Passive Tracer Validity for Cooling Effectiveness Through Flow Computation in a Turbine Rim Seal Environment

2011 ◽  
Author(s):  
Guillaume Boutet-Blais ◽  
Julie Lefrancois ◽  
Guy Dumas ◽  
Steve Julien ◽  
Jean-Francois Harvey ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Thermal Conditions ◽  
Operating Conditions ◽  
Passive Tracer ◽  
Turbine Stage ◽  
Cooling Effectiveness ◽  
Through Flow ◽  
Purge Flow ◽  
Unsteady Rans ◽  
The Right

This paper reports the first phase of an investigation aiming to determine the validity of using a CO2 marker in cold rig experiments to characterize the thermal performances of turbine rim seals under actual engine operating conditions. For comparison purposes, simulations are carried out for two sets of operating conditions, namely cold rig (with uniform low temperature) and real turbine thermal conditions (high temperature gaspath and cold purge flow). Sealing effectiveness based on the CO2 diagnostic under cold rig operating conditions is compared to sealing effectiveness based on the computed temperature field under real engine temperature conditions. Unsteady RANS simulations with different purge flow rates are performed. Tested geometries include a 180° domain presenting a simplified rim seal geometry with no vanes nor blades in the gaspath, and a 24° sector of a complete turbine stage including 3 vanes and 4 blades. Three-dimensional flow structures known to affect ingestion are found with both geometries but appear to be sensitive to the differences in operating conditions. Indeed, their circumferential number and strength differ between the two scenarios of conditions. Furthermore, it is found that the cold rig predictor tends to slightly overestimate the sealing effectiveness, while providing nonetheless the right trends and reasonably accurate average values in levels of actual sealing. At this stage of the investigation, we conclude that it seems adequate to use a passive tracer in cold rig experiments to compare performances of rim seal designs.

Effect of Wake Passing on Unsteady Aerodynamic Performance in a Turbine Stage

2006 ◽  
Author(s):  
K. Yamada ◽  
K. Funazaki ◽  
K. Hiroma ◽  
M. Tsutsumi ◽  
Y. Hirano ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Three Dimensional ◽  
Suction Side ◽  
Turbine Stage ◽  
Three Dimensional Flow ◽  
Unsteady Aerodynamic ◽  
Unsteady Effect ◽  
Unsteady Rans ◽  
Wake Passing ◽  
Stage Efficiency

In the present work, unsteady RANS simulations were performed to clarify several interesting features of the unsteady three-dimensional flow field in a turbine stage. The unsteady effect was investigated for two cases of axial spacing between stator and rotor, i.e. large and small axial spacing. Simulation results showed that the stator wake was convected from pressure side to suction side in the rotor. As a result, another secondary flow, which counter-rotated against the passage vortices, was periodically generated by the stator wake passing through the rotor passage. It was found that turbine stage efficiency with the small axial spacing was higher than that with the large axial spacing. This was because the stator wake in the small axial spacing case entered the rotor before mixing and induced the stronger counter-rotating vortices to suppress the passage vortices more effectively, while the wake in the large axial spacing case eventually promoted the growth of the secondary flow near the hub due to the migration of the wake towards the hub.

Experimental Measurements of Ingestion Through Turbine Rim Seals: Part 1—Externally-Induced Ingress

2011 ◽  
Author(s):  
Carl M. Sangan ◽  
Kunyuan Zhou ◽  
J. Michael Owen ◽  
Oliver J. Pountney ◽  
Mike Wilson ◽  
...  
Keyword(s):  
Three Dimensional ◽  
External Pressure ◽  
Operating Conditions ◽  
Turbine Stage ◽  
Research Facility ◽  
Three Dimensional Flow ◽  
Co2 Gas ◽  
Gas Concentration ◽  
Hot Gas ◽  
New Research

This paper describes a new research facility which experimentally models hot gas ingestion into the wheel-space of an axial turbine stage. Measurements of CO2 gas concentration in the rim-seal region and inside the cavity are used to assess the performance of two generic (though engine-representative) rim-seal geometries in terms of the variation of concentration effectiveness with sealing flow rate. The variation of pressure in the turbine annulus, which governs this externally-induced (EI) ingestion, was obtained from steady pressure measurements downstream of the vanes and near the rim seal upstream of the rotating blades. Although the ingestion through the rim seal is a consequence of an unsteady, three-dimensional flow field and the cause-effect relationship between pressure and the sealing effectiveness is complex, the experimental data is shown to be successfully calculated by simple effectiveness equations developed from a previously published orifice model. The data illustrate that, for similar turbine-stage velocity triangles, the effectiveness can be correlated using a non-dimensional sealing parameter, Φo. In principle, and within the limits of dimensional similitude, these correlations should apply to a geometrically-similar engine at the same operating conditions. Part 2 of this paper describes an experimental investigation of rotationally-induced (RI) ingress, where there is no mainsteam flow and consequently no circumferential variation of external pressure.

Unsteady Aerodynamics of a Low Aspect Ratio Turbine Stage: Modeling Issues and Flow Physics

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
G. Persico ◽  
A. Mora ◽  
P. Gaetani ◽  
M. Savini
Keyword(s):  
Aspect Ratio ◽  
Coming Out ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Fast Response ◽  
Operating Conditions ◽  
Pressure Probe ◽  
Turbine Stage ◽  
Time Resolved ◽  
Low Aspect Ratio

In this paper the three-dimensional unsteady aerodynamics of a low aspect ratio, high pressure turbine stage are studied. In particular, the results of fully unsteady three-dimensional numerical simulations, performed with ANSYS-CFX, are critically evaluated against experimental data. Measurements were carried out with a novel three-dimensional fast-response pressure probe in the closed-loop test rig of the Laboratorio di Fluidodinamica delle Macchine of the Politecnico di Milano. An analysis is first reported about the strategy to limit the CPU and memory requirements while performing three-dimensional simulations of blade row interaction when the rotor and stator blade numbers are prime to each other. What emerges as the best choice is to simulate the unsteady behavior of the rotor alone by applying the stator outlet flow field as a rotating inlet boundary condition (scaled on the rotor blade pitch). Thanks to the reliability of the numerical model, a detailed analysis of the physical mechanisms acting inside the rotor channel is performed. Two operating conditions at different vane incidence are considered, in a configuration where the effects of the vortex-blade interaction are highlighted. Different vane incidence angles lead to different size, position, and strength of secondary vortices coming out from the stator, thus promoting different interaction processes in the subsequent rotor channel. However some general trends can be recognized in the vortex-blade interaction: the sense of rotation and the spanwise position of the incoming vortices play a crucial role on the dynamics of the rotor vortices, determining both the time-mean and the time-resolved characteristics of the secondary field at the exit of the stage.

scholarly journals Prediction of Film Cooling Effectiveness of Steam

1982 ◽  
Author(s):  
Je-Chin Han ◽  
P. E. Jenkins
Keyword(s):  
Film Cooling ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Air Cooling ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Gas Turbine Blades ◽  
Fluid Properties ◽  
Three Dimensional Models

The intent of this work is to show, analytically, that superheated steam can provide better film cooling than conventional air for gas turbine blades and vanes. Goldstein’s two-dimensional and Eckert’s three-dimensional models have been reexamined and modified in order to include the effects of thermal-fluid properties of foreign gas injection on the film cooling effectiveness. Based on the modified models, the computed results for steam film cooling effectiveness, showing an increase of 80 to 100 percent when compared with air cooling at the same operating conditions, are presented.

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.

Numerical Study of a Rotating Blade Platform With Film Cooling From Cavity Purge Flow in a 1-1/2 Turbine Stage

2006 ◽  
Author(s):  
Huitao Yang ◽  
Hamn-Ching Chen ◽  
Je-Chin Han
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Turbine Stage ◽  
Transfer Coefficients ◽  
Adiabatic Wall ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Rotating Speed ◽  
Rotating Blade ◽  
Purge Flow

Numerical simulations were performed to predict the effect of cavity purge flow on the rotating blade platform in a 1-1/2 turbine stage using a Reynolds stress turbulence model together with a non-equilibrium wall function. Simulations were carried out with a sliding mesh for the rotor under three rotating speeds (2000, 2550 and 3000 rpm) and three purge-to-mainstream mass flow ratios (0.5%, 1% and 1.5%) to investigate the effects of rotating speed and coolant purging rate on the rotating blade platform film cooling. The adiabatic film cooling effectiveness was evaluated using the adiabatic wall temperatures with and without coolant purging to examine the true effect of coolant protection. The film cooling effectiveness increases with increasing coolant purging flow ratio from 0.5% to 1.5% of mainstream. Higher rotating speed also enhances film cooling effectiveness for the range of rotating speed considered. The predicted laterally averaged adiabatic film cooling effectiveness is in good agreement with the corresponding experiment data except for the platform leading edge region. However, the detailed effectiveness distribution on the platform is not well predicted by this study. In addition, the detailed instantaneous film cooling effectiveness and the associated heat transfer coefficients for four different time phases are also reported.

Prediction of Film Cooling and Heat Transfer on a Rotating Blade Platform With Stator-Rotor Purge and Discrete Film-Hole Flows in a 1-1/2 Turbine Stage

2007 ◽  
Author(s):  
H. Yang ◽  
Z. Gao ◽  
H. C. Chen ◽  
J. C. Han ◽  
M. T. Schobeiri
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Turbine Stage ◽  
Transfer Coefficients ◽  
Work Process ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Heat Transfer Coefficients ◽  
Rotating Blade ◽  
Purge Flow

Numerical simulations were performed to predict the film cooling effectiveness and heat transfer coefficient distributions on a rotating blade platform with stator-rotor purge flow and downstream discrete film-hole flows in a 1-1/2 turbine stage using a Reynolds stress turbulence model together with a non-equilibrium wall function. Simulations were carried out with sliding mesh for the rotor under three rotating speeds (2000, 2550, and 3000 rpm) to investigate the effects of rotation and stator-rotor interaction on the rotor blade platform purge flow cooling and discrete-hole film cooling and heat transfer. The adiabatic film cooling effectiveness and heat transfer coefficients were calculated using the adiabatic wall temperatures with and without coolant to examine the true coolant protection excluding the effect of turbine work process. The stator-rotor interaction strongly impacts the purge slot film cooling and heat transfer at the platform leading portion, while only slightly affects the downstream discrete-hole film cooling near the platform trailing portion. In addition, the effect of turbine work process on the film cooling effectiveness and the associated heat transfer coefficients have been reported.

An Analysis of Grease and Oil Lubricated Spiral Grooved Bearings

1974 ◽  
Vol 96 (2) ◽  
pp. 275-283
Author(s):  
D. M. Dewar
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Three Dimensional ◽  
Thermal Conditions ◽  
Load Carrying Capacity ◽  
Thrust Bearings ◽  
Through Flow ◽  
Load Carrying ◽  
Running Torque ◽  
Spiral Groove Bearing

Mathematical models for grease and oils are put forward and used to solve a two-dimensional Reynolds’ equation with a quasi three-dimensional energy equation for any geometry of spiral groove bearing. Using numerical methods, results are presented for the temperature distributions in through-flow and block-centered thrust bearings; conical bearings and herringbone grooved journal bearings can also be dealt with. The overall bearing parameters, namely, load-carrying capacity, stiffness, and running torque at various eccentricity ratios are shown along with their dependence upon the prevailing thermal conditions.

scholarly journals Impacts of the Properties Heterogeneity on 3D Magnetic Dusty Nanofluids Flow Within Cubic Porous Enclosures Contain Isothermal Cylinders

2021 ◽  
Author(s):  
Z. Z. Rashed
Keyword(s):  
Porous Medium ◽  
Three Dimensional ◽  
Thermal Conditions ◽  
Circular Cylinders ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Flow Domain ◽  
Isothermal Cylinders ◽  
The Right ◽  
Volume Method

Abstract This paper examines the controlling of the three dimensional dusty nanofluid flow using the two circular cylinders having different thermal conditions. The cylinders are located in the middle area while the location of the right cylinder is changeable. The 3D cubic flow domain is filled by a non-Darcy porous medium and a magnetic field in Z-direction is taken place. The non-homogeneous two phase model of the nanofluid is applied while the permeability and thermal conductivity of the porous medium are assumed heterogonous. The current situation is represented by two systems of the equations for the nanofluid and dusty phases. The solutions methodology is depending on the 3D SIMPLE scheme together with the finite volume method. The major outcomes indicating to that the flow can be well controlled using the inner isothermal cylinders. Also, the cases of the heterogeneity in \(X-Y\) and \(X-Z\) directions give the lowest values of \({Nu}_{av}\).

Experimental Measurements of Ingestion Through Turbine Rim Seals—Part I: Externally Induced Ingress

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Carl M. Sangan ◽  
Oliver J. Pountney ◽  
Kunyuan Zhou ◽  
Mike Wilson ◽  
J. Michael Owen ◽  
...  
Keyword(s):  
Three Dimensional ◽  
External Pressure ◽  
Operating Conditions ◽  
Turbine Stage ◽  
Three Dimensional Flow ◽  
Co2 Gas ◽  
Gas Concentration ◽  
Hot Gas ◽  
Mainstream Flow ◽  
New Research

This paper describes a new research facility which experimentally models hot gas ingestion into the wheel-space of an axial turbine stage. Measurements of the CO2 gas concentration in the rim-seal region and inside the cavity are used to assess the performance of two generic (though engine-representative) rim-seal geometries in terms of the variation of concentration effectiveness with sealing flow rate. The variation of pressure in the turbine annulus, which governs this externally-induced (EI) ingestion, was obtained from steady pressure measurements downstream of the vanes and near the rim seal upstream of the rotating blades. Although the ingestion through the rim seal is a consequence of an unsteady, three-dimensional flow field and the cause-effect relationship between the pressure and the sealing effectiveness is complex, the experimental data is shown to be successfully calculated by simple effectiveness equations developed from a previously published orifice model. The data illustrate that, for similar turbine-stage velocity triangles, the effectiveness can be correlated using a nondimensional sealing parameter, Φo. In principle, and within the limits of dimensional similitude, these correlations should apply to a geometrically-similar engine at the same operating conditions. Part II of this paper describes an experimental investigation of rotationally-induced (RI) ingress, where there is no mainstream flow and consequently no circumferential variation of external pressure.

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