UAV icing: the influence of airspeed and chord length on performance degradation

Hann, Richard; Johansen, Tor Arne

doi:10.1108/aeat-06-2020-0127

Cited by 27 publications

(9 citation statements)

References 20 publications

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“…Especially for unmanned aerial vehicles (UAVs), for which icing impacts their operational range [33], this measurement capability is critical. As a result of the UAVs' reduced size and flight at lower Reynolds numbers [34,35] compared to manned aviation, new ice accretion studies must be conducted for their specific flight conditions.…”

Section: Introductionmentioning

confidence: 99%

Ice Accretion: Image Post-Processing Measurement Techniques for 2D Ice Shapes

et al. 2023

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Ice accretion poses substantial safety hazards for the manned and unmanned aviation industries. Its study is essential for icing events risk assessment and for the development of efficient ice protection systems. The existing ice accretion measurement techniques—casting, molding, and laser-scanning—are time-consuming, sometimes cumbersome to use, and highly expensive, while hand tracing is inexpensive, but has lower accuracy and time-consuming post-processing. This work presents two low-cost, fast, and easy-to-use measurement techniques for 2D ice accretion profiles. Both employ algorithms of automatic ice shape detection, one based on unmediated image-processing, another based on the processing of manual ice tracings. The techniques are applied to ice accretion experiments conducted in an icing wind tunnel at low Reynolds numbers, and their results are validated against ice thickness caliper measurements. A comparison of the results shows that both techniques accurately measure the leading-edge ice thickness and the 2D shape of the ice accretion profiles. One technique is faster, with higher measurement accuracy, but produces interrupted-line 2D ice profiles and requires good lighting conditions, while the other generates continuous-line 2D profiles and has no application restriction, but it is slower, with lower accuracy. A discussion is conducted, aiming to help one determine the best applications for each ice accretion measurement technique presented.

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Section: Introductionmentioning

confidence: 99%

Ice Accretion: Image Post-Processing Measurement Techniques for 2D Ice Shapes

et al. 2023

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“…For example, the Reynolds numbers in cruise flight are typically one or two orders of magnitude lower for UAVs than for manned aircraft. Since lower Reynolds numbers result in more severe icing [11,12], UAVs face more risk when flying in icing conditions than manned aircraft. Other differences between UAVs and manned aircraft are the flight altitude, the weight, the propulsion system, and the degree of autonomy.…”

Section: Introductionmentioning

confidence: 99%

UAV Icing: Intercycle Ice Effects on Aerodynamic Performance

Wallisch¹,

Hann²

2023

SAE Technical Paper Series

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<div class="section abstract"><div class="htmlview paragraph">Atmospheric in-flight icing poses a challenge to all aircraft including unmanned aerial vehicles (UAVs). Aircraft should avoid icing conditions unless they have ways of mitigating the negative effects of icing, e.g., if they are equipped with an ice protection system (IPS). When de-icing systems are used, a certain amount of ice is allowed to accumulate before it is removed. This intercycle ice deteriorates the aerodynamics by reducing the lift, adding mass, and increasing the drag. This study combines the energy that is required to compensate for the added drag of intercycle ice shapes with the energy required for a wing IPS and compares the energy needs for different IPS operations. Two different kinds of intercycle ice shapes are simulated numerically using FENSAP-ICE, one ice shape that would accrete on an unprotected wing and one ice shape that would accrete when using a parting strip, a continuously heated element at the leading edge. The results show that both intercycle ice shapes deteriorate the aerodynamic performance of the airfoil significantly compared to a clean airfoil. Additionally, the results show that the aerodynamics deteriorate fastest in the initial stages of ice accretion, likely caused by fast horn growth and a fast transition from laminar to turbulent flow. The aerodynamic performance is combined with energy requirements of electrothermal de-icing tests in an icing wind tunnel. The results show that de-icing with a parting strip is more energy-efficient than de-icing without a parting strip and anti-icing. In addition, it is found that the energy required for the IPS on a wing is significantly larger than the energy required to compensate for the added intercycle drag. Considering these results during the development and operation of an IPS will help to improve the range and endurance of UAVs in icing conditions.</div></div>

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“…Rime ice occurs at lower temperatures, has a more streamlined shape, and has a "stickier" property. Mixed ice is a mix of these two [7].…”

Section: Introductionmentioning

confidence: 99%

UAV Icing: Icing Cases for Validation of Path Planning Method

Cheung¹,

Hann²,

Johansen³

2023

SAE Technical Paper Series

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<div class="section abstract"><div class="htmlview paragraph">As part of the complete solution to deal with atmospheric in-flight icing on unmanned aerial vehicles (UAV), a path planner is a valuable tool for finding an optimal path for accomplishing UAV missions. When considering icing conditions, the planner manages areas with icing risk. Together with an electro-thermal ice protection system (IPS), the path planner can optimize energy consumption by comparing energy consumed flying through the cloud or around it, as the UAV can now more safely pass through the ice. The UAV’s aerodynamic stability is also considered by meeting lift requirements, producing enough thrust, and having battery capacity left. These are constraints in the planner to ensure that the UAV can complete its mission. Benchmark icing cases are constructed to validate that the path planner performs as intended. A particle swarm optimization (PSO) is used as a method in the planner due to its ability to handle highly nonlinear problems and to be able to explore the solution space effectively. Weather conditions are chosen following Federal Aviation Administration 14 CFR Part 25 Appendix C icing design envelopes required for certification. A cloud with ice is designed within a defined mission area. The constructed cloud will change size between simulations, where, by a specific cloud size, the PSO predicts that less energy is consumed flying through the iced area with an IPS than flying around it. With these icing cases, a baseline is set for future validation. The work performed in this paper will be used to validate the PSO algorithm. This paper can also benefit any UAV users that require a robust path planner by using the icing cases to identify any inconsistencies in their code. The results show that one version of the PSO handles most of these icing cases well. Inconsistencies were identified when using these icing cases, but this study makes an excellent example of how they can be used.</div></div>

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UAV icing: the influence of airspeed and chord length on performance degradation

Cited by 27 publications

References 20 publications

Ice Accretion: Image Post-Processing Measurement Techniques for 2D Ice Shapes

Ice Accretion: Image Post-Processing Measurement Techniques for 2D Ice Shapes

UAV Icing: Intercycle Ice Effects on Aerodynamic Performance

UAV Icing: Icing Cases for Validation of Path Planning Method

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