Dynamic Particle Deposition Effects on Aeroengine Turbine Performance: An Unsteady Simulation Study

Particle deposition in turbine engines is a complex phenomenon exacerbated by the inhalation of airborne contaminants such as volcanic ash, dust, sand, and combustion by-products. These particles, subjected to the harsh environment within the turbine and characterized by high temperatures, pressures, and velocities which tend to adhere to the turbine components. The accretion of such particles not only alters the geometric profile of the airfoils, increasing surface roughness, but also has profound implications on aerodynamic losses and heat transfer processes. Indeed, this process has significant effect on the performance, efficiency, and lifespan of turbine engines, especially in aircraft and power generation systems. Denser deposits further exacerbate the situation by obstructing film cooling holes, thereby diminishing cooling performance and, by extension, the overall efficiency and operational safety of aeroengines. Understanding the dynamics of particle deposition helps in developing strategies to mitigate its effects and enhance engine reliability and longevity. To this account, a new study published in the International Journal of Thermal Sciences and conducted by Dr. Zihan Hao, Associate Professor Xing Yang, and Professor Zhenping Feng from the Institute of Turbomachinery at Xi’an Jiaotong University the authors explored the complex dynamics of particle deposition in high-pressure turbine stators of aeroengines. This exploration uncovered the nuanced progression of particle accumulation on the stator vane surfaces and also elucidated the consequential alterations in the aerodynamic performance and heat transfer characteristics of the turbine cascade passages. The cornerstone of the new study lies in the integration of unsteady simulations, a sophisticated particle-wall interaction model, and dynamic mesh update technology, facilitating a comprehensive understanding of the dynamic deposition process and its impacts.

The researchers adopted robust and comprehensive methodology which encompassed a detailed computational model of the first-stage high-pressure turbine vane passage. This model, subjected to real cruise working conditions, serves as a fertile ground for simulating the complex interplay between the particulate matter and the turbine environment. Utilizing the Discrete Phase Model (DPM) for precise particle trajectory prediction and an accelerated deposition method, the study achieved a realistic representation of particle accumulation over an equivalent of 1000 operational hours in a matter of seconds within the simulation framework. An important aspect of their methodology is the dynamic mesh update technology, orchestrated through a user-defined function (UDF), which carefully adjusts the mesh in response to the deposition patterns. This approach ensured the accuracy of the simulation and also embodies the dynamic nature of particle deposition, which allows for a nuanced analysis of its effects on the turbine’s performance. The authors’ findings are both illuminating and consequential. Initially, slight deposits were observed to mitigate the thermal load on the vane surfaces, potentially offering a brief respite. However, as deposition progresses, a stark increase in the heat transfer coefficient across the vane surfaces is noted, underscoring a rapid escalation in thermal stress. The accumulation of deposits predominantly on the pressure side of the stator vane leads to a notable reduction in the flow path area, engendering increased energy dissipation as the mainstream gas navigates through the fouled stator. This, in turn, precipitates a deterioration in aerodynamic performance. Moreover, the researchers revealed that the dynamic deposition process engenders localized deposits forming peak-to-valley patterns, significantly influencing the flow field structures, aerodynamic losses, and heat transfer coefficients. These insights highlighted the profound impact of particle deposition on the operational efficiency and longevity of turbine engines. In essence, the research conducted by Hao, Yang, and Feng is a significant advancement in the understanding of particle deposition dynamics in turbine engines. It lays the groundwork for future investigations aimed at mitigating the adverse effects of such deposits, potentially through advanced cooling designs and deposition-resistant materials. As we venture further into the realm of advanced gas turbine technologies, the insights garnered from this study will undoubtedly play a pivotal role in shaping the future of aeroengine design and maintenance strategies, ensuring safer, more efficient, and longer-lasting turbine engines.