EBFOG: Deposition, Erosion, and Detachment on High-Pressure Turbine Vanes

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Nicola Casari ◽  
Michele Pinelli ◽  
Alessio Suman ◽  
Luca di Mare ◽  
Francesco Montomoli
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Flight Crew ◽  
High Pressure Turbine ◽  
Turbine Performance ◽  
Turbine Vanes ◽  
Volcanic Ash Cloud ◽  
Engine Stability

Fouling and erosion are two pressing problems that severely affect gas turbine performance and life. When aircraft fly through a volcanic ash cloud, the two phenomena occur simultaneously in the cold as well as in the hot section of the engine. In the high-pressure turbine (HPT), in particular, particles soften or melt due to the high gas temperatures and stick to the wet surfaces. The throat area, and hence the capacity, of the HPT is modified by these phenomena, affecting the engine stability and possibly forcing engine shutdown. This work presents a model for deposition and erosion in gas turbines and its implementation in a three-dimensional Navier–Stokes solver. Both deposition and erosion are taken into account, together with deposit detachment due to changed flow conditions. The model is based on a statistical description of the behavior of softened particles. The particles can stick to the surface or can bounce away, eroding the material. The sticking prediction relies on the authors' Energy Based FOulinG (EBFOG) model. The impinging particles which do not stick to the surface are responsible for the removal of material. The model is demonstrated on a HPT vane. The airfoil shape evolution over the exposure time as a consequence of the impinging particles has been carefully monitored. The variation of the flow field as a consequence of the geometrical changes is reported as an important piece of on-board information for the flight crew.

EBFOG: Deposition, Erosion and Detachment on High Pressure Turbine Vanes

2017 ◽  
Author(s):  
Nicola Casari ◽  
Michele Pinelli ◽  
Alessio Suman ◽  
Francesco Montomoli ◽  
Luca di Mare
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Navier Stokes ◽  
Flight Crew ◽  
High Pressure Turbine ◽  
Area Reduction ◽  
Performance Deterioration ◽  
Engine Stability

Fouling and erosion are two pressing problems that severely affect gas turbine performance and life. When aircraft fly through a volcanic ash cloud the two phenomena occur simultaneously in the cold as well as in the hot section of the engine. In the high pressure turbine, in particular, the particles soften or melt due to the high gas temperatures and stick to the wet surfaces. The throat area, and hence the capacity, of the HP turbine is modified by these phenomena, affecting the engine stability and possibly forcing engine shutdown. This work presents a model for deposition and erosion in gas turbines and its implementation in a three dimensional Navier-Stokes solver. Both deposition and erosion are kept into account, together with deposit detachment due to changed flow conditions. The model is based on a statistical description of the behaviour of softened particles. The particles can stick to the surface or can bounce away, eroding the material. The sticking prediction relies on the authors’ EBFOG model. The impinging particles which do not stick to the surface are responsible for the removal of material. The model is demonstrated on a high pressure turbine vane. The performance deterioration and the throat area reduction rate are carefully monitored. The safe-to-fly time through a cloud can be inferred from the outcome of this work as important piece of on-board information for the flight crew.

Design Optimization of Profiled Endwall With Consideration of Cooling and Rim Seal Flow Effects

2016 ◽  
Author(s):  
Huimin Tang ◽  
Shuaiqiang Liu ◽  
Hualing Luo
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Secondary Flow ◽  
Three Dimensional ◽  
Great Influence ◽  
Optimization Procedure ◽  
Secondary Flows ◽  
High Pressure Turbine ◽  
Operation Condition ◽  
Turbine Performance

Profiled endwall is an effective method to improve aerodynamic performance of turbine. This approach has been widely studied in the past decade on many engines. When automatic design optimisation is considered, most of the researches are usually based on the assumption of a simplified simulation model without considering cooling and rim seal flows. However, many researchers find out that some of the benefits achieved by optimization procedure are lost when applying the high-fidelity geometry configuration. Previously, an optimization procedure has been implemented by integrating the in-house geometry manipulator, a commercial three-dimensional CFD flow solver and the optimization driver, IsightTM. This optimization procedure has been executed [12] to design profiled endwalls for a turbine cascade and a one-and-half stage axial turbine. Improvements of the turbine performance have been achieved. As the profiled endwall is applied to a high pressure turbine, the problems of cooling and rim seal flows should be addressed. In this work, the effects of rim seal flow and cooling on the flow field of two-stage high pressure turbine have been presented. Three optimization runs are performed to design the profiled endwall of Rotor-One with different optimization model to consider the effects of rim flow and cooling separately. It is found that the rim seal flow has a significant impact on the flow field. The cooling is able to change the operation condition greatly, but barely affects the secondary flow in the turbine. The influences of the profiled endwalls on the flow field in turbine and cavities have been analyzed in detail. A significant reduction of secondary flows and corresponding increase of performance are achieved when taking account of the rim flows into the optimization. The traditional optimization mechanism of profiled endwall is to reduce the cross passage gradient, which has great influence on the strength of the secondary flow. However, with considering the rim seal flows, the profiled endwall improves the turbine performance mainly by controlling the path of rim seal flow. Then the optimization procedure with consideration of rim seal flow has also been applied to the design of the profiled endwall for Stator Two.

scholarly journals Calculation and Correlation of the Unsteady Flowfield in a High Pressure Turbine

2002 ◽  
Author(s):  
Milind A. Bakhle ◽  
Jong S. Liu ◽  
Josef Panovsky ◽  
Theo G. Keith ◽  
Oral Mehmed
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Forced Vibrations ◽  
Forced Response ◽  
Operating Conditions ◽  
Test Facility ◽  
Navier Stokes ◽  
Turbine Stage ◽  
High Pressure Turbine

Forced vibrations in turbomachinery components can cause blades to crack or fail due to high-cycle fatigue. Such forced response problems will become more pronounced in newer engines with higher pressure ratios and smaller axial gap between blade rows. An accurate numerical prediction of the unsteady aerodynamics phenomena that cause resonant forced vibrations is increasingly important to designers. Validation of the computational fluid dynamics (CFD) codes used to model the unsteady aerodynamic excitations is necessary before these codes can be used with confidence. Recently published benchmark data, including unsteady pressures and vibratory strains, for a high-pressure turbine stage makes such code validation possible. In the present work, a three dimensional, unsteady, multi blade-row, Reynolds-Averaged Navier Stokes code is applied to a turbine stage that was recently tested in a short duration test facility. Two configurations with three operating conditions corresponding to modes 2, 3, and 4 crossings on the Campbell diagram are analyzed. Unsteady pressures on the rotor surface are compared with data.

Deposition of Volcanic Materials in the Hot Sections of Two Gas Turbine Engines

1993 ◽  
Vol 115 (3) ◽  
pp. 641-651 ◽  
Author(s):  
J. Kim ◽  
M. G. Dunn ◽  
A. J. Baran ◽  
D. P. Wade ◽  
E. L. Tremba
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Volcanic Ash ◽  
Turbine Engines ◽  
Inlet Temperature ◽  
High Pressure Turbine ◽  
Deposition Behavior ◽  
Turbine Engine ◽  
Turbine Vanes ◽  
Volcanic Ash Cloud

This paper reports the results of a series of tests designed to determine the melting and subsequent deposition behavior of volcanic ash cloud materials in modern gas turbine engine combustors and high-pressure turbine vanes. The specific materials tested were Mt. St. Helens ash and a soil blend containing volcanic ash (black scoria) from Twin Mountain, NM. Hot section test systems were built using actual engine combustors, fuel nozzles, ignitors, and high-pressure turbine vanes from an Allison T56 engine can-type combustor and a more modern Pratt and Whitney F-100 engine annular-type combustor. A rather large turbine inlet temperature range can be achieved using these two combustors. The deposition behavior of volcanic materials as well as some of the parameters that govern whether or not these volcanic ash materials melt and are subsequently deposited are discussed.

3D-Modelling and Simulation of Physicochemical Transformations in a High-Pressure Turbine (HPT) of an Aircraft Engine

2014 ◽  
Author(s):  
T. H. Nguyen ◽  
F. Garnier
Keyword(s):  
High Pressure ◽  
Large Scale ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Navier Stokes ◽  
Geometrical Parameters ◽  
High Pressure Turbine ◽  
3D Design ◽  
Complex Interactions ◽  
Fluent Software

In this work, the 3D design of the stator, rotor of a turbine is performed. A one way coupling between a detailed physicochemical box model and multidimensional Navier-Stokes solver (FLUENT software) is used. Various series of three-dimensional calculations including approximately 500,000 elements are carried out to calculate aero-thermodynamics fields for a first stage of high-pressure turbine of the CFM56 aero-engine. The results show that blades of early turbine stages, directly downstream of combustor are subjected to relatively high levels of unsteadiness generated from complex significant three dimensional shear layers. The latter causes the formation of large-scale turbulent. By consequence, the complex interactions between the geometrical parameters, thermodynamical and chemical processes involving aerosol precursor formation in the turbine are analyzed and investigated.

Deposition of Volcanic Materials in the Hot Sections of Two Gas Turbine Engines

1992 ◽  
Author(s):  
J. Kim ◽  
M. G. Dunn ◽  
A. J. Baran ◽  
D. P. Wade ◽  
E. L. Tremba
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Volcanic Ash ◽  
Turbine Engines ◽  
Inlet Temperature ◽  
High Pressure Turbine ◽  
Deposition Behavior ◽  
Turbine Engine ◽  
Turbine Vanes ◽  
Volcanic Ash Cloud

This paper reports the results of a series of tests designed to determine the melting and subsequent deposition behavior of volcanic ash cloud materials in modern gas turbine engine combustors and high pressure turbine vanes. The specific materials tested were Mt. St. Helens ash and a soil blend containing volcanic ash (black scoria) from Twin Mountain, New Mexico. Hot section test systems were built using actual engine combustors, fuel nozzles, ignitors, and high pressure turbine vanes from an Allison T56 engine can-type combustor and a more modern Pratt and Whitney F-100 engine annular-type combustor. A rather large turbine inlet temperature range can be achieved using these two combustors. The deposition behavior of volcanic materials as well as some of the parameters that govern whether or not these volcanic ash materials melt and subsequently deposit are discussed.

Feasibility Study of Incorporating Flow Unsteadiness in Control of Secondary Flows in Shrouded Turbines

2013 ◽  
Author(s):  
Jie Gao ◽  
Qun Zheng ◽  
Xiaoquan Jia
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Internal Flow ◽  
Secondary Flows ◽  
Navier Stokes ◽  
High Pressure Turbine ◽  
Numerical Investigations ◽  
Flow Interactions ◽  
Turbine Cascades ◽  
Flow Effects

The internal flow in turbomachinery is inherently unsteady, and the endwall losses are major sources of lost efficiency in high-pressure turbine cascades. Therefore, the investigation of the unsteady endwall flow interactions is valuable to improve the performance of high-pressure turbines. Unsteady and steady numerical investigations of endwall flow interactions of 1.5-stage shrouded turbines with straight and bowed vanes are performed using a three-dimensional Navier-Stokes viscous solver. Emphasis is placed on how unsteady stator-rotor interactions affect shrouded turbine endwall secondary flows, on the basis of which the feasibility of incorporating the unsteady endwall flow effects in the control of secondary flows is discussed in detail. Results from this investigation are well presented and discussed in this paper.

A Systematic Experimental Study on the Aerodynamics of Leading Edge Film Cooling on a Large Scale High Pressure Turbine Cascade

1998 ◽  
Author(s):  
Sabine Ardey ◽  
Leonhard Fottner
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Injection Site ◽  
Film Cooling ◽  
Gas Turbines ◽  
Large Scale ◽  
Three Dimensional ◽  
Leading Edge ◽  
Turbine Cascade ◽  
High Pressure Turbine

Systematic isothermal investigations on the aerodynamic effects of leading edge film cooling were carried out on a large scale high pressure turbine cascade named AGTB. In the vicinity of the stagnation point the AGTB turbine cascade has one injection site on the suction side and one on the pressure side. Three injection geometries were tested: Slots (two dimensional geometry), streamwise inclined holes (symmetrical three dimensional geometry) and compound angle holes (fully three dimensional geometry). The injection angle in streamwise direction, the blowing ratio, the inlet turbulence intensity, the inlet Mach number, and the inlet Reynolds number were kept constant at values typically found in modern gas turbines. The measured data comprise the coolant plenum state, the cascade inlet conditions, the flow field in the cascade exit plane including secondary flows, the static pressure distribution in the mid span section of the blade and in the near hole region, the coolant flow field close to the injection site on the leading edge, Schlieren images of the coolant penetration height and oil-and-dye flow visualizations of the blade surface. The experimental data are summarized and documented as a test case that can be used for validation purposes of prediction methods.

Design of an Intermediate Turbine Duct Downstream of a High Pressure Turbine

2016 ◽  
Author(s):  
Chaoshan Hou ◽  
Hu Wu
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Low Pressure ◽  
Aerodynamic Load ◽  
Duct Flow ◽  
Original Design ◽  
High Pressure Turbine ◽  
Intermediate Turbine Duct ◽  
Low Pressure Turbine ◽  
Inlet Conditions

The flow leaving the high pressure turbine should be guided to the low pressure turbine by an annular diffuser, which is called as the intermediate turbine duct. Flow separation, which would result in secondary flow and cause great flow loss, is easily induced by the negative pressure gradient inside the duct. And such non-uniform flow field would also affect the inlet conditions of the low pressure turbine, resulting in efficiency reduction of low pressure turbine. Highly efficient intermediate turbine duct cannot be designed without considering the effects of the rotating row of the high pressure turbine. A typical turbine model is simulated by commercial computational fluid dynamics method. This model is used to validate the accuracy and reliability of the selected numerical method by comparing the numerical results with the experimental results. An intermediate turbine duct with eight struts has been designed initially downstream of an existing high pressure turbine. On the basis of the original design, the main purpose of this paper is to reduce the net aerodynamic load on the strut surface and thus minimize the overall duct loss. Full three-dimensional inverse method is applied to the redesign of the struts. It is revealed that the duct with new struts after inverse design has an improved performance as compared with the original one.

Effect of Outer Fin Axial Gap on the Sealing Effectiveness and Fluid Dynamics of Radial Rim Seal

2017 ◽  
Author(s):  
Zhigang Li ◽  
Jun Li ◽  
Liming Song ◽  
Qing Gao ◽  
Xin Yan ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Flow Rate ◽  
Gas Turbines ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Navier Stokes ◽  
Hot Gas

The modern gas turbine is widely applied in the aviation propulsion and power generation. The rim seal is usually designed at the periphery of the wheel-space and prevented the hot gas ingestion in modern gas turbines. The high sealing effectiveness of rim seal can improve the aerodynamic performance of gas turbines and avoid of the disc overheating. Effect of outer fin axial gap of radial rim seal on the sealing effectiveness and fluid dynamics was numerically investigated in this work. The sealing effectiveness and fluid dynamics of radial rim seal with three different outer fin axial gaps was conducted at different coolant flow rates using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulent model solutions. The accuracy of the presented numerical approach for the prediction of the sealing performance of the turbine rim seal was demonstrated. The obtained results show that the sealing effectiveness of radial rim seal increases with increase of coolant flow rate at the fixed axial outer fin gap. The sealing effectiveness increases with decrease of the axial outer fin gap at the fixed coolant flow rate. Furthermore, at the fixed coolant flow rate, the hot gas ingestion increases with the increase of the axial outer fin gap. This flow behavior intensifies the interaction between the hot gas and coolant flow at the clearance of radial rim seal. The preswirl coefficient in the wheel-space cavity is also illustrated to analyze the flow dynamics of radial rim seal at different axial outer fin gaps.

Sign in / Sign up

Export Citation Format

Share Document