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        <title>Frontiers in Mechanical Engineering | Turbomachinery section | New and Recent Articles</title>
        <link>https://www.frontiersin.org/journals/mechanical-engineering/sections/turbomachinery</link>
        <description>RSS Feed for Turbomachinery section in the Frontiers in Mechanical Engineering journal | New and Recent Articles</description>
        <language>en-us</language>
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        <pubDate>2026-05-15T07:34:08.850+00:00</pubDate>
        <ttl>60</ttl>
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        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2025.1658430</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2025.1658430</link>
        <title><![CDATA[Guided wave based health monitoring of composite wind turbine blades: multi-level damage assessment]]></title>
        <pubdate>2026-01-08T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Anjaly J. Pillai</author><author>Shirsendu Sikdar</author>
        <description><![CDATA[Structural health monitoring (SHM) of wind turbines is critical for maintaining continuous operation, minimizing maintenance expenses, and maximizing energy production. Recent advancements in sensor technology have made it possible to gather extensive ultrasonic guided wave (UGW) data from wind turbine components, enabling assessment of their structural integrity. This research examines UGW-based nondestructive evaluation techniques applied to composite wind turbine blades under varied structural conditions using experimental and numerical analysis. UGW signals recorded through an actuator-sensor network contain essential information on blade health. A Random Forest model is used to predict changes in A0 and S0 mode group velocities and amplitudes due to erosion/corrosion, longitudinal debonding, and transverse debonding across damage sizes ranging from 0 to 40 mm. To assess prediction reliability, 95% confidence intervals are included as uncertainty bands; narrower bands suggest higher confidence, while a wider band indicates greater uncertainty. Sensitivity analysis highlights the impact of damage size and type on UGW signal properties, supporting improved predictions. This study underscores the potential of UGW-based SHM to enhance wind turbine reliability and promote sustainable energy generation.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2025.1716347</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2025.1716347</link>
        <title><![CDATA[Multi-objective optimization of a multiphase pump booster unit for enhanced hydraulic performance]]></title>
        <pubdate>2026-01-07T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Pingyang Dong</author><author>Guangtai Shi</author><author>Yexiang Xiao</author><author>Haigang Wen</author><author>Wenjuan Lv</author><author>Xiaodong Peng</author>
        <description><![CDATA[As key equipment in oil and gas transmission systems, multiphase pumps are crucial for ensuring a closed oilfield collection and transmission. The booster unit as the core component of the multiphase pump, has blade shapes that significantly impact the pump efficiency and its gas-liquid mixing performance. To enhance the efficiency of the booster unit and improve its gas-liquid mixing, this study first employed an optimal Latin hypercube design to sample blade shape parameters and establish a design library. The effects of these parameters were systematically investigated via numerical simulation. Subsequently, an approximate prediction model was developed and integrated into a multi-objective optimization framework to identify Pareto-optimal blade configurations. Following optimization, the pump efficiency increased from 52.60% to 54.56% (a 3.59% improvement), while the gas uniformity at the impeller outlet decreased from 0.3229 to 0.3040 (a 6.22% reduction). Comparative analysis of internal and external characteristics confirmed improved gas dispersion and more refined flow field structures within the optimized booster unit. The proposed methodology integrates advanced sampling, modeling, and optimization techniques, providing a systematic and efficient strategy for the performance-driven design of multiphase pump blades. This framework offers significant potential for enhancing the hydraulic performance and operational stability of such critical transport equipment.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2025.1711624</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2025.1711624</link>
        <title><![CDATA[Numerical investigation of Pelton bucket geometries for performance improvement]]></title>
        <pubdate>2025-12-03T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Hiren Shah</author><author>Gaurangkumar Chaudhari</author><author>Vijay Dhiman</author><author>Ravi Bhatt</author><author>Sachin Salunkhe</author><author>Lenka Cepova</author>
        <description><![CDATA[The Pelton turbine is the most effective impulse turbine and has excellent operational performance in high water heads as well as low water rates. The bucket splitter design plays a crucial role, as its design is responsible for its efficiency. The water jet strikes the bucket splitter and produces the forces that move the turbine runner to generate mechanical energy from the kinetic head. A comparative analysis of seven differently designed Pelton turbine buckets is done in this paper. Finite Element Analysis (FEA), as a constructive method to check the static structural analysis in the Pelton turbine bucket, has been used to compare the performance. The effect of changing various parameters like bucket exit angle, bucket width, and bucket thickness on the life of the bucket is discussed here. This study aims to compare and achieve the best design of the Pelton bucket to improve its strength by reducing von mises stress and reducing the deformation. Bucket width is achieved as 110 mm, thickness 5 mm, splitter tip level, and cutout length both at 3 mm, and cutout width at 23.25 mm for effective flow over the bucket surface. The bucket exit angle at the middle section is achieved as 15° to reduce the von mises stress and deformation significantly.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2025.1678531</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2025.1678531</link>
        <title><![CDATA[A laser imaging technique for measuring particle distribution at a gas turbine engine inlet]]></title>
        <pubdate>2025-10-10T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Kristopher T. Olshefski</author><author>Gwibo Byun</author><author>John Gillespie</author><author>K. Todd Lowe</author><author>Wing F. Ng</author>
        <description><![CDATA[The present study demonstrates the novel application of a method for assessing particle spatial distribution at the inlet of a gas turbine engine that is undergoing solid particulate ingestion. Termed the Particle Visualization by Illuminated Scattering (ParVIS) technique, this method requires a laser sheet, camera, and in-situ particle feed rate reference measurement to provide imaging-based measurements of integrated particle mass flow and concentration distribution across the illuminated engine inlet plane. This is accomplished by incorporating an in-situ calibration constant that takes into account both the particle mass flow rate and the integrated pixel intensity across the captured region, which exhibits a proportional relationship. For these tests, a Rolls-Royce M250 turboshaft engine was operated at a ground idle condition (air intake mass flow of 0.744 kg/s), and crushed quartz sand was delivered at a maximum average rate of approximately 1.5 g/min. The results show accurate estimations of the injected particle mass flow, with an average root-mean-square error of 0.06 g/min, or 6%, compared to the monitored mass flow value obtained using a precision scale.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2025.1683572</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2025.1683572</link>
        <title><![CDATA[Design of a real-time abnormal detection system for rotating machinery based on YOLOv8]]></title>
        <pubdate>2025-10-07T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Jianli Chen</author><author>Jie Tong</author><author>Jiang Su</author>
        <description><![CDATA[To address the issues of low detection accuracy and poor real-time performance in existing methods for detecting minor abnormalities such as cracks, oil leaks, and loose bolts in rotating industrial machinery under dynamic vibration conditions, this paper proposes a lightweight detection system based on YOLOv8 (You Only Look Once version 8) with adaptive feature enhancement. First, this paper employs a temporal motion compensation module based on optical flow to estimate and correct the vibration displacement between adjacent frames. Second, this paper designs a lightweight YOLOv8 network, using depthwise separable convolution instead of traditional convolution. Finally, this paper employs a weighted fusion strategy to improve the accuracy of small object detection in complex backgrounds. This model is deployed on the Jetson AGX Xavier edge computing platform, utilizing FP16 (half-precision floating-point) / INT8 (8-bit integer) quantization and asynchronous pipeline inference to ensure real-time processing capabilities on edge devices. The experimental results show that the method achieves an average detection accuracy of 97.8% (mAP@0.5) and 86.6% (mAP@0.5:0.95), with an average inference speed of 29.5 FPS (frames per second). This demonstrates that the method has reached industrial-grade performance in terms of detection accuracy, real-time performance, and deployment stability, making it highly valuable for practical applications.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2025.1440903</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2025.1440903</link>
        <title><![CDATA[Optimizing the labyrinth geometric parameters and modelling a new twin seal configuration for improved sealing efficiency in gas turbines]]></title>
        <pubdate>2025-02-27T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>B. Vijayaragavan</author><author>S. P. Asok</author><author>M. K. Marichelvam</author>
        <description><![CDATA[Labyrinth seals are the non-contact seals used in turbo machinery to control the leakage of the secondary fluid flow. The main compressor supplies the compressed air required to generate hot gases in the combustion chamber. The secondary fluid is the part of the compressed air from the main compressor, which is used for cooling the inner components of turbomachinery. The non-contact nature of the seal results in an additional expense of compressed cooling air, which increases the power input to the main compressor. An improvement in the labyrinth’s sealing efficiency increases turbomachines’ fuel efficiency. The sealing characteristics of the labyrinth profile are highly influenced by the geometric parameters of the labyrinth seal. The geometric parameters of the straight-through labyrinth seal are optimized towards reduced leakage flow, and the optimized parameters are used to develop a new type of “Twin Labyrinth Seal.” The design variables considered in the optimization studies are tooth thickness, cavity width, and cavity depth of the labyrinth, while leakage mass flow rate is the variable to be minimized. Leakage characteristics for different configurations of the twin labyrinth seal are explored using numerical analysis. The standard k-epsilon two-equation viscous model simulates turbulence in the flow through the labyrinth path. The twin labyrinth configuration E with the least leakage is identified with an improved leakage control by 38% compared to the straight-through configuration of the tooth-on stator type. The results from the numerical analysis are validated with experiments. The significance of the effective clearance and divergence angle on the leakage characteristics of the twin labyrinth are discussed.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2024.1420472</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2024.1420472</link>
        <title><![CDATA[A model to assess the importance of runway and taxiway particles to aircraft engine compressor deterioration]]></title>
        <pubdate>2024-08-22T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Stefano Scarso</author><author>Stephan Staudacher</author><author>Jürgen Mathes</author><author>Norman Schwarz</author>
        <description><![CDATA[During service, civil turbofans experience environmentally induced deterioration. Predicting this in a digital service twin model is computationally challenging due to the need to model both deterioration mechanisms and environmental conditions. For compressor erosion, a key challenge is to model particle ingestion throughout a flight mission (FM). During ground operations, these particles may be airborne or deposited on runways and taxiways. This work assesses the impact of the latter on turbofan core compressor deterioration during a mission. The airflow field in front of the engine intake is approximated using potential flow theory. Comparisons with measurements show that the predicted air velocity near the engine is underestimated since the inlet ground vortices generated from viscous effects are neglected. The forces acting on the particles are derived from the flow field. It turns out that most particles are lifted from the ground during take-off (TO). Yet only smaller particles below ≈ 50 µm are ingested into the engine intake. A deterioration model based on flat plate erosion experiments is used to compute mission severity, assuming all particles are similar to medium Arizona Road Dust. The results indicate that the engine’s distance from the ground, power setting, and the number of particles on the ground are key parameters influencing the impact of runway and taxiway particles. Considering the underestimation of the airflow field and thus the number of particles ingested, it is concluded that runway and taxiway particles play a major role in turbofan compressor deterioration.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2024.1369876</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2024.1369876</link>
        <title><![CDATA[Model-based performance study of an industrial single spool gas turbine 9EA-GT by changing the inlet guide vane angle and modifying the compressor map]]></title>
        <pubdate>2024-04-19T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Adel Alblawi</author>
        <description><![CDATA[In this article, an industrial gas turbine engine with a single spool (single spool 9EA-GT) is discussed, and a thermodynamic model for computing steady-state performance is presented. In addition, a novel component map production method for investigating a gas turbine engine (GTE) is developed for a different compressor and turbine by downloading from the GasTurb 12 tool and scaling to the compressor and turbine’s design points. A system of controlling engine flow capacitance by changing inlet guide vanes (IGVs) is presented. Adjusting the controllable IGV blades can optimize all the engine units by continuously correcting the compressor features map. The airflow via the compressor, which in turn controls the airflow throughout the entire system, is managed by IGVs. The computations for steady-state performance involve two models: steady-state behavior at engine startup (from 65% to 100% speed, without load) and steady-state behavior while loading (continuous speed of 100%). In this model, the challenges brought by the lack of understanding of stage-by-stage performance are resolved by building artificial machine maps using suitable scaling methods to generalized maps derived from the previous research and validating them with experimental observations from real power plants. The engine performance simulation utilizing the maps is carried out using MATLAB. Assessment results are found to be in good agreement with the actual performance data. During a steady start, the control system used in this study decreased the fuel consumption, exhaust gas mass flow rate, and compressor-driven power for the GTE by 9.5%, 19.3%, and 37.5%, respectively, and those variables decreased by 1%, 12.2%, and 19.7%, respectively, when loading the engine.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2024.1362431</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2024.1362431</link>
        <title><![CDATA[The influence of gear load distribution based on coupled systems on gearbox meshing noise]]></title>
        <pubdate>2024-04-02T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Lundun Zhang</author><author>Teng Wan</author><author>Chunyou Zhang</author>
        <description><![CDATA[Introduction: With the rapid development of the gearbox manufacturing industry, the internal gear response has received attention, and the control of meshing noise during gear operation has been studied. Conventional noise reduction methods are usually based on gear order, and with the improvement of gearbox manufacturing technology, this method gradually becomes difficult to cope with a wide range of data.Methods: To expand the search domain of noise control systems, this study combines gear response and gear order, and adds the condition of gear uniform load. For common noise reduction problems in composite systems, this study improves the time-varying stiffness excitation mechanism and generates a coupled system.Results: Finally, this study conducts experiments on the Gmnoi dataset and compares it with three systems including quantum genetics to verify the superiority of the proposed system. The suppression effects of the four systems on gear meshing noise were 98.4%, 95.8%, 93.5%, and 92.7%, respectively. Their highest performance for different gear groups was 623, 514, 406, and 423, respectively.Discussion: The experimental results showed that the proposed coupling system has strong robustness and high accuracy in controlling gearbox meshing noise, and is of great significance in reducing noise pollution and improving the working environment of the gearbox.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2023.1261017</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2023.1261017</link>
        <title><![CDATA[Characterization of wind turbine flow through nacelle-mounted lidars: a review]]></title>
        <pubdate>2023-11-02T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Stefano Letizia</author><author>Peter Brugger</author><author>Nicola Bodini</author><author>Raghavendra Krishnamurthy</author><author>Andrew Scholbrock</author><author>Eric Simley</author><author>Fernando Porté-Agel</author><author>Nicholas Hamilton</author><author>Paula Doubrawa</author><author>Patrick Moriarty</author>
        <description><![CDATA[This article provides a comprehensive review of the most recent advances in the planning, execution, and analysis of inflow and wake measurements from nacelle-mounted wind Doppler lidars. Lidars installed on top of wind turbines provide a holistic view of the inflow and wake characteristics required to characterize and optimize wind turbine performance, carry out model validation and calibration, and aid in real-time control. The need to balance the enhanced capabilities and limitations of lidars compared to traditional anemometers inspired a broad variety of approaches for scan design and wind reconstruction, which we discuss in this review. We give particular emphasis to identifying common guidelines and gaps in the available literature with the aim of providing an exhaustive picture of the state-of-the-art techniques for reconstructing wind plant flow using nacelle-mounted lidars.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2023.1145305</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2023.1145305</link>
        <title><![CDATA[Insensitivity to propagation timing in a preview-enabled wind turbine control experiment]]></title>
        <pubdate>2023-05-23T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Michael Sinner</author><author>Vlaho Petrović</author><author>David Stockhouse</author><author>Apostolos Langidis</author><author>Manuel Pusch</author><author>Martin Kühn</author><author>Lucy Y. Pao</author>
        <description><![CDATA[Lidar scanners are capable of taking measurements of a wind field upstream of a wind turbine. The wind turbine controller can use these measurements as a “preview” of future disturbances impacting the turbine. Such preview-enabled (or feedforward) controllers show superior performance to standard wind turbine control configurations based purely on a feedback architecture. To capitalize on the performance improvements that preview wind measurements can provide, feedforward control actions should be timed to coincide with the arrival of the wind field at the wind turbine location. However, the time of propagation of the wind field between the lidar measurement location and the wind turbine is not perfectly known. Moreover, the best time to take feedforward control action may not perfectly coincide with the true arrival time of the wind disturbance. This contribution presents results from an experiment where preview-enabled model predictive control was deployed on a fully-actuated, scaled model wind turbine operating in a wind tunnel testbed. In the study, we investigate the sensitivity of the controller performance to the assumed propagation delay using a range of wind input sequences. We find that the preview-enabled controller outperforms the feedback only case across a wide range of assumed propagation delays, demonstrating a level of robustness to the time alignment of the incoming disturbances.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2023.1108180</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2023.1108180</link>
        <title><![CDATA[Large-eddy simulation of a 15 GW wind farm: Flow effects, energy budgets and comparison with wake models]]></title>
        <pubdate>2023-03-27T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Oliver Maas</author>
        <description><![CDATA[Planned offshore wind farm clusters have a rated capacity of more than 10 GW. The layout optimization and yield estimation of wind farms is often performed with computationally inexpensive, analytical wake models. As recent research results show, the flow physics in large (multi-gigawatt) offshore wind farms are more complex than in small (sub-gigawatt) wind farms. Since analytical wake models are tuned with data of existing, sub-gigawatt wind farms they might not produce accurate results for large wind farm clusters. In this study the results of a large-eddy simulation of a 15 GW wind farm are compared with two analytical wake models to demonstrate potential discrepancies. The TurbOPark model and the Niayifar and Porté-Agel model are chosen because they use a Gaussian wake profile and a turbulence model. The wind farm has a finite size in the crosswise direction, unlike as in many other large-eddy simulation wind farm studies, in which the wind farm is effectively infinitely wide due to the cyclic boundary conditions. The results show that new effects like crosswise divergence and convergence occur in such a finite-size multi-gigawatt wind farm. The comparison with the wake models shows that there are large discrepancies of up to 40% between the predicted wind farm power output of the wake models and the large-eddy simulation. An energy budget analysis is made to explain the discrepancies. It shows that the wake models neglect relevant kinetic energy sources and sinks like the geostrophic forcing, the energy input by pressure gradients and energy dissipation. Taking some of these sources and sinks into account could improve the accuracy of the wake models.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2022.973293</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2022.973293</link>
        <title><![CDATA[Film-cooling hole optimization and experimental validation considering the lateral pressure gradient]]></title>
        <pubdate>2023-01-09T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Hao Zhang</author><author>Jinlan Gou</author><author>Peng Yin</author><author>Xinrong Su</author><author>Xin Yuan</author>
        <description><![CDATA[The flow in the turbine endwall region consists of the complicated secondary flow structures driven by the lateral pressure gradient, which heavily affects the performance of film cooling. In this work, the film-cooling hole design optimization is performed considering the existence of the lateral pressure gradient in the real flow environment. Results have shown that the optimal film-cooling hole design is heavily influenced by the lateral pressure gradient in the endwall region, especially the compound angle design is clearly different from the flat plate flow environment. The optimization results are further validated with experiments using the pressure-sensitive paint (PSP) technique, and the film cooling performance is shown to be improved by 42.9%. This work demonstrates the importance of considering the real flow environment in the film-cooling hole design and also can provide guidance to the film-cooling hole design in the endwall region.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2022.924755</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2022.924755</link>
        <title><![CDATA[Environmental particle rebound/deposition modeling in engine hot sections]]></title>
        <pubdate>2023-01-05T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Lei-Yong Jiang</author><author>Patrick Trembath</author><author>Prakash Patnaik</author><author>Michele Capurro</author>
        <description><![CDATA[The aircraft engine hot section is most vulnerable and failure prone to environmental particle ingestion, which, particularly for helicopters, can cause detrimental effects ranging from reduced performance to complete engine failure. The objective of this work is to develop an analytical tool to assess environmental particle impact on engine hot sections. The current state of the art in experimental and analytical research on environmental particle ingestion related to engine hot sections was reviewed, with emphasis on sand particles. From these efforts, the available experimental data for model calibration were identified, and an innovative particle rebound/deposition model has been developed. A semi-empirical approach is selected to model particles bouncing off metal surfaces, where the coefficients of restitution measured in a temperature range of 297–1323 K are used to calculate particle bounce-back velocity components. The developed deposition model is based on non-dimensional parameter analysis over more than seventy experiments related to particle deposition in engine hot sections. The metal surface temperature, one of two critical parameters in particle deposition, is also included in the model. The model was successfully implemented into commercial software and checked step by step. It was calibrated by two cases: sand [Arizona road dust (ARD)] particle impingement on a circular plate and Mt. St. Helens volcanic ash impinging on a first-stage air-cooled nozzle guide vane (NGV). For the former case, the calibrated model predicts fairly well the variation of particle deposition rate with flow/particle temperature. The latter case indicates that the particle deposition rate at engine operating conditions can be assessed by the developed model. Due to the lack of experimental data that would permit a full calibration/validation, for the time being the model can be only used under limited conditions. As additional relevant experimental data appears, the model will be continuously improved.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2022.918708</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2022.918708</link>
        <title><![CDATA[Experimental and numerical investigation into the effect of surface roughness on particle rebound]]></title>
        <pubdate>2022-10-07T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Johannes Altmeppen</author><author>Heike Sommerfeld</author><author>Christian Koch</author><author>Stephan Staudacher</author>
        <description><![CDATA[Erosion damage and particle deposition are crucial wear phenomena in gas turbine engines. As a result, compressor efficiency decreases, stability margin reduces, and maintenance cost increases. Hence, predicting these phenomena in an accurate manner is of paramount importance for a cost-efficient, safe, and sustainable operation. Erosion and particle deposition in the annulus are affected by particle transportation in the fluid and particle-wall interaction. The latter involves the particle impact, the potential damage of the surface and/or the particle, and the particle rebound. Particle rebounds are statistical in nature due to the target surface roughness, the variability in particle sizes, and superimposed effects caused by particle shapes as well as particle rotation and particle break-up during contact. Multiple studies investigated the statistics of particle rebound, providing empirical-based models for median and spread. However, modeling the particle-wall interaction and its data spread on a transparent physical basis allows separating the effect of target roughness from superimposed effects. The presented article pursues this objective by assessing the statistical spread of particle rebound data through multiple techniques and utilizing their interdependencies. It combines experimental, numerical, and analytical considerations. For the first time, coherent boundary conditions for the experimental, numerical and analytical setup allow the distinction of the effect of roughness from the integral effect of the superimposed phenomena. A sandblast test rig equipped with laser measurement equipment was used to measure particle rebound from flat titanium and stainless steel plates at different angles. The numerical setup is developed under OpenFOAM 6 using a RANS solver for transient simulations with compressible media in combination with one-way coupled particle flows. The numerical model includes the rebound spread model proposed by Altmeppen et al. combined with the quasi-analytical rebound model proposed by Bons et al. The statistical spread of particle rebound is investigated for roughness levels that are similar to the ones of deteriorated high-pressure compressor blades as discussed by Gilge et al. The measured surface roughness of the experimentally investigated targets is used as input parameters to the numerical framework. The rebound statistics obtained in the numerical simulation are compared to the rebound data measured in the experiment. Based on this study, conclusions are drawn about which part of the rebound spread is attributable to surface roughness and which is caused by superimposed effects. It was found that the effect of surface roughness as characterized by Altmeppen et al. contributes in the order of 46 % to the rebound spread for small impact angles. However, the share in spread due to roughness gradually decreases with increasing global impact angles to a level of 13 % for angles close to 90°. The remaining percentage of rebound spread is attributed to superimposing phenomena. In addition to the rolling and sliding of aspherical particles, further phenomena such as plastic deformation and erosion of the roughness peaks during contact and the associated dissipation of energy gain in importance for steeper impact angles. Therefore, the effect of surface roughness should not be neglected in numerical simulations of particle-laden flows. Modeling the superimposed phenomena which are observed to be dominating at high impact angles opens up a further field of research.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2022.951986</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2022.951986</link>
        <title><![CDATA[Development of an anisokinetic particle sampling probe for use in a gas turbine engine compressor]]></title>
        <pubdate>2022-09-30T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Kristopher Olshefski</author><author>Addison Collins</author><author>Thomas Coulon</author><author>Todd Lowe</author><author>Wing Ng</author>
        <description><![CDATA[Sand and dust particle ingestion is an inevitability for aircraft operating in arid environments. For conventional takeoff and landing aircraft, significant dust can be ingested into the gas turbine powerplant. Helicopters and vertical takeoff and landing (VTOL) aircraft are at especially high risk due to their tendency to blow significant debris into the air during takeoff and landing operations. The present study highlights the development of an anisokinetic particle sampling probe for use in aircraft engines to obtain real-time measurement of ingested particles often present in these harsh environments. Offtake of particles during engine operation in dusty conditions will provide researchers with an improved understanding of particle breakage tendency and component erosion susceptibility. Three foundational studies were conducted to establish a baseline understanding of probe performance: an aerodynamic study, a particle tracking study, and a particle sampling study. These studies were performed using the Free Jet rig at the Advanced Propulsion and Power Laboratory at Virginia Tech. Particles as large as 1.3 mm were sampled at Mach numbers where M = (0.25, 0.70) and yaw angles ranging from 0° to 45° relative to freestream, conditions not previously investigated. Results indicate that the probe operates sub-isokinetically throughout the full range of test conditions and that probe aerodynamic capture efficiency is inversely proportional to both Mach number and yaw angle. However, this efficiency limitation does not notably influence the sampling probe’s ability to capture the test dust of interest. While the presence of the probe in the flow does result in an airflow velocity reduction of up to 55%, due to their relatively large Stokes numbers the particles of interest only experience a decrease of roughly 5%. These results indicate that this probe is capable of providing researchers with valuable particle size and shape information through effective particle sampling at particle sizes (100 μm ≤ dp ≤ 1,300 μm) and speeds (M ≥ 0.25) not previously investigated.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmech.2022.925395</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmech.2022.925395</link>
        <title><![CDATA[Prediction of Compressor Blade Erosion Experiments in a Cascade Based on Flat Plate Specimen]]></title>
        <pubdate>2022-07-25T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Max Lorenz</author><author>Markus Klein</author><author>Jan Hartmann</author><author>Christian Koch</author><author>Stephan Staudacher</author>
        <description><![CDATA[Erosion is an essential deterioration mechanism in compressors of jet engines. Erosion damage predictions require the determination of erosion rates through flat plate experiments. The applicability of the erosion rates is limited to conditions that are comparable to the prevailing boundary conditions of the flat plate experiment. A performed dimensional analysis enables the correct transfer of the flat plate erosion rates to the presented physical calculation model through limits in spatial and time resolution. This efficient approach avoids computationally intensive single-impact computations. The approach features a re-meshing procedure that adheres to the limits derived by the dimensional analysis. The computation approach is capable of describing local geometry changes on cascade compressor blades which are exposed to erosive particles. A linear erosion cascade experiment performed on NASA Rotor 37 provides validation data for the calculated erosion-induced shape change. Arizona Road Dust particles are used to deteriorate Ti-Al6-4V compressor blades. The experiment is performed at an incidence of i = 7°and Ma = 0.76 representing ground idle conditions. The presented parametric study for element size and time step revealed preferable values for the presented computation. Calculations performed with the determined values showed that the erosion prediction is within the measurement tolerance of the experiment and, therefore, high accordance between the computation and the experiment is achieved. To extend the current state of the art, it is demonstrated that the derived discretization is decisive for the correct reproduction of the eroded geometries and fitting parameters are no longer needed. The good agreement between the experimental measurements and the calculated results confirms the correct application of the physical model to the phenomenology of erosion. Thus, the presented physical model offers a novel approach to adapting deterioration mechanisms caused by erosion to any compressor blade geometry.]]></description>
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