Programme for Research-Development-Innovation on Space Technology and Advanced Research - STAR Prof. dr.ing. Sterian DANAILA STAR Programme Annual Conference - 26-27 June 2013, Bucharest, Romania Coordinating organization UNIVERSITY POLITEHNICA OF BUCHAREST- Research Center for Aeronautics and Space Project manager Sterian DĂNĂILĂ Address: Bucharest, Str. Gheorghe Polizu , , No 1, CP 011061 Partner organization INCAS – NATIONAL INSTITUTE FOR AEROSPACE RESEARCH “ELIE CARAFOLI” Address: Iuliu Maniu, No 220, CP 061126 Partner team leader Mihai Victor PRICOP Address: Str. Iuliu Maniu, No 220, CP 061126 Practical relevance of the project The main goal of the proposal is providing several validated and verified numerical tools for the thermal inverse problem arising in supersonic/hypersonic flows. This objective is of paramount importance in the aerodynamic prediction of the reentry behavior of space vehicles. A vehicle entering the atmosphere from space experiences an extreme thermal environment due to the very large velocities involved. The extremely high kinetic energy of the on-coming air (up to about 100MW/m2) is suddenly converted into thermal energy as the air passes through the bow shock. This energy conversion raises the temperature of the air to as high as 20,000K, resulting in dissociation and possibly ionization of the air molecules. When this super-heated air flows over the vehicle, it results in very high heat transfer to the surface, requiring a thermal protection system to ensure the survival of the vehicle. To predict flow and thermal field quantities, models of hypersonic flow, aerothermochemistry, thermal radiation and turbulence are needed. A space capsule reentering the atmosphere, with relevant physical phenomena The purpose of this proposal is two-fold: -first, recovering the field distribution of major quantities characterizing the flow between the bow shock wave and a bluntnosed body travelling at supersonic / hypersonic speeds from the air data systems; - second, uncertainty quantification. Scientific relevance of the project DIRECT problems We associate direct mathematical physics problems with classical boundary value problems often encountered in mathematical physics. In a direct problem, it is required to find a solution that satisfies some given partial differential equation and some initial and boundary conditions. Boundary and initial conditions are formulated to identify, among the whole set of possible solutions of a partial differential equation, a desired solution. With this circumstance, the notion of wellposed statement of a problem is related (the notion of well-posedness of a problem according to J. Hadamard). INVERSE problems Inverse modeling is to find the causal characteristics from the finite effectual information like the distributions of pressure, temperature, concentrations, etc. According to different causal characteristics, the inverse modeling can be categorized into boundary, retrospective, coefficient and geometric problems. Boundary problems are to find the boundary conditions that form a certain parameter field; retrospective problems (time reversed problems) are to find the initial conditions; coefficient problems are to find some coefficients in the governing equation, for example, the diffusion coefficient of contaminant transport; and geometric problems are to reconstruct the geometric characteristics of a domain. Project goal The main goal of the proposal is providing several validated and verified numerical tools for the thermal inverse problem arising in supersonic/hypersonic flows. Objectives 1) Formulation and solution of the inverse thermal problem in the interior of the reentry body. Starting from the knowledge of temperature distribution in several points at body surface and/or interior of the body we will determine the heat flux at the fluid-solid interface; 2) Formulation and solution of the thermal inverse problem in the adjacent fluid flow. Starting from the knowledge of the heat flux at body surface and/or the pressure at points on the surface, the far-field parameters of the fluid will be determined such that to obtain the previously mentioned conditions; 3) Theoretical model and computing code for the POD analysis in the inverse problem in the supersonic/hypersonic flow. The last result is considered useful for the ESA research programs because it could be applied for the calibration of various ESA numerical codes already in use against the experimental data. This result is independent of the CFD code; 4) Obtaining experimental data in order to validate POD analysis. Estimated results The engineering verified software package for inverse thermal and flow fields calculations in supersonic/hypersonic laminar and turbulent flows Start date of the project 19.11.2012 End date of the project 19.11.2014 Human resources involved Work plan of the project Implementation status of the project_1 Activitate II.1 Probleme cuplate de aerotermodinamica si conductie interioara M=8 , p0=22 Pa, T0=245 K, 2265547 elemente, alfa= 2 W/m2.K (T interior sfera 300 K). M=9 , p0=20 Pa, T0=233 K, 3675239 elemente, alfa= 2 W/m2.K (T interior sfera 300 K). Implementation status of the project_2 Activitate II.1 Probleme cuplate de aerotermodinamica si conductie interioara Geometria IXV a fost modificata in prima faza prin eliminarea spatiului dintre corp si flaps M= 3.5 cu o incidenta de = 288.15K = 6 bar. Grila initiala 9,4 mil elemente Grila adaptata 20 mil. elemente Implementation status of the project_3 Activitate II.2 Dezvoltare programe de calcul si verificari pentru problema inversa de transfer de caldura MODEL MATEMATIC Evolutionary inverse problems 1D NON-LOCALLY DISTURBED INITIAL CONDITION Evolutionary inverse problems 2 D ADDITIVE REGULARIZED SCHEME Implementation status of the project_4 Evolutionary inverse problems 2D ITERATIVE REFINEMENT OF THE INITIAL CONDITION Unsteady inverse problem 1D RIGHT-HAND SIDE IDENTIFICATION Steady inverse problem 2D RIGHT-HAND SIDE IDENTIFICATION POISSON EQUATION IN A RECTANGLE Parabolic Unsteady Inverse Problems Implementation status of the project _5 Activitate II.4 Definirea instrumentarii si geometriei modelului experimental Mature designs – second iteration IXV like reentry body Forces/Moments model -dorsal repositioning of the sting, as result of CFD analysis, to minimize -aluminum alloy 7075 pithing moment -using existing WT model balance/sting Temperature instrumentated model Implementation status of the project_6 Activitate II.4 Definirea instrumentarii si geometriei modelului experimental Material and instrumentation acquisition -Aluminum alloy 7075 T651, 850 x 400 x 120mm (115Kg) for manufacturing of 2 sphere and 2 IXV models -32 channel National Instruments acquisition system & associated thermocouples: NI 9213, NI 9232, NI 9237, K-Type Thermocouples Flow assessment technologies -Specific oil/pigment powder -Dorsal video camera Shock wave and separation Recalibration of trisonic WT using ONERA M4R model Risk analysis and contingency plan (lessons learned) Risk identification No Material risk Solution plan 1 Computer network availability for computations Identification of similar facilities in consortium partners (INCAS facility) Human risk Solution plan Impossibility to achieve a task due to personnel lack Identification of PhD or master students to be involved in project 1 Project’s contribution to the goal of the STAR Programme The proposed work may contribute to the ESA’s PRIDE Programme with a better understanding of: a) the basic flow physics during the reentry, b) the sources of uncertainties in CFD predictions, c) the way to follow to improve CFD calculation quality. The uncertainty qualification, as actual research subject is included in ESA_IPC_2011_19,rev5_TRP 2011-13 implementation status. The proposed work aims at providing future interdisciplinary collaboration opportunities for the Romanian institutions within long term ESA’s Programmes. The software produced in the work can be developed for the thermal inverse problem predictions, the issue related to the in-flight data measurements (as ESA's PRIDE Programme provides). Proposal Software for thermal and flow fields supersonic/hypersonic boundary layers. Verifications qualification was approved by ESA, contract in negotiation. analysis in the and uncertainty Dissemination activities Papers: 1. Aspects regarding hybrid combustion instability control, author: Sterian DANAILA, accepted for 64th International Astronautical Congress, Beijing, China, 23-27 September 2013, http://www.iafastro.net/iac/browse.lite/IAC-13/C4/2/ 2. Assessment of the effects of volcanic ash/dust clouds on aircraft safety authors: Dragos Isvoranu , Sterian Danaila, AWERProcedia Advances in Applied Sciences, 2013. 3. Experimental results and numerical simulations for transonic flow over the ONERA M4R model, authors: Andreea BOBONEA, Mihai Leonida NICULESCU, Mihai Victor PRICOP, Adrian Chelaru, Florin MUNTEANU, Marius Gabriel COJOCARU, INCAS Bulletin, Volume 5, Issue 2, April-June 2013. Conclusions So far we have performed numerical simulations of heat transfer phenomena in hypersonic regime for: canonical configuration of the project (sphere) with the introduction of a molecular dissociation of air. modified IXV re-entry vehicle in wind tunnel conditions. We developed a total of 16 computer programs in FORTRAN language that implements various methods of solving inverse thermal steady and unsteady problems. Using these methods is therefore possible to: a) re-determine the predicted aerodynamic heating in a numerical experiment and/or b) determine the aerodynamic heating in an experiment or in real conditions, using measured temperatures. The project is carried out according to the schedule specified in the contract.

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