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Usage of gas turbine engines has increased by day due to rising demand for military and civil applications. This case results in investigating diverse topics related to energy efficiency and irreversibility of these systems. The purpose of this paper is to perform a detailed entropy assessment of turbojet engines for different flight conditions.

In this study, for small turbojet engines used in unmanned aerial vehicles, parametric cycle analysis is carried out at (sea level-zero Mach (hereinafter phase-I)) and (altitude of 9,000 m- Mach of 0.7 (hereinafter phase-II)). Based on this analysis, variation of performance and thermodynamic parameters with respect to change in isentropic efficiency of the compressor (CIE) and turbine (TIE) is examined at both phases. In this context, the examined ranges for CIE is between 0.78 and 0.88 whereas TIE is between 0.85 and 0.95.

Increasing isentropic efficiency decreases entropy production of the small turbojet engine. Moreover, the highest entropy production occurs in the combustor in the comparison of other components. Namely, it decreases from 2.81 to 2.69 kW/K at phase-I and decreases from 1.44 to 1.39 kW/K at phase-II owing to rising CIE.

It is thought that this study helps in understanding the relationship between entropy production and the efficiency of components. Namely, the approach used in the current analysis could help decision-makers or designers to determine the optimum value of design variables.

Due to rising isentropic efficiencies of both components, it is observed that specific fuel consumption (SFC) decreases whereas specific thrust (ST) increases. Also, the isentropic efficiency of a compressor affects relatively SFC and ST higher than that of the turbine.

THE aircraft gas turbine is intriguing in that there were early attempts at its development not only by the established aero engine companies and research establishments in many countries, but also by manufacturers of marine and industrial turbines and — most successfully — by individuals. The aero engine companies failed because in virtually every instance they attempted to produce a power unit of comparable or lower specific fuel consumption to the traditional piston engine. This led to unduly complex designs involving unattainably high component efficiencies and turbine temperatures at far too early a stage in the development of the new prime mover.

IN investigating what powerplants will best meet the needs of the long‐range supersonic airliner we have to postulate that there will be such an aircraft and we need further to have some idea of its nature to match the engines to it, while equally, if we think about it, the kind of engines which could be available will react on the design of the airframe. So it appears that we must look at these two fields at first separately and then jointly in order to evolve a design specification for the complete aircraft. Moreover, the whole conception of a modern commercial aircraft has become so complex, in meeting a great diversity of operational requirements, that even in the fairly narrow process of matching the airframe and its engines a wide range of factors must be taken into consideration.

This paper aims to investigate the cycle performance of a small size turbojet engine used in unmanned aerial vehicles at 0–5,000 m altitude and 0–0.8 Mach flight speeds with real component maps.

The engine performance calculations were performed for both on-design and off-design conditions through an in-house code generated for simulating the performance of turbojet engines at different flight regimes. These calculations rely on input parameters in which fuel composition are obtained through laboratory elemental analysis.

Exemplarily, according to comparative results between in-house developed performance code and commercially available software, there is 0.25% of the difference in thrust value at on-design conditions.

Once the on-design performance parameters and fluid properties were determined, the off-design operation calculations were performed based on the compressor and turbine maps and scaling methodology. This method enables predicting component maps and fitting them to real conditions.

A method to be used easily by researchers on turbojet engine performance calculations which best fits to real conditions.

THIS paper is not intended to provide any startling revelations of Soviet technology but is a detailed survey and analysis of contemporary developments in Soviet turbine powered transport aircraft. The major portion of the work is based on Soviet sources of information in an attempt to assure authenticity and accuracy.

Already in service or under development are over a dozen or more aircraft and missiles in the general Mach 2 to 5 bracket using air breathing propulsion systems. Other major high speed projects are also at the study stage. While the subsonic combustion ramjet can span this field and beyond, the turbine engine has to transmute through a number of basic configurations to maintain an optimum mode of propulsion as Mach number increases. At present the ramjet is confined to use in missiles and the turbine engine is primarily an aircraft power unit. The trend is apparent already, however, for the turbine engine to move closer to a ramjet cycle when used above Mach 3. The following paper summarizes the features of the major high speed aircraft and missiles in being or soon to be built.

The purpose of this paper is to present an assessment method of the toxicity emission evaluation during combustion in the miniature turbojet engine.

A small-scale turbojet engine was used for the research because measurements on real aircraft turbines are complex and expensive. The experiment was performed in accordance with innovative BAT – CELL Bio – Ambient Cell method which consists of determination of virtual toxic impact of the gas mixture on the living cells; it is therefore a direct method. The most significant innovation of this method is that, during the test, which consists of exposing the cells to the gas mixture, the cells are deprived of culture fluid.

The preliminary analysis shows that the method used here allows to determine the virtual impact of the gases on the human respiratory system and skin. It could be useful in defining the arduousness of an airport. The obtained results show that both of exhaust gases represent similar toxicity.

The new in vitro method allows to determine the virtual impact of the gases on the human respiratory system and skin. Significant potential for further research not only on the miniaturised engines, but also in the case of real objects, as this method does not have to be performed in a laboratory.

The work presents potential application of the innovatory method for exhaust gases toxicity evaluation in jet engines, which could be useful in defining the arduousness of an airport.

This paper aims to theoretically investigate a knowledge management model from the combined perspective of knowledge acquisition and knowledge application and its effect on organizational performance.

This study reviews prior research on knowledge acquisition and knowledge application, puts forward the concepts of “the extensiveness of knowledge acquisition” and “the concentration of knowledge application” and more importantly proposes an integrated model by combining these two dimensions. Four case examples of enterprises are subsequently described and analyzed to illustrate the sources of knowledge acquisition, the objects of knowledge application and their influences on organizational performance.

Four knowledge management modes and their impacts are confirmed in this study. Specifically, the organization of the turbojet engine mode (high extensiveness of knowledge acquisition and high concentration of knowledge application) can achieve good performance. The pipeline mode (high extensiveness of knowledge acquisition and low concentration of knowledge application) is the second, which has limited influence on good organizational performance. Organizations with the flashlight mode (low extensiveness of knowledge acquisition and high concentration of knowledge application) can achieve limited performance under the appropriate environment. The candle mode (low extensiveness of knowledge acquisition and low concentration of knowledge application) is the worst, performance of which is poor due to the break of the knowledge chain.

This paper holds that organizations should actively use the turbojet engine mode, adopt the pipeline mode and the flashlight mode cautiously, and avoid falling into the candle mode.

To the best of the authors’ knowledge, this study is among the first to propose the concepts of “the extensiveness of knowledge acquisition” and “the concentration of knowledge application,” and provides a combined model for analyzing differences in organizational performance from the perspective of knowledge.

The date: October 2, 1942. Shrouded by World War II secrecy, a small glider‐like aircraft taxied to the end of a runway on a dry California lake bed, throttled up, and gathered speed for its 10‐minute flight that began the jet age in the United States.

The purpose of this paper is to examine the toxicological impacts of exhaust generated during the combustion process of aviation fuel containing synthesized hydrocarbons.

Tests on aircraft turbine engines in full scale are complex and expensive. Therefore, a miniature turbojet engine was used in this paper as a source of exhaust gases. Toxicity was tested using innovative BAT–CELL Bio–Ambient Cell method, which consists of determination of real toxic impact of the exhaust gases on the human lung A549 and mouse L929 cells. The research was of a comparative nature. The engine was powered by a conventional jet fuel and a blend of conventional jet fuel with synthesized hydrocarbons.

The results show that the BAT–CELL method allows determination of the real exhaust toxicity during the combustion process in a turbine engine. The addition of a synthetic component to conventional jet fuel affected the reduction of toxicity of exhaust gases. It was confirmed for both tested cell lines.

In the literature related to the area of aviation, numerous publications in the field of testing the emission of exhaust gaseous components, particulates or volatile organic compounds can be found. However, there is a lack of research related to the evaluation of the real exhaust toxicity. In addition, it appears that the data given in aviation sector, mainly related to the emission levels of gaseous exhaust components (CO, Nox and HC) and particulate matters, might be insufficient. To fully describe the engine exhaust emissions, they should be supplemented with additional tests, i.e. in terms of toxicity.