A Simple Physics-Based Model for Particle Rebound and Deposition in Turbomachinery

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
J. P. Bons ◽  
R. Prenter ◽  
S. Whitaker

A new model is proposed for predicting particle rebound and deposition in environments relevant to gas turbine engines. The model includes the following physical phenomena: elastic deformation, plastic deformation, adhesion, and shear removal. It also incorporates material property sensitivity to temperature and tangential-normal rebound velocity cross-dependencies observed in experiments. The model is well-suited for incorporation in computational fluid dynamics (CFD) simulations of complex gas turbine flows due to its algebraic (explicit) formulation. Model predictions are compared to coefficient of restitution data available in the open literature as well as deposition results from two different high-temperature turbine deposition facilities. While the model comparisons with experiments are in many cases promising, several key aspects of particle deposition remain elusive. The simple phenomenological nature of the model allows for parametric dependencies to be evaluated in a straightforward manner. It is hoped that this feature of the model will aid in identifying and resolving the remaining stubborn holdouts that prevent a universal model for particle deposition.

Author(s):  
J. P. Bons ◽  
R. Prenter ◽  
S. Whitaker

A new model is proposed for predicting particle rebound and deposition in environments relevant for gas turbine engines. The model includes the following physical phenomena: elastic deformation, plastic deformation, adhesion, and shear removal. It also incorporates material property sensitivity to temperature and tangential-normal rebound velocity cross-dependencies observed in experiments. The model is well-suited for incorporation in CFD simulations of complex gas turbine flows due to its algebraic (explicit) formulation. Model predictions are compared to coefficient of restitution data available in the open literature as well as deposition results from two different high temperature turbine deposition facilities. While the model comparisons with experiments are in many cases promising, several key aspects of particle deposition remain elusive. The simple phenomenological nature of the model allows for parametric dependencies to be evaluated in a straightforward manner. It is hoped that this feature of the model will aid in identifying and resolving the remaining stubborn holdouts that prevent a universal model for particle deposition.


Author(s):  
Y. Levy ◽  
F. C. Christo ◽  
I. Gaissinski ◽  
V. Erenburg ◽  
V. Sherbaum

This study investigates the performance and the conditions under which flameless oxidation can be achieved for a given annular adiabatic combustor. Numerical modelling of velocity, temperature and species fields are performed for different flow configurations of air and methane streams injected into a proposed design of a gas-turbine combustor. Parametric analysis was performed by systematically varying several parameters: radius of a recirculation zone, radius of the combustor, location of air and fuel ports, air and fuel velocities magnitudes and injection angles. The analysis was performed initially using a three-step global chemistry model to identify a design (geometry and operating conditions) that yield flameless combustion regime. The selected design was then modelled using a skeletal (46 reactions) and a detailed (309 reactions) chemical kinetics mechanism. The k–ε turbulence model was used in the most calculations. Overall, similar qualitative flow, temperature, and species patterns were predicted by both kinetics models; however the detailed mechanism provides quantitatively more realistic predictions. An optimal flow configuration was achieved with exhaust NOx emissions of < 7.5 ppm, CO < 35ppm, and a pressure-drop < 5%, hence meeting the design criteria for gas turbine engines. This study demonstrates the feasibility of achieving ultra-low NOx and CO emissions utilising a flameless oxidation regime.


Author(s):  
John T. Pearson ◽  
Yogi Sheoran ◽  
Bill Schuster

Gas turbine engines often pass through tests in enclosed test facilities. One problem that arises during these tests is the infrasound phenomenon. Infrasound can be a problem for many reasons, ranging from rattling windows to structural damage to the test cell. The aim of this paper is to understand the cause of severe infrasound experienced at Honeywell Aerospace and to evaluate and select a solution using advanced Computational Fluid Dynamics (CFD) techniques. These CFD simulations modeled an entire test cell with an engine in place, which is a more complete approach than what is reported in the literature. The DES turbulence model was applied in a transient, compressible, turbulent simulation in order to capture small pressure fluctuations. Test data taken using an engine/test cell configuration that does not cause problems was used to successfully validate the CFD approach. It was found that the narrow, high-velocity exhaust plume examined in this study impacted the convex blast plate in the aft portion of the test cell having diffused only slightly. The exhaust then rebounded and buffeted the plume, causing extreme dynamic loading. Through a modification to the blast basket, it was shown that the problem would be alleviated and sound pressure levels in the test cell would be reduced by 5 to 32 dB, depending on location in the test cell.


Author(s):  
Meinhard T. Schobeiri ◽  
Seyed M. Ghoreyshi

The current article introduces a physics based revolutionary technology that enables energy efficiency and environmental compatibility goals of future generation aircraft and power generation gas turbines. An Ultra-High Efficiency Gas Turbine technology (UHEGT) is developed, where the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed in three stages and integrated within the first three HP-turbine stator rows. The proposed distributed combustion results in high thermal efficiencies, which cannot be achieved by conventional gas turbine engines. Particular fundamental issues of aero-thermodynamic design, combustion, and heat transfer are addressed in this study along with comprehensive CFD simulations. The aero-thermodynamic study shows that the UHEGT-concept improves the thermal efficiency of gas turbines 5–7% above the current most advanced high efficiency gas turbine engines, such as Alstom GT24. Multiple configurations are designed and simulated numerically to achieve the optimum configuration for UHEGT. CFD simulations include combustion process in conjunction with a rotating turbine row. Temperature and velocity distributions are investigated as well as power generation, pressure losses, and NOx emissions. Results show that the configuration in which fuel is injected into the domain through cylindrical tubes provides the best combustion process and the most uniform temperature distribution at the rotor inlet.


1997 ◽  
Vol 28 (7-8) ◽  
pp. 536-542
Author(s):  
A. A. Khalatov ◽  
I. S. Varganov

1988 ◽  
Author(s):  
James C. Birdsall ◽  
William J. Davies ◽  
Richard Dixon ◽  
Matthew J. Ivary ◽  
Gary A. Wigell

2020 ◽  
pp. 22-29
Author(s):  
A. Bogoyavlenskiy ◽  
A. Bokov

The article contains the results of the metrological examination and research of the accuracy indicators of a method for diagnosing aircraft gas turbine engines of the D30KU/KP family using an ultra-high-frequency plasma complex. The results of metrological examination of a complete set of regulatory documents related to the diagnostic methodology, and an analysis of the state of metrological support are provided as well. During the metrological examination, the traceability of a measuring instrument (diagnostics) – an ultrahigh-frequency plasma complex – is evaluated based on the scintillation analyzer SAM-DT-01–2. To achieve that, local verification schemes from the state primary standards of the corresponding types of measurements were built. The implementation of measures to eliminate inconsistencies identified during metrological examination allows to reduce to an acceptable level the metrological risks of adverse situations when carrying out aviation activities in industry and air transportation. In addition, the probability of occurrence of errors of the first and second kind in the technological processes of tribodiagnostics of aviation gas turbine engines is reduced when implementing a method that has passed metrological examination in real practice. At the same time, the error in determining ratings and wear indicators provides acceptable accuracy indicators and sufficient reliability in assessing the technical condition of friction units of the D-30KP/KP2/KU/KU-154 aircraft engines.


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