Benjamin J. Brelje

Bio: Benjamin J. Brelje is an academic researcher from University of Michigan. The author has contributed to research in topics: Propulsion & Multidisciplinary design optimization. The author has an hindex of 3, co-authored 9 publications receiving 181 citations.

Development of a Conceptual Design Model for Aircraft Electric Propulsion with Efficient Gradients

Abstract: Research on electric aircraft propulsion has greatly expanded in the last decade, revealing new insights on the unique features of the electric aircraft design problem, and identifying shortcomings in existing analysis techniques and tools In this paper, we survey currently-available analysis codes for aircraft with electric propulsion We introduce a new conceptual design and optimization toolkit-OpenConcept-built for aircraft incorporating electric propulsion Open Concept consists of three parts: a library of simple, conceptual-level models of common electric propulsion components; a set of analysis routines necessary for aircraft sizing and optimization; and several example aircraft models All of Open Concept's codes have been analytically differentiated, enabling the use of OpenMDAO 2's efficient Newton solver, as well as gradient-based optimization methods Open Concept supports parametric cost modeling and waste heat management at the component level, enabling realistic thermal and economic constraints in optimization studies We present a case study involving the electrification of existing turboprop airplanes We model the Daher TBM 850 and Beechcraft King Air C90GT in Open Concept, and validate the sizing, weights, fuel burn, and takeoff field length analyses We then define a series hybrid electric propulsion architecture for the King Air, and perform a retrofit study Finally, we perform multidisciplinary design optimization to minimize both fuel burn and trip cost for varying design ranges and assumed battery specific energy levels We ran more than 750 multidisciplinary optimization cases with full mission analysis Each optimization runs in approximately 2 minutes on a typical notebook PC We demonstrate that Open Concept is a flexible and efficient way of performing conceptual-level analysis of aircraft with unconventional propulsion architectures

Aerostructural Wing Optimization for a Hydrogen Fuel Cell Aircraft

Abstract: Hydrogen has been identified as a potential fuel for air transportation without carbon emissions. Hydrogen containsmuch higher energy per unit mass than any conceivable rechargeable battery, potentially making longer-range missions possible than pure electric configurations. However, hydrogen’s low volumetric energy density presents practical challenges. Hydrogen must either be kept under deep cryogenic conditions or compressed under very high pressure. Either solution is likely to require adding significant drag and tank weight to the airplane. This is a packing optimization problem subject to aerostructural physics, and we can employ multidisciplinary design optimization techniques to provide insight into optimal wing design for novel hydrogen aircraft concepts. In this paper, we extend prior work on wing packing optimization subject to aerodynamics only, and now incorporate structural analysis and structure geometry into the problem. We optimize the range of a hydrogen-electric aircraft with hydrogen fuel storage located inside the wing outer mold line. The geometry of the hydrogen storage tanks influences the shape of the wing as well as the weight and volumetric capacity of the tank. While the effect of hydrogen storage on other aircraft concepts cannot be generalized from this study, the optimization methods we use are promising for performing relevant aircraft design trade studies. The optimizer finds the correct tradeoff between weight, drag, and fuel storage for the mission, subject to spatial integration feasibility. In our test scenario, we find that the optimal aerostructural design involves substantial wing root thickening.

Flexible Formulation of Spatial Integration Constraints in Aerodynamic Shape Optimization

Abstract: In aircraft design, spatial integration limits aerodynamic and structural performance. While the outer mold line shape determines aircraft aerodynamic characteristics, aircraft systems and passenge...

OpenMDAO: an open-source framework for multidisciplinary design, analysis, and optimization

Abstract: Multidisciplinary design optimization (MDO) is concerned with solving design problems involving coupled numerical models of complex engineering systems. While various MDO software frameworks exist, none of them take full advantage of state-of-the-art algorithms to solve coupled models efficiently. Furthermore, there is a need to facilitate the computation of the derivatives of these coupled models for use with gradient-based optimization algorithms to enable design with respect to large numbers of variables. In this paper, we present the theory and architecture of OpenMDAO, an open-source MDO framework that uses Newton-type algorithms to solve coupled systems and exploits problem structure through new hierarchical strategies to achieve high computational efficiency. OpenMDAO also provides a framework for computing coupled derivatives efficiently and in a way that exploits problem sparsity. We demonstrate the framework’s efficiency by benchmarking scalable test problems. We also summarize a number of OpenMDAO applications previously reported in the literature, which include trajectory optimization, wing design, and structural topology optimization, demonstrating that the framework is effective in both coupling existing models and developing new multidisciplinary models from the ground up. Given the potential of the OpenMDAO framework, we expect the number of users and developers to continue growing, enabling even more diverse applications in engineering analysis and design.

Electric Power Systems in More and All Electric Aircraft: A Review

Abstract: Narrow body and wide body aircraft are responsible for more than 75% of aviation greenhouse gas (GHG) emission and aviation, itself, was responsible for about 2.5% of all GHG emissions in the United States in 2018. This situation becomes worse when considering a 4-5% annual growth in air travel. Electrified aircraft is clearly a promising solution to combat the GHG challenge; thus, the trend is to eliminate all but electrical forms of energy in aircraft power distribution systems. However, electrification adds tremendously to the complexity of aircraft electric power systems (EPS), which is dramatically changing in our journey from conventional aircraft to more electric aircraft (MEA) and all electric aircraft (AEA). In this article, we provide an in-depth discussion on MEA/AEA EPS: electric propulsion, distributed propulsion systems (DPS), EPS voltage levels, power supplies, and EPS architectures are discussed. Publications on power flow (PF) analysis and management of EPS are reviewed, and an initial schematic of a potential aircraft EPS with electric propulsion is proposed. In this regard, we also briefly review the components required for MEA/AEA EPS, including power electronics (PE) converters, electric machines, electrochemical energy units, circuit breakers (CBs), and wiring harness. A comprehensive review of each of the components mentioned above or other topics except for those related to steady state power flow in MEA/AEA EPS is out of this article's scope and should be found somewhere else. At the close of the paper, some challenges in the path towards AEA are presented. Unless the discussed challenges are satisfactorily addressed and solved, arriving at an AEA that can properly operate over commercial missions will not be possible.

A review of concepts, benefits, and challenges for future electrical propulsion-based aircraft

Abstract: Electrification of the propulsion system has opened the door to a new paradigm of propulsion system configurations and novel aircraft designs, which was never envisioned before. Despite lofty promises, the concept must overcome the design and sizing challenges to make it realizable. A suitable modeling framework is desired in order to explore the design space at the conceptual level. A greater investment in enabling technologies, and infrastructural developments, is expected to facilitate its successful application in the market. In this review paper, several scholarly articles were surveyed to get an insight into the current landscape of research endeavors and the formulated derivations related to electric aircraft developments. The barriers and the needed future technological development paths are discussed. The paper also includes detailed assessments of the implications and other needs pertaining to future technology, regulation, certification, and infrastructure developments, in order to make the next generation electric aircraft operation commercially worthy.

Review of Electric Machines in More-/Hybrid-/Turbo-Electric Aircraft

Abstract: Aircraft electrification is currently the best alternative to address the rising demand for more air transportation and deal with anticipated economic and environmental impacts. Although the all-electric-aircraft (AEA) concept is not yet a feasible solution, the more-electric aircraft (MEA) is gaining significant attention. Electrical systems either partially or entirely replace the large and inefficient hydraulic, pneumatic, and mechanical conventional aircraft actuating systems. The upgrade could also encompass the propulsion system, as in hybrid- and turbo-electric aircraft. This upgrade reduces the aircraft weight, reduces the usage of pollutant fluids, increases fuel efficiency, reduces carbon emissions, and increases aircraft controllability and reliability. This article reviews various application areas of electric machines in electrified aircraft, such as actuation, taxiing, propulsion, and generation. Moreover, it reviews the main types of currently/to be utilized electric machines and the critically required specifications. Finally, a comparison between the different considered machines and potential future research is discussed.

ADflow: An Open-Source Computational Fluid Dynamics Solver for Aerodynamic and Multidisciplinary Optimization

Abstract: Computational fluid dynamics through the solution of the Navier–Stokes equations with turbulence models has become commonplace. However, simply solving these equations is not sufficient to be able ...