Thermo-Structural Analysis of High-Pressure Turbine Blade

2020 ◽  
Vol 15 (3) ◽  
pp. 78-82
Author(s):  
Chiranjivi Dahal ◽  
Janak Kumar Tharu ◽  
Hari Bahadur Dura
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Centrifugal Force ◽  
Rotational Velocity ◽  
Rotation Velocity ◽  
Tip Clearance ◽  
High Pressure Turbine ◽  
Clearance Ratio ◽  
Blade Clearance ◽  
Very High

Turbine blade tip clearance plays major role in smooth running of axial turbines. The turbine blade clearance contributes 20-40% of total loss in gas turbine. In Rolls Royce MT2 Turbine with 2% tip to span clearance ratio, tip clearance accounts for 40% of total losses. Turbine blade clearance is necessary as the turbine blade operates at very high temperature up to 1700 ºC and very high centrifugal load. Small turbine tip clearance may forbid expansion of turbine blade which will result in turbine tip rubbing with the casing. High pressure turbine blade experiences high thermal and centrifugal stress. The objective of this paper is to study the individual and combined effect of these stress. The material used for analysis is cast based nickel alloy IN-738. The melting range of this alloy is 1230-1315 ºC with thermal expansion coefficient of 15.39E-6 per ºC. The turbine blade geometry with height 120 mm is used for analysis. The Mathematical modelling of above geometry shows that the centrifugal force with rotation velocity 100 rad/s produces 0.00252424 mm elongation and combined thermal-centrifugal loading produces 1.46520576 mm elongation. The results form ANSYS is used for verification and the elongation due to centrifugal stress is 0.0014885 mm and combined stress produces elongation of 1.2608 mm. The total elongation from analytical method and ANSYS are similar. It shows that the effect due to centrifugal force on turbine blade is less compared to thermal effect. For operating condition of 816 ºC temperature and 100 rad/s rotational velocity, the overall stress contributes around 1.22 % elongation of turbine blade span.

scholarly journals Machine Learning for Turbulence Model Development Using a High-Fidelity HPT Cascade Simulation

2017 ◽  
Author(s):  
Jack Weatheritt ◽  
Richard Pichler ◽  
Richard D. Sandberg ◽  
Gregory Laskowski ◽  
Vittorio Michelassi
Keyword(s):  
High Pressure ◽  
Evolutionary Algorithm ◽  
Turbine Blade ◽  
A Priori ◽  
Model Development ◽  
Boussinesq Approximation ◽  
High Pressure Turbine ◽  
Stress Strain ◽  
Non Linear ◽  
Anisotropy Tensor

The validity of the Boussinesq approximation in the wake behind a high-pressure turbine blade is explored. We probe the mathematical assumptions of such a relationship by employing a least-squares technique. Next, we use an evolutionary algorithm to modify the anisotropy tensor a priori using highly resolved LES data. In the latter case we build a non-linear stress-strain relationship. Results show that the standard eddy-viscosity assumption underpredicts turbulent diffusion and is theoretically invalid. By increasing the coefficient of the linear term, the farwake prediction shows minor improvement. By using additional non-linear terms in the stress-strain coupling relationship, created by the evolutionary algorithm, the near-wake can also be improved upon. Terms created by the algorithm are scrutinized and the discussion is closed by suggesting a tentative non-linear expression for the Reynolds stress, suitable for the wake behind a high-pressure turbine blade.

Heat Transfer and Aerodynamics of Over-Shroud Leakage Flows in a High-Pressure Turbine

2009 ◽  
Author(s):  
Knut Lehmann ◽  
Richard Thomas ◽  
Howard Hodson ◽  
Vassilis Stefanis
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Large Scale ◽  
Suction Side ◽  
Surface Flow ◽  
Tip Clearance ◽  
Flow Visualisation ◽  
Leakage Flow ◽  
High Pressure Turbine ◽  
High Heat Transfer

An experimental study has been conducted to investigate the distribution of the convective heat transfer on the shroud of a high pressure turbine blade in a large scale rotating rig. A continuous thin heater foil technique has been adapted and implemented on the turbine shroud. Thermochromic Liquid Crystals were employed for the surface temperature measurements to derive the experimental heat transfer data. The heat transfer is presented on the shroud top surfaces and the three fins. The experiments were conducted for a variety of Reynolds numbers and flow coefficients. The effects of different inter-shroud gap sizes and reduced fin tip clearance gaps were also investigated. Details of the shroud flow field were obtained using an advanced Ammonia-Diazo surface flow visualisation technique. CFD predictions are compared with the experimental data and used to aid interpretation. Contour maps of the Nusselt number reveal that regions of highest heat transfer are mostly confined to the suction side of the shroud. Peak values exceed the average by as much as 100 percent. It has been found that the interaction between leakage flow through the inter-shroud gaps and the fin tip leakage jets are responsible for this high heat transfer. The inter-shroud gap leakage flow causes a disruption of the boundary layer on the turbine shroud. Furthermore, the development of the large recirculating shroud cavity vortices is severely altered by this leakage flow.

Influence of Different Parametrizations on the Optimum Design of a High Pressure Turbine Blade Firtree

2016 ◽  
Author(s):  
Frank Wagner ◽  
Arnold Kühhorn ◽  
Thomas Weiss ◽  
Dierk Otto
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Parametric Models ◽  
Limiting Factor ◽  
High Pressure Turbine ◽  
The Creation ◽  
High Flexibility ◽  
Critical Regions

Today the design processes in the aero industry face many challenges. Apart from automation itself, a suitable parametric geometry setup plays a significant role in making workflows usable for optimization. At the same time there are tough requirements against the parametric model. For the lowest number of possible parameters, which should be intuitively ascertainable, a high flexibility has to be ensured. Within the parameter range an acceptable stability is necessary. Under these constraints the creation of such parametric models is a challenge, which should not be underestimated especially for a complex geometry. In this work different kinds of parametrization with different levels of complexity will be introduced and compared. Thereby several geometry elements will be used to handle the critical regions of the geometry. In the simplest case a combination of lines and arcs will be applied. These will be replaced by superior elements like a double arc construct or different formulations of b-splines. There will be an additional focus on the variation of spline degree and control points. To guarantee consistency a set of general parameters will be used next to the specific ones at the critical regions. The different parameter boundaries have a influence on the possible geometries and should therefore be tested separately before an optimization run. The analysis of the particular parametrization should be compared against the following points: • effort for the creation of the parametrization in theory • required time for the implementation in the CAD software • error-proneness/robustness of the parametrization • flexibility of the possible geometries • accuracy of the results • influence of the number of runs on the optimization • comparison of the best results Even though this assessment matrix is only valid for the considered case, it should show the general trend for the creation of these kinds of parametric models. This case takes a look at a firtree of a high pressure turbine blade, which is a scaled version of the first row from a small to medium aero engine. The failure of such a component can lead to a critical engine failure. For that reason, the modeling/meshing must be done very carefully and the contact between the blade and the disc is of crucial importance. It is possible to use scaling factors for three dimensional effects to reduce the problem to a two dimensional problem. Therefore the contact description is shortened from face-to-line to line-to-point. The main aim of the optimization is the minimization of the tension (notch stress) at the inner bends of the blade respectively at the outer bends of the disc. This has been the limiting factor in previous investigations. At this part of the geometry the biggest improvement are expected from a superior parametrization. Another important constraint in the optimization is the pressure contact (crushing stress) between blade and disc. Additionally the geometry is restricted with measurements of the lowest diameter at specific fillets to fulfill manufacturing requirements.

scholarly journals Analysis of the effect of intermittency in a high-pressure turbine blade

2020 ◽  
Vol 32 (9) ◽  
pp. 095101
Author(s):  
D. Dupuy ◽  
L. Gicquel ◽  
N. Odier ◽  
F. Duchaine ◽  
T. Arts
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
High Pressure Turbine

Modeling and Impact of High-pressure Turbine Blade Trailing Edge Film Cooling Hole Variations

2020 ◽  
Author(s):  
Jan Kamenik ◽  
David J. Toal ◽  
Andy Keane ◽  
Lars Högner ◽  
Marcus Meyer ◽  
...  
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Film Cooling ◽  
High Pressure Turbine ◽  
Trailing Edge ◽  
Cooling Hole

Multistage Compressor and Turbine Modeling for the Prediction of the Maximum Turbine Speed Resulting From Shaft Breakage

2009 ◽  
Author(s):  
M. Haake ◽  
R. Fiola ◽  
S. Staudacher
Keyword(s):  
High Pressure ◽  
Tip Clearance ◽  
Maximum Speed ◽  
High Pressure Turbine ◽  
High Pressure Compressor ◽  
Failure Event ◽  
Turbine Speed ◽  
Shaft Failure ◽  
Pressure Compressor ◽  
Vane Tip

A mathematical model for the prediction of the maximum speed of a high pressure turbine following a shaft failure event was developed. The model predicts the high pressure compressor and ducting system pre- and post-stall behavior like rotating stall and surge after the shaft breakage. The corresponding time-dependent high pressure turbine inlet conditions are used to calculate the turbine maximum speed, taking into account friction and blade&vane tip clearance variations as a result of the rearward movement of the turbine and destruction of the turbine blading. The compressor and ducting system is modeled by a 1-dimensional, stage-by-stage approach. The approach uses a finite-difference numerical technique to solve the nonlinear system of equations for continuity, momentum and energy including source terms for the compressible flow through inlet ducting, compressor and combustor. The compressor blade forces and shaft work are provided by a set of quasi steady state stage characteristics being valid for pre-stall and post-stall operations. The maximum turbine speed is calculated from a thermodynamic turbine stand-alone model, derived from a performance synthesis program. Friction and blade&vane tip clearance variations are determined iteratively from graphical data depending on the axial rearward movement of the turbine. The compressor and ducting system model was validated in pre-stall and post-stall operation mode with measured high pressure compressor data of a modern 2-shaft engine. The turbine model was validated with measured intermediate pressure shaft failure data of a 3-shaft engine. The shaft failure model was applied on a modern 2-shaft engine. The model was used to carry out a sensitivity study to demonstrate the impact of control system reactions on the resulting maximum high pressure turbine speed following a shaft failure event.

Using CFD to Reduce Resonant Stresses on a Single-Stage, High-Pressure Turbine Blade

2002 ◽  
Author(s):  
J. P. Clark ◽  
A. S. Aggarwala ◽  
M. A. Velonis ◽  
R. E. Gacek ◽  
S. S. Magge ◽  
...  
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Guide Vane ◽  
Turbine Blades ◽  
Suction Side ◽  
Lessons Learned ◽  
Single Stage ◽  
Navier Stokes ◽  
High Pressure Turbine ◽  
Time Resolved

The ability to predict levels of unsteady forcing on high-pressure turbine blades is critical to avoid high-cycle fatigue failures. In this study, 3D time-resolved computational fluid dynamics is used within the design cycle to predict accurately the levels of unsteady forcing on a single-stage high-pressure turbine blade. Further, nozzle-guide-vane geometry changes including asymmetric circumferential spacing and suction-side modification are considered and rigorously analyzed to reduce levels of unsteady blade forcing. The latter is ultimately implemented in a development engine, and it is shown successfully to reduce resonant stresses on the blade. This investigation builds upon data that was recently obtained in a full-scale, transonic turbine rig to validate a Reynolds-Averaged Navier-Stokes (RANS) flow solver for the prediction of both the magnitude and phase of unsteady forcing in a single-stage HPT and the lessons learned in that study.

scholarly journals Erratum to: Dynamic probabilistic design approach of high-pressure turbine blade-tip radial running clearance

2016 ◽  
Vol 86 (1) ◽  
pp. 225-225
Author(s):  
Cheng-Wei Fei ◽  
Yat-Sze Choy ◽  
Dian-Yin Hu ◽  
Guang-Chen Bai ◽  
Wen-Zhong Tang
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Design Approach ◽  
Probabilistic Design ◽  
High Pressure Turbine ◽  
Blade Tip

Time-Averaged and Time-Accurate Aero-Dynamics for the Recessed Tip Cavity of a High-Pressure Turbine Blade and the Outer Stationary Shroud: Comparison of Computational and Experimental Results

2004 ◽  
Author(s):  
Brian R. Green ◽  
John W. Barter ◽  
Charles W. Haldeman ◽  
Michael G. Dunn
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Computational Models ◽  
Turbine Rotor ◽  
Single Stage ◽  
Cfd Modeling ◽  
Blade Surface ◽  
High Pressure Turbine ◽  
Pressure Transducers ◽  
Blade Tip

The unsteady aero-dynamics of a single-stage high-pressure turbine blade operating at design corrected conditions has been the subject of a thorough study involving detailed measurements and computations. The experimental configuration consisted of a single-stage high-pressure turbine and the adjacent, downstream, low-pressure turbine nozzle row. All three blade-rows were instrumented at three spanwise locations with flush-mounted, high frequency response pressure transducers. The rotor was also instrumented with the same transducers on the blade tip and platform and the stationary shroud was instrumented with pressure transducers at specific locations above the rotating blade. Predictions of the time-dependent flow field around the rotor were obtained using MSU-TURBO, a 3D, non-linear, computational fluid dynamics (CFD) code. Using an isolated blade-row unsteady analysis method, the unsteady surface pressure for the high-pressure turbine rotor due to the upstream high-pressure turbine nozzle was calculated. The predicted unsteady pressure on the rotor surface was compared to the measurements at selected spanwise locations on the blade, in the recessed cavity, and on the shroud. The rig and computational models included a flat and recessed blade tip geometry and were used for the comparisons presented in the paper. Comparisons of the measured and predicted static pressure loading on the blade surface show excellent correlation from both a time-average and time-accurate standpoint. This paper concentrates on the tip and shroud comparisons between the experiments and the predictions and these results also show good correlation with the time-resolved data. These data comparisons provide confidence in the CFD modeling and its ability to capture unsteady flow physics on the blade surface, in the flat and recessed tip regions of the blade, and on the stationary shroud.

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