Electric Flight - Potential and Limitations

During the last years, the development of electric propulsion systems is pushed strongly, most notably for automotive applications. For ground based transportation, the system mass is relevant, but of relatively low importance. The paper addresses the application of electric propulsion systems in aeronautics, where all systems are much more constrained by their mass. After comparing different propulsion system architectures the focus is cast on the energy storage problem and here especially on battery storage systems. Using first order principles the limitations and required technology developments are demonstrated by introducing battery powered electric propulsion systems to small and medium sized aircraft

Potential und Grenzen bei der Optimierung des Flügelgrundrisses mit und ohne Lastabminderung im Flugzeugkonzeptentwurf

Lastabminderung ist eine Technologie, die Treibstoffeffizienz eines Verkehrsflugzeugs durch einen leichteren Flügel zu steigern. Die Reduktion der aerodynamischen Lasten am transsonischen, gepfeilten Außenflügel ermöglicht zusätzlich schlankere Flügel für neuartige Konzepte. Lastabminderung hat Einfluss auf den optimalen Flügelgrundriss und sollte daher bereits im Konzeptentwurf berücksichtigt werden. In dieser Veröffentlichung wird ein Entwurfsprozess gezeigt, der die relevanten Disziplinen durch vereinfachte aber physikalisch-basierte Modelle in den Gesamtentwurf einbindet. Es werden Ersatzmodell-basierte Optimierungen der Flügelform durchgeführt, wobei der Zielparameter ein kombinierter Treibstoffverbrauch relevanter Bewertungsmissionen ist. Die Ergebnisse zeigen, dass aktive Lastabminderung die Flügelmasse reduziert und der direkte Einfluss aktiver Lastabminderung spannweitenabhängig ist. Für die Optimierung zeigt das Optimum mit Lastabminderung ein Potential von 11.6 % Treibstoffreduktion gegenüber einer Ausgangskonfiguration. Auch ohne Lastabminderung lassen sich durch Geometrieoptimierung signifikante Reduktionen erreichen. Die Gründe dafür und Randbedingungen wie die Rollsteuerung mit einem flexiblen Flügels werden diskutiert

Exploring Vehicle Level Benefits of Revolutionary Technology Progress via Aircraft Design and Optimization

It is always a strong motivation for aeronautic researchers and engineers to reduce the aircraft emissions or even to achieve emission-free air transport. In this paper, the impacts of different game-changing technologies together on the reduction of aircraft fuel consumption and emissions are studied. In particular, a general tool has been developed for the technology assessment, integration and also for the overall aircraft multidisciplinary design optimization. The validity and robustness of the tool has been verified through comparative and sensitivity studies. The overall aircraft level technology assessment and optimization showed that promising fuel efficiency improvements are possible. Though, additional strategies are required to reach the aviation emission reduction goals for short and medium range configurations

Chlorate and Other Oxychlorine Contaminants Within the Dairy Supply Chain

The presence of chlorate in milk and dairy products can arise from the use of chlorinated water and chlorinated detergents for cleaning and sanitation of process equipment at both farm and food processor level. Chlorate and other oxychlorine species have been associated with inhibition of iodine uptake in humans and the formation of methemoglobin, with infants and young children being a high‐risk demographic. This comprehensive review of chlorate and chlorine derivatives in dairy, highlights areas of concern relative to the origin and/or introduction of chlorate within the dairy supply chain. This review also discusses the associated health concerns, regulations, and chemical behavior of chlorate and chlorine‐derived by‐products, and provides a summary of mechanisms for their detection and removal

Evaluation of the BLWF Code - A Tool for the Aerodynamic Analysis of Transonic Transport Aircraft COnfigurations

The BLWF code [1] was developed by researchers at the Central Aerohydrodynamic Institute (TsAGI). The BLWF code has been developed for preliminary aerodynamic analysis of transonic transport aircraft configurations. It can be used for rapid computations of viscous transonic flow over wing/body/nacelle/ tail configurations. Numerical simulations of the flow past the DLR-F6 wing-body configuration have been performed to evaluate the accuracy and efficiency of this code, when used for preliminary aerodynamic analysis of transonic transport configurations. A brief description of computational methods is given in Section 1. The numerical results and discussion are given in Section 2. The computational results for a prescribed Mach number (Ma=0.75) and prescribed design lift coefficient (CL=0.5) are compared with the available experimental data. The effect of Mach number on the aerodynamic performance is investigated by computations at Mach numbers from 0.2 to 0.9, with fixed Reynolds number and varying angles of attack. According to the evalution results, the BLWF code is well suited for the preliminary aerodynamic analysis of transonic transport aircraft configurations

Comparison between Gradient-free and Adjoint Based Aerodynamic Optimization of a Flying Wing Transport Aircraft in the Preliminary Design.

This paper describes investigations of planform and shape optimizations for a flying wing transport aircraft with an Euler continuous adjoint method. For a prescribed lift the cost function will be the drag, which has to be minimized and implies a maximization of L/D. The results presented for the gradient based method using an adjoint solver are compared to an optimization performed with a gradient free approach. The different workflows and procedures will demonstrate the advantages and disadvantages of each particular optimization approach. The optimization procedure uses a freeform deformation technique for the design parameterization of the shape as well as for the surface mesh deformation required to determine the gradients. This combination of both tasks into one tool is advantageous because performing finite differences for evaluating the mesh sensitivities can be carried out with a constant grid topology. An example design case is also shown for demonstration purposes

HALE Platforms - A Feasibility Study

The report describes results of a feasibility study concerning solar powered High Altitude Long Endurance (HALE) Unmanned Aerial Vehicles (UAV). The high altitude concept was examined in order to allow the vehicles to operate above commercial air traffic.  The study also produced possible solutions for different flight altitudes and payload requirements.  It has been prepared in a cooperation of several DLR institutes, reflecting their specific know-how.  A range of feasible solutions for fixed-wing aircraft as well as airships under different requirements (altitude, payload, velocity) have been examined. Conceptual design and analysis tools were applied to size plaforms

Process Implementation for the System Evaluation of new Low-Noise STOL Transportation Concepts

The German Aerospace Center (DLR) has initiated the project Quiet Short Take-Off and Landing (QSTOL) to set up a multidisciplinary analysis process for new low-noise STOL transportation concepts. The process chain consists of expert tools from various DLR institutes and their partners which are harmonized in input and output data. Involved disciplines are aircraft design, engine cycle modeling, flight mechanics, air traffic integration, and noise prediction. The influence of aircraft design modifications on flight performance/operational procedures, ground noise impact, and air traffic intergration can be evaluated. Obviously, these diciplines are highly correlated and need to be integrated into one multidisciplinary process. The implementation of this new process along with first applications are addressed in this paper. A conventional medium-range transport aircraft is modified for QSTOL operation. Structural modifications of the airframe and a geared turbofan engine concept are investigated. The effects of these measures on ground noise impact, field performance, and air traffic integration are discussed