlo" approach described by Wang and Modest [6] and implemented in a library that can be interfaced with a variety of CFD codes to analyze radiative heat transfer in particle-laden flows. The implementation is in a library where MPI-based parallelism is used for performance on modern HPC resources.…”

“…The subscript η is the wavenumber; in the most general case the emission/absorption (κ η ) coefficient is frequency de pendent, and the scattering coefficient (σ sη ) is both direction and frequency dependent. The function Φ η (sˆi, sˆ) is the scattering phase function, supplying the probability that a ray coming from ŝ i is scattered into the direction ŝ. Wang and Modest [6] solve this equation with the aid of a discrete particle method where the medium (not necessarily comprised of physical particles) is represented by a collection of virtual particles. With a slight modification of the emissions function, we use a similar formulation to solve the radiative transfer problem for a physical particle field.…”

Comparison of accuracy and computational expense of radiation models in simulation of non-premixed turbulent jet flames

“…On the other hand, G g depends on the properties at every point in the domain, and the one-point PDF employed here is not sufficient to close this term. Only when using the discrete particle PMC scheme developed by Wang and Modest [22] absorption TRI can be evaluated exactly, whereas for the case of a finite-volume-based RTE solvers absorption TRI needs to be modeled through the OTFA [21], i.e., for optically thin eddies In the present study a wedge-like 3-D grid system consisting of 3300 cells is employed to simulate 2-D axisymmetric flames by applying periodic boundary conditions on the sides. The wedge angle is 10°and its dimensions in the x-and y-directions are 20d j and 100d j , respectively.…”

Spectral Photon Monte Carlo With Energy Splitting Across Phases for Gas–Particle Mixtures

“…Tess e et al [16,17] developed their PMC methods to model the radiative transfer in a turbulent sooty flame, in which a narrow-band correlated-k model was used for spectral integration. Wang and Modest [18,19] developed several emission and absorption schemes for discrete particle fields, which can be utilized to perform PMC simulations in such media. The PMC method has also been applied in a variety of other participating media.…”