Effect of Ingress on Turbine Disks

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
GeonHwan Cho ◽  
Carl M. Sangan ◽  
J. Michael Owen ◽  
Gary D. Lock
Keyword(s):  
Three Dimensional ◽  
Rotating Disk ◽  
Disk Surface ◽  
Temperature History ◽  
Ir Sensors ◽  
History Of ◽  
Turbine Disks ◽  
Thermal Buffering ◽  
Adiabatic Effectiveness ◽  
Semi Empirical

The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the seal. This paper describes experimental measurements which quantify the effect of ingress on both the stator and rotor disks in a wheel-space pressurized by sealing flow. Infrared (IR) sensors were developed and calibrated to accurately measure the temperature history of the rotating disk surface during a transient experiment, leading to an adiabatic effectiveness. The performance of four generic (though engine-representative) single- and double-clearance seals was assessed in terms of the variation of adiabatic effectiveness with sealing flow rate. The measurements identify a so-called thermal buffering effect, where the boundary layer on the rotor protects the disk from the effects of ingress. It was shown that the effectiveness on the rotor was significantly higher than the equivalent stator effectiveness for all rim seals tested. Although the ingress 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 time-averaged experimental data are shown to be successfully predicted by relatively simple semi-empirical models, which are described in a separate paper. Of particular interest to the designer, significant ingress can enter the wheel-space before its effect is sensed by the rotor.

Effect of Ingress on Turbine Discs

2015 ◽  
Author(s):  
GeonHwan Cho ◽  
Carl M. Sangan ◽  
J. Michael Owen ◽  
Gary D. Lock
Keyword(s):  
Three Dimensional ◽  
Temperature History ◽  
Infrared Sensors ◽  
Rotating Disc ◽  
Hot Gas ◽  
Mainstream Flow ◽  
History Of ◽  
Thermal Buffering ◽  
Adiabatic Effectiveness ◽  
Semi Empirical

The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the seal. This paper describes experimental measurements which quantify the effect of ingress on both the stator and rotor discs in a wheel-space pressurised by sealing flow. Infrared sensors were developed and calibrated to accurately measure the temperature history of the rotating disc surface during a transient experiment, leading to an adiabatic effectiveness. The performance of four generic (though engine-representative) single- and double-clearance seals was assessed in terms of the variation of adiabatic effectiveness with sealing flow rate. The measurements identify a so-called thermal buffering effect, where the boundary layer on the rotor protects the disc from the effects of ingress. It was shown that the effectiveness on the rotor was significantly higher than the equivalent stator effectiveness for all rim seals tested. Although the ingress 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 time-averaged experimental data is shown to be successfully predicted by relatively simple semi-empirical models, which are described in a separate paper. Of particular interest to the designer, significant ingress can enter the wheel-space before its effect is sensed by the rotor.

Optimization of Laser Hardening Processes for Industrial Parts With Complex Geometry via Predictive Modeling

2009 ◽  
Author(s):  
Neil S. Bailey ◽  
Yung C. Shin
Keyword(s):  
Phase Transformation ◽  
Thermal Model ◽  
Complex Geometry ◽  
Solid Phase ◽  
Three Dimensional ◽  
Laser Hardening ◽  
Temperature History ◽  
Temperature Phase ◽  
Laser Systems ◽  
History Of

A predictive laser hardening model for industrial parts with complex geometric features has been developed and used for optimization of hardening processes. A transient three-dimensional thermal model is combined with a three-dimensional kinetic model for steel phase transformation and solved in order to predict the temperature history and solid phase history of the workpiece while considering latent heat of phase transformation. Further, back-tempering is also added to the model to determine the phase transformation during multitrack laser hardening. The integrated model is designed to accurately predict temperature, phase distributions and hardness inside complex geometric domains. The laser hardening parameters for two industrial workpieces are optimized for two different industrial laser systems using this model. Experimental results confirm the validity of predicted results.

Effects of Geometrical Structure on Flows Around a Rotating Disk in an Enclosure

2007 ◽  
Author(s):  
T. Watanabe ◽  
H. Furukawa ◽  
M. Suzuki
Keyword(s):  
Phase Velocity ◽  
Geometrical Structure ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Side Wall ◽  
Rotating Disk ◽  
Disk Surface ◽  
Practical Applications ◽  
Entire Flow ◽  
Radial Gap

Flows around a rotating disk in a cylindrical enclosure are typical models of flows found in fluid machinery and chemical reactors. They have their practical applications and draw engineering interests. When the radius of the disk is infinite, it is known that circular rolls, spiral rolls, turbulent spirals and turbulent spots appear. In this case, the parameters governing the flows are the Reynolds number based on the angular velocity of the disk and the axial gap between the disk surface and the end wall of the enclosure. We consider, in this paper, a more practical configuration. The disk has its thickness comparable with the axial height of the enclosure, and the radial gap between the disk rim and the side wall of the enclosure is not negligible. Vortex flows are driven by the centrifugal force around the disk rim, and they are expected to have effects on the entire flow. We performed numerical and experimental studies and investigated the unsteady three-dimensional behaviors. A new criterion to identify flow patterns is introduced and the Hopf bifurcation points from the axisymmetric flows to the three-dimensional flows are determined. The phase velocity of the spiral rolls are measured by a time-dependent analysis. The influence of the geometrical structure on the phase velocity is estimated. New types of flows are found, where bead-like vortices appear and spiral rolls with positive and negative front angles coexist.

Stationary travelling cross-flow mode interactions on a rotating disk

1998 ◽  
Vol 355 ◽  
pp. 285-315 ◽  
Author(s):  
T. C. CORKE ◽  
K. F. KNASIAK
Keyword(s):  
Three Dimensional ◽  
Cross Flow ◽  
Logarithmic Spiral ◽  
Rotating Disk ◽  
Disk Surface ◽  
Flow Mode ◽  
Stationary Mode ◽  
Dimensional Boundary ◽  
Fixed Radius

This work involves the study of the development of Type 1 stationary and travelling cross-flow modes in the three-dimensional boundary layer over a rotating disk. In order to control the characteristics of the stationary modes, we utilized organized patterns of roughness which were applied to the disk surface. These consisted of ink dots which were equally spaced in the azimuthal direction at a fixed radius in order to enhance particular azimuthal wavenumbers. Logarithmic spiral patterns of dots were also used to enhance azimuthal wave angles. Velocity fluctuation time series were decomposed into the components corresponding to the stationary and travelling modes using the instantaneous disk position as a reference. Their development was documented through the linear and nonlinear stages leading to turbulence. The linear stage agreed well with linear stability predictions for both modes. In the nonlinear stage we documented a triad coupling between pairs of travelling modes and a stationary mode. The strongest of these was a difference interaction which led to the growth of a low-azimuthal-number, stationary mode. This mode had the largest amplitude and appeared to dominate transition. In retrospect, we can observe the signs of this mechanism in past flow visualization (Kobayashi, Kohama & Takamadate 1980), and it can account for the ‘jagged’ front normally associated with cross-flow-dominated transition on swept wings.

A New Temperature Based Method for Determination of Lifetime Consumption of Turbo-Machinery Components During Operation

2017 ◽  
Author(s):  
M. Sistaninia ◽  
D. Ugel ◽  
S. Olmes
Keyword(s):  
Gas Turbines ◽  
Low Cycle Fatigue ◽  
Thermal Inertia ◽  
Load Cycle ◽  
Weighting Factor ◽  
Empirical Correlation ◽  
Temperature History ◽  
History Of ◽  
High Thermal Inertia ◽  
Semi Empirical

In order to operate the turbo-machineries more flexibly, a lifetime counting method was developed which enables estimating lifetime consumption of high thermal-inertia components based on the temperature history of the components. It can account for consumed fatigue life at the locations of temperature measurement during the turbo-machine operation. By considering the operation history, the structural component can be operated closer to its lifetime limits, to increase the intervals between inspections, and therefore to extend the operational lifetime of the turbo-machine. In this method the cold start (CS) to full load cycle, with the number of cycles to crack initiation Ncs, is defined as reference load cycle. The damage weighting factor Ni/NCS for cyclic event i is then calculated based on a semi-empirical correlation between Ni/NCS and the temperature history of the part. The semi-empirical correlation can be determined for each component or each location depending on the required precision. It is determined based on the Low Cycle Fatigue (LCF) life calculated for different Gas Turbine (GT) operation scenarios. The damage weighting factors are then employed to calculate the lifetime consumption using Miner’s rule. The predictions of this method for the turbine housings of several Gas Turbines (GTs) were evaluated against finite element (FE) results. Multiple load cases were considered for each GT. It is shown that this approach can account for the lifetime consumption using the minimum required number of GT operation parameters.

Apatite fission track analysis: geological thermal history analysis based on a three-dimensional random process of linear radiation damage

1990 ◽  
Vol 332 (1627) ◽  
pp. 419-438 ◽  
Keyword(s):  
Random Process ◽  
Three Dimensional ◽  
Temperature History ◽  
Apatite Crystal ◽  
Maximum Temperature ◽  
Geological Time ◽  
Full Likelihood ◽  
History Analysis ◽  
History Of ◽  
Uplift And Erosion

Spontaneous fission of uranium atoms over geological time creates a random process of linearly shaped features (fission tracks) inside an apatite crystal. The theoretical distributions associated with this process are governed by the elapsed time and temperature history, but other factors are also reflected in empirical measurements as consequences of sampling by plane section and chemical etching. These include geometrical biases leading to over-representation of long tracks, the shape and orientation of host features when sampling totally confined tracks, and ‘gaps’ in heavily annealed tracks. We study the estimation of geological parameters in the presence of these factors using measurements on both confined tracks and projected semi-tracks. Of particular interest is a history of sedimentation, uplift and erosion giving rise to a twocomponent mixture of tracks in which the parameters reflect the current temperature, the maximum temperature and the timing of uplift. A full likelihood analysis based on all measured densities, lengths and orientations is feasible, but because some geometrical biases and measurement limitations are only partly understood it seems preferable to use conditional likelihoods given numbers and orientations of confined tracks

Effect of Ingestion on Temperature of Turbine Disks

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Oliver J. Pountney ◽  
Carl M. Sangan ◽  
Gary D. Lock ◽  
J. Michael Owen
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Rotating Disk ◽  
Thermochromic Liquid Crystal ◽  
Hot Gas ◽  
Nusselt Numbers ◽  
Turbine Disks ◽  
Adiabatic Effectiveness ◽  
Axial Clearance ◽  
First Time

This paper describes experimental results from a research facility which experimentally models hot-gas ingress into the wheel-space of an axial turbine stage with an axial-clearance rim seal. Thermochromic liquid crystal (TLC) was used to determine the effect of ingestion on heat transfer to the rotating disk; as far as the authors are aware, this is the first time that the measured effects of ingestion on adiabatic temperature have been published. An adiabatic effectiveness for the rotor was defined, and this definition was used to determine when the effect of ingress was first experienced by the rotor. Concentration measurements on the stator were used to determine the sealing effectiveness of the rim seal, and transient heat transfer tests with heated sealing air were used to determine the adiabatic effectiveness of the rotor. The thermal buffer ratio, which is defined as the ratio of the sealing flow rate when ingress first occurs to that when it is first experienced by the rotor, was shown to depend on the turbulent flow parameter. The local Nusselt numbers, Nu, which were measured on the rotor, were significantly smaller than those for a free disk; they decreased as the sealing flow rate decreased and as the ingress correspondingly increased. The values of Nu and adiabatic effectiveness obtained in these experiments provide data for the validation of CFD codes but caution is needed if they (particularly the values of Nu) are to be extrapolated to engine conditions.

Sea Urchins and Circuses: The Modernist Natural Histories of Jean Painlevé and Alexander Calder

2018 ◽  
Vol 13 (2) ◽  
pp. 187-211
Author(s):  
Patricia E. Chu
Keyword(s):  
New Media ◽  
Sea Urchins ◽  
Life Sciences ◽  
Three Dimensional ◽  
Machine Age ◽  
Avant Garde ◽  
History Of ◽  
And Performance ◽  
The One ◽  
Natural Historian

The Paris avant-garde milieu from which both Cirque Calder/Calder's Circus and Painlevé’s early films emerged was a cultural intersection of art and the twentieth-century life sciences. In turning to the style of current scientific journals, the Paris surrealists can be understood as engaging the (life) sciences not simply as a provider of normative categories of materiality to be dismissed, but as a companion in apprehending the “reality” of a world beneath the surface just as real as the one visible to the naked eye. I will focus in this essay on two modernist practices in new media in the context of the history of the life sciences: Jean Painlevé’s (1902–1989) science films and Alexander Calder's (1898–1976) work in three-dimensional moving art and performance—the Circus. In analyzing Painlevé’s work, I discuss it as exemplary of a moment when life sciences and avant-garde technical methods and philosophies created each other rather than being classified as separate categories of epistemological work. In moving from Painlevé’s films to Alexander Calder's Circus, Painlevé’s cinematography remains at the forefront; I use his film of one of Calder's performances of the Circus, a collaboration the men had taken two decades to complete. Painlevé’s depiction allows us to see the elements of Calder's work that mark it as akin to Painlevé’s own interest in a modern experimental organicism as central to the so-called machine-age. Calder's work can be understood as similarly developing an avant-garde practice along the line between the bestiary of the natural historian and the bestiary of the modern life scientist.

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