Strongly Coupled Fluid–Structure Interaction in a Three-Dimensional Model Combustor During Limit Cycle Oscillations

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Mina Shahi ◽  
Jim B. W. Kok ◽  
J. C. Roman Casado ◽  
Artur K. Pozarlik
Keyword(s):  
Limit Cycle ◽  
Acoustic Waves ◽  
Fluid Structure Interaction ◽  
Transfer Model ◽  
Air Cooling ◽  
Three Dimensional Model ◽  
Structural Vibrations ◽  
Liner Material ◽  
Fluid Structure ◽  
Structure Interaction

Due to the high temperature of the flue gas flowing at high velocity and pressure, the wall cooling is extremely important for the liner of a gas turbine engine combustor. The liner material is heat-resistant steel with relatively low heat conductivity. To accommodate outside wall forced air cooling, the liner is designed to be thin, which unfortunately facilitates the possibility of high-amplitude wall vibrations (and failure due to fatigue) in case of pressure fluctuations in the combustor. The latter may occur due to a possible occurrence of a feedback loop between the aerodynamics, the combustion, the acoustics, and the structural vibrations. The structural vibrations act as a source of acoustic emitting the acoustic waves to the confined fluid. This leads to amplification in the acoustic filed and hence the magnitude of instability in the system. The aim of this paper is to explore the mechanism of fluid–structure interaction (FSI) on the LIMOUSINE setup which leads to limit cycle of pressure oscillations (LCO). Computational fluid dynamics (CFD) analysis using a RANS approach is performed to obtain the thermal and mechanical loading of the combustor liner, and finite element model (FEM) renders the temperature, stress distribution, and deformation in the liner. Results are compared to other numerical approaches like zero-way interaction and conjugated heat transfer model (CHT). To recognize the advantage/disadvantage of each method, validation is made with the available measured data for the pressure and vibration signals, showing that the thermoacoustic instabilities are well predicted using the CHT and two-way coupled approaches, while the zero-way interaction model prediction gives the largest discrepancy from experimental results.

Torque Analysis of IPMC Actuated Fin of a Micro Fish like Device Using Two-Way Fluid Structure Interaction Approach

2015 ◽  
Vol 25 ◽  
pp. 25-38
Author(s):  
Mazhar Ul Haq ◽  
Zhao Gang ◽  
Zhuang Zhi Sun ◽  
S.M. Aftab
Keyword(s):  
Numerical Simulation ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Pressure Profile ◽  
Three Dimensional Model ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Flow Speeds ◽  
Interaction Approach

In this paper, a numerical simulation of three dimensional model of IPMC actuated fin of a fish like micro device is presented using two-way fluid structure interaction approach. The device is towed by the surface vessel through a tow cable. Fin is acting as dorsal fin of the fish to control depth of the device and also acts as a stabiliser against its roll motion. Fin's displacement disturbs water flow streamlines around it, as a result velocity and pressure profile of fluid's domain changes around the actuated fin. As fin's position continuously changes throughout its actuation cycle, this makes it transient structural problem coupled with a fluid domain. Fin's displacement is received by the fluid and resulting fluid forces are received by the fin making it a two-way fluid structure interaction (FSI) problem. Such problems are solved by multi field numerical simulation approach. This multifield numerical simulation is performed in ANSYS WORKBENCH by coupling transient structural and Fluid Flow (CFX) analysis systems. It is desirous to determine the torque acting on the fin due to fluid forces through its actuation cycle by IPMC actuators. The objective of this study is to develop the methodology (two-way fluid structural interaction (FSI)) used to simulate the transient FSI response of the IPMC actuated fin, subjected to large displacement against different flow speeds. Efficacy of fin as depressor and riser is also required to be judged by monitoring the forces acting on wing in response to its displacement under IPMC actuation. Same approach is also applicable to the self-propelled systems.

Simplified Analysis Strategies for Fluid-Structure Interaction in High Speed Turbomachinery

2009 ◽  
Author(s):  
Brittany Consuegra ◽  
George T. Flowers
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Fluid Structure Interaction ◽  
Parameter Analysis ◽  
Structural Vibrations ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Machine Failure ◽  
Lumped Parameter ◽  
Wide Range

High pressure seals are usually mounted between the rotating and stationary components in high-pressure turbomachinery and often experience intense vibration. These vibrations can interact with the fluid to produce unsteady flows, which can in turn induce structural vibrations that result in machine failure. The reduction of the adverse effects of these vibrations is considered one of the most challenging problems for turbopump design. However, detailed analyses of such fluid-structure interaction problems can be extremely time-consuming and inefficient. The purpose of the present study is to evaluate the effectiveness of simplified, lumped-parameter techniques in analyzing and predicting such behavior, as compared to more sophisticated techniques, with the goal of defining the range of validity for such techniques. A fluid-structure driven vibration is evaluated using a lumped parameter analysis for a wide range of parametric configurations and the results are validated and compared using a bench-top laboratory test rig.

Fluid–Structure Interaction Effects in the Dynamic Response of Free-Standing Plates to Uniform Shock Loading

2006 ◽  
Vol 74 (5) ◽  
pp. 1042-1045 ◽  
Author(s):  
Nayden Kambouchev ◽  
Raul Radovitzky ◽  
Ludovic Noels
Keyword(s):  
Dynamic Response ◽  
Shock Intensity ◽  
Acoustic Waves ◽  
Shock Loading ◽  
Fluid Structure Interaction ◽  
Mass Range ◽  
Free Standing ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Transmitted Impulse

The problem of uniform shocks interacting with free-standing plates is studied analytically and numerically for arbitrary shock intensity and plate mass. The analysis is of interest in the design and interpretation of fluid–structure interaction (FSI) experiments in shock tubes. In contrast to previous work corresponding to the case of incident blast profiles of exponential distribution, all asymptotic limits obtained here are exact. The contributions include the extension of Taylor’s FSI analysis for acoustic waves, the exact analysis of the asymptotic limits of very heavy and very light plates for arbitrary shock intensity, and a general formula for the transmitted impulse in the intermediate plate mass range. One of the implications is that the impulse transmitted to the plate can be expressed univocally in terms of a single nondimensional compressible FSI parameter.

Numerical Modelling of Fluid Structure Interaction in Blood Vessels

2005 ◽  
Author(s):  
Ian Owens Pericevic ◽  
Moji Moatamedi ◽  
M hamed Souli
Keyword(s):  
Pressure Pulse ◽  
Physiological State ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Theoretical Description ◽  
Numerical Code ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Fluid Structure ◽  
Structure Interaction

This paper examines the capabilities offered by the fluid structure interaction (FSI) algorithms in LS-DYNA for solving problems in vascular biomechanics. In this work a case was examined in which the onset of a pressure pulse was simulated at the entrance of a straight segment of artery. The resulting dynamic response in the form of a propagating pulse wave through the vessel wall was analyzed and compared to both previous numerical results and theory. The results from the three dimensional model compared well to the theoretical description of an idealized thin-walled artery. Results were further compared to those obtained from similar research. The numerical methodologies applied in the three dimensional model were used in the development of an experiment providing a realistic physical model of a carotid artery in its physiological state. The experiment is to be used for further validation of the numerical code.

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