Dust Ingestion in a Rotorcraft Engine Compressor: Experimental and Numerical Study of the Fouling Rate

Abstract

Helicopters often operate in dusty sites, ingesting huge amounts of contaminants during landing, take-off, hover-taxi, and ground operations. In specific locations, the downwash of the rotor may spread soil particles from the ground into the environment and, once ingested by the engine, may stick to the compressor airfoils. In the present work, the Allison 250 C18 engine’s multistage axial-flow compressor is employed to study the fouling rate on rotor blades and stator vanes from both numerical and experimental standpoints. The compressor is operated in a typical ground-idle operation, in terms of the rotational regime and contaminant concentration, in laboratory-controlled conditions. The mass of deposits is collected from the airfoil surfaces at the end of the test and compared to that estimated through the numerical model. The experimental test shows that the airfoils collect almost 1.6% of the engine’s total mass ingested during a ground-idle operation. The capability of numerical methods to predict the fouling rate on the rotating and stationary airfoils of a multistage compressor is tested through the implementation of literature based deposition models. Sticking models show a good agreement in terms of the relative results; nevertheless, an overestimation of the deposited mass predicted is observed.

Off-Design Analysis Method for Compressor Fouling Fault Diagnosis of Helicopter Turboshaft Engine

“…It is difficult to obtain the required data because of the limited availability of gas turbine operational data and a lack of deteriorated engine data. Thus, most of the significant studies in the past are based on the analysis of industrial or axial compressors [15]. Considering the use of both axial and centrifugal compressors in helicopter turboshaft engines, this study can complement previous studies.…”

Health and Safety Effects of Airborne Soil Dust in the Americas and Beyond

“…For aircraft and airports, mitigation of brownout hazard has included field‐based (Gillies et al., 2010) and numerical modeling (Jasion & Shrimpton, 2012) to understand brownout intensity and duration—a function of aircraft type and design (Ghosh & Rajagopalan, 2022), engine configuration and characteristics (Vulpio et al., 2021), land surface conditions and pilot education (McDonald, 2013), and development of sensors and engineering controls that would avoid or overcome the phenomenon (summarized, e.g., in Shimkin et al., 2020). Cognitive training of pilots may also increase their situational awareness in brownout conditions and reduce the hazard (Innes et al., 2021).…”

Compressor fouling detection by image analysis

“…To compare the image detection of the deposits (black and white pictures) with the actual intensity of the deposits, a procedure reported in [32,33] has been carried out. The estimation of the deposited mass on the blade surface represents the basis for the proper comprehension of the fouling effects [34 -36].…”