Forced Response Method for Annular Combustors: Stationary Acoustic Pressure Wave Excitations

2008 ◽  
Author(s):  
Sanghum Baik ◽  
Mehmet Dede
Keyword(s):  
Pressure Wave ◽  
Acoustic Pressure ◽  
Forced Response ◽  
Acoustic Pressure Wave ◽  
Response Method

A Forced Response Method for Annular Combustors Excited by Traveling Acoustic Pressure Waves

2008 ◽  
Author(s):  
Sanghum Baik ◽  
Mehmet Dede
Keyword(s):  
Finite Element ◽  
Pressure Wave ◽  
Acoustic Pressure ◽  
Response Prediction ◽  
Element Model ◽  
Forced Response ◽  
Response Analysis ◽  
Element Analysis ◽  
Variable Theory ◽  
Response Method

Recent progress in the development of an industry level tool for computing forced response of annular combustors is presented. Hereby, in addressing productivity issues caused by huge finite element model of full-wheel combustor, the theoretical framework of cyclic symmetry is introduced. The complex-variable theory, which originated for capturing natural frequency and mode shape characteristics of rotationally periodic structure, was extended for real-number-based finite element analysis (FEA) to solve forced response problem; specifically, a systematic method was developed to create cyclic domain replica of traveling pressure wave loading on full-wheel combustor. In this paper, theoretical descriptions of the physics-based, practical forced response analysis technique will be provided, and its implementation into building the tool of industrial level will be discussed. The technology developed herein will be verified using a simple cylindrical structure that is excited by acoustic pressure wave that travels in circumferential direction with a certain number of nodal diameter. In the end, a practical application to forced response prediction of a combustor component will be presented.

scholarly journals Laser-induced optical breakdown applied for laser spark ignition

2010 ◽  
Vol 28 (1) ◽  
pp. 109-119 ◽  
Author(s):  
E. Schwarz ◽  
S. Gross ◽  
B. Fischer ◽  
I. Muri ◽  
J. Tauer ◽  
...  
Keyword(s):  
Pressure Wave ◽  
Internal Combustion Engines ◽  
Acoustic Pressure ◽  
Laser System ◽  
Optical Breakdown ◽  
Acoustic Energy ◽  
Pollutant Emission ◽  
High Peak Power ◽  
Laser Spark ◽  
Acoustic Pressure Wave

AbstractIn the present article, the experimental investigation of optical breakdown induced by ns/mJ pulses at two wavelengths, 1064 nm and 532 nm, in air of atmospheric pressure is reported and discussed. The obtained breakdown thresholds were compared with theory and are in good agreement. The generated plasmas have been characterized by their amount of scattered laser light, energy transmission, and change of the transmitted temporal shape. Laser-induced plasma formation in a gas, in air, also generates an acoustic pressure wave. The acoustic energy is compared to the laser pulse energy and is found to be linearly dependent. Moreover, the frequency distribution of the characteristic acoustic pressure wave was analyzed. The experiments described were accomplished in order to optimize a laser ignition system with regard to efficiency and costs. The laser system employed for these investigations is a compact high peak power, passively Q-switched, longitudinally diode-pumped solid-state laser. Such a “laser spark plug” should replace conventional spark plugs in internal combustion engines because conventional ignition has reached its limits in terms of efficiency and durability. Thereby, a reduction of pollutant emission should also be feasible.

scholarly journals INFLUENCE OF ACOUSTIC PRESSURE WAVE ON THE MOVEMENT OF THE UNDERWATER

2021 ◽  
Vol 2 (11(75)) ◽  
pp. 34-42
Author(s):  
V. Mel’nick ◽  
N. Gnateiko
Keyword(s):  
Comparative Analysis ◽  
Pressure Wave ◽  
Total Pressure ◽  
Acoustic Pressure ◽  
Pressure Pulse ◽  
Moving Medium ◽  
Translational Movement ◽  
Acoustic Pressure Wave ◽  
Real Medium ◽  
Forced Movement

The forced movement of the submarine under the action of an acoustic pressure wave at rectilinear and uniform movement of the device is analyzed. The analysis of the dynamics of translational movement of the hull under the action of an acoustic pressure wave in an ideal environment, which makes it possible to assess the physical properties of the environment and the elastic properties of the outer hull on the value of the maximum movement of the submarine. It is proved that if the total pressure pulse is limited, then the water particles will receive certain displacements and it can be expected that under these conditions the displacement of the submarine will be determined. The results of the analysis make it possible to conduct a comparative analysis of the translational movement of the submarine under the action of an acoustic pressure wave, taking into account the characteristics of the moving medium, more precisely, taking into account the viscosity of the real medium

Sign in / Sign up

Export Citation Format

Share Document