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1 – 10 of over 2000The purpose of this paper is to provide a relatively straightforward approach of implementing standard statistical process control (SPC) concepts while instituting problem‐solving…
Abstract
Purpose
The purpose of this paper is to provide a relatively straightforward approach of implementing standard statistical process control (SPC) concepts while instituting problem‐solving intonations in aero‐engine maintenance processes.
Design/methodology/approach
The inspection workflow approach is presented in order to aid in collecting and monitoring critical aero‐engine data. Observed defects are categorized according to a Pareto analysis assisted by a cause‐and‐effect diagram. A binomial process capability analysis is performed on nonconforming aero‐engines based on operating curves produced specifically for this case study. The time frame for experimental analysis is reflected in a span of six months.
Findings
It is found that a significant number of aero‐engines may be benefited by entering a more progressive maintenance program relying on predictive maintenance on the way to establishing a more effective Total Productive Maintenance scheme.
Research limitations/implications
The case study showcases an approach to aero‐engine rejection statistical rates by accepting the fact that maintenance process may not be viewed as a process that may be limited to constant sampling.
Practical implications
For a long time, total quality management (TQM) tools have been deeply rooted in design, manufacturing and assembling of airliners and jet fighters alike. However, a comprehensive study focusing on the maintenance function of such complex machines may prove worthwhile now that an unstable global economy may prohibit extensive replacement of aging flying fleets.
Originality/value
With the lack of a prior practical unfolding in the field of genuine aero‐engine maintenance, this presentation aims to fill in the gap for engine rejection treatment. The variant operating curve notion introduced in the text is also a unique idea espoused for variable sampling situations when a binomial distribution is adopted.
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Nowadays, a large amount of data related to aero engine in various types can be created in a single day and it is very important to well organize and store these data. The paper…
Abstract
Purpose
Nowadays, a large amount of data related to aero engine in various types can be created in a single day and it is very important to well organize and store these data. The paper aims to discuss this issue.
Design/methodology/approach
This paper puts forward the problem of data management with the fast development of aero engine and sets the compression system as an example to see the inner relationships of data from the initial design procedure to the final operation and maintenance part. There are five principles, namely digitization, accuracy, normative, integrality and validity, involved in managing the data effectively.
Findings
These data resources arranged according to the five principles can be well organized and better used.
Originality/value
At the end, the top design of aero engine data sharing platform is investigated and five layers including data layer, data access layer, communication layer, business logic layer and application layer are designed and presented to support the platform.
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The functionality and reliability of an overhauled aero-engine is determined by all configuration changes in the overhaul process. Identifying, recording, auditing, tracking and…
Abstract
Purpose
The functionality and reliability of an overhauled aero-engine is determined by all configuration changes in the overhaul process. Identifying, recording, auditing, tracking and tracing of configuration modifications are significant and meaningful. Considering the barriers to these goals, this paper aims to put forward an approach to configuration management in the aero-engine overhaul process.
Design/methodology/approach
The overhaul configuration management model is proposed to describe an aero-engine’s configuration evolution trajectory in the overhaul process. The controlling and auditing procedures are put forward to control and audit parts’ return-to-zero statuses and overproof statuses. And some searching algorithms are also designed to enable tracking and tracing of the configuration status along the time coordinate, or get a snapshot of an aero-engine’s configuration at a certain time. The above model, procedures and algorithms have been implemented and adopted to fulfill the configuration management requirements in the aero-engine overhaul process.
Findings
The approach is effective in identifying, recording, controlling, auditing, tracking and tracing configuration changes in the overhaul process.
Practical implications
The approach’s implementation and adoption present a practical example for aero-engines’ configuration management issue in the overhaul process.
Originality/value
The work proposes an original aero-engine configuration management solution for the overhaul process and enables a reliable and accurate configuration management mode.
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Fernando Tejero, David MacManus, Jesús Matesanz García, Avery Swarthout and Christopher Sheaf
Relative to in-service aero-engines, the bypass ratio of future civil architectures may increase further. If traditional design rules are applied to these new configurations and…
Abstract
Purpose
Relative to in-service aero-engines, the bypass ratio of future civil architectures may increase further. If traditional design rules are applied to these new configurations and the housing components are scaled, then it is expected that the overall weight, nacelle drag and the effects of aircraft integration will increase. For this reason, the next generation of civil turbofan engines may use compact nacelles to maximise the benefits from the new engine cycles. The purpose of this paper is to present a multi-level design and optimisation process for future civil aero-engines.
Design/methodology/approach
An initial set of multi-point, multi-objective optimisations for axisymmetric configurations are carried out to identify the trade-off between intake and fancowl bulk parameters of highlight radius and nacelle length on nacelle drag. Having identified the likely optimal part of the design space, a set of computationally expensive optimisations for three-dimensional non-axisymmetric configurations is performed. The process includes cruise- and windmilling-type operating conditions to ensure aerodynamic robustness of the downselected configurations.
Findings
Relative to a conventional aero-engine nacelle, the developed process yielded a compact aero-engine configuration with mid-cruise drag reduction of approximately 1.6% of the nominal standard net thrust.
Originality/value
The multi-point, multi-objective optimisation is carried out with a mixture of regression and classification functions to ensure aerodynamic robustness of the downselected configurations. The developed computational approach enables the optimisation of future civil aero-engine nacelles that target a reduction of the overall fuel consumption.
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Longbiao Li, Suyi Bi and Youchao Sun
– The purpose of this paper is to develop a method to predict the multi-failure risk of aero engine in service and to evaluate the effectiveness of different corrective actions.
Abstract
Purpose
The purpose of this paper is to develop a method to predict the multi-failure risk of aero engine in service and to evaluate the effectiveness of different corrective actions.
Design/methodology/approach
The classification of failure risk level, the determination of hazard ratio and the calculation of risk factor and the risk per flight have been proposed. The multi-failure risk assessment process of aero engine has been established to predict the occurrence of failure event and assess the failure risk level. According to the history aero engine failure data, the multi-failure risk, i.e., overheat, blade wounding, pump failure, blade crack, pipe crack and combustor crack, has been predicted considering with and without corrective action. Two corrective actions, i.e., reduce the maintenance interval and redesign the failure components, were adopted to analyze the decreasing of risk level.
Findings
The multi-failure risk of aero engine with or without corrective action can be determined using the present method. The risk level of combustor crack decreases from high-risk level of 1.18×1e−9 without corrective action to acceptable risk level of 0.954×1e−9 by decreasing the maintenance interval from 1,000 to 800 h, or to 0.912×1e−9 using the redesign combustor.
Research limitations/implications
It should be noted that probability of detection during maintenance actions has not been considered in the present analysis, which would affect the failure risk level of aero engine in service.
Social implications
The method in the present analysis can be adapted to other types of failure modes which may cause significant safety or environment hazards, and used to determine the maintenance interval or choose appropriate corrective action to reduce the multi-failure risk level of aero engine.
Originality/value
The maintenance interval or appropriate corrective action can be determined using the present method to reduce the multi-failure risk level of aero engine.
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Yasin Şöhret and T. Hikmet Karakoc
It is essential to develop more environment-friendly energy systems to prevent climate change and minimize environmental impact. Within this scope, many studies are performed on…
Abstract
Purpose
It is essential to develop more environment-friendly energy systems to prevent climate change and minimize environmental impact. Within this scope, many studies are performed on performance and environmental assessments of many types of energy systems. This paper, different from previous studies, aims to prove exergy performance of a low-emission combustor of an aero-engine.
Design/methodology/approach
It is a well-known fact that, with respect to previous exergy analysis, highest exergy destruction occurs in the combustor component of the engine. For this reason, it is required to evaluate a low-emission aero-engine combustor thermodynamically to understand the state of the art according to the authors’ best of knowledge. In this framework, combustor has been operated at numerous conditions (variable engine load) and evaluated.
Findings
As a conclusion of the study, the impact of emission reduction on performance improvement of the aero-engine combustors exergetically is presented. It is stated that exergy efficiency of the low-emission aero-engine combustor is found to be 64.69, 61.95 and 71.97 per cent under various operating conditions.
Practical implications
Results obtained in this paper may be beneficial for researchers who are interested in combustion and propulsion technology and thermal sciences.
Originality/value
Different from former studies, the impact of operating conditions on performance of a combustor is examined from the viewpoint of thermodynamics.
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M. Mary Victoria Florence and E. Priyadarshini
This study aims to propose the use of time series autoregressive integrated moving average (ARIMA) models to predict gas path performance in aero engines. The gas path is a…
Abstract
Purpose
This study aims to propose the use of time series autoregressive integrated moving average (ARIMA) models to predict gas path performance in aero engines. The gas path is a critical component of an aero engine and its performance is essential for safe and efficient operation of the engine.
Design/methodology/approach
The study analyzes a data set of gas path performance parameters obtained from a fleet of aero engines. The data is preprocessed and then fitted to ARIMA models to predict the future values of the gas path performance parameters. The performance of the ARIMA models is evaluated using various statistical metrics such as mean absolute error, mean squared error and root mean squared error. The results show that the ARIMA models can accurately predict the gas path performance parameters in aero engines.
Findings
The proposed methodology can be used for real-time monitoring and controlling the gas path performance parameters in aero engines, which can improve the safety and efficiency of the engines. Both the Box-Ljung test and the residual analysis were used to demonstrate that the models for both time series were adequate.
Research limitations/implications
To determine whether or not the two series were stationary, the Augmented Dickey–Fuller unit root test was used in this study. The first-order ARIMA models were selected based on the observed autocorrelation function and partial autocorrelation function.
Originality/value
Further, the authors find that the trend of predicted values and original values are similar and the error between them is small.
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The paper aims to present a modified particle swarm optimization (MPSO) approach for automatic generation of near‐optimal pipe routes in constrained aero‐engine 3D rotational…
Abstract
Purpose
The paper aims to present a modified particle swarm optimization (MPSO) approach for automatic generation of near‐optimal pipe routes in constrained aero‐engine 3D rotational space.
Design/methodology/approach
Pipe assembly for aero‐engine is formulated as searching for the optimal pipe paths meeting certain objectives in a constrained 3D rotational space. The routing space is first modelled by grid discretization in the cylindrical coordinate system, and then is simplified into several 2D planes by mapping development. The objective function is formulated to minimize the pipe lengths and the number of pipe turns, to place pipes next to the inner jacket as close as possible, and also to make pipe trajectories closely follow around obstacle contours while avoiding collisions. Then, an MPSO approach, which adopts a discrete operator and a fixed‐length encoding mechanism, is developed to seek optimal solutions to the objective function. The convergence of MPSO is theoretically proved. Finally, numerical computations of pipe‐routing examples are conducted by using Matrix Laboratory and Unigraphics NX 4.0 system, which demonstrates effectiveness and efficiency of the proposed method.
Findings
Results show that MPSO can quickly find the optimal pipe routes meeting certain engineering constraints, and also manifests better computation convergences.
Practical implications
The application of the MPSO approach in pipe routing for aero‐engines is demonstrated. MPSO is a general modified particle swarm optimization version that it is not restricted to the pipe‐routing problems, and the routing approach can also be applied in similar path‐planning problems such as robot path‐planning and very large‐scale integration design.
Originality/value
The paper develops a new formulation for aero‐engine pipe‐routing problems, and presents an MPSO approach to find the optimal pipe paths.
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Devoted to a description and evaluation of a selected maintenance process (assembly) at the aero‐engines maintenance unit of a large aerospace company by implementation of TQM…
Abstract
Purpose
Devoted to a description and evaluation of a selected maintenance process (assembly) at the aero‐engines maintenance unit of a large aerospace company by implementation of TQM tools, this paper attempts to identify the causes behind the defect observed and form the scientific platform for initiatives in a TQM‐governed enterprise and to broaden the principles of TQM for the selected process, prior to moving to a more structured plan that will include the entire unit.
Design/methodology/approach
Process monitoring and evaluation are organised by an application of control charts in order to provide vital information regarding the level of control in the selected process. Quality control data are contrasted with component specifications by employing control charts to provide a metric for the level of the process capability index. As a result a Fishbone diagram is constructed to identify existing interrelations between the causes responsible for the defect observed.
Findings
The maintenance process selected was the assembly process of an aero‐engine module (exhaust nozzle unit) at the aero‐engines maintenance unit of a large aerospace company. Process evaluation by means of multivariate control charts and tolerance analysis exhibited poor results. It was observed that certain measurement stations were out of control, whilst low actual capability index values were exhibited in others..
Research limitations/implications
Process monitoring and evaluation carried out for the purposes of the present study had the form of an off‐line tool. The paper shows that the aero‐engines maintenance unit had no infrastructure for an online process control and monitoring system. Consequently, performed analysis indicated that the implied assembly process was inadequately implemented. As a result, the maintained assembly units were out of stated specifications limits.
Originality/value
The study contributes to the literature on TQM in the aerospace maintenance business.
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BMW is a company that can look back on a long tradition in engine construction. This not only applies to developing innovative car engines, which were always a little ahead of…
Abstract
BMW is a company that can look back on a long tradition in engine construction. This not only applies to developing innovative car engines, which were always a little ahead of their time, but also to designing aero engines. It is now possible to present the public with a record of aero‐engine construction that was long believed to have been lost without trace: a BMW type 803 A aero engine built in 1944, comprising two 4‐cylinder double‐radial engines that together develop some 4,000 hp. This unique example is now being exhibited at the Deutsches Museum in Munich.