Exploration of the Potential of Civil Unmanned Aerial Vehicles Powered by Micro Gas Turbine Propulsion System

Exploration of the Potential of Civil Unmanned Aerial Vehicles Powered by Micro Gas Turbine Propulsion System

Beuselinck, S.M.L.

Colonna, P. (mentor)
Voskuijl, M. (mentor)
Visser, W.P.J. (mentor)

Aerospace Engineering

Aerodynamics, Wind Energy & Propulsion

Flight Performance and Propulsion

2015-05-13

Civil Unmanned Aerial Vehicles (UAVs) are outnumbered compared to the military equivalents. They could however be of great value to various organizations, companies and the general public. They currently seem to be on the verge of a breakthrough. An interesting technology that could help increase the flight performance of civil UAVs is the micro gas turbine technology. This is a promising propulsion system that is being developed at the moment. It could become a solid competitor for other propulsion systems used to power UAVs due to the higher power-to-weight ratio, lower complexity, higher energy density potential and power density advantage. This could fuel the continuous expansion of civil UAVs even more. The objective of this Master thesis is to investigate the difference in flight performance between a UAV powered by a reciprocating engine and a micro gas turbine; to explore the potential of a UAV powered by a micro gas turbine based propulsion system. The exploration study first identifies the most promising application. Followed by nominating an existing UAV design as a baseline, based on the closest requirement match with the selected application. The Harfang EADS, powered by a Rotax 914 turbocharged reciprocating engine, acts as the baseline UAV. The flight performance of this UAV is determined by a software package in which point performance is integrated to obtain path performance of a typical mission profile. The aerodynamic model of the baseline UAV is determined using a combination of a vortex lattice method and the thin plate approximation. Weight estimation relationships are used to determine the components weight and the center of gravity location. Fuel flow and thrust data of the reciprocating engine are derived from the operating manual of the Rotax 914 engine, while thrust management tables from another Master thesis are used to model different micro gas turbine sizes (86, 70 and 60 kW), each having a number of technology levels. The influence of some of the assumed parameters is investigated by a sensitivity analysis. Minor modifications to the UAV dimensions resulted in a none notable effect on the mission performance of the baseline UAV. Increasing the critical Reynolds number on the other hand had a significant effect on the drag coefficient, while the influence of the Oswald factor on the drag coefficient gradually increased as function of the angle of attack. Changes to the drag coefficient and user-specified propeller propulsion efficiency of the baseline UAV both had limited effect on the mission performance. Modifications to the specific fuel consumption of the reciprocating engine resulted in a more pronounced effect. The research indicates an increase in mission endurance of 4% for the 60 kW micro gas turbine with the highest technology level compared to the reciprocating engine using the same UAV platform. A take-off weight reduction of 18% can be obtained if the UAV platform is optimized for this micro gas turbine by a redesign process; modifying the wing, fuselage and empennage design. The fuel weight is reduced by 12.5% compared to the reciprocating engine as a result of the increased mission endurance and redesign process. The micro gas turbine can therefore perform the same mission as the reciprocating engine with less fuel. This Master thesis therefore concluded that there is a performance gain possible if a reciprocating engine is replaced by a micro gas turbine. This performance gain could also be transformed into a fuel weight reduction, proving the potential of civil UAVs powered by a micro gas turbine based propulsion system.

aeronautics
UAV
flight performance
micro gas turbine
conceptual design

http://resolver.tudelft.nl/uuid:56a7c878-9d66-4306-9ad4-ececb4de8394

Student theses

master thesis

(c) 2015 Beuselinck, S.M.L.