Wing Thickness Optimization for Box Wing Aircraft

2020 ◽  
Vol 14 (2) ◽  
pp. 242-249
Author(s):  
Jemitola P. Olugbeji ◽  
Okafor E. Gabriel ◽  
Godwin Abbe
Keyword(s):  
Performance Studies ◽  
Search Algorithm ◽  
Operating Cost ◽  
Research Work ◽  
Sweep Angle ◽  
Second Stage ◽  
Direct Operating Cost ◽  
Aircraft Performance ◽  
Optimization Methodology ◽  
Aircraft Configurations

Background: In the interest of improving aircraft performance, studies have highlighted the benefits of Box wing configurations over conventional cantilever aircraft configuration. Generally, the greater an aircraft's average thickness to chord ratio (τ), the lower the structural weight as well as volumetric capacity for fuel. On the other hand, the lower the ., the greater the drag reduction. A review of patents related to the Box-wing aircraft was carried out. While methodologies for optimizing wing thickness of conventional aircrafts have been studied extensively, limited research work exist on the methodology for optimizing the wing thickness to chord ratio of the Box wing aircraft configurations. Methods: To address this gap, in this work, a two stage optimization methodology based on gradient search algorithm and regression analysis was implemented for the optimization of Box wing aircrafts wing thickness to chord ratio. The first stage involved optimizing the All Up Mass (AUM), Direct Operating Cost (DOC) and Zero Lift Drag Coefficients (CDO), with respect to the aft and fore sweep angle for some selected τ values. At the second stage, a suitability function (γ) was optimized with respect to the aft and fore sweep angle for some selected τ values. A comparative study was further carried out using the proposed methodology on similar size cantilever wing aircraft. Results: From the result, an optimal τ value was reached. Also the τ value for the cantilever aircraft found based on the proposed methodology was similar to the true τ value of the adopted aircraft, thereby validating the methodology. Conclusion: Based on the optimal τ value reached from this work, the Box wing aircraft are suitable for thin airfoils.

On the Optimal Precoder Design for Energy-Efficient and Secure MIMO Systems

2017 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Tung T. Vu ◽  
Ha Hoang Kha
Keyword(s):  
Energy Efficiency ◽  
Mimo Systems ◽  
Search Algorithm ◽  
Multiple Input Multiple Output ◽  
Research Work ◽  
Computational Cost ◽  
Optimal Solution ◽  
Secrecy Rate ◽  
Highly Nonlinear ◽  
Precoder Design

In this research work, we investigate precoder designs to maximize the energy efficiency (EE) of secure multiple-input multiple-output (MIMO) systems in the presence of an eavesdropper. In general, the secure energy efficiency maximization (SEEM) problem is highly nonlinear and nonconvex and hard to be solved directly. To overcome this difficulty, we employ a branch-and-reduce-and-bound (BRB) approach to obtain the globally optimal solution. Since it is observed that the BRB algorithm suffers from highly computational cost, its globally optimal solution is importantly served as a benchmark for the performance evaluation of the suboptimal algorithms. Additionally, we also develop a low-complexity approach using the well-known zero-forcing (ZF) technique to cancel the wiretapped signal, making the design problem more amenable. Using the ZF based method, we transform the SEEM problem to a concave-convex fractional one which can be solved by applying the combination of the Dinkelbach and bisection search algorithm. Simulation results show that the ZF-based method can converge fast and obtain a sub-optimal EE performance which is closed to the optimal EE performance of the BRB method. The ZF based scheme also shows its advantages in terms of the energy efficiency in comparison with the conventional secrecy rate maximization precoder design.

scholarly journals Aero-Structural Optimization of Joined-Wing Aircraft

2017 ◽  
Vol 2017 (4) ◽  
pp. 48-63
Author(s):  
Miłosz Kalinowski
Keyword(s):  
Structural Optimization ◽  
Search Algorithm ◽  
Optimization Methods ◽  
Global Search ◽  
Preliminary Design ◽  
Electric Aircraft ◽  
Modular Algorithm ◽  
Lifting Surfaces ◽  
Joined Wing ◽  
Aircraft Configurations

Abstract Joined-wing aircraft due to its energy characteristics is a suitable configuration for electric aircraft when designed properly. However, because of the specific for this aircraft phenomenons (e.g. static indeterminacy of structure, aerodynamic interference of lifting surfaces) it demands more complicated methods to model its behavior than a traditional aircraft configurations. For these reasons the aero-structural optimization process is proposed for joined-wing aircrafts that is suitable for preliminary design. The process is a global search, modular algorithm based on automatic geometry generator, FEM solver and aerodynamic panel method. The range of aircraft was assumed as an objective function. The algorithm was successfully tested on UAV aircraft. The improvement of 19% of total aircraft range is achieved in comparison to baseline aircraft. Time of evaluation of this global search algorithm is similar to the time characteristic for local optimization methods. It allows to reduce the time and costs of preliminary design of joined-wing.

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

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.

scholarly journals Variable cant angle winglets for improvement of aircraft flight performance

Meccanica ◽  
2020 ◽  
Vol 55 (10) ◽  
pp. 1917-1947
Author(s):  
J. E. Guerrero ◽  
M. Sanguineti ◽  
K. Wittkowski
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Fuel Efficiency ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Sweep Angle ◽  
Aircraft Flight ◽  
Induced Drag ◽  
Aircraft Performance

Abstract Traditional winglets are designed as fixed devices attached at the tips of the wings. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving aircraft performance and fuel efficiency. However, because winglets are fixed surfaces, they cannot be used to control lift-induced drag reductions or to obtain the largest lift-induced drag reductions at different flight conditions (take-off, climb, cruise, loitering, descent, approach, landing, and so on). In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different flight phases. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle on the performance of a benchmark wing at Mach numbers of 0.3 and 0.8395. The results obtained demonstrate that by adjusting the cant angle, the aerodynamic performance can be improved at different flight conditions.

Large-scale economic load dispatch using squirrel search algorithm

2020 ◽  
Vol 14 (6) ◽  
pp. 1351-1380
Author(s):  
Sakthivel V.P. ◽  
Suman M. ◽  
Sathya P.D.
Keyword(s):  
Power Plants ◽  
Large Scale ◽  
Optimization Problems ◽  
Search Algorithm ◽  
Optimization Technique ◽  
Research Work ◽  
Superior Performance ◽  
Economic Load Dispatch ◽  
Fuel Cost ◽  
Content Type

Purpose Economic load dispatch (ELD) is one of the crucial optimization problems in power system planning and operation. The ELD problem with valve point loading (VPL) and multi-fuel options (MFO) is defined as a non-smooth and non-convex optimization problem with equality and inequality constraints, which obliges an efficient heuristic strategy to be addressed. The purpose of this study is to present a new and powerful heuristic optimization technique (HOT) named as squirrel search algorithm (SSA) to solve non-convex ELD problems of large-scale power plants. Design/methodology/approach The suggested SSA approach is aimed to minimize the total fuel cost consumption of power plant considering their generation values as decision variables while satisfying the problem constraints. It confers a solution to the ELD issue by anchoring with foraging behavior of squirrels based on the dynamic jumping and gliding strategies. Furthermore, a heuristic approach and selection rules are used in SSA to handle the constraints appropriately. Findings Empirical results authenticate the superior performance of SSA technique by validating on four different large-scale systems. Comparing SSA with other HOTs, numerical results depict its proficiencies with high-qualitative solution and by its excellent computational efficiency to solve the ELD problems with non-smooth fuel cost function addressing the VPL and MFO. Moreover, the non-parametric tests prove the robustness and efficacy of the suggested SSA and demonstrate that it can be used as a competent optimizer for solving the real-world large-scale non-convex ELD problems. Practical implications This study has compared various HOTs to determine optimal generation scheduling for large-scale ELD problems. Consequently, its comparative analysis will be beneficial to power engineers for accurate generation planning. Originality/value To the best of the authors’ knowledge, this manuscript is the first research work of using SSA approach for solving ELD problems. Consequently, the solution to this problem configures the key contribution of this paper.

Next Generation Turboprop Gearboxes

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.

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

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.

Future Aero-Engines’ Optimisation for Minimal Operating Costs

2008 ◽  
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.

scholarly journals Cruise Flight Performance Optimization for Minimizing Green Direct Operating Cost

2019 ◽  
Vol 11 (14) ◽  
pp. 3899 ◽  
Author(s):  
Tian ◽  
Wan ◽  
Ye ◽  
Xing
Keyword(s):  
Environmental Effects ◽  
Performance Optimization ◽  
Meteorological Data ◽  
Operating Cost ◽  
Numerical Test ◽  
Flight Performance ◽  
Time Dynamic ◽  
Direct Operating Cost ◽  
Greenhouse Effects ◽  
Cruise Flight

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.

Optimum Conditions for the Operation of Airline Aircraft

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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