A new computational method for predicting the thermal bow of a rotor

2018 ◽  
Vol 233 (12) ◽  
pp. 4372-4380 ◽  
Author(s):  
M Zhuo ◽  
LH Yang ◽  
K Xia ◽  
L Yu
Keyword(s):  
Analytical Solution ◽  
Gas Turbine ◽  
Turbine Rotor ◽  
Computational Method ◽  
Practical Significance ◽  
Complex Structures ◽  
Heavy Duty ◽  
Element Analysis ◽  
First Order ◽  
Heavy Duty Gas Turbine

In a heavy-duty gas turbine, when hot rotor is left cooled in standstill condition, thermal bow occurs due to natural convection, which may result in high vibrations in a subsequent restart. Usually, a turning gear is immediately started after shutdown of gas turbine to slowly roll and uniformly cool the rotor in order to prevent thermal bow, which is called turning gear operation. The minimum turning time and the acceptable temperature of wheel space are two important indexes of turning gear operation, and their determination highly depends on accurate prediction of thermal bow. This paper proposes an analytical method to predict the thermal bow behavior of rotors with complex structures and investigates the effect of turning time on thermal bow. First, the general form of analytical solution of rotor thermal bow is derived and validated through both finite element analysis and experiments. Then the analytical solution is applied in a heavy-duty gas turbine to predict the most severe thermal bow behavior of the rotor with no turning gear in operation before standstill. Finally, the effect of turning time on thermal bow is investigated, and the indexes to achieve acceptable thermal bow are discussed. Results show that the shape of thermal bow of the gas turbine rotor is close to the first-order mode shape; the peak of the most severe thermal bow reaches 0.7 mm after 3.8 h of cooling and the decrease of thermal bow is much slower than the increase. Besides, the maximum thermal bow of the rotor due to insufficient turning gear operation presents an exponential decay with turning time and lies in linear relationship with the temperature of the same location. These two relationships help determine the minimum turning time and acceptable temperature of wheel space to attain an acceptable bow and thus have practical significance to develop and optimize turning gear operations.

Probabilistic Fracture Mechanics for Heavy Duty Gas Turbine Rotor Forgings

2017 ◽  
Author(s):  
Kai Kadau ◽  
Phillip W. Gravett ◽  
Christian Amann
Keyword(s):  
Fracture Mechanics ◽  
High Performance ◽  
Computing Methodology ◽  
Direct Simulation Monte Carlo ◽  
Turbine Rotor ◽  
Heavy Duty ◽  
Element Analysis ◽  
Probabilistic Fracture Mechanics ◽  
Risk Of Failure ◽  
Heavy Duty Gas Turbine

We developed and successfully applied a direct simulation Monte-Carlo scheme to quantify the risk of fracture for heavy duty rotors commonly used in the energy sector. The developed Probabilistic Fracture Mechanics high-performance computing methodology and code ProbFM routinely assesses relevant modes of operation for a component by performing billions of individual fracture mechanics simulations. The methodology can be used for new design and life-optimization of components, as well as for the risk of failure quantification of in service rotors and their re-qualifications in conjunction with non-destructive examination techniques, such as ultrasonic testing. The developed probabilistic scheme integrates material data, ultra-sonic testing information, duty-cycle data, and finite element analysis in order to determine the risk of failure. The methodology provides an integrative and robust measure of the fitness for service and allows for a save and reliable operation management of heavy duty rotating equipment.

Experience With Large Heavy-Duty Gas Turbine Rotors

1981 ◽  
Author(s):  
O. R. Schmoch ◽  
B. Deblon
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Strength Properties ◽  
Operating Conditions ◽  
Material Strength ◽  
Heavy Duty ◽  
Turbine Rotors ◽  
Heavy Duty Gas Turbine ◽  
Response To Temperature

The peripheral speeds of the rotors of large heavy-duty gas turbines have reached levels which place extremely high demands on material strength properties. The particular requirements of gas turbine rotors, as a result of the cycle, operating conditions and the ensuing overall concepts, have led different gas turbine manufacturers to produce special structural designs to resolve these problems. In this connection, a report is given here on a gas turbine rotor consisting of separate discs which are held together by a center bolt and mutually centered by radial serrations in a manner permitting expansion and contraction in response to temperature changges. In particular, the experience gained in the manufacture, operation and servicing are discussed.

Probabilistic Fracture Mechanics for Heavy-Duty Gas Turbine Rotor Forgings

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Kai Kadau ◽  
Phillip W. Gravett ◽  
Christian Amann
Keyword(s):  
Fracture Mechanics ◽  
High Performance ◽  
Computing Methodology ◽  
Direct Simulation Monte Carlo ◽  
Turbine Rotor ◽  
Heavy Duty ◽  
Element Analysis ◽  
Nondestructive Examination ◽  
Probabilistic Fracture Mechanics ◽  
Heavy Duty Gas Turbine

We developed and successfully applied a direct simulation Monte Carlo (MC) scheme to quantify the risk of fracture for heavy-duty rotors commonly used in the energy sector. The developed probabilistic fracture mechanics (FM), high-performance computing methodology, and code ProbFM routinely assess relevant modes of operation for a component by performing billions of individual FM simulations. The methodology can be used for new design and life optimization of components, as well as for the risk of failure RoF quantification of in service rotors and their requalifications in conjunction with nondestructive examination techniques, such as ultrasonic testing (UT). The developed probabilistic scheme integrates material data, UT information, duty-cycle data, and finite element analysis (FEA) in order to determine the RoF. The methodology provides an integrative and robust measure of the fitness for service and allows for a save and reliable operation management of heavy-duty rotating equipment.

A New Superalloy Enabling Heavy Duty Gas Turbine Wheels for Improved Combined Cycle Efficiency

2017 ◽  
Author(s):  
Andrew Detor ◽  
◽  
Richard DiDomizio ◽  
Don McAllister ◽  
Erica Sampson ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Heavy Duty ◽  
Heavy Duty Gas Turbine ◽  
Cycle Efficiency

Impact of Different Film-Cooling Modes at Trailing Edge on the Aerodynamic Performance of Heavy Duty Gas Turbine Cascade

2011 ◽  
Vol 84-85 ◽  
pp. 259-263
Author(s):  
Xun Liu ◽  
Song Tao Wang ◽  
Xun Zhou ◽  
Guo Tai Feng
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Large Mass ◽  
Turbine Cascade ◽  
Heavy Duty ◽  
Trailing Edge ◽  
Central Difference ◽  
Adiabatic Effectiveness ◽  
Heavy Duty Gas Turbine ◽  
The Impact

In this paper, the trailing edge film cooling flow field of a heavy duty gas turbine cascade has been studied by central difference scheme and multi-block grid technique. The research is based on the three-dimensional N-S equation solver. By way of analysis of the temperature field, the distribution of profile pressure, and the distribution of film-cooling adiabatic effectiveness in the region of trailing edge with different cool air injection mass and different angles, it is found that the impact on the film-cooling adiabatic effectiveness is slightly by changing the injection mass. The distribution of profile pressure dropped intensely at the pressure side near the injection holes line with the large mass cooling air. The cooling effect is good in the region of trailing edge while the injection air is along the direction of stream.

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