Unsteady conductive heat transfer for bodies in an infinite medium

The results are presented of Nusselt number calculations for bodies of different geometrical shape located in an infinite medium, the surface temperature of the bodies being functions of time. A number of particular cases are investigated.     

Radiant heat transfer in a closed system of semiopaque bodies separated by an emitting and absorbing gas medium

A radiant heat-transfer problem is solved for a closed emitting system bounded by a nonisothermal semiopaque shell with the absorption and emission of a nonisothermal gas medium taken into account.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 2, pp. 305–309, February, 1988.     

Exact numerical solutions for radiative heat transfer in cylindrical furnaces

Exact expressions for the distributions of the components of radiative flux density and the radiative energy source term in terms of wall and medium temperature distributions have been formulated for an emitting absorbing medium of constant properties bounded by black walls of a cylindrical enclosure. The accuracy of numerical solutions has been tested on an idealized enclosure for which exact analytical solution of the expressions is possible and shown to have six-figure accuracy. The exact expressions have then been solved numerically for an enclosure problem based on data reported previously on a large scale experimental furnace. The principal feature of the data is highly non-uniform temperature distributions which are typical of the conditions encountered in industrial furnaces. These data have been chosen because of their practical importance and the non-availability of exact solutions for such data. The resulting exact solutions have been tabulated and are intended to serve in the future as standards for testing the accuracy of the approximate predictions produced using various three-dimensional flux models in cylindrical configurations.     

Unsteady-state radiative heat transfer between two opaque bodies of finite dimensions

The unsteady-state radiative interaction of two opaque gray bodies according to the Stefan-Boltzmann law is considered. The problem is reduced to a non-linear Volterra integral equation for the net radiation density. A solution is obtained for a linear approximation. The general case and the short-time behavior are discussed.     

Differential equations for the study of radiative heat exchange in an absorbing-emitting medium

Exact differential equations have been derived for the sums and differences of hemispherical radiative flows in an absorbing-emitting medium. A method is given for the solution of these equations for a flat layer.     

Radiant heat transfer in an absorbent medium

A dependence is obtained for the radiation flux vector in the form of a series. A calculation formula taking the anisotropy of the radiation field into account is proposed.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 1, pp. 134–139, January, 1980.     

Regular solution of inverse optimal design problems for axisymmetric systems of radiative heat transfer

Inverse optimal design problems are considered for axisymmetric systems of heat transfer with only radiative heat transfer. In these problems, the geometry of thermal system is preassigned, and it is required to find the optimal distribution of temperature on the heater surface, which provides for the preassigned distribution of radiative heat flux (at a given temperature) on the surface being heated. Variational methods of regularization are employed for solving these problems, namely, Tikhonov’s regularization method and parametric regularization. Minimization problems are solved numerically by gradient methods. The conjugate problem method is used for calculating the gradient of discrepancy functional. Examples of solution of model problems are given.     

Cooling of a plane slab of an absorbing gray medium with simultaneous conduction and radiation heat transfer

A method for calculating transient heat transfer by radiation and conduction in a slab of a gray absorbing medium is discussed. The results are given from calculations of the cooling of a slab having a transparent upper boundary and a diffusely reflecting lower boundary in contact with an opaque material.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 41, No. 5, pp. 874–879, November, 1981.     

Modeling of radiative heat transfer and mass transfer processes in drop-flow-based heat exchangers for spacecraft

Modeling of radiative heat transfer and mass transfer in drop-flow-based heat exchangers for spacecraft is considered. A Monte Carlo-based numerical model is presented. Results obtained with the aid of the model are analyzed and compared with existing data. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 71, No. 1, pp. 92–96, January–February, 1998.     

Two-dimensional radiative heat transfer with allowance for shading

Radiative heat transfer with account taken for shading in an infinite cylinder whose contour is made up of arbitrary straight-line segments and which has variable temperature and emissivity on its two sides is examined.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 30, No. 1, pp. 49–57, January, 1976.     

Rigorous constructive solutions in radiative heat transfer

A method based on integral Fourier transform technique is proposed for obtaining both the total and angular radiation intensity in a nonconservative, isotropically scattering, finite slab with an internal source and with general transparent boundary conditions. The theory of the method is first presented, and it is shown to provide rigorous constructive solutions for the problem. Numerical results for various physical situations are then reported and compared with previous other results wherever possible. The case of the universal functions Θ(τ) and $\text{Θ}{}_{\mathrm{g}}\text{(τ)}$ is also considered.     

Hybrid numerical method for solution of the radiative transfer equation in one, two, or three dimensions

A hybrid method is presented by which Monte Carlo (MC) techniques are combined with an iterative relaxation algorithm to solve the radiative transfer equation in arbitrary one-, two-, or three-dimensional optical environments. The optical environments are first divided into contiguous subregions, or elements. MC techniques are employed to determine the optical response function of each type of element. The elements are combined, and relaxation techniques are used to determine simultaneously the radiance field on the boundary and throughout the interior of the modeled environment. One-dimensional results compare well with a standard radiative transfer model. The light field beneath and adjacent to a long barge is modeled in two dimensions and displayed. Ramifications for underwater video imaging are discussed. The hybrid model is currently capable of providing estimates of the underwater light field needed to expedite inspection of ship hulls and port facilities.     

Analysis of radiative heat transfer in nonisothermal cavities

A simple numerical method is proposed for the calculation of radiative heat transfer in diffuse nonisothermal cavities. Numerical results are given for a parabolic temperature distribution along the length of a cylindrical cavity     

The transfer of heat between moving bodies in contact

We present a solution for the problem of the distribution of temperature and that of the intensity of heat flows in bodies that are in contact in the case of steady-state heat transfer and great velocities of motion.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 16, No. 3, pp. 484–488, March, 1969.     

Finite-difference time-domain solution of light scattering and absorption by particles in an absorbing medium

The three-dimensional (3-D) finite-difference time-domain (FDTD) technique has been extended to simulate light scattering and absorption by nonspherical particles embedded in an absorbing dielectric medium. A uniaxial perfectly matched layer (UPML) absorbing boundary condition is used to truncate the computational domain. When computing the single-scattering properties of a particle in an absorbing dielectric medium, we derive the single-scattering properties including scattering phase functions, extinction, and absorption efficiencies using a volume integration of the internal field. A Mie solution for light scattering and absorption by spherical particles in an absorbing medium is used to examine the accuracy of the 3-D UPML FDTD code. It is found that the errors in the extinction and absorption efficiencies from the 3-D UPML FDTD are less than approximately 2%. The errors in the scattering phase functions are typically less than approximately 5%. The errors in the asymmetry factors are less than approximately 0.1%. For light scattering by particles in free space, the accuracy of the 3-D UPML FDTD scheme is similar to a previous model [Appl. Opt. 38, 3141 (1999)].     

Finite-difference time-domain solution of light scattering by an infinite dielectric column immersed in an absorbing medium

The two-dimensional (2-D) finite-difference time-domain (FDTD) method is applied to calculate light scattering and absorption by an arbitrarily shaped infinite column embedded in an absorbing dielectric medium. A uniaxial perfectly matched layer (UPML) absorbing boundary condition is used to truncate the computational domain. The single-scattering properties of the infinite column embedded in the absorbing medium, including scattering phase functions and extinction and absorption efficiencies, are derived by use of an area integration of the internal field. An exact solution for light scattering and absorption by a circular cylinder in an absorbing medium is used to examine the accuracy of the 2-D UPML FDTD code. With use of a cell size of 1/120 incident wavelength in the FDTD calculations, the errors in the extinction and absorption efficiencies and asymmetry factors from the 2-D UPML FDTD are generally smaller than approximately 0.1%. The errors in the scattering phase functions are typically smaller than approximately 4%. With the 2-D UPML FDTD technique, light scattering and absorption by long noncircular columns embedded in absorbing media can be accurately solved.     

Heat transfer in a cylindrical layer of an absorbing medium bounded by nonblack surfaces

The temperature field and the radiative-conductive heat flow in a cylindrical layer of a weakly-absorbing medium are computed.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 18, No.1, pp. 31–38, January, 1970.     

Photon diffusion coefficient in an absorbing medium

A number of investigators have recently claimed, based on both analysis from transport theory and transport-theory-based Monte Carlo calculations, that the diffusion coefficient for photon migration should be taken to be independent of absorption. We show that these analyses are flawed and that the correct way of extracting diffusion theory from transport theory gives an absorption-dependent diffusion coefficient. Experiments by two different sets of investigators give conflicting results concerning whether the diffusion coefficient depends on absorption. The discrepancy between theory and the earlier set of experiments poses an interesting challenge.     

Inverse problems of radiative heat transfer in polydispersed media

We consider statements of inverse problems of radiative and coupled heat and mass-transfer in dispersed media. We review some of the recent papers and discuss the algorithm of the method of inverse dynamical systems.Translated from Inzhenerno-Fizieheskii Zhurnal,Vol. 56, No. 3, pp. 503–509, March, 1989.     

Study of radiative heat transfer in a fluidized bed

The radiative component can be measured with the aid of two radiometer probes. Experimental data for bed temperatures up to 1700° K are presented as functions of the principal hydrodynamic and thermal parameters.