A hybrid propulsion system for a high-endurance UAV: configuration selection, aerodynamic study, and gas turbine bench tests

2014 ◽  
Vol 02 (01) ◽  
pp. 16-35 ◽  
Author(s):  
R. Capata ◽  
L. Marino ◽  
E. Sciubba

In recent years, renewed interest in the development of unmanned aerial vehicles (UAVs) has led to a wide range of interesting applications in reconnaissance and surveillance. In these missions, the noise produced by propeller-driven UAVs is a major drawback, which can be partially solved by installing an electric motor to drive the propeller. While the evolution of high performance brushless motors makes electric propulsion particularly appealing, at least for small and medium UAVs, all electric propulsion systems developed to date are penalized by the limited range and endurance that can be provided by a reasonably sized battery pack. In this paper we propose a hybrid propulsion system based on a recently developed ultramicro gas–turbine (UMGT), which can be used to power an electric generator, providing a significant range and (or) mission time extension. The UMGT is undergoing operational testing in our laboratory, to identify the most suitable configuration and to improve performance: a new compact regenerative combustion chamber was developed and several tests are being carried out to reduce its weight and size so as to increase, all other things being equal, the vehicle payload. This paper aims to propose a high endurance UAV, by a preliminary configuration selection and aerodynamic study of its performance.

Author(s):  
Roberto Capata ◽  
Luca Marino ◽  
Enrico Sciubba

In recent years, a renewed interest in the development of unmanned air vehicles (UAVs) led to a wide range of interesting applications in the fields of reconnaissance and surveillance. In these types of mission, the noise produced by propeller driven UAVs is a major drawback, which can be partially solved by installing an electric motor to drive the propeller. The evolution of high performance brushless motors makes electric propulsion particularly appealing, at least for small and medium size UAVs. All electric propulsion systems developed to date are though penalized by the limited range/endurance that can be provided by a reasonably sized battery pack. In this paper we propose a hybrid propulsion system based on a recently developed, high efficiency microturbine which can be used to power an electric generator, thus providing a significant range/mission time extension. The UMTG is undergoing operational testing in our Laboratory, to identify its most suitable configuration and to improve its performance: a new compact regenerative combustion chamber was developed and several tests were performed to reduce its weight and size so as to increase the vehicle payload. In a high range/endurance mission the ultramicro turbine drives the electrical motor that powers the propeller only during the cruise phase (the so-called “transfer to target”), while in the final approach, in which a quiet flight attitude is mandatory, a (smaller) battery pack drives the motor directly and the UMTG is turned off. The mission requirements considered for the preliminary design of the UAV consist of a long endurance (> 12 hours) step, with a cruise speed of 33.3 m/s and a dash speed of 45 m/s at an altitude of 5000 meters. The maximum take-off weight is 500 N, with a payload of 80 N. Under the above assumptions, a flying wing configuration for the UAV was defined, with a length of 1.6 meters and a span of 2.5 meters. A system of elevons assures the pitch and roll motion while a double vertical tail, in which a pusher propeller is lodged, guarantees the yaw stability and control.


Author(s):  
Roberto Capata ◽  
Luca Marino ◽  
Enrico Sciubba

In recent years, a renewed interest in the development of unmanned air vehicles (UAV’s) led to a wide range of interesting applications in the fields of reconnaissance and surveillance. In these types of mission, the noise produced by propeller driven UAVs is a major drawback, which can be partially solved by installing an electric motor to drive the propeller. The evolution of high performance brushless motors makes electric propulsion particularly appealing, at least for small and medium size UAVs. All electric propulsion systems developed to date are though characterized by the limited range/endurance that can be obtained with a reasonably sized battery pack. In this paper we propose a hybrid propulsion system based on recently developed, high efficiency micro-turbines which can be used to power an electric generator. The UMGT is under evaluation in our department, to achieve the optimal configuration and performances. For this scope a new compact regenerative combustion chamber has been developed and several tests has been carried out, with the aim to reduce weight and dimension and increase vehicle payload. In a high range/endurance mission the ultra-micro-turbine can provide the energy required for the cruise phase (the so-called “transfer to target”), while in the final approach, in which a quiet flight attitude is a demanding item, the battery pack drives the motor. The mission requirements adopted in the preliminary aircraft design presented here consist mainly of a long endurance (> 12 hours) step, with a cruise speed of 33.3 m/s and a dash speed of 45 m/s at an altitude of 5000 meters. The maximum take-off weight is 500 N, with a payload of 80 N. Under the above assumptions, a flying wing configuration for the UAV was defined, with a length of 1.6 meters and a span of 2.5 meters. A system of elevons assures the pitch and roll motion while a double vertical tail, in which a pusher propeller is lodged, guarantees the yaw stability and control.


Author(s):  
Babak Aryana

This two-part article introduces a novel hybrid propulsion system based on the DEA compressor. The system encompasses a Pulse Detonation TurboDEA as the master engine that supplies several full-electric ancillary thrusters called DEAThruster. The system, called the propulsion set, can be categorized as a distributed propulsion system based on the design mission and number of ancillary thrusters. Part A of this article explains the design process comprising intake, compressor, detonation process, diffuser, axial turbine, and the exit nozzle. The main target is to design a high-performance low emission propulsion system capable of serving in a wide range of altitudes and flight Mach numbers that covers altitudes up to 20,000 m and flight Mach number up to the hypersonic edge. Designing the propulsion set, the design point is considered at the static condition in the sea level. Design results show the propulsion set can satisfy all requirements necessary for its mission.


2000 ◽  
Author(s):  
Emiliano Cioffarelli ◽  
Enrico Sciubba

Abstract A hybrid propulsion system of new conception for medium-size passenger cars is described and its preliminary design developed. The system consists of a turbogas set operating at fixed rpm, and a battery-operated electric motor that constitutes the actual “propulsor”. The battery pack is charged by the thermal engine which works in an electronically controlled on/off mode. Though the idea is not entirely new (there are some concept cars with similar characteristics), the present study has important new aspects, in that it bases the sizing of the thermal engine on the foreseen “worst case” vehicle mission (derived from available data on mileage and consumption derived from road tests and standard EEC driving mission cycles) that they can in fact be accomplished, and then proceeds to develop a control strategy that enables the vehicle to perform at its near–peak efficiency over a wide range of possible missions. To increase the driveability of the car, a variable-inlet vane system is provided for the gas turbine. After developing the mission concept, and showing via a thorough set of energy balances (integrated over various mission profiles), a preliminary sizing of the turbogas set is performed. The results of this first part of the development program show that the concept is indeed feasible, and that it has important advantages over both more traditional (Hybrid Vehicles powered by an Internal Combustion Engine) and novel (All-Electric Vehicle) propulsion systems.


Author(s):  
Michael Schneider ◽  
Jens Dickhoff ◽  
Karsten Kusterer ◽  
Wilfried Visser

Abstract In the recent decades, civil aviation was growing 4.7% per annum. In order to reduce emissions promoting the global warming process, alternative propulsion systems are needed. Full-electric propulsion systems in aviation might have the potential for emission-free flights using renewable energy. However, several research efforts indicate electric propulsion only seems feasible for small aircraft. Especially due to the low energy density of batteries compared to fossil fuels. For this reason, hybrid propulsion systems came into focus, combining the benefits of all-electric and conventional propulsion system concepts. It is also considered as bridging technology, system test and basis for component development — and therewith paves the way towards CO2 free aviation. In the ‘HyFly’ project (supported by the German Luftfahrtforschungsprogramm LuFo V-3), the potential of a hybrid electric concept for a short/mid-range 19 PAX aircraft is assessed — not only on system but also on single component basis. In a recent study, the propulsion architecture and the operating mode of the gas turbine and the electric components have been defined [1]. In this paper, the advantages of the hybrid propulsion architecture and a qualitative assessment of component life are presented. Methods for life time prediction for the aircraft engine, the electric motor, the reluctance generator and the battery are discussed. The impact of turbine inlet temperature on life consumption is analyzed. The life cycle of the aircraft engine and the electric components including gradual component deterioration and consequent performance degradation is simulated by using an in-house gas turbine simulation tool (GTPsim). Therefore, various effects on electric propulsion system can be predicted for the entire drivetrain system in less than one hour.


2021 ◽  
Vol 14 (5) ◽  
pp. 249
Author(s):  
Anton Varyukhin ◽  
Viktor Zakharchenko ◽  
Vladimir Lomazov ◽  
Denis Zhuravlev ◽  
Flyur Ismagilov ◽  
...  

Author(s):  
K. W. Ramsden

The implementation of new technology in the gas turbine industry is accelerating at a rate which demands increasing specialisation by its engineering design staff. Simultaneously, this industry has been adopting concurrent engineering practices to reduce product lead-time. Accordingly, the industry now requires its engineers to acquire early competence in a wide range of technological disciplines. In addition, the individual must have a thorough understanding of the impact of component design decisions on both other components and on the engine as a whole. Against this background, gas turbine educational providers must respond to these increasing demands with teaching programmes that facilitate a faster and deeper understanding of this very complex product. The ambition of the teacher, however, to adequately prepare the student will continue to be limited by time constraints within lecture courses. Hitherto, this has normally resulted in class worked examples which are necessarily narrow in scope and confined to a limited range of design cases. This paper describes a teaching methodology which is structured to facilitate in-depth understanding of the key interactions between aerodynamics, thermodynamics and mechanical integrity arising in axial compressor design optimisation. This is achieved interactively through a combination of lectures, a hand worked multistage preliminary compressor design, a series of personal computer based design optimisation workshops and a final collective design assessment.


Author(s):  
M. S. N. Murthy ◽  
Subhash Kumar ◽  
Sheshadri Sreedhara

Abstract A gas turbine engine (GT) is very complex to design and manufacture considering the power density it offers. Development of a GT is also iterative, expensive and involves a long lead time. The components of a GT, viz compressor, combustor and turbine are strongly dependent on each other for the overall performance characteristics of the GT. The range of compressor operation is dependent on the functional and safe limits of surging and choking. The turbine operating speeds are required to be matched with that of compressor for wide range of operating conditions. Due to this constrain, design for optimum possible performance is often sacrificed. Further, once catered for a design point, gas turbines offer low part load efficiencies at conditions away from design point. As a more efficient option, a GT is practically achievable in a split configuration, where the compressor and turbine rotate on different shafts independently. The compressor is driven by a variable speed electric motor. The power developed in the combustor using the compressed air from the compressor and fuel, drives the turbine. The turbine provides mechanical shaft power through a gear box if required. A drive taken from the shaft rotates an electricity generator, which provides power for the compressor’s variable speed electric motor through a power bank. Despite introducing, two additional power conversions compared to a conventional GT, this split configuration named as ‘Part Electric Gas Turbine’, has a potential for new applications and to achieve overall better efficiencies from a GT considering the poor part load characteristics of a conventional GT.


Author(s):  
Ahmed E. E. Khalil ◽  
Ashwani K. Gupta

Distributed Combustion provides significant performance improvement of gas turbine combustors including uniform thermal field in the entire combustion chamber (improved pattern factor), ultra low emission of NOx and CO, low noise, enhanced stability and higher efficiency. Distributed combustion with swirl have been investigated to determine the beneficial aspects of such flows on clean and efficient combustion under simulated gas turbine combustion conditions with close focus on NOx emission. Near Zero emissions of NO and CO have been demonstrated using methane under distributed combustion conditions with heat release intensities commensurable to gas turbine applications. In this paper, distributed combustion is further investigated using both gaseous and liquid fuels with emphasis on pollutants emission and combustor performance with each fuel. Performance evaluation with the different fuels is established to outline the flexibility of the combustor in handling a wide range of fuels with different calorific values and phases with focus on ultra-low pollutants emission. Results obtained on pollutants emission and OH* chemiluminescence for the specific fuels examined at various equivalence ratios are presented. Near distributed combustion conditions with less than 5 PPM of NO emission were demonstrated under novel premixed conditions for the various fuels tested thus outlining the combustor ability to handle different fuels with high performance. Further reduction of NOx can be made with true distributed combustion condition.


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