Numerical Analysis of the Stability and Operation of an Axial Compressor Connected to an Array of Pulsed Detonation Combustors

2021 ◽  
Author(s):  
Louise Dittmar ◽  
Panagiotis Stathopoulos
Keyword(s):  
Numerical Analysis ◽  
Axial Compressor ◽  
Pulsed Detonation ◽  
The Stability

A Study of Influences of Inlet Total Pressure Distortions On Clearance Flow in an Axial Compressor

2021 ◽  
Author(s):  
Guoming Zhu ◽  
Xiaolan Liu ◽  
Bo Yang ◽  
Moru Song
Keyword(s):  
Total Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Leading Edge ◽  
Stall Margin ◽  
Flow Cells ◽  
Static Pressure Distribution ◽  
Speed Flow ◽  
Clearance Flow ◽  
The Stability

Abstract The rotating distortion generated by upstream wakes or low speed flow cells is a kind of phenomenon in the inlet of middle and rear stages of an axial compressor. Highly complex inflow can obviously affect the performance and the stability of these stages, and is needed to be considered during compressor design. In this paper, a series of unsteady computational fluid dynamics (CFD) simulations is conducted based on a model of an 1-1/2 stage axial compressor to investigate the effects of the distorted inflows near the casing on the compressor performance and the clearance flow. Detailed analysis of the flow field has been performed and interesting results are concluded. The distortions, such as total pressure distortion in circumferential and radial directions, can block the tip region so that the separation loss and the mixing loss in this area are increased, and the efficiency and the total pressure ratio are dropped correspondingly. Besides, the distortions can change the static pressure distribution near the leading edge of the rotor, and make the clearance flow spill out of the rotor edge more easily under near stall condition, especially in the cases with co-rotating distortions. This phenomenon can be used to explain why the stall margin is deteriorated with nonuniform inflows.

scholarly journals An integral equation formulation of the N-body dielectric spheres problem. Part 1: Numerical analysis

2020 ◽  
Author(s):  
Muhammad Hassan ◽  
Benjamin Stamm
Keyword(s):  
Integral Equation ◽  
Numerical Analysis ◽  
Error Analysis ◽  
Convergence Rates ◽  
A Priori ◽  
Approximation Error ◽  
Spherical Particles ◽  
Integral Equation Formulation ◽  
Dielectric Spheres ◽  
The Stability

In this article, we analyse an integral equation of the second kind that represents the solution of N interacting dielectric spherical particles undergoing mutual polarisation. A traditional analysis can not quantify the scaling of the stability constants- and thus the approximation error- with respect to the number N of involved dielectric spheres. We develop a new a priori error analysis that demonstrates N-independent stability of the continuous and discrete formulations of the integral equation. Consequently, we obtain convergence rates that are independent of N.

Numerical analysis of the anti-seepage measures for high earth rockfill dam on deep overburden

2012 ◽  
Vol 170-173 ◽  
pp. 1872-1877 ◽  
Author(s):  
Jun Yan ◽  
Si Hong Liu ◽  
Bin Zhou
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Seepage Field ◽  
Seepage Analysis ◽  
The Real ◽  
Rockfill Dam ◽  
The Stability ◽  
High Rockfill Dam ◽  
At Home

The anti-seepage measures of a high earth rockfill dam built on the foundation with a deep overburden affects the stability and safety of the dam greatly. Nowadays there are few researches on this area both at home and abroad. On the basis of the finite element seepage analysis of the Pubugou high rockfill dam in which core walls and two cut-off walls are designed as the anti-seepage measures, the real seepage behavior of the seepage field is obtained in this paper, as well as the seepage characters of the seepage field under different arrangements of the cut-off walls. The conclusions have a certain referential value for the design of the anti-seepage measures for the similar projects with the foundation of a deep overburden.

Tailored Structural Design and Aeromechanical Control of Axial Compressor Stall—Part I: Development of Models and Metrics

2004 ◽  
Vol 126 (1) ◽  
pp. 52-62 ◽  
Author(s):  
O. G. McGee ◽  
M. B. Graf ◽  
L. G. Fre´chette
Keyword(s):  
Structural Design ◽  
Axial Compressor ◽  
Feedback Stabilization ◽  
Feedback Controllers ◽  
Pressure Sensing ◽  
Stall Inception ◽  
Control Authority ◽  
The Stability ◽  
The Impact ◽  
Control Part

This two-part paper presents general methodologies for the evaluation of passive compressor stabilization strategies using tailored structural design and aeromechanical feedback control (Part I), and quantitatively compares the performance of several aeromechanical stabilization approaches which could potentially be implemented in gas turbine compression systems (Part II). Together, these papers offer a systematic study of the influence of ten aeromechanical feedback controllers to increase the range of stable compressor operation, using static pressure sensing and local structural actuation to postpone modal stall inception. In this part, the stability of aeromechanically compensated compressors was determined from the linearized structural-hydrodynamic equations of stall inception. New metrics were derived, which measure the level of aeromechanical damping, or control authority of aeromechanical feedback stabilization. They indicate that the phase between the pressure disturbances and the actuation is central to assess the impact of aeromechanical interactions on compressors stability.

Numerical and Experimental Buckling and Post - Buckling Analysis of Composite Cylindrical Panel with Delamination

2013 ◽  
Vol 477-478 ◽  
pp. 39-42
Author(s):  
Marek Barski ◽  
Aleksander Muc ◽  
Przemysław Pastuszak ◽  
Agnieszka Bondyra
Keyword(s):  
Numerical Analysis ◽  
Experimental Verification ◽  
Experimental Analysis ◽  
Cylindrical Panel ◽  
Composite Panel ◽  
Fem Method ◽  
Buckling Behavior ◽  
Post Buckling ◽  
The Stability ◽  
Composite Cylindrical Panel

The present work is devoted to the analysis of a buckling behavior of a cylindrical composite panel. The considered structure is subjected to the uniform axial compression. The wall of the panel consists of the 8 layers. In addition, in the geometrical center of the structure there is a square delamination located between the fourth and the fifth layer. The main goal is to determine the buckling and post - buckling behavior as well as the influence of the delamination on the stability of the structure. The nonlinear numerical analysis is carried out with aid of the FEM method. The experimental verification is also performed. The results obtained from numerical and experimental analysis show very similar behavior of the structure.

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