Development of Engines for Unmanned Air Vehicles: Some Factors to be Considered

Nelson, Jeff; Dix, Donald M.

doi:10.21236/ada412680

Cited by 9 publications

(11 citation statements)

References 2 publications

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“…Currently, it is understood that whilst existing classes of gas turbine engines have shown great advancements in recent years, in terms of both efficiency and performance, the concept of MTE's remains relatively undeveloped. It can be seen from Figure 1 above that the selection of engines in this thrust category consists mainly of turbojets, with a distinct lack of turbofan engines [5]. This observation forms the fundamental premises of this report, micro turbojet engines offer a simple design for producing high levels of thrust, however, suffer from poor efficiency and therefore increased specific fuel consumption.…”

Section: • the Large Difference In Reynolds Number Between Large And mentioning

confidence: 77%

“…Inlet Mach number is fixed at 0.5 (≈160 m/s) for the design point of cruise conditions. The design parameters already identified from engine simulation are as follows: : = 0.815 [5] Next the overall annulus dimensions, inlet and outlet of compressor (hub-to-tip ratio -rh = hub radius, rt = tip radius) are sized (see Figure 16).…”

Section: One Dimensional Meanline Calculationmentioning

confidence: 99%

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Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

Large¹,

Pesyridis²

2018

Preprint

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In this study, the on-going research into the improvement of micro-gas turbine propulsion system performance and the suitability for application as propulsion systems for small tactical UAVs (<600 kg) is investigated. The study is focused around the concept of converting existing micro turbojet engines to turbofan with the use of a continuously variable gearbox, thus maintaining a single spool configuration and relative design simplicity. This is an effort to reduce the initial engine development cost, whilst improving propulsive performance. The BMT 120 KS micro turbojet engine is selected for performance evaluation of the conversion process using gas turbine performance software, GasTurb13. The preliminary design of a matched low-pressure compressor (LPC) for the proposed engine is then performed using meanline calculation methods. According to the analysis carried out, an improvement in the converted micro gas turbine engine performance in terms of thrust and specific fuel consumption is achieved. Furthermore, with the introduction of a CVT gearbox, fan speed operation may be adjusted independently of the core, allowing increased thrust generation or better fuel consumption. Therefore, enabling a wider gamut of operating conditions and enhances the performance and scope of tactical UAV.

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Section: • the Large Difference In Reynolds Number Between Large And mentioning

confidence: 77%

Section: One Dimensional Meanline Calculationmentioning

confidence: 99%

Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

Large¹,

Pesyridis²

2018

Preprint

View full text Add to dashboard Cite

show abstract

“…While turbojet engines may offer a simple design capable of providing high levels of thrust, they are usually marked by poor fuel consumption; turbofan engines, on the other hand, while being more complex and expensive, can provide similar or higher levels of thrust at a greater efficiency. In order to improve the performance while reducing the TSFC, which is considered to be the most influential engine characteristic relating to efficiency [1], the sensible solution is to introduce a turbofan into the microgas turbine category. If an efficient, well-performing, affordable turbofan can be successfully designed, the application of microgas turbines may be expanded into fields for which were prior considered unsuitable.…”

Section: Introductionmentioning

confidence: 99%

“…To maintain the distinct advantages of engines equipped with bypass, while reducing the development cost and time to a mere fraction of those of a new engine [1], a turbofan design derived from a pre-existing turbojet may offer a good concession.…”

Section: Introductionmentioning

confidence: 99%

Micro-Turbojet to Turbofan Conversion Via Continuously Variable Transmission: Thermodynamic Performance Study

Kadosh

Cukurel

2016

Journal of Engineering for Gas Turbines and Power

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In this study, the viability, performance, and characteristics of a turbojet-to-turbofan conversion through the use of a continuously variable transmission (CVT) are investigated. By an in-house thermodynamic simulation code, the performance of the simple cycle turbojet, a direct shaft joined turbofan, and a CVT coupled turbofan with variable bypass is contrasted. The baseline turbojet and turbofan findings are validated against a commercial software. The comparison indicates high quantitative agreement. Analyzing the results of the turbofan engine equipped with a variable bypass and CVT, it is observed that both the thrust and the efficiency are increased. The augmented thrust is observed to be an artifact of enhanced component matching and wider operational range introduced by variable bypass capability. On the other hand, the introduction of CVT contributes to the reduction in fuel consumption. Therefore, the current research suggests that adaptation of a micro-turbojet into a variable cycle micro-turbofan will greatly improve the performance and efficiency of existing engines, in addition to providing a pathway toward extended use in various applications.

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“…It can be seen from Figure 1 that the selection of engines in this thrust category consists mainly of turbojets, with a distinct lack of turbofan engines (modified from [5]). This observation forms the fundamental premises of this report, micro turbojet engines offer a simple design for producing high levels of thrust, but they suffer from poor efficiency and therefore increased specific fuel consumption.…”

mentioning

confidence: 99%

Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

Large

Pesyridis

2019

Aerospace

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In this study, the on-going research into the improvement of micro-gas turbine propulsion system performance and the suitability for its application as propulsion systems for small tactical UAVs (<600 kg) is investigated. The study is focused around the concept of converting existing micro turbojet engines into turbofans with the use of a continuously variable gearbox, thus maintaining a single spool configuration and relative design simplicity. This is an effort to reduce the initial engine development cost, whilst improving the propulsive performance. The BMT 120 KS micro turbojet engine is selected for the performance evaluation of the conversion process using the gas turbine performance software GasTurb13. The preliminary design of a matched low-pressure compressor (LPC) for the proposed engine is then performed using meanline calculation methods. According to the analysis that is carried out, an improvement in the converted micro gas turbine engine performance, in terms of thrust and specific fuel consumption is achieved. Furthermore, with the introduction of a CVT gearbox, the fan speed operation may be adjusted independently of the core, allowing an increased thrust generation or better fuel consumption. This therefore enables a wider gamut of operating conditions and enhances the performance and scope of the tactical UAV.

show abstract

Development of Engines for Unmanned Air Vehicles: Some Factors to be Considered

Abstract: Subject Terms Report Classification unclassified Classification of this page unclassified Classification of Abstract unclassified Limitation of Abstract UU Number of Pages90

Cited by 9 publications

References 2 publications

Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

Micro-Turbojet to Turbofan Conversion Via Continuously Variable Transmission: Thermodynamic Performance Study

Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

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