Passive Morphing in Aerospace Composite Structures

2021 ◽  
Vol 889 ◽  
pp. 53-58
Author(s):  
Prakash Jadhav

Attempts to add the advanced technologies to aerospace composite structures like fan blade have been on in recent times to further improve its performance. As part of these efforts, it has been proposed that the blade morph feasibility could be studied by building and optimizing asymmetric lay up of composite plies inside the blade which will help generate enough passive morphing between max cruise and climb conditions of the flight. This will have a direct efficiency (Specific Fuel Consumption) benefit. This research describes the various ideas that were tried using in house-developed lay-up optimization code and Ansys commercial software to study the possibility of generating enough passive morphing in the blade. In the end, this report concludes that the required degree of passive morphing could not be generated using various ideas with passive morphing technology and only up to some extent of morphing is shown to be feasible using the technologies used here.

Author(s):  
Fernando Colmenares ◽  
Daniele Pascovici ◽  
Stephen Ogaji ◽  
Pericles Pilidis

Aviation plays a key role in economic prosperity and quality of lifestyle. However there is an increasing concern that current trends of consumption of natural resources cannot continue. It is imperative that major targeted investments are made into economical and reliable environment friendly propulsion and power solutions. A significant amount of this investment will be in the aerospace sector. A well utilised civil aircraft may burn more than 2000 times its weight in fuel during its life, so the examination of the propulsion system is essential from an environmental point of view. A preliminary parametric study for geared, intercooled and/or recuperated turbofan for short range commercial transport applications has been performed with regard to fuel consumption and emissions. A high by-pass ratio turbofan engine with performance characteristics and technology from the year 2000 was set up as a baseline. The results offer interesting qualitative comparisons showing that, for instance, a recuperated engine will yield a lower fuel burn for lower OPR values. An engine with a mid-compressor intercooler may give significant reduction of NOx emissions whilst increasing the amount of CO2. The intercooled and recuperated cycle offers higher thermal efficiencies (i.e. higher fuel consumption benefit) in comparison to other cycles at medium OPR values; therefore NOx formation may be reduced as well as the engine core weight. Additionally, the inherent advantage of high BPR against low BPR turbofans in terms of SFC is evident (GTF). Clearly, therefore, an increase of BPR is an inevitable solution for the reduction of both fuel consumption and the level of noise produced, however this may involve NOx and integration penalties, hence innovative cycles (e.g.: ICR) and state of the art combustor technology (e.g.: PERM and LDI combustors) must be considered. This is first on the series of work that would be carried out on the cycles being proposed in this paper. Further work on the issues of weight, noise, aircraft performance, other emissions, economics, etc, so-called a multidisciplinary objective assessment, would be published when completed. Also, at this time the design has been limited to take-off being the point of maximum aerodynamic performance. An extension to full mission is currently under investigation.


Author(s):  
Andy M. Williams ◽  
Alan T. Baker ◽  
Ramkumar Vijayakumar

Air systems are becoming increasingly complex and important for achieving IC engine performance and emission targets. Turbocharging is becoming increasingly prevalent enabling high power density engines, improved pumping work and improved fuel economy. Turbo-compounding allows turbine energy to contribute directly to crankshaft work with the aim of improving fuel economy. Turbodischarging allows turbine energy to be used to extract exhaust gases from the engine reducing pumping work and residual gas fraction while simultaneously increasing the amount of energy that can be recovered by the turbine(s). The optimum energy flow split between turbocharging, turbodischarging and turbocompounding has not previously been explored. This paper presents results of a study investigating the potential of tri-directional energy flow optimisation in comparison to uni-directional optimisation and bi-directional optimisation (i.e. using all three approaches, any two approaches or turbocharging alone). Thermodynamic analysis demonstrates the potential of bi-directional optimisation to achieve realistically 4% fuel consumption benefit for both turbocharging and discharging, and turbocharging and compounding on gasoline engines from pumping work alone. The peak benefit of the former occurs at a slightly lower engine torque than the latter as the energy cost of a unit fuel consumption benefit with turbodischarging increases with increasing levels of exhaust depressurisation. The Tri-directional optimisation shows a complex optimum position utilising all three systems and achieving a realistic peak benefit of 4.4% fuel consumption improvement. Optimisation on diesel engine architectures suggests significantly lower potential in the order of 1% benefit while lean burn gas engines showed up to 2.6% benefit. Sensitivity to compression and expansion efficiencies, exhaust manifold volume and system temperatures are presented. The future hybridisation of IC engine air systems may enable energy storage. This paper offers fundamental insight into the marginal fuel cost of capturing energy from the three systems and the marginal fuel value of using stored energy in the air system.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Dinc ◽  
Yousef Gharbia

Abstract In this study, exergy efficiency calculations of a turboprop engine were performed together with main performance parameters such as shaft power, specific fuel consumption, fuel flow, thermal efficiency etc., for a range of flight altitude (0–14 km) and flight speeds (0–0.6 Mach). A novel exergy efficiency formula was derived in terms of specific fuel consumption and it is shown that these two parameters are inversely proportional to each other. Moreover, a novel exergy efficiency and thermal efficiency relation was also derived. The relationship showed that these two parameters are linearly proportional to each other. Exergy efficiency of the turboprop engine was found to be in the range of 23–33%. Thermal efficiency of the turboprop engine was found to be around 25–35%. Exergy efficiency is higher at higher speeds and altitude where the specific fuel consumption is lower. Conversely, exergy efficiency of the engine is lower for lower speeds and altitude where the specific fuel consumption is higher.


Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).


Author(s):  
Teja Gonguntla ◽  
Robert Raine ◽  
Leigh Ramsey ◽  
Thomas Houlihan

The objective of this project was to develop both engine performance and emission profiles for two test fuels — a 6% water-in-diesel oil emulsion (DOE-6) fuel and a neat diesel (D100) fuel. The testing was performed on a single cylinder, direct-injection, water-cooled diesel engine coupled to an eddy current dynamometer. Output parameters of the engine were used to calculate Brake Specific Fuel Consumption (BSFC) and Engine Efficiency (η) for each test fuel. DOE-6 fuels generated a 24% reduction in NOX and a 42% reduction in Carbon Monoxide emissions over the tested operating conditions. DOE-6 fuels presented higher ignition delays — between 1°-4°, yielded 1%–12% lower peak cylinder pressures and produced up to 5.5% lower exhaust temperatures. Brake Specific Fuel consumption increased by 6.6% for the DOE-6 fuels as compared to the D100 fuels. This project is the first research done by a New Zealand academic institution on water-in-diesel emulsion fuels.


Author(s):  
A A Abdel-Rahman ◽  
M K Ibrahim ◽  
A A Said

This paper discusses the possibility of improving the part load performance of diesel electric turbocharged engines operating at constant speed conditions. A sequential turbocharged system is proposed, where the compressors are connected In series. The study focused on two turbocharged diesel–electric generating sets existing at Ameria Petroleum Refining Company in Alexandria, Egypt. The results of the prediction showed that, at part load, both the maximum pressure and temperature were increased, and the brake specific fuel consumption was reduced considerably (by about 10 per cent).


Author(s):  
Adel Ghenaiet

This paper presents an evolutionary approach as the optimization framework to design for the optimal performance of a high-bypass unmixed turbofan to match with the power requirements of a commercial aircraft. The parametric analysis had the objective to highlight the effects of the principal design parameters on the propulsive performance in terms of specific fuel consumption and specific thrust. The design optimization procedure based on the genetic algorithm PIKAIA coupled to the developed engine performance analyzer (on-design and off-design) aimed at finding the propulsion cycle parameters minimizing the specific fuel consumption, while meeting the required thrusts in cruise and takeoff and the restrictions of temperatures limits, engine size and weight as well as pollutants emissions. This methodology does not use engine components’ maps and operates on simplifying assumptions which are satisfying the conceptual or early design stages. The predefined requirements and design constraints have resulted in an engine with high mass flow rate, bypass ratio and overall pressure ratio and a moderate turbine inlet temperature. In general, the optimized engine is fairly comparable with available engines of equivalent power range.


2015 ◽  
Vol 82 ◽  
pp. 96-102 ◽  
Author(s):  
Sebastiano Breda ◽  
Fabio Berni ◽  
Alessandro d’Adamo ◽  
Francesco Testa ◽  
Elena Severi ◽  
...  

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