Heat transfer—A review of 2005 literature

Multilevel nested reliability-based design optimization with hybrid intelligent regression for operating assembly relationship

Multi-objective reliability-based design optimization approach of complex structure with multi-failure modes

Novel method and model for dynamic reliability optimal design of turbine blade deformation

Because of the randomness of many impact factors influencing the dynamic assembly relationship of complex machinery, the reliability analysis of dynamic assembly relationship needs to be accomplished considering the randomness from a probabilistic perspective. To improve the accuracy and efficiency of dynamic assembly relationship reliability analysis, the mechanical dynamic assembly reliability(MDAR) theory and a distributed collaborative response surface method(DCRSM) are proposed. The mathematic model of DCRSM is established based on the quadratic response surface function, and verified by the assembly relationship reliability analysis of aeroengine high pressure turbine(HPT) blade-tip radial running clearance(BTRRC). Through the comparison of the DCRSM, traditional response surface method(RSM) and Monte Carlo Method(MCM), the results show that the DCRSM is not able to accomplish the computational task which is impossible for the other methods when the number of simulation is more than 100 000 times, but also the computational precision for the DCRSM is basically consistent with the MCM and improved by 0.40∼4.63% to the RSM, furthermore, the computational efficiency of DCRSM is up to about 188 times of the MCM and 55 times of the RSM under 10000 times simulations. The DCRSM is demonstrated to be a feasible and effective approach for markedly improving the computational efficiency and accuracy of MDAR analysis. Thus, the proposed research provides the promising theory and method for the MDAR design and optimization, and opens a novel research direction of probabilistic analysis for developing the high-performance and high-reliability of aeroengine.

Distributed collaborative response surface method for mechanical dynamic assembly reliability design

Secondary effects, such as heat transfer from fluid to engine structure and the resulting changes in tip and seal clearances affect component performance and stability. A tip clearance model to be used in transient synthesis codes has been developed. The tip clearance model is derived as a state space structure. The model parameters have been identified from thermomechanical finite element models. The model calculates symmetric rotor tip clearance changes in the turbomachinery and symmetric seal clearance changes in the secondary air system for engine transients within the entire flight envelope. The resulting changes in efficiency, capacity, and cooling airflows are fed into the performance program. Corrections for tip clearance changes on the component characteristics are derived from rig tests. The effect of seal clearance changes on the secondary air system is derived using sophisticated air system models. The clearance model is validated against FE thermomechanical models. The modeling method of modifying the component characteristics is verified comparing engine simulation and test data, which show good agreement. Based on a representative transient maneuver typical transient overshoots in fuel flow and turbine gas temperature and changes in component stability margins can be shown. With the use of this model in the performance synthesis the transient engine performance can be predicted more accurate than currently in the engine development program.

Modeling and Validation of the Thermal Effects on Gas Turbine Transients

Secondary effects, such as heat transfer from fluid to engine structure and the resulting changes in tip and seal clearances affect component performance and stability. A tip clearance model to be used in transient synthesis codes has been developed. The tip clearance model is derived as a state space structure. The model parameters have been identified from thermo-mechanical finite element models. The model calculates symmetric rotor tip clearance changes in the turbo-machinery and symmetric seal clearance changes in the secondary air system for engine transients within the entire flight envelope. The resulting changes in efficiency, capacity and cooling air flows are fed into the performance program. Corrections for tip clearance changes on the component characteristics are derived from rig tests. The effect of seal clearance changes on the secondary air system is derived using sophisticated air system models. The clearance model is validated against FE thermo-mechanical models. The modeling method of modifying the component characteristics is verified comparing engine simulation and test data which show good agreement. Based on a representative transient maneuver typical transient overshoots in fuel flow and turbine gas temperature and changes in component stability margins can be shown. With the use of this model in the performance synthesis the transient engine performance can be predicted more accurate than currently in the engine development program.Copyright © 2004 by ASME

Annette E. Nielsen

Papers

Modeling and Validation of the Thermal Effects on Gas Turbine Transients

Modeling and Validation of the Thermal Effects on Gas Turbine Transients