Experimental analysis of micro-sized particles time-wise adhesion: the influence of impact velocity and surface roughness

Suman, Alessio; Vulpio, Alessandro; Fortini, Annalisa; Fabbri, Elettra; Casari, Nicola; Merlin, Mattia; Pinelli, Michele

doi:10.1016/j.ijheatmasstransfer.2020.120632

Cited by 26 publications

(10 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The contaminants were dosed using a variable-speed rotating ring to increase or decrease the mass per unit of time prepared for Venturi's sucking process. The dosing system and the setup of the contaminant injection are described in [16].…”

Section: Methodsmentioning

confidence: 99%

Compressor fouling detection by image analysis

Suman

Zanini

Pinelli

2023

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Gas turbine fouling is commonly known as responsible for performance degradation in terms of compression ratio and efficiency. The adhesion of micro-sized particles (soil, soot, salt, etc.) caused the modification of the blade shapes and the surface roughness. Both of these two effects determine the modification of the compressor performance over the unit operation. Due to the lack of capability to forecast the fouling intensity, it could be useful to estimate the fouling intensity during the machine overhaul, collecting strategical data by which a specific characterization of a given machine in a given operating site can be done. The present paper proposes and validates a helpful methodology for estimating the deposit intensity by an image analysis procedure. An image-detection technique has been carried out before and after the contamination process, and, using a subtraction process, a quantitative analysis of the fouled regions can be developed. The results show that, with a careful light and camera setup, the intensity of the deposits can be estimated with an acceptable tolerance band, which allows the possibility of collecting quantitative data on compressor deposits during overhaul operations. This generates a valuable starting point for predicting the overtime degradation of the unit and/or estimating the filtration section efficiency.

show abstract

Section: Methodsmentioning

confidence: 99%

Compressor fouling detection by image analysis

Suman

Zanini

Pinelli

2023

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…Across the stages, the increase of the flow temperature moves the air away from the saturated condition, leading to a reduction of this effect. The increased air velocity over the stages may promote the particle bounce instead of adhesion and may increase the removal action on the deposit due to the shear velocity [40].…”

Section: Dust Collection Measurementsmentioning

confidence: 99%

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

et al. 2021

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…The contamination section is positioned 2-m far from the compressor inlet (ensuring the kinematic equilibrium between powder and airflow as well as the uniform particle distribution at the compressor inlet section), and it is based on the particle feeder TOPAS SAG40U that prepares and injects the solid contaminants by a two Venturi eductors which guarantee the proper soot particle injection process (the powder is prepared, deagglomerated, and dosed by the first Venturi nozzle, while the second one, mounted inside the compressor inlet pipeline, injects the powder contaminating the airflow). The dosing system and the setup of the contaminant injection are described in [17].…”

Section: Experimental Apparatusmentioning

confidence: 99%

Off-line washing effectiveness on a multistage axial compressor

et al. 2021

Self Cite

View full text Add to dashboard Cite

The interaction between gas turbines and airborne particles determines detrimental effects on the performance, efficiency, and reliability of the power unit. When it is possible, the interaction is reduced by the use of inlet separators and filtration systems. In an aero engine, these barriers are difficult to implement, and only bigger particles (usually greater than 10 μm) are separated from the airflow. Small units, especially those equips helicopters, are usually affected by fouling issues, especially when the aircraft is employed in harsh environments such as firefighting and rescue activities. To recover this contamination, the unit is washed after the mission by ground operations to restore the unit performance by removing the deposits. This operation occurs during a sub-idle unit operation, and the washing process has to be effective when the engine operates in this off-design condition. In this paper, the evaluation of the washing performance during a sub-idle unit operation is carried out. The compressor unit is a multistage axial compressor that equips the Allison 250-C18 engine. The washing operation was performed by water, and a sensitivity analysis is carried out to discover the capability of water droplets to remove the contaminants. The experimental analysis involves the contamination of the unit by micro-sized soot particles and a washing operation by micro-sized water droplets. These experimental results are compared to numerical simulations to discover the effects of the washing operation on a small power unit during sub-idle operating conditions. The off-design regime imposes a specific evaluation of the proper setup of the washing strategy: flow separations involve wider regions in the compressor unit, and the removal capability is strongly related to the droplet path through the stages. The results show how in the off-design washing operation, the droplet diameter has greater importance than the water flow rate for reducing the deposits over the compressor stages.

show abstract

Experimental analysis of micro-sized particles time-wise adhesion: the influence of impact velocity and surface roughness

Cited by 26 publications

References 27 publications

Compressor fouling detection by image analysis

Compressor fouling detection by image analysis

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

Off-line washing effectiveness on a multistage axial compressor

Contact Info

Product

Resources

About