scholarly journals ECONOMIC AND ECOLOGICAL ASPECTS OF THE USE OF NEW CRYOGENIC AVIATION FUELS

Author(s):  
Alexey Tikhonov

Until recently, the high rates of aircraft engine engineering’s development were ensured by the technological solutions improvement and the desire to approximate as much as possible the ideal thermodynamic cycle of turbojet engines. The traditional fuel for turbojet engines is an aviation kerosene – Jet-A fuel group and their regional analogies. The traditional way of aircraft engines efficiency increasing is a raising of a temperature in front of the high-pressure turbine. New alloys and technologies allow to increase the aircraft engines efficiency to a certain level. Raising the temperature in the combustion chamber by 50 degrees increases the efficiency, which leads to a 5% reduction in fuel consumption. However, this approach is technology limited and does not provide innovative solutions. The aircraft engine engineering’s development tempo in the 21st century continues to accelerate. The main driver of such processes in recent years is the tightening of economic and environmental requirements. Many aircraft manufacturers are actively looking for ways to reach a new qualitative level in terms of turbojet engines economic efficiency and meeting strict environmental requirements. The paper considers the feasibility of using new cryogenic fuels in aircraft turbojet engines, and possible ways for aircraft industry successful development.

1978 ◽  
Author(s):  
A. W. T. Mottram

The industrial gas turbine requires continual improvement in order to increase output and efficiency, to extend its life and to meet fresh environmental requirements. In the compact industrial gas turbine, derived from the aircraft engine, the required improvements are achieved in three ways: (a) new features are incorporated which have been developed to meet the specific requirements of industrial applications, (b) technical improvements developed initially for aircraft engines are applied to existing industrial engines, and (c) new engines developed for aircraft and to a higher technical standard are introduced into industrial service. This paper describes recent improvements to Rolls-Royce compact industrial gas turbines with particular reference to the Olympus C and Olympus 593.


1986 ◽  
Vol 64 (11) ◽  
pp. 2624-2633 ◽  
Author(s):  
Peter F. Major ◽  
Lawrence M. Dill ◽  
David M. Eaves

Three-dimensional interactions between grouped aerial predators (frontal discs of aircraft engines), either linearly arrayed or clustered, and flocks of small birds were studied using interactive computer simulation techniques. Each predator modelled was orders of magnitude larger than an individual prey, but the prey flock was larger than each predator. Expected numbers of individual prey captured from flocks were determined for various predator speeds and trajectories, flock–predator initial distances and angles, and flock sizes, shapes, densities, trajectories, and speeds. Generally, larger predators and clustered predators caught more prey. The simulation techniques employed in this study may also prove useful in studies of predator–prey interactions between schools or swarms of small aquatic prey species and their much larger vertebrate predators, such as mysticete cetaceans.The study also provides a method to study problems associated with turbine aircraft engine damage caused by the ingestion of small flocking birds, as well as net sampling of organisms in open aquatic environments.


1921 ◽  
Vol 25 (123) ◽  
pp. 130-165

In the following paper the writer's aim is to indicate certain possible lines of development and research which his own investigations and preliminary experiments have shown to be at least worthy of serious consideration.If we review the present state of the art we find the position to be substantially as follows :—From a thermodynamic point of view the performance of the modern aero engine has approached so nearly to the ideal obtainable from the cycle on which it operates that there is little scope for improvement.


Author(s):  
Kenro Obuchi ◽  
Fumiaki Watanabe ◽  
Hiroshi Kuroki ◽  
Hiroyuki Yagi ◽  
Kazuyoshi Arai

Ceramic matrix composites (CMCs) have lower density and a higher service temperature limit than nickel based alloys which have been used for turbine components of aircraft engines. These properties of CMCs have the potential to reduce the weight of turbine components and improve turbine thermal efficiency with a higher turbine inlet temperature (TIT). One of the technical issues of the CMC turbine vane is a relatively lower impact resistance than nickel based alloy turbine vanes. There are various previous works about impact resistance of CMCs, but there is little work that assumed actual engine conditions. The objective of this work was to verify the resistance of SiC/SiC CMC turbine vane to the impact phenomena that occur in the actual aircraft engine. The field damage survey was conducted on actual metal turbine vanes of commercial engines overhauled in IHI. The survey made it clear that the typical damage was less-than-0.127-mm-dent at the leading edge. In addition, the dropped weight impact test using the actual turbine airfoil which is made from a nickel based alloy was conducted at ambient temperature. The amount of energy required to make the dent of a certain size that was observed in actual metal turbine vanes was estimated. Then, the dropped weight impact test using the CMC test piece with a leading edge shape was conducted at the impact energy estimated by the metal turbine airfoil. The results showed that the failure mode of the CMC test piece was local damage with dents of a certain size and not a catastrophic failure mode. From this work, the damage to be assumed on CMC vane in actual aircraft engines was identified. As a future task, the effect of the damage to the fatigue capability of CMC turbine vanes needs to be investigated.


Author(s):  
Shubo Yang ◽  
Xi Wang

Limit protection, which frequently exists as an auxiliary part in control systems, is not the primary motive of control but is a necessary guarantee of safety. As in the case of aircraft engine control, the main objective is to provide the desired thrust based on the position of the throttle; nevertheless, limit protection is indispensable to keep the engine operating within limits. There are plenty of candidates that can be applied to design the regulators for limit protection. PID control with gain-scheduling technique has been used for decades in the aerospace industry. This classic approach suggests linearizing the original nonlinear model at different power-level points, developing PID controllers correspondingly, and then scheduling the linear time-invariant (LTI) controllers according to system states. Sliding mode control (SMC) is well-known with mature theories and numerous successful applications. With the one-sided convergence property, SMC is especially suitable for limit protection tasks. In the case of aircraft engine control, SMC regulators have been developed to supplant traditional linear regulators, where SMC can strictly keep relevant outputs within their limits and improve the control performance. In aircraft engine control field, we all know that the plant is a nonlinear system. However, the present design of the sliding controller is carried out with linear models, which severely restricts the valid scope of the controller. Even if the gain scheduling technique is adopted, the stability of the whole systems cannot be theoretically proved. Research of linear parameter varying (LPV) system throws light on a class of nonlinear control problems. In present works, we propose a controller design method based on the LPV model to solve the engines control problem and achieve considerable effectiveness. In this paper, we discuss the design of a sliding controller for limit protection task of aircraft engines, the plant of which is described as an LPV system instead of LTI models. We define the sliding surface as tracking errors and, with the aid of vertex property, present the stability analysis of the closed-loop system on the sliding surface. An SMC law is designed to guarantee that the closed-loop system is globally attracted to the sliding surface. Hot day (ISA+30° C) takeoff simulations based on a reliable turbofan model are presented, which test the proposed method for temperature protection and verify its stability and effectiveness.


2021 ◽  
Vol 850 (1) ◽  
pp. 012010
Author(s):  
S Yuvaraj ◽  
C J Thomas Renald ◽  
A P Senthil Kumar ◽  
K Sadesh ◽  
D Naveen Promoth

Abstract In the current age drones are broadly utilized for different applications in pretty much every field. Because of the disturbing expense of the glow fuel utilized in the RC motors, utilization of the equivalent includes a ton of capital. Adding to it, the current fuel brings about intermittent combustion is in demand of alternate fuel. This paper manages the investigation of existing fuel synthesis and discovering the cost required to dispose of the high capital included, so that considerably more tests and study utilizing the RC Engines 2.5 cc can be completed easily. Methanol and Castor oil Combination is considered as an alternate fuel. The approach includes testing of the fuel to decipher the substance parts and their individual pieces through a progression of tests. Followed by the study of possible additives to enhance the performance of the engine without actually altering the timing intervals. The new creation of the fuel showed up is blended in with extraordinary hardware and the equivalent is tried for essential fuel properties viz., Density, Flash point, Fire point, Calorific value, and so forth The productivity arrangement is made utilizing a pulley instrument and the equivalent is tried for both the energizes. Performance of the R/C aircraft engine was tested with existing glow fuel and the new blend. Results are compared and concluded that the designed blend is a potent alternate fuel for R/C aircraft engines. *Future scope: It can be further tested for its SFC and emission standards. The outcome shows that the new fuel is exceptionally cost productive and the essential substance properties are profoundly improved.


Author(s):  
Henrik von der Haar ◽  
Ulrich Hartmann ◽  
Christoph Hennecke ◽  
Friedrich Dinkelacker ◽  
Joerg R. Seume

Defects in combustion chambers of aircraft engines might have an impact on the reliability of the downstream turbine and the machine’s performance. Detecting failures in the combustion chamber of an aircraft engine during operation may improve the resource management and the availability of the system. Aim of the ongoing research project is to find an approach to evaluate the state of the jet engine by analyzing the temperature and emissions field in the exhaust jet. This investigation is part of the collaborative research center SFB 871. The SFB 871 deals with the improvement of the regeneration process of complex capital goods such as aircraft engines. Maintenance, repair, and overhaul processes would be more efficient if the internal status of the engine would be known while still on the wing before it is disassembled. The feasibility of this approach is investigated for a pilot scaled model combustor, which provides optical access and allows the selection of “defined errors” in the combustor. It consists of an atmospheric tubular combustor with an array of eight premixed swirl burners with a maximum output of 160 kW. The operating conditions of one of the eight burners concerning power and air-fuel ratio, can be controlled. A power distribution between the burners is typical fault in an aircraft combustor and will be investigated in this study. It is observed that it is possible to determine small deviations by measuring density profiles applying a tomographic background-oriented schlieren (BOS) technique behind the combustor. Additionally, particle image velocimetry is used to measure differences in the velocity field of the exhaust gases. This study shows that a minimum power deviation of one burner in an array of a total of eight burners is detectable in the exhaust plane with the above mentioned measurement techniques.


2014 ◽  
Vol 616 ◽  
pp. 126-134 ◽  
Author(s):  
Janka Mihalčová ◽  
Peter Šmeringai

The article deals with the issue of ensuring the reliability of aircraft engines operation via hydraulic fluids properties monitoring. There are presented the results of the hydraulic fluid Aero Shell Fluid 41 (ASF 41) properties evaluation in the hydraulic system of a double-flow turbosupercharged aircraft engine AI-25TL. In the hydraulic fluid, there were observed the quantity and distribution of mechanical particles according to their size in accordance with the ISO Cleanliness Code, ISO 4406.There was also determined kinematic viscosity according to the standard EN ISO 3104+AC. FTIR analysis of the infrared spectrum was used to determine the degradation degree of the hydraulic fluid physical-chemical properties.


Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 461 ◽  
Author(s):  
Etienne Harkemanne ◽  
Olivier Berten ◽  
Patrick Hendrick

In an aircraft engine, some pieces are describing a rotating movement. These parts are in contact with rotating and non-rotating parts through the bearings and gears. The different contact patches are lubricated with oil. During the lifetime of the engine, mechanical wear is produced between the contacts. This wear of the bearings and gears will produce some debris in the oil circuit of the engine. To ensure the effective operation of the aircraft engines, the debris monitoring sensors play a significant role. They detect and collect the debris in the oil. The analysis of the debris can give an indication of the overall health of the engine. The aim of the paper is to develop, design and model an oil test bench to simulate the oil lubrication circuit of an aircraft engine to test two different debris monitoring sensors. The methodology consists of studying the oil lubrication system of the aircraft engine. The first step is to build the oil test bench. Once the oil test bench is functional, tests are performed on the two debris monitoring sensors. A test plan is followed, three sizes of debris, like the type and sizes of debris found in the aircraft engine oil, are injected in the oil. The test parameters are the oil temperature, the oil flow rate and the mass of debris injected. Each time debris is injected, it is detected and caught by the two sensors. The test results given by the two sensors are similar to the mass debris injected into the oil circuit. The two sensors never detect the total mass of debris injected in the oil. On average, 55%–60% of the mass injected is detected and caught by the two sensors. The sensors are very efficient at detecting debris whose size corresponds to the design range parameters of the sensors, but the efficiency falls when detecting debris whose size lies outside this range.


2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Felix Döring ◽  
Stephan Staudacher ◽  
Christian Koch ◽  
Matthias Weißschuh

Airborne particles ingested in aircraft engines deposit on compressor blading and end walls. Aerodynamic surfaces degrade on a microscopic and macroscopic scale. Blade row, compressor, and engine performance deteriorate. Optimization of maintenance scheduling to mitigate these effects requires modeling of the deterioration process. This work provides a deterioration model on blade row level and the experimental validation of this model in a newly designed deposition test rig. When reviewing previously published work, a clear focus on deposition effects in industrial gas turbines becomes evident. The present work focuses on quantifying magnitudes and timescales of deposition effects in aircraft engines and the adaptation of the generalized Kern and Seaton deposition model for application in axial compressor blade rows. The test rig's cascade was designed to be representative of aircraft engine compressor blading. The cascade was exposed to an accelerated deposition process. Reproducible deposition patterns were identified. Results showed an asymptotic progression of blade row performance deterioration. A significant increase in total pressure loss and decrease in static pressure rise were measured. Application of the validated model using existing particle concentration and flight cycle data showed that more than 95% of the performance deterioration due to deposition occurs within the first 1000 flight cycles.


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