Airplane Design Optimization for Minimal Global Warming Impact

Abstract

This paper presents a method to assess the key performance indicators of aircraft designed for minimum direct operating cost and aircraft designed for minimum global-warming impact. The method comprises a multidisciplinary aircraft optimization algorithm capable of changing wing, engine and mission design variables while including constraints on flight and field performance. The presented methodology uses traditional Class-I methods augmented with dedicated Class-II models to increase the sensitivity of the performance indicators to relevant design variables. The global-warming impact is measured through the average temperature response caused by several emission species, including CO 2 , NO x and contrail formation, over a prolonged period of one hundred years. The analysis routines are verified against experimental data or higher-order methods. The design algorithm is subsequently applied to a single-aisle, medium-range aircraft, demonstrating that a 45% reduction in average temperature response can be achieved by flying at 8.64 km and Mach 0.61, and by reducing the engine overall pressure ratio to 34 when compared to an aircraft optimized for minimal operating costs or fuel burn. However, if the total productivity of the aircraft fleet is to be maintained, the potential reduction shrinks to 38%. Nomenclature Latin Symbols aspect ratio [-] wing span [m] chord length [m] or climb rate [m/s] lift coefficient [-] drag coefficient [-] 0

Comparison of Future Aviation Fuels to Minimize the Climate Impact of Commercial Aircraft

“…Therefore, this section describes these design steps in more detail. Since the methods for medium-range, kerosene and hydrogen aircraft have been introduced in previous research [15,16], the focus in this section is the method extension stemming from the analysis of SAF as well as the application to the three different categories.…”

“…Additionally, the optimal aircraft design and/or operational parameters can vary with the selected fuel. The general optimization problem for each combination of fuel and aircraft category can be formulated as follows (adapted from Reference [15]):…”

“…Table 1 summarizes these variables and their bounds. Furthermore, the four constraints in Equation (1) confine the design space [16]. Firstly, the approach speed app limits the wing loading / at landing.…”

“…These two parameters are determined from the wing loading / , a design variable, and the minimum thrust-to-weight ratio ( / ) which satisfies performance constraints related to the take-off distance, cruise speed and altitude, and climb gradients according to CS25 regulations. The program automatically selects the minimum T/W value which satisfies these requirements for the selected wing loading [16].…”

“…For the hydrogen aircraft, a cylindrical tank with spherical endcaps is added behind the cabin in the rear-fuselage section. The tank is sized according to the maximum fuel it has to hold, according to the conceptual methods introduced in Reference [15]. The fuselage tank causes the longitudinal center-of-gravity (c.g.)…”