Sergey A. Budnik

Identification of thermal properties of materials with applications for spacecraft structures

This paper presents the results of computational and experimental studies of particular thermal processes in composite materials. The considered approach is based on the mathematical theory of ill-posed problems of mathematical physics. In the majority of cases this methodology is used for optimization, but in a number of practical situations it is the sole technique available, as, for example, in measuring the transient heat fluxes and heat transfer coefficients. Owing to the structural version and homogeneous surface heating in specimens a one-dimensional heat transfer process is realized. A complex of thermal properties of the composite material (thermal conductivity λ(T) and heat capacity coefficient C(T)) is estimated. The initial data for such problems are formed grounded on the results of measurements and include the boundary conditions and temperature–time values in several internal points of specimens. The type of boundary conditions and the number of points of temperature measurement should meet the conditions of uniqueness of the inverse problem solution under analysis.

Estimation of thermal properties of materials with application for inflatable spacecraft structure testing

The general method of iterative regularization is concerned with application to the estimation of material properties. The objective of this article is to estimate thermal and thermokinetic properties of advanced materials using the approach based on inverse methods. An experimental–computational system is presented for investigating the thermal and kinetics properties of composite materials by methods of inverse heat transfer problems and this is developed at the Thermal Laboratory of the Department of Space Systems Engineering, Moscow Aviation Institute. The system is aimed at investigating the materials in conditions of unsteady contact heating over a wide range of temperature changes and heating rates in vacuum, air and inert gas mediums.

Parametric identification of a mathematical model of heat transfer in carbon–carbon (C–C) materials for aeronautical application

This paper is devoted to the development of heat transfer models that are adequate to the real processes by using the experimental and computational methodology based on the theory of inverse heat transfer problems.

Identification of radiative heat transfer parameters in multilayer thermal insulation of spacecraft

Purpose The purpose of this study is to optimize multilayer vacuum thermal insulation (MLI) of modern high-weight spacecrafts. An adequate mathematical simulation of heat transfer in the MLI is impossible if there is no available information on the main insulation properties. Design/methodology/approach The results of experiments in thermo-vacuum facilities are used to re-estimate some radiative properties of metallic foil/metalized polymer foil and spacer on the basis of the inverse problem solution. The experiments were carried out for the sample of real MLI used for the BP-Colombo satellite (ESA). The recently developed theoretical model based on neglecting possible near-field effects in radiative heat transfer between closely spaced aluminum foils was used in theoretical predictions of heat transfer through the MLI. Findings A comparison of the computational results and the experimental data confirms that there are no significant near-field effects between the neighboring MLI layers. It means that there is no considerable contradiction between the far-field model of radiative transfer in MLI and the experimental estimates. Originality/value An identification procedure for mathematical model of the multilayer thermal insulation showed that a modified theoretical model developed recently can be used to estimate thermal properties of the insulation at conditions of space vacuum.

Mathematical Model of Heat Transfer in High-Porous Materials

The main purpose of this study was to confirm operability and effectiveness of the complex methods developed for theoretical prediction and experimental-computational determining some properties of modern highly porous materials, used as thermal protection shields in objects of space engineering, power engineering, etc. Them concern Fibrous Materials (FM), Open-Cell Reticulated Foams (OCRF) etc. The basis for the method proposed is in the combination of Direct Mathematical Simulation (DMS) for global structure of the complex irregular systems, which have the property of local regularity and Inverse Heat Transfer Problem (IHTP) methods. This approach makes possible to obtain and to predict such properties as radiation and molecular thermal conductivities, energy accommodation coefficient, complex refractive index, scattering indicatrix, scattering and absorption factors, etc. Such problems are of great practical importance in the study of material properties.Copyright