This paper presents a review of erosion and deposition research in turbomachines and the associated degradation in engine performance caused by particulate matter ingestion Parameters affecting surface material losses as a result of erosion and development of experimental and analytical approaches to predict flowpath erosion and deposition are discussed Tests results that quantify the effects of temperature, impact particle composition, impact velocity and angle, and surface material composition are reviewed along with particle restitution data (ratios of rebound to impact velocities and angles) Development and application of models using these data to calculate surface erosion in turbomachinery are described These models predict particle trajectories in turbomachinery passages to determine impact rates, impact velocities, impact angles and uses the experimentally-obtained erosion data to calculate material losses Literature on the effects of erosion on turbomachine performance and life is surveyed Mechanisms of particle delivery and attachment upon arrival at turbomachine flowpath surfaces are also discussed along with experiential models that have been developed to predict surface deposit buildup Delivery to turbine surfaces can occur as a result of inertial flight, as for erosion, but also through transport mechanisms involving turbulence, Brownian diffusion, and thermophoresis The particle size range, where each of these mechanisms is dominant for delivery to surfaces, is described The history and experience of developing models that use these mechanisms to quantify particle delivery rates to turbine flow path surfaces is discussed, along with the use of sticking fraction data to determine the amount of material retained on the surfaces after delivery and the resulting deposit buildup rates Finally, factors that control whether extreme rates of deposition can occur in turbomachinery are described

Erosion and Deposition in Turbomachinery

https://research.birmingham.ac.uk/portal/files/53643809/APEN2017.pdf

Performance-based health monitoring, diagnostics and prognostics for condition-based maintenance of gas turbines: A review

This paper presents the results of a combined experimental and computational research program to investigate turbine vane and blade material surface deterioration caused by solid particle impacts. Tests are conducted in the erosion wind tunnel for coated and uncoated blade materials at various impact conditions. Surface roughness measurements obtained prior and subsequent to the erosion tests are used to characterize the change in roughness caused by erosion. Numerical simulations for the three-dimensional flow field and particle trajectories through a low-pressure gas turbine are employed to determine the particle impact conditions with stator vanes and rotor blades using experimentally based particle restitution models. Experimental results are presented for the measured blade material/coating erosion and surface roughness. The measurements indicate that both erosion and surface roughness increase with impact angle and particle size. Computational results are presented for the particle trajectories through the first stage of a low-pressure turbine of a high bypass turbofan engine. The trajectories indicate that the particles impact the vane pressure surface and the aft part of the suction surface. The impacts reduce the particle momentum through the stator but increase it through the rotor. Vane and blade surface erosion patterns are predicted based on the computed trajectories and the experimentally measured blade coating erosion characteristics.

/pdf/turbine-blade-surface-deterioration-by-erosion-4e3nhvtcqq.pdf

Turbine Blade Surface Deterioration by Erosion

This paper is concerned with robust aerodynamic design of compressor blades against erosion. The proposed approach combines a multiobjective genetic algorithm with geometry modeling methods, high-fidelity computational fluid dynamics, and surrogate models to arrive at robust designs on a limited computational budget. The multiobjective formulation used here allows explicit trade-off between the mean and variance of the performance to be carried out. Detailed numerical studies are presented for robust geometric design of a typical compressor fan blade section to illustrate the proposed methodology. The performance of a selected robust optimal solution on the Pareto front is compared to a deterministic optimal solution to demonstrate that significant improvements in the mean shift and variance can be achieved.

/pdf/robust-design-of-compressor-fan-blades-against-erosion-4ltdacx0kw.pdf

Robust Design of Compressor Fan Blades Against Erosion

In this paper, common faults in main components of an industrial two-shaft gas turbine are simulated, and the fault signatures are determined in both part and full-load conditions. As fouling and erosion are the most important and effective causes of performance deterioration in gas turbines (GTs), the effects of these faults on the performance of all three main components including compressor, gas generator turbine, and power turbine are studied and their effects on the overall efficiency of the whole system are analyzed. In this study, the faults simulation is performed by changing the health parameters (flow capacity and isentropic efficiency) of each GT components via modification of the compressor and turbines characteristic curves. The results obtained from the compressor fouling simulation are validated against the published experimental data; the validation results represent acceptable simulation accuracy in estimation of the measurement parameters deviation. Moreover, the fault signatures are determined in full-load conditions, and the effects of the examined faults on the main GT parameters are analyzed; in this way, the key measurement parameters in identification of these faults are introduced. Finally, in order to identify the fault signatures in part-load conditions, the fault implantation process is performed for each 10% reduction in gas turbine loads. Simulation results demonstrate that the fault signatures have different sensitivity to load variations, and thus, these are in general a function of the GT loading conditions.

Simulation of Full and Part-Load Performance Deterioration of Industrial Two-Shaft Gas Turbine

This paper presents the results of a simulation of compressor performance deterioration due to blade erosion. The simulation at both design and off-design conditions is based on a mean line row by row model, which incorporates the effects of blade roughness and tip clearance. The results indicate a pronounced effect of blade erosion on the compressor adiabatic efficiency and a lesser effect on the pressure ratio. The loss in performance is mainly caused by the increased blade surface roughness and was highest at 100% speed.

/pdf/modeling-of-compressor-performance-deterioration-due-to-1pxa3a0jyc.pdf

D. Singh

Papers

Modeling of Compressor Performance Deterioration Due to Erosion