Semi-structured meshes for axial turbomachinery blades

Sbardella, L.; Sayma, A. I.; Imregun, M.

doi:10.1002/(sici)1097-0363(20000315)32:5<569::aid-fld975>3.0.co;2-v

Cited by 32 publications

(12 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The turbomachinery blades are discretised using a semi-structured mesh which consists of brick elements in the boundary layer and triangular prisms (wedges) further away in the blade passage (14,15) . This is achieved by generating a 2D grid in a projection of a bladeto-blade circumferential surface, containing quadrilaterals in the boundary layer and triangles in the core of the passage.…”

Section: Methodsmentioning

confidence: 99%

A numerical study of high pressure turbine forced response in the presence of damaged nozzle guide vanes

Mare

Imregun

Smith³

et al. 2007

Aeronaut. j.

Self Cite

View full text Add to dashboard Cite

This paper reports results from numerical computations of low engine order and blade-passing forced response on the rotor of a high pressure turbine due to severe damage to a single nozzle guide vane. The computations are performed using a time-domain, nonlinear viscous compressible flow simulation code. The flow and the levels of forcing for a few selected modes are compared for the undamaged and the damaged configurations. The results show that the response in various modes is affected to a different extent by the damage. The main blade-passing response was found to be largely unaffected, if not marginally reduced. On the other hand, the vibration levels for some modes were seen to be up to eight times higher because of the low-order excitation harmonics created by the damaged passage.

show abstract

Section: Methodsmentioning

confidence: 99%

A numerical study of high pressure turbine forced response in the presence of damaged nozzle guide vanes

Mare

Imregun

Smith³

et al. 2007

Aeronaut. j.

Self Cite

View full text Add to dashboard Cite

show abstract

“…For optimum spatial discretisation, a 3D semi-structured mesh approach is used for turbomachinery blades providing geometric flexibility. 22 The approach makes use of a structured body fitted grid near the blade and an unstructured grid occupying the interface between the structured one around the blades as shown in Figure 1. Mixing planes have been used for steady state computations using a single blade passage with repeated periodic boundaries.…”

Section: Methodsmentioning

confidence: 99%

Full annulus numerical study of hot streaks propagation in a hydrogen-rich syngas-fired heavy duty axial turbine

Ioannou

Sayma

2017

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract This paper presents a study of the effect of fuel composition on hot streaks propagation in a high-pressure turbine using a full annulus unsteady CFD analysis of the first two stages. Hot streaks result from the inherent no-uniformities of temperature profiles at the exit of the combustion chamber. Variations in composition arise from current challenges requiring gas turbines to adapt to fuel variations driven by the need to reduce CO 2 emissions through the use of synthetic hydrogen rich fuels (Syngas) typically generated from the gasification of coal or solid waste. Syngas containing 80% hydrogen has been used in this study in a heavy duty gas turbine modified to accommodate the low calorific value fuel. Calculations were conducted on the baseline gas turbine originally designed for natural gas for the comparative study. Applying combustor representative hot streak profiles, analyses were performed for different hot streak distributions and locations. Analysis of results focused on the segregation of cold and hot fluid patterns and the effects of hot streaks on secondary flows and temperature re-distributions up to the second turbine stage. The hot flow pattern is affected by the fuel composition, resulting in more concentrated thermal wake shapes for syngas when compared to the reference natural gas fuel. In effect, the interaction with the secondary flow leads to more intense flow turning of the pressure side leg of the horseshoe vortex in the first rotor passage. The higher temperature levels in the case of syngas, in combination with the effect of the enhanced secondary flow, result in higher radial spread of the hot fluid that tends to migrate towards the blade hub and tip with the effects being obvious further downstream the first turbine stage. Permanent repository link

show abstract

“…The used meshes are semiunstructured i.e. structured in the spanwise direction but each layer contains an unstructured mesh, compare ( 19 , 20 ) for a more detailed description of the meshing philosophy. Fillets and varying gap sizes are taken into account, compare also ( 9 , 20 ) .…”

Section: Compressor Rig Test Casementioning

confidence: 99%

Analysis of mistuned forced response in an axial high-pressure compressor rig with focus on Tyler–Sofrin modes

et al. 2019

View full text Add to dashboard Cite

This paper aims at contributing to a better understanding of the effect of Tyler–Sofrin Modes (TSMs) on forced vibration responses by analysing a 4.5-stage research axial compressor rig. The first part starts with a brief review of the involved physical mechanisms and necessary prerequisites for the generation of TSMs in multistage engines. This review is supported by unsteady CFD simulations of a quasi 2D section of the studied engine. It is shown that the amplitude increasing effect due to mistuning can be further amplified by the presence of TSMs. Furthermore, the sensitivity with respect to the structural coupling of the blades and the damping as well as the shape of the expected envelope is analysed.The second part deals with the Rotor 2 blisk of the research compressor rig. The resonance of a higher blade mode with the engine order of the upstream stator is studied in two different flow conditions realised by different variable stator vane (VSV) schedules which allows to separate the influence of TSMs from the impact of mistuning. A subset of nominal system modes representation of the rotor is used to describe its mistuned vibration behaviour, and unsteady CFD simulations are used to characterise the present strength of the TSMs in the particular operating conditions. Measured maximum amplitude vs blade pattern and frequency response functions are compared against the predictions of the aeromechanical models in order to assess the strength of the TSMs as well as its influence on vibration levels.

show abstract

Semi-structured meshes for axial turbomachinery blades

Cited by 32 publications

References 7 publications

A numerical study of high pressure turbine forced response in the presence of damaged nozzle guide vanes

A numerical study of high pressure turbine forced response in the presence of damaged nozzle guide vanes

Full annulus numerical study of hot streaks propagation in a hydrogen-rich syngas-fired heavy duty axial turbine

Analysis of mistuned forced response in an axial high-pressure compressor rig with focus on Tyler–Sofrin modes

Contact Info

Product

Resources

About