Computational evaluations of emissions indexes released by the STRATOFLY air-breathing combined propulsive system

Abstract

Purpose The purpose of this study is to provide the description of a computational methodology to model the combined propulsive systems of hydrogen propelled air-breathing scramjet vehicles and to evaluate the pollutant and climate-changing emissions. Design/methodology/approach Emissions indexes of nitrogen oxide (EINO) and water vapour released by the air turbo rocket (ATR) and dual mode ramjet (DMR) engines of the STRATOFLY air-breathing, hypersonic scramjet vehicle, propelled by hydrogen/air were evaluated. ATR engine operation was assessed for several cruise conditions in both subsonic and supersonic flight regimes in Ecosimpro software, which is an object-oriented thermodynamic design and simulation platform. ATR combustor inlet flow conditions play a key role in the computation of species mass fractions, and these conditions are highly dependent on turbomachinery performance and engine flight regime. A propulsive operational database was created by varying mass flow rates of fuel and flight conditions such as cruise speed and altitude to investigate possible engine operations. The all-inlet conditions in this map are provided to the Cantera-Python chemical/combustion chemistry solver implementing a specially designed and formulated 0D kinetic-thermodynamic methodology successfully used to model and simulate the electric spark ignition required to activate the combustion process of the reacting mixture in the ATR combustion chambers, whereas the coupled aero-thermodynamic/aero-propulsive 0D/1D code i.e. Scramjet PREliminary Aerothermodynamic Design (SPREAD), designed and developed by the Italian Aerospace Research Centre (CIRA) was used for DMR calculations. Results show low emissions of NO according to the optimized design of the ATR; on the other hand, a tuning of operational conditions is needed for DMR, with its complete re-design to be more conclusive. Analogously, the released amount of water vapour is in good agreement with the required combustion efficiency and the expected propulsive performance. Findings Results show low emissions of NO according to the optimized design of the ATRs; on the other hand, a tuning of operational conditions is needed for DMR, with its complete re-design to be more conclusive. Analogously, the released amount of water vapour is in good agreement with the required combustion efficiency and the expected propulsive performance. Originality/value Applications of innovative 0D/1D chemical kinetic methodology and in-house codes.

Chemical Kinetic Analysis of High-Pressure Hydrogen Ignition and Combustion toward Green Aviation

“…CIRA is in charge of the assessment of available hydrogen/air reaction mechanisms, in particular with (i) a thorough investigation of detailed and reduced kinetic mechanisms performed through a literature survey, (ii) theoretical investigations and identification of the most performing kinetic schemes for hydrogen/air combustion at selected operative flight conditions, and (iii) 0D/1D simulations of hydrogen/air combustion and comparison of ignition delay times and adiabatic flame temperatures against the available literature experimental data. The work described in the present paper emanates directly from what was recently accomplished in the previous H2020 STRATOFLY project [3][4][5][6] and the present task represents a continuation and extension of it to a wider range of operative conditions. The optimal scheme arises as a suitable trade-off between the accuracy, required for a truthful description of ignition and combustion phenomena, and the computational costs, associated with the available calculation speed and memory storage capacity.…”

Guest editorial: The 11th EASN international conference special issue: “emerging technologies & innovative concepts in aviation and space”

“…Mazur et al (2022) investigated the overall framework in which the Urban Air Mobility deployment is expected to be implemented in the near future. Saccone et al (2022) presented the results of an Horizon 2020 programme, whose aim was the improvement of enabling technologies for the multidisciplinary design and development of a future and re-usable hypersonic, civil, airbreathing, hydrogen-propelled passenger aircraft for stratospheric flight with great care to the environmental impact. In "Enabling SAT single pilot operations: Tactical Separation System design advancements in the COAST Project" and in the "Design Advancements for an Integrated Mission Management System for Small Air Transport vehicles in the COAST project", the ongoing activities of a Clean Sky 2 programme were described by Di Vito et al (2022a, 2022b The editors of this Special Issue would like to thank the authors for their high-quality contributions and for making this Special Issue manageable.…”