Rotorcraft flight-propulsion control integration: An eclectic design concept

The NASA Ames and Lewis Research Centers, in conjunction with the Army Research and Technology Laboratories, have initiated and partially completed a joint research program focused on improving the performance, maneuverability, and operating characteristics of rotorcraft by integrating the flight and propulsion controls. The background of the program, its supporting programs, its goals and objectives, and an approach to accomplish them are discussed. Results of the modern control governor design of the General Electric T700 engine and the Rotorcraft Integrated Flight-Propulsion Control Study, which were key elements of the program, are also presented

Rotorcraft flight-propulsion control integration

The NASA Ames and Lewis Research Centers, in conjunction with the Army Research and Technology Laboratories have initiated and completed, in part, a joint research program focused on improving the performance, maneuverability, and operating characteristics of rotorcraft by integrating the flight and propulsion controls. The background of the program, its supporting programs, its goals and objectives, and an approach to accomplish them are discussed. Results of the modern control governor design of the T700 and the Rotorcraft Integrated Flight-Propulsion Control Study, which were key elements of the program, are also presented

Bewertung des Rekuperatorpotenzials eines 300-kW-Turbowellen-Hubschraubermotors

In this thesis, an integrated rotorcraft multidisciplinary simulation framework has been developed to comprehensively evaluate the potential of the rotorcraft adopting a recuperator under various flight conditions as well as at mission levels. Through the execution of multi-objective genetic algorithm (GA) optimization, the Pareto front model is derived qualifying the associated interdependency and trade-off between the fuel saving potential and recuperator weight penalty. The proposed methodology proves to be a computationally efficient tool for the multidisciplinary design and optimization of the recuperated rotorcraft powerplant system.In dieser Arbeit wurde ein integriertes multidisziplinäres Simulationssystem für Drehflügler entwickelt, um das Potenzial des Drehflüglers für den Einsatz eines Rekuperators unter verschiedenen Flugbedingungen sowie auf Missionsebene umfassend zu bewerten. Durch die Ausführung einer Optimierung mit einem genetischen Algorithmus mit mehreren Zielsetzungen (GA) wird das Pareto-Frontmodell abgeleitet, das die damit verbundene Abhängigkeit und den Kompromiss zwischen dem Kraftstoffeinsparpotenzial und der Gewichtsstrafe für den Rekuperator qualifiziert. Die vorgeschlagene Methodik erweist sich als rechnerisch effizientes Werkzeug für die multidisziplinäre Auslegung und Optimierung eines derart modifizierten Triebwerkssystems für Drehflügler

Novel turboshaft engines design and optimisation for rotorcraft applications.

Since the inception of the first gas turbine engines, scientists and aircraft propulsion designers have attempted to improve engine efficiency, size, weight, fuel consumption and power output. In the current scenario, where the conventional gas turbine technology has almost reached its maturity, companies and researchers are starting to seek new engine architectures and novel cycles to comply with the next future aviation challenges. One of the proposed solutions is the implementation of an auxiliary combustion process into the turbines, known as reheated cycle. In the reheated cycle, the gas from an expansion process (through a turbine stage or a whole turbine) is burned before the next expansion. This concept has the potential to increase the specific work, at the same time the thermal efficiency is improved. Numerous investigations have been performed on the application of the reheated cycle to turbojet and civil turbofan engines. However, no studies are published about the potential application of this technology in rotorcraft powerplants. Therefore, the aim of this research project is to accomplish an exhaustive analysis and optimisation of a reheated turboshaft engine in terms of thermal efficiency and engine weight. The optimal engines identified at this stage are to be evaluated at mission level in order to assess the final impact on mission fuel abatement. For this matter, models for the performance simulation of a representative helicopter and for the thermodynamic analysis of the engine architectures have been developed and validated against experimental data. An additional module estimating the cooling flows fluctuation with the engine cycle parameters has been coupled with the engine performance model. Finally, a procedure for the sizing of reheated turboshaft engines have been developed and validated by the author. The different models have been built after a reference Twin-Engine Medium (T EM) helicopter, the Sikorsky UH-60A Black Hawk helicopter powered by two General Electric T700-GE-700 turboshaft engines. The aforementioned models have been integrated in a common simulation framework for the completion of a preliminary parametric analysis showing the sensitivity of the reheated configurations to changes in the engine design variables. In particular, three distinct reheated architectures have been investigated together with a conventional engine for comparison purposes. The individual response of each engine architecture has been discussed. The deployed framework has been then coupled with a Genetic Algorithm optimiser to efficiently seek for the best candidate engines in terms of total weight and Specific Fuel Consumption at cruise (SFCcr). At this step, Response Surface Models (RSMs) have been developed for the fast estimation of engine weight and coupled with the optimiser routine. It has been proven that the reheated engines have the potential to reduce engine mass and increase thermal efficiency in comparison with the baseline engine, although the optimal conventional engine still shows superior performance under the conditions simulated. This conclusion has been also confirmed by the results obtained at mission level. A final mission level multi-objective optimisation has been conducted for the conventional engine targeting the minimisation of the overall mission fuel burn and NOᵪ emissions. A representative model for the prediction of the combustor emissions production has been developed and validated for this purpose. The trade-off existing between fuel efficiency and pollutant depletion has been highlighted along with the potential benefits in block fuel and NOᵪ inventory.PhD in Aerospac

Aeronautical Engineering: A special bibliography with indexes, supplement 62

This bibliography lists 306 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1975

Aeronautical engineering: A continuing bibliography with indexes (supplement 219)

This bibliography lists 586 reports, articles, and other documents introduced into the NASA scientific and technical information system in October, 1987

Aeronautical Engineering: A continuing bibliography with indexes

This bibliography lists 512 reports, articles and other documents introduced into the NASA scientific and technical information system in April 1982

Aeronautical Engineering: A continuing bibliography with indexes, supplement 134

This bibliography lists 387 reports, articles, and solar documents introduced into the NASA scientific and technical information system in March 1981

Aeronautical engineering: A continuing bibliography with indexes (supplement 271)

This bibliography lists 666 reports, articles, and other documents introduced into the NASA scientific and technical information system in October, 1991. Subject coverage includes design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Aeronautical Engineering: A special bibliography with indexes, supplement 54

This bibliography lists 316 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1975