Feasibility of a Helium Closed-Cycle Gas Turbine for UAV Propulsion

Emmanuel O Osigwe,Theoklis Nikolaidis,Arnold Gad-Briggs

doi:10.3390/app11010028

Emmanuel O Osigwe, Theoklis Nikolaidis + Show 1 more

Open Access

https://doi.org/10.3390/app11010028

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Journal: Applied Sciences	Publication Date: Dec 22, 2020
Citations: 1	License type: CC BY 4.0

Affiliation: Cranfield University

Abstract

When selecting a design for an unmanned aerial vehicle, the choice of the propulsion system is vital in terms of mission requirements, sustainability, usability, noise, controllability, reliability and technology readiness level (TRL). This study analyses the various propulsion systems used in unmanned aerial vehicles (UAVs), paying particular focus on the closed-cycle propulsion systems. The study also investigates the feasibility of using helium closed-cycle gas turbines for UAV propulsion, highlighting the merits and demerits of helium closed-cycle gas turbines. Some of the advantages mentioned include high payload, low noise and high altitude mission ability; while the major drawbacks include a heat sink, nuclear hazard radiation and the shield weight. A preliminary assessment of the cycle showed that a pressure ratio of 4, turbine entry temperature (TET) of 800 °C and mass flow of 50 kg/s could be used to achieve a lightweight helium closed-cycle gas turbine design for UAV mission considering component design constraints.

Highlights

In the context of this paper, the term unmanned aerial vehicles (UAV), referred to as uncrewed aerial vehicles, are aircraft that use aerodynamic forces to provide lift either directly or by forward motion, with no human on board and controlled autonomously or remotely
While alternate propulsion systems may exhibit some of the attributes required for small UAV missions, this paper provides a balanced view of the merits and demerits of using helium closed-cycle gas turbine for UAV propulsion in terms of cycle performance and system design
The top-level requirement of high payload, high altitude, long-endurance, and range are representative of the mission requirements which could be reasonably expected but sufficiently stringent to test the real application of the closed-cycle gas turbine system for UAV propulsion

Summary

Introduction

In the context of this paper, the term unmanned aerial vehicles (UAV), referred to as uncrewed aerial vehicles, are aircraft that use aerodynamic forces to provide lift either directly or by forward motion, with no human on board and controlled autonomously or remotely. There are projections for significant growth in the use of UAVs in both civil and military applications due to the added economic and technological value related to them [2,3] Despite these projections, there are still many challenges facing the industry, with the salient ones being the choice of the propulsion system, the energy source, the conversion system, the fluid media, and the thrust converter. The considerations of energy source, conversion system, fluid media and thrust converter are linked to the choice of the propulsion system

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