Cast-in-Pair Blade Release Simulation and Comparison to Experiments With a Full Scale Rig

2012 ◽  
Author(s):  
Erlantz Cristóbal ◽  
Sergio Moñux ◽  
Carlos Cerezo ◽  
David Cendón ◽  
Francisco Galvez ◽  
...  
Keyword(s):  
Material Model ◽  
Low Pressure ◽  
Full Scale ◽  
Design Solution ◽  
Directionally Solidified ◽  
Low Pressure Turbine ◽  
Failure Event ◽  
Containment Test ◽  
Explicit Solver ◽  
Blade Casting

This paper deals with the simulation of a Low Pressure Turbine (LPT) blade release and the subsequent impact onto the casing. The blade design is a cast-in-pair novel configuration where two airfoils are attached to a single firtree. This design solution was implemented in the first stage of the Low Pressure Turbine of the TP400-D6 engine using a directionally solidified M247 alloy. Due to the novelty of the design configuration a case containment test was carried out for certification versus CS-E810 EASA airworthiness requirement. The test was full scale reproducing engine-operating temperature and red line rotational speed. The objective of the present work is the simulation of the blade release failure event including the interaction with the trailing blades and the severe impact onto the casing. The simulation is compared and validated against the results of the full-scale rig. Material behaviour under impact working condition is characterised through Hopkinson bar tests, ballistic tests and triaxial traction tests. Johnson-Cook constitutive and failure material models are generated for the blade casting, the case forge material and the shroud seal segment. This material model is a temperature and strain-rate dependant flow stress model. Containment simulation is carried out with LS-DYNA implicit/explicit solver. Simulation work includes meshing and boundary conditions effects on model fidelity. Case damage progression is linked to each of the different airfoil portions as contact occurs. The friction contribution to the case and blades interface and to the case final form is also revised. In addition, the importance of the trailing blades and the interaction with the released blade is assessed. Interaction effect comprises both the resulting damage between airfoils and the change in primary release trajectory. Finally, simulation results are compared to the full scale rig results. Case-impacted final geometry and internal energy from simulation are checked against test evidences.

An Experimental Investigation of Thermal Wetness Loss in the Full Scale Size Low Pressure Turbine

2014 ◽  
Author(s):  
Tomohiko Tsukuda ◽  
Hiroki Sato ◽  
Daisuke Nomura ◽  
Sakae Kawasaki ◽  
Naoki Shibukawa
Keyword(s):  
Experimental Investigation ◽  
Three Dimensional ◽  
Low Pressure ◽  
Full Scale ◽  
Inlet Temperature ◽  
Low Pressure Turbine ◽  
Last Stage ◽  
Condensation Model ◽  
Generator Output ◽  
Non Equilibrium

Experimental investigation with a full scale low pressure steam turbine is carried out to reveal the thermal wetness loss. This paper focuses on thermal wetness loss of the last stage in a six-stage low pressure turbine. The temperature of superheating at the inlet of the last stage varies within a range of several tens of degrees under the condition that enthalpy at the stage outlet is below the saturation point. Radial distributions of pressure and temperature at the stage inlet and outlet are measured with rake probes and traverse probes, whereas the stage outlet enthalpy is identified by using the generator output and turbine mass flow rate. Higher stage efficiency is obtained the superheating inlet temperature becomes higher in this experimental condition. A three-dimensional CFD taking into consideration a non-equilibrium/equilibrium condensation model is carried out to understand the experimental results. A non-equilibrium condensation model can take into account the thermal wetness loss associated with supercooling and non-equilibrium condensation. The amount of thermal wetness loss is evaluated by comparing the results of non-equilibrium and equilibrium condensation models. The results show that the degree of superheating at the inlet of the stage affects the supercooling temperature distribution in the last stage flow path, resulting in lower thermal wetness loss at a higher inlet superheat condition.

Cracks on the Roots of Turbine Blades of the Low-Pressure Turbine in a Steam Power Plant

2015 ◽  
Vol 52 (4) ◽  
pp. 214-225 ◽  
Author(s):  
E. Plesiutschnig ◽  
R. Vallant ◽  
G. Stöfan ◽  
C. Sommitsch ◽  
M. Mayr ◽  
...  
Keyword(s):  
Power Plant ◽  
Turbine Blades ◽  
Low Pressure ◽  
Steam Power ◽  
Steam Power Plant ◽  
Low Pressure Turbine

Low-pressure turbine disc fi rtree slots’ life and reliability enhancement by ultrasonic surface hardening

2020 ◽  
pp. 491-495
Author(s):  
A.M. Tomashevich ◽  
G.G. Shirvan’yants ◽  
D.A. Teryaev
Keyword(s):  
Residual Stress ◽  
Low Pressure ◽  
Fatigue Tests ◽  
Compression Stress ◽  
Cycle Basis ◽  
Low Pressure Turbine ◽  
Working Stress ◽  
Turbine Disc ◽  
Axial Residual Stress ◽  
Reliability Enhancement

The possibility of life and reliability enhancing of AL-31F low pressure turbine disc’s fir-tree slots by ultrasonic hardening is considered. Having disc’s material properties studied, working stress derivation is executed which was further used for following comparative fatigue tests. Also, Davidenkov method residual stress analysis is carried out which showed 95.3 % change to compression stress for circumferential residual stress and 80.9 % change to compression stress for axial residual stress which proves possibility of fir-tree slots’ life and reliability enhancement by ultrasonic hardening. Comparative fatigue tests with N = 4•10 5 cycles basis showed that the hardened samples standing out the cycle basis during higher oscillatory amplitudes (and, thus, affecting loads) than the non-hardened basic ones.

scholarly journals Prediction of Transient Pressure Fluctuations within a Low-Pressure Turbine Cascade Using a Lanczos-Filtered Harmonic Balance Method

2021 ◽  
Vol 6 (3) ◽  
pp. 25
Author(s):  
Jan Philipp Heners ◽  
Stephan Stotz ◽  
Annette Krosse ◽  
Detlef Korte ◽  
Maximilian Beck ◽  
...  
Keyword(s):  
Turbulence Model ◽  
Harmonic Balance ◽  
Separation Bubble ◽  
Pressure Fluctuations ◽  
Harmonic Balance Method ◽  
Low Pressure ◽  
Filter Method ◽  
Turbine Cascade ◽  
Transient Pressure ◽  
Low Pressure Turbine

Unsteady pressure fluctuations measured by fast-response pressure transducers mounted in a low-pressure turbine cascade are compared to unsteady simulation results. Three differing simulation approaches are considered, one time-integration method and two harmonic balance methods either resolving or averaging the time-dependent components within the turbulence model. The observations are used to evaluate the capability of the harmonic balance solver to predict the transient pressure fluctuations acting on the investigated stator surface. Wakes of an upstream rotor are generated by moving cylindrical bars at a prescribed rotational speed that refers to a frequency of f∼500 Hz. The excitation at the rear part of the suction side is essentially driven by the presence of a separation bubble and is therefore highly dependent on the unsteady behavior of turbulence. In order to increase the stability of the investigated harmonic balance solver, a developed Lanczos-type filter method is applied if the turbulence model is considered in an unsteady fashion.

Interaction of Wheelspace Coolant and Main Flow in a New Aeroderivative LPT

2006 ◽  
Author(s):  
Francesco Montomoli ◽  
Michela Massini ◽  
Nicola Maceli ◽  
Massimiliano Cirri ◽  
Luca Lombardi ◽  
...  
Keyword(s):  
Flux Distribution ◽  
Low Pressure ◽  
Main Flow ◽  
Space Region ◽  
Heat Flux Distribution ◽  
Gas Generator ◽  
Component Reliability ◽  
Accuracy Requirement ◽  
Low Pressure Turbine ◽  
Hot Gas

Increased computational capabilities make available for the aero/thermal designers new powerful tools to include more geometrical details, improving the accuracy of the simulations, and reducing design costs and time. In the present work, a low-pressure turbine was analyzed, modeling the rotor-stator including the wheel space region. Attention was focused on the interaction between the coolant and the main flow in order to obtain a more detailed understanding of the behavior of the angel wings, to evaluate the wall heat flux distribution, and to prevent hot gas ingestion. Issues of component reliability related to thermal stress require accurate modeling of the turbulence and unsteadiness of the flow field. To satisfy this accuracy requirement, a full 3D URANS simulation was carried out. A reduced count ratio technique was applied in order to decrease numerical simulation costs. The study was carried out to investigate a new two-stage Low Pressure Turbine from GE Infrastructure Oil&Gas to be coupled to a new aeroderivative gas generator, the LM2500+G4, developed by GE Infrastructure, Aviation.

Influence of Hot Streak Temperature Ratio on Low Pressure Stage of a Vaneless Counter-Rotating Turbine

2007 ◽  
Author(s):  
Qingjun Zhao ◽  
Fei Tang ◽  
Huishe Wang ◽  
Jianyi Du ◽  
Xiaolu Zhao ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Secondary Flow ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Temperature Ratio ◽  
High Pressure Turbine ◽  
Pressure Stage ◽  
Low Pressure Turbine ◽  
Hot Streak

In order to explore the influence of hot streak temperature ratio on low pressure stage of a Vaneless Counter-Rotating Turbine, three-dimensional multiblade row unsteady Navier-Stokes simulations have been performed. The predicted results show that hot streaks are not mixed out by the time they reach the exit of the high pressure turbine rotor. The separation of colder and hotter fluids is observed at the inlet of the low pressure turbine rotor. After making interactions with the inner-extending shock wave and outer-extending shock wave in the high pressure turbine rotor, the hotter fluid migrates towards the pressure surface of the low pressure turbine rotor, and the most of colder fluid migrates to the suction surface of the low pressure turbine rotor. The migrating characteristics of the hot streaks are predominated by the secondary flow in the low pressure turbine rotor. The effect of buoyancy on the hotter fluid is very weak in the low pressure turbine rotor. The results also indicate that the secondary flow intensifies in the low pressure turbine rotor when the hot streak temperature ratio is increased. The effects of the hot streak temperature ratio on the relative Mach number and the relative flow angle at the inlet of the low pressure turbine rotor are very remarkable. The isentropic efficiency of the Vaneless Counter-Rotating Turbine decreases as the hot streak temperature ratio is increased.

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