The internal distribution of spectral radiation absorption in a semitransparent spherical particle irradiated uniformly and isotropically is determined by the ray tracing method, and the detailed computation formulae for the internal spectral radiation absorption are deduced. The computed results show that the peak of internal volumetric spectral radiation absorption may locate at the interior shell of the particle. The dimensionless volumetric spectral radiation absorption is higher near the center for weakly absorbing or small spheres, but the dimensionless volumetric spectral radiation absorption is higher near the surface for strongly absorbing or large spheres. The corresponding physical interpretations of the internal spectral absorption distribution are given.

The transient temperature responses in a one-dimensional semitransparent slab with variable refractive index caused by a pulse irradiation are studied. The processes of the transient coupled radiative-conductive heat transfer in the semitransparent slab are analyzed numerically. An implicit central-difference scheme is employed for handling the energy equation, while a discrete curved ray-tracing method is used to solve the radiative transfer equation. The transient temperature responses in the case of constant refractive index are compared with those in the case of variable spatial refractive index. The results show that the spatial variation of refractive index has significant influences on the transient temperature responses of semitransparent slab. Omitting the spatial variation of refractive index may result in errors of transient temperature responses within semitransparent slab to some extent. The effects of optical thickness and refractive index gradient on the transient temperature responses are significant. Increasing the slab optical thickness, the effects of refractive index gradient on the transient temperature responses increase, especially for the non-incident surface.

A Monte Carlo curved ray-tracing method is used to analyze the radiative heat transfer in one-dimensional absorbing-emitting-scattering semitransparent slab with variable spatial refractive index. A problem of radiative equilibrium with linear variable spatial refractive index is taken as an example in this paper. The predicted temperature distributions are determined by the proposed method and compared with the data in references. The results show that influences of refractive index gradient are important and the influences increase with the refractive index gradient, the temperature distribution approaches to the one obtained for a constant refractive index when the slab optical thickness is far greater than 1.0, and the effect of the scattering phase function is similar to that in the medium with constant refractive index.

An iteration method is extended to analyze the influences of the turbulent fluctuation on the reconstruction of Reynolds time-averaged temperature in turbulent axisymmetric free flames when the temperature profiles are retrieved by the low time-resolution data of outgoing emission and transmission radiation intensities. A simplified probability density function is used to simulate the turbulent fluctuation of temperature and absorption coefficient. The effects of turbulent fluctuating intensities on the estimation of the Reynolds time-averaged temperature and absorption coefficient are examined. The results show that the effects of turbulent fluctuation on the reconstruction of time-averaged absorption coefficient are not significant. In the case of weak turbulent fluctuation, the influences of turbulent fluctuation on the estimation of time-averaged temperature profiles are small. But in the case of strong turbulent fluctuation, the influences of turbulent fluctuation on the estimation of time-averaged temperature profiles are significant.

The internal distribution of spectral radiation absorption in one-dimensional semitransparent slab, sphere and cylinder irradiated uniformly and isotropically is determined by the ray tracing method, and the detailed theory for computation are deduced. The computed results show that the internal distribution of spectral radiation absorption in slab differs from that in spherical and cylindrical particles. The peak of internal volumetric spectral radiation absorption may locate at interior shell of the semitransparent sphere and cylinder. The dimensionless volumetric spectral radiation absorption is higher near the center for weakly absorbing or small size parameter, but is higher near the surface for strongly absorbing or large spheres and cylinders. Refraction focuses the rays close to the sphere and cylinder center. With the increases of the refractive index, the dimensionless volumetric spectral radiation absorption increases near the sphere and cylinder centers and decreases near the sphere and cylinder surfaces.