![]() ![]() The components are then assembled to construct the three powertrains for the hybrid-electric propulsion systems (Series, Parallel and Turboelectric) and parametric studies are carried out to study the influence of various battery parameters and hybridization factor. To this end, the hybrid-electric propulsive system components are modeled, validated, and evaluated using computational and experimental data presented in the literature. A hybrid-electric propulsion concept applied to a regional aircraft is studied in the context of the FutPrInt50 project. In the aviation industry, a comprehensive understanding of greening technologies such as electrification of the propulsion system for commercial aircraft is required. To enable this connectivity, one must find a way to progress towards a more sustainable transportation. It is possible with additional effort to extend existing model capabilities to deal with supersonic transports optimal cruise parameters. An intended application is in the conceptual development stages for early design optimizations of future airplanes. ![]() The model represents a powerful tool to estimate important cruise performance airspeeds located in the transonic regime. The algorithm can be utilized to identify most beneficial input parameter values and combinations for the cruise flight phase. Such physics-based semi-empirical model can be used for a wide range of turbofans. Additionally, a semi-empirical turbofan thrust model usable for a wide range of bypass ratios and the entire flight envelope was developed. Other novel features of this article include a new semi-empirical fuel-flow law, which was also extensively tested. This guess resulted in fast quadratic convergence in all computations. ![]() A methodology for an initial guess was developed starting with the maximum-range cruise Mach without the wave-drag included. The NR method was first tested for accuracy and convergence using known analytical solutions. Numerical Newton–Raphson nonlinear solvers were used to find real positive roots of such polynomials. The resulting nonlinear equations are of 12th- and 13th-order. For maximum range cruise estimations, an optimization criterion based on maximizing specific air range was used. In this study, a new semi-empirical transonic wave drag model using modified Lock’s equation was developed. In the initial design phase and later when the preliminary wind-tunnel and/or CFD computations and drag polars are known with increased accuracy, a method of estimating cruise performance is needed. Modern jet airplanes cruise most efficiently in the vicinity of the drag-divergence or drag-rise Mach numbers. One of the most difficult steps in estimating the cruise performance characteristics of high-subsonic transport-category turbofan-powered airplanes is the estimation of the transonic wave drag. ![]()
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