Cruise Flight Performance Optimization for Minimizing Green Direct Operating Cost

To cope with the environmental impact of aviation and pollution problems in the future, airlines need to assess environmental impacts and offer countermeasures in advance. In order to measure the influence of environment on the airlines’ operational costs, this paper establishes an aircraft green direct operating cost (GDOC) model to quantify adverse environmental effects, such as air pollution and greenhouse effects, into the direct operating cost (DOC). Furthermore, fuel consumption, flight time, and distance in the cruising stage account for about 80% of the entire flight mission, and optimizing cruise flight performance can contribute greatly to reduce GDOC. Therefore, this paper sets up an optimal control model to minimize GDOC, establishes a discrete time dynamic system for optimizing the cruise altitude and speed profiles, and searches the optimal results by using dynamic programming. Besides, as meteorological conditions affect aircraft aerodynamics, fuel flow rate, contrail formation, and so on, this paper analyzes meteorological uncertainty by using historic meteorological data. Finally, a route is selected as an example, and the rationality of the optimal results is proven by comparing GDOC with DOC. The results and discussion of the numerical test also show that environmental effects on aircraft operation can be reduced significantly by adopting GDOC as the optimization objective, especially the contrail cost, and the step-climb cruise mode can further reduce GDOC effectively.

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Enabling the potential of hybrid electric propulsion through lean-burn-combustion turbofans

Journal of the Global Power and Propulsion Society ◽

10.33737/jgpps/140592 ◽

2021 ◽

Vol 5 ◽

pp. 164-176

Author(s):

Stavros Vouros ◽

Mavroudis Kavvalos ◽

Smruti Sahoo ◽

Konstantinos Kyprianidis

Keyword(s):

Electric Propulsion ◽

Direct Injection ◽

Operating Cost ◽

Pollutant Emissions ◽

Civil Aviation ◽

Lean Burn ◽

Lean Direct Injection ◽

Direct Operating Cost ◽

Hybrid Electric ◽

The Impact

Hybrid-electric propulsion has emerged as a promising technology to mitigate the adverse environmental impact of civil aviation. Boosting conventional gas turbines with electric power improves mission performance and operability. In this work the impact of electrification on pollutant emissions and direct operating cost of geared turbofan configurations is evaluated for an 150-passenger aircraft. A baseline two-and-a-half-shaft geared turbofan, representative of year 2035 entry-into-service technology, is employed. Parallel hybridization is implemented through coupling a battery-powered electric motor to the engine low-speed shaft. A multi-disciplinary design space exploration framework is employed comprising modelling methods for multi-point engine design, aircraft sizing, performance and pollutant emissions, mission and economic analysis. A probabilistic approach is developed considering uncertainties in the evaluation of direct operating cost. Sensitivities to electrical power system technology levels, as well as fuel price and emissions taxation are quantified at different time-frames. The benefits of lean direct injection are explored along short-, medium-, and long-range missions, demonstrating 32% NO<italic><sub>x</sub></italic> savings compared to traditional rich-burn, quick-mix, lean-burn technologies in short-range operations. The impact of electrification on the enhancement of lean direct injection benefits is investigated. For hybrid-electric powerplants, the take-off-to-cruise turbine entry temperature ratio is 2.5% lower than the baseline, extending the corresponding NO<italic><sub>x</sub></italic> reductions to the level of 46% in short-range missions. This work sheds light on the environmental and economic potential and limitations of a hybrid-electric propulsion concept towards a greener and sustainable civil aviation.

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Flight Performance Optimization of a Multi-Lift Rotorcraft Formation

AIAA Atmospheric Flight Mechanics Conference ◽

10.2514/6.2017-1638 ◽

2017 ◽

Author(s):

Jacob Enciu ◽

Joseph F. Horn

Keyword(s):

Performance Optimization ◽

Flight Performance

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Next Generation Turboprop Gearboxes

Volume 2: Aircraft Engine; Marine; Microturbines and Small Turbomachinery ◽

10.1115/82-gt-236 ◽

1982 ◽

Author(s):

W. L. McIntire ◽

D. A. Wagner

Keyword(s):

Operating Cost ◽

Past Experience ◽

Reduction Ratio ◽

Next Generation ◽

Propulsion Systems ◽

Aircraft Systems ◽

General Arrangement ◽

Significant Interest ◽

Direct Operating Cost ◽

New Generation

A new generation of fuel-efficient turboprop propulsion systems is under consideration now that fuel is a significant portion of the direct operating cost of aircraft. Systems in the 5000- to 15,000-hp (3730- to 11,185-kW) range that use conventional propellers or the new propfan are being studied. Reduction gearing for this next generation of turboprops is of significant interest due to new requirements for cruise speed life, and reliability. Detroit Diesel Allison’s past experience with the T56 family of turboprop reduction gearboxes is recounted. Probable requirements of the next generation of reduction gearboxes are discussed since new requirements for gearboxes combined with past experience should determine the profile of the next generation of gearboxes. A discussion of gearbox general arrangement and its impact on airframe installation is included, along with comments on reduction ratio, gear arrangement, accessory drives, reliability goals, and probable technology needs.

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Automated Optimum Design of Refrigerated Warehouses

Journal of Mechanical Design ◽

10.1115/1.3454113 ◽

1979 ◽

Vol 101 (4) ◽

pp. 633-639

Author(s):

B. D. Gupta ◽

S. S. Rao

Keyword(s):

Optimum Design ◽

Meteorological Data ◽

Operating Cost ◽

Building Envelope ◽

Penalty Function Method ◽

Functional Requirements ◽

Existing Building ◽

Total Cost ◽

Initial Cost ◽

Average Maximum

The main consideration in the design of refrigerated commercial warehouses, apart from energy required for operation, is the total cost (initial plus operating costs). There is no simple explicit relation between the total cost and the energy required to maintain the desired inside conditions. Qualitatively, one feels that a design involving less initial cost requires larger energy input and hence a higher operating cost. With limited energy resources, it is necessary to conserve energy or use it optimally. A unified approach to find the optimal combination of initial cost and operating cost (energy) is presented in this paper. Since the thickness of insulation is one of the important factors to be considered in reducing the external load and hence the energy requirements, the optimum building envelope and insulation thicknesses are found for a specified volume and location by using the interior penalty function method of optimization. The procedure outlined in this paper can be used for new as well as existing building to fulfill the functional requirements optimally and thus conserve the energy to the greatest possible extent. For the computation of heat gain, the design day, based on the average maximum solar air temperature computed from the hourly meteorological data, is chosen. The resulting computer program is used to find the effect of some of the parameters like wall thickness, type of insulation, orientation of building and economics model on the optimum design.

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Application of the Geared Turbofan With Constant Volume Combustor on Short-Range Aircraft: A Feasibility Study

Volume 4: Cycle Innovations; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine ◽

10.1115/gt2009-59096 ◽

2009 ◽

Author(s):

Fernando Colmenares Quintero ◽

Rob Brink ◽

Stephen Ogaji ◽

Pericles Pilidis ◽

Juan Carlos Colmenares Quintero ◽

...

Keyword(s):

Feasibility Study ◽

Short Range ◽

Operating Cost ◽

Constant Volume ◽

Superior Performance ◽

Wave Rotor ◽

Environmental Aspects ◽

Direct Operating Cost ◽

Combustion Technology ◽

Further Development

Recently a considerable effort was made to understand the gas- and thermodynamics of wave rotor combustion technology. Pressure-gain combustors potentially have superior performance over conventional combustors due to their unsteady flow behaviour. Wave rotor combustion provides semi-constant volume combustion and could be integrated in the steady-flow gas turbine. However, a feasibility study to assess the economical and environmental aspects of this concept has not been conducted for short-range missions. Preliminary Multidisciplinary Design Framework was developed to assess novel and radical engine cycles. The tool comprises modules to evaluate noise, emissions and environmental impact. Uncertainty can be accounted for with Monte Carlo simulation. The geared turbofan with constant volume combustor is simulated and benchmarked against a baseline geared turbofan engine. Results indicate that the former complies with CAEP/6 and FAR Part 36 regulations for noise and emissions. Furthermore, acquisition cost of the engine is higher, but engine direct operating cost decreases by 25.2%. The technology requires further development to meet future noise and emissions requirements.

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Future Aero-Engines’ Optimisation for Minimal Operating Costs

Volume 2: Controls, Diagnostics and Instrumentation; Cycle Innovations; Electric Power ◽

10.1115/gt2008-50127 ◽

2008 ◽

Cited By ~ 1

Author(s):

Fernando Colmenares ◽

Daniele Pascovici ◽

Stephen Ogaji ◽

Pericles Pilidis ◽

Alexander Garci´a ◽

...

Keyword(s):

Public Awareness ◽

Operating Cost ◽

Design Tool ◽

Commercial Aircraft ◽

Commercial Aviation ◽

Passenger Traffic ◽

Direct Operating Cost ◽

Promising Solution ◽

Aero Engines ◽

Bypass Ratio

While aircraft environmental performance has been important since the beginnings of commercial aviation, continuously increasing passenger traffic and a rise in public awareness have made aircraft noise and emissions two of the most pressing issues hampering commercial aviation growth today. The focus of this study is to determine the feasibility of vey-high bypass ratio, geared and contra-rotating aero engines (see figures 2–4) for short range commercial aircraft in terms of economics and environment. This involves optimising the engines’ design point to minimise the direct operating cost and evaluating the economic and environmental impact. The results present a great potential benefit of the geared turbofan compared to high BPR one (baseline) to reduce DOC; however this may involve NOx penalties, that is an increase of 11.6% in comparison to the baseline. The CRTF engine seems to be, at least according to the simulations, a very promising solution in terms of environmental and economical performance. This is one on the series of work that would be carried out using the design tool proposed. Further work on the assessment of more radical turbofans at different economical and environmental scenarios would be published when completed.

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Optimum Conditions for the Operation of Airline Aircraft

Journal of the Royal Aeronautical Society ◽

10.1017/s0368393100131554 ◽

1953 ◽

Vol 57 (516) ◽

pp. 823-824

Author(s):

J. M. Stephenson

Keyword(s):

Fuel Consumption ◽

Operating Cost ◽

Practical Case ◽

Optimum Conditions ◽

Realistic Approach ◽

Direct Operating Cost ◽

Usual Concept ◽

Airline Company

In A. H. Stratford's interesting note in the August Journal, he assumes that an airline is presented with an aircraft of given performance, and must decide what is the best range for it to fly. Surely the practical case is the exact opposite: that an operator wishes to carry passengers or freight between two given points, and must choose between perhaps three or four available types of aircraft. Moreover, it is up to the operator to tell the manufacturers which feature he wants improved (e.g. fuel consumption, take-off distance, and so on), when he is ready to order replacements.Secondly, Mr. Stratford wishes to replace the usual concept of direct operating cost per payload ton mile by that of per cent, profit, as a measure of the efficiency of operation over a certain route. While this may be a more realistic approach to the problem of a private airline company, operating over a single route, its merit is not so obvious for the large national or subsidised airlines, which are often required to fly unprofitable routes.

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The PT6 Engine: 30 Years of Gas Turbine Technology Evolution

Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery ◽

10.1115/93-gt-006 ◽

1993 ◽

Cited By ~ 1

Author(s):

M. Badger ◽

A. Julien ◽

A. D. LeBlanc ◽

S. H. Moustapha ◽

A. Prabhu ◽

...

Keyword(s):

Gas Turbine ◽

Low Cost ◽

New Technology ◽

Operating Cost ◽

Weight Ratio ◽

High Standard ◽

Direct Operating Cost ◽

Cost Development ◽

Engine Reliability ◽

Cycle Temperature

The PT6 engine entered service in the mid-1960’s. Since then, application of new technology, has enabled low cost development of engines approaching 1500 KW, the introduction of electronic controls, improved power-to-weight ratio, higher cycle temperature and reduced specific fuel consumption. At the same time, PT6 field experience in business, commuter, helicopter and trainer applications has resulted in engines with low Direct Operating Cost and a reputation for rugged design and a high standard of engine reliability. This paper will highlight some interesting examples of this technical evolution, including the development of electronic controls and the application of the latest 3D aerodynamic and stress analysis to both compressor and turbine components.

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