An Impact Assessment of Degrading Elements on the Overall Benefit of Aircraft with Hybrid Laminar Flow Control

Pohya, Ahmad Ali; Wicke, Kai

doi:10.2514/6.2019-1589

Cited by 4 publications

(8 citation statements)

References 9 publications

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“…4 Laminar effectivity [%] in dependence of the number of insects on the aircraft. Adapted from [18] laminar flow area without insect contamination is determined. Second, insects are placed iteratively and randomly on the leading edge of the wing, the tail plane, and the engine nacelle, which reduces the laminar flow area.…”

Section: Impact Of Insect Contaminationmentioning

confidence: 99%

“…The laminar effectivity for the all-electric air taxi is scaled by the wingspan. In contrast to Pohya [18] and Wicke [17], in this study the number of insects on the aircraft is not constant for each flight cycle but is estimated separately for each mission and investigation time. The number of insects on the aircraft is depending on the season, and cross of in Figure 5 insect ρ ins constant to a height of 200 m above ground level and decreases exponentially to zero at height of 1800 m above ground level [19].…”

Section: Impact Of Insect Contaminationmentioning

confidence: 99%

“…For example, bug wiper systems are used to remove insects from the leading edge of glider wings during flight to increase the performance [16]. Studies by Wicke [17] and Pohya [18] on the impact of insect contamination on the effectiveness of natural laminar flow and hybrid laminar flow control applications show a significant negative effect on the energy consumption of commercial transport aircraft. The method developed by Wicke [17] and Pohya [18] for the determination of laminar effectiveness in dependence of the insect contamination is adapted in the following for the application case of short range operation of small aircraft.…”

Section: Impact Of Insect Contaminationmentioning

confidence: 99%

“…The aim is to determine the drag increase due to insect contamination. As shown in Figure 3 these turbulent wedge is assumed to be 15° [18]. With the increased turbulent flow area and the decreased laminar flow area the drag is increased.…”

Section: Impact Of Insect Contaminationmentioning

confidence: 99%

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A method to determine the availability and performance of air taxis in real weather conditions

Wortmann,

Hagemann,

Stumpf

2024

Preprint

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The success of an on-demand air taxi transportation system depends, in part, on its availability during daily operations. To further analyze such a system, this paper introduces a method for determining the availability and performance of air taxis under real weather conditions. Therefore, the integration of weather data from the European Center for Medium-Range Weather Forecast (ECMWF) and real trajectories into the mission analysis tool of the aircraft preliminary design software Multidisciplinary Integrated Conceptual Aircraft Design and Optimization Environment (MICADO) for small aircraft is carried out for the first time. This allows the estimation of the performance of air taxis under real weather and operating conditions already at the aircraft preliminary design stage and potential technical deficits can be identified at an early design stage. Two single engine, fixed-wing air taxi designs, one with a hybrid-electric powertrain and one with an all-electric powertrain, are investigated in this paper. The results show that the availability is strongly limited by the visual meteorological conditions minima (VMC minima). The maximum availability of the short reference flight route between Nuernberg and Egelsbach is 41.78 % and the maximum availability of the long reference flight route between Augsburg and Moenchengladbach is 20.48 %. The availability of the hybrid-electric air taxi is not limited, as all investigated flights under sufficient VMC can be performed with this aircraft while complying with the required reserves. However, the availability of the all-electric air taxis is limited due to its performance. Because of adverse wind conditions, not all flights investigated under sufficient VMC can be performed with the all-electric air taxi while complying with the required reserves, as the energy demand is too high. For the all-electric air taxi, a 13.2 % increase in gravimetric battery energy density (GBED) is needed to ensure sufficient performance. The findings indicate the necessity of considering the real operating conditions in the preliminary design of small aircraft. The methodology outlined in this paper assists in enhancing the robustness of preliminary aircraft designs.

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Section: Impact Of Insect Contaminationmentioning

confidence: 99%

Section: Impact Of Insect Contaminationmentioning

confidence: 99%

Section: Impact Of Insect Contaminationmentioning

confidence: 99%

Section: Impact Of Insect Contaminationmentioning

confidence: 99%

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A method to determine the availability and performance of air taxis in real weather conditions

Wortmann,

Hagemann,

Stumpf

2024

Preprint

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“…It models the lifecycle of an aircraft from its order through decades of operation and maintenance until its end of life, enabling not only the evaluation of the overall economic effectiveness, but also in-depth operational insights. An exemplary application can be found in (Pohya & Wicke, 2019). In its current status, LYFE considers one aircraft (and one set of engines) at a time, whereas the next update will incorporate fleet wide operations including a management of spare parts and engines (described in Section 3.2) and the methodology as shown in (Pohya, Wehrspohn, & Wicke, 2020).…”

Section: Lifecycle Simulation Framework Lyfementioning

confidence: 99%

An Assessment of the Economic Viability of Engine Wash Procedures on the Lifecycle Costs of an Aircraft Fleet.

Wehrspohn¹,

Pohya

Wicke³

2021

PHME_CONF

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Aircraft operators find themselves in a highly complex and competitive environment in which the economic pressure on companies is constantly increasing. In addition, annual air traffic is expected to increase by 4-5% (despite the Covid-19 pandemic), which requires significant improvements of aircraft efficiency. To address this on European and global scale, long-term economic and ecologic goals have been defined in the "Flightpath 2050" by the European Commission. One way to reduce both operating costs and environmental impact is to reduce aircraft fuel consumption. Regularly performed engine washes can reduce the accumulation of dirt and debris in the engine and partially restore the performance degradation as well as lower the wear and tear of the engine. This results in lower exhaust gas temperature and a slower aging engine with longer intervals between required maintenance events. Most engine wash studies have drawn their system boundary around the engine and consider only the one-time improvements that result from a wash. Long term effects that build on these improvements, such as changes in maintenance and replacement cycles, are usually not considered. Few studies are available that extend their system boundary and consider changes in maintenance costs. Yet the value of engine wash processes is often quantified on an insufficient setting, especially when environmental conditions and fleet effects are neglected. To estimate the overall benefit and assess the impact on lifecycle costs, a full evaluation of engine wash within an entire fleet is required and fleet effects such as the possibility of downrating the engine for a smaller aircraft should be considered. The aim of this work is to quantify the true value of engine wash procedures considering both physical constraints as well as operational fleet wide considerations. Using discrete event simulations at fleet level, a detailed investigation of the primary and secondary effects and a quantification of lifecycle costs will be performed. Particular attention will be paid to the influence on maintenance costs as well as the economic effect of increased time on wing. With the help of an improved environmental modeling and with the consideration of fleet effects, a holistic statement is possible. To investigate this problem, a lifecycle costing method, named LYFE, developed by DLR will be used. LYFE uses discrete event simulation to model the product lifecycle from order to operation until disposal of an aircraft fleet. For this analysis the tool will be extended to separate the lifecycles of the engines and those of the aircraft, so the engines can change the aircraft and the downrating of the engine for a smaller aircraft can be modeled. In order to represent the contamination and the performance degradation of the engines as realistically as possible, data on the outside air temperature, dust, pollution and other particles in certain regions at the various airports are also included in the tool. Furthermore, the option of derating the engine’s thrust is considered. The lifecycle of two different fleets will be simulated and studied. The difference between the two fleets is that the baseline fleet does not perform any engine washes, while the study fleet performs engine washes. Both fleets consist of different types of aircraft, so that downrating of the engines is possible and the entire lifecycles of the aircraft can be mapped. The evaluation follows two approaches: firstly, the engine wash is carried out and examined regularly; secondly, the intervals at which the engine wash is carried out are optimized in such a way that the lifecycle costs of the fleet are as low as possible. In both cases the number of engines necessary to operate the fleet will be the basis for an overall statement. With this holistic view of how engine washes within a fleet affect its lifecycle costs, a much more realistic statement about this on-wing maintenance action is possible.

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Introducing variance-based global sensitivity analysis for uncertainty enabled operational and economic aircraft technology assessment

Pohya

Wicke

Kilian

2022

Aerospace Science and Technology

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An Impact Assessment of Degrading Elements on the Overall Benefit of Aircraft with Hybrid Laminar Flow Control

Cited by 4 publications

References 9 publications

A method to determine the availability and performance of air taxis in real weather conditions

A method to determine the availability and performance of air taxis in real weather conditions

An Assessment of the Economic Viability of Engine Wash Procedures on the Lifecycle Costs of an Aircraft Fleet.

Introducing variance-based global sensitivity analysis for uncertainty enabled operational and economic aircraft technology assessment

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