Thermal Diagnostics of Aerospace Structures
Thermal Diagnostics Technologies for Development, Verification and Emergency Prevention of Aerospace Structures
Tech Area / Field
- SAT-MAS/Manned Space Station/Space, Aircraft and Surface Transportation
- SAT-OTH/Other/Space, Aircraft and Surface Transportation
- SAT-SAF/Space Safety/Space, Aircraft and Surface Transportation
- SAT-UNM/Unmanned Spacecraft/Space, Aircraft and Surface Transportation
8 Project completed
Senior Project Manager
Ryzhova T B
MAI (Moscow Aircraft Institute), Russia, Moscow
- NPO Lavochkin, Russia, Moscow reg., Khimki
- University of Leeds, UK, Leeds\nEADS Space Transportation (EADS ST GmbH), Germany, Bremen\nUniversità di Roma "La Sapienza" / Dipartimento di Ingegneria Aerospaziale e Astronautica, Italy, Rome\nEuropean Space Agency, The Netherlands, Noordwijk\nEcole Politechnique de l'Uniersite de Nantes, France, Nantes\nDLR, Germany, Bonn
Project summaryIn spacecraft engineering we deal with structures operating in the conditions of intensive, often extreme thermal effects. The general tendency in the development of technology is connected with the increase of the number of responsible, thermally loaded engineering objects, with the toughening of conditions of their thermal loading by a simultaneous increase of reliability and safe life and a reduction of specific consumption of materials. For space vehicles and reusable transportation systems the support of thermal conditions is one of the most important aspects of design, determining the main design solutions. Of great importance is the thermal condition support for different engines, power plants, heat-exchange apparatus etc. The distinctive features of modern heat-loaded structures in space engineering are non-stationarity, non-linearity, multidimensionality and conjugate nature of heat-and-mass transfer processes. These distinctions confine a possibility of using many traditional design-and-theory and experiment methods. So, in developing spacecrafts of different mission and type, traditionally there were both the development of new approaches and the improvement of available research techniques. Similar problems exist in other branches of Industry.
Design optimization of heat-loaded objects as well as thermal control during operation time and corresponded emergency monitoring is actually an important problem in the presence of weight and cost restrictions on structures developed for any mission, for example, manned space stations, unmanned spacecraft and especially space systems like “Space Shuttle”, “Hermes” etc. The same problems are very important for internal combustion engines, nuclear power plants, metallurgical and chemical equipment etc. Here, it is impossible to create thermal protection systems, meeting modern requirements, without carrying out of extensive theoretical and experimental studies of thermal state of the structures used. The priority and general orientation in the development of theoretical and experimental foundations of research, support and optimization of thermal conditions of structures of all prototypes of modern technology should be given to the development and broad application of methods of mathematical and physical simulation of a thermal state of the objects under study and, especially, experimental-and-theoretical methods of thermal diagnostics based on the solution of inverse heat-and-mass transfer problems. The researches of recent years showed that the utilization of such an approach is the most perspective and fruitful. It allows to take into consideration the actually existing effects of non-stationarity and non-linearity of heat-and-mass transfer processes, it displays high information efficiency and gives a possibility to conduct testing close to the maximum to full-scale or directly during operation of spacecraft.
The modern approaches to a thermal control of spacecrafts assume broad application of mathematical and physical simulation methods. But mathematical simulation is impossible if there is no true information available on the external heat fluxes, temperatures, etc. of objects analyzed. In the majority of cases in practice the direct measurement of thermal states or external heat loading for space structures, especially of complex composition, is impossible. There is only one way, which permits to overcome these complexities - the indirect measurement. Mathematically, such an approach is usually formulated as a solution of the inverse problem: through direct measurements of some characteristics of system’s state (available temperature, component concentration, etc.) define the total thermal state of a system analyzed, for example, the heat fluxes or/and temperature at the external surface. Violation of cause-and-effect relations in the statement of these problems results in their correctness in mathematical sense (i.e., the absence of existence and/or uniqueness and/or stability of the solution). Hence to solve such problems we develop special methods usually called regularized.
The approaches to estimate thermal states of complex space structure based on methods of ill-posed problem solving were widely analyzed in Russia (USSR) and in other countries having displayed efficiency in the development and investigation of modern structure in spacecraft, aircraft, automotive industries, metallurgy, power engineering etc. A new technologies of diagnostics for thermal analysis of space structure being developed is a combination of sufficiently accurate measurements of primary heat values in testing conditions to the maximum approximate to full-scale conditions and ultimately correct mathematical treatment of experimental data based on the theory of inverse problems.
The global purpose of this project is the development of the methods and tools of thermal diagnostics for widely implementation into practice of thermal control and emergency monitoring of spacecraft.
The achievement of this purpose is connected with
- the application of mathematical simulation methods permitting to analyse the structure operation as a component of the technical object;
- the application of modern high-effective methods and facilities for thermal diagnostics, based on the technique of inverse heat transfer problems;
- the implementation of above technology as experimental-computational system providing to efficiently analyse the data of thermophysical experiments and to estimate thermal state of spacecraft structures.
A successful solution of this problem is possible only considering its, physical, mathematical and technical aspects. Here it is necessary
- to develop the non-linear mathematical models (one-, two- and three-dimensional) for heat transfer analysis at space structures (one- and multilayer, regular and nonregular shape);
- to create the computational algorithms and to develop a software for solving the problems of thermal analysis for diagnostics of a thermal state and estimating of external heat fluxes at the surface of the complex structures at non-steady heating based on inverse methods;
- to create the computational algorithms and to develop a software for solving the problems of thermal analysis, to estimate total thermal state of structures on-line (at real time, express-diagnostics);
- to develop technique to estimate thermal stress state of structure;
- to develop measurement tools (thermosensors, heat flux sensors, etc.);
- to develop and to produce a prototype of automatic control system of thermal diagnostics;
- to develop and to produce a prototype of movable (portative) automatic control system of thermal diagnostics;
- to modernize hardware of test facilities TVS-2 (including electromechanical tools, data recording tools and creating new special modules);
- to develop a methodical support for providing and executing thermal testing for experimental verification of the developed methods and tools of thermal diagnostics;
- to conduct the experimental-and-computational study at stand TVS-2 for verification the developed methods and tools of thermal diagnostics;
- to conduct the experimental-and-computational study of some thermal loaded structures according to interest of the Project collaborators ESTEC/ESA, EADS(Germany), Ecole Polytechnique (France), University of Leeds (England).
The Project can be considered as Applied Research.
The anticipated results can be effectively used in development of thermal control and protection systems and emergency monitoring and prevention not only in aerospace engineering, but also in heat and nuclear power plants, ferrous and non-ferrous metallurgy, machine building, chemical industry, medicine, in particular
- in thermal analysis of high-porous materials for combustion chambers in power plants and metallurgy;
- in thermal analysis of the state of ceramic pipelines and gas conduits in chemical engineering plants;
- in thermal analysis of a ceramic heat shield in the fuel cores of electric power stations in the conditions of their real operation.
Thus, the developed technology implementation will allow to broaden largely the information on the thermal state of structures used and newly developed and will give a possibility to introduce new structures and products and bring new power-consumable processes to a commercial status.
The methodology of investigations being developed will permit
- on a common theoretical base to solve a set of problems emerging in designing, developing and operating thermal-loaded structures;
- to consider to the maximum the actually existing non-stationarity, non-linearity and multidimensionality of heat-and-mass transfer processes running in space structures and on the surface of structures, this sufficiently increasing the accuracy of the results of research;
- to increase the information efficiency of experiments and tests; provide a possibility to conduct them in the conditions approximate to the maximum to full-scale conditions;
- to reduce largely the volume of necessary experimental investigations and tests, and, consequently, the expenses in resources and time for the development of technology prototypes.
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