Research On Design Of Thermal-acoustics-vibration Coupling Experiment Based On Time Variation

The design of the experiment of thermal-acoustics-vibration coupling in engine combustor was researched in this thesis. The first research done was the coupling mechanism of thermal-acoustics-vibration, which was followed by another research on time-varying modal parameters identification by using Hilbert-Huang Transform(HHT). HHT provides an approach for vibration data processing of experiments on combustor with time-varying operating conditions. Then a combustion test rig and an acoustics-vibration test box were designed and processed. Lastly the preliminary data were obtained through simulations on the combustor with one-way Fluid-Structure Interaction(FSI) method.This research is as follows:Firstly, thorough research was carried out on coupling mechanism of thermal-acoustics-vibration coupling in an engine combustor. The application of Lean-Premixed(LP) combustion systems results in the instability of combustion which generates thermal-acoustic oscillations,eventually evolving into thermal-acoustics-vibration coupling. Because this phenomena visibly shows time-varying characteristics, the approaches for doing the experiments on thermal-acoustics-vibration coupling on the combustor with time-varying operating conditions and identification of time-varying modal parameters, need to be researched on.Secondly, the approach of processing vibration data of thermal-acoustics-vibration coupling in an engine combustor with time-varying operating conditions was researched. HHT method was used to identify the time-varying modal parameters. The results of simulation proved that this method can be used to process the vibration data from thermal-acoustics-vibration coupling in engine combustor with time-varying operating conditions.Thirdly, two sets of laboratory test equipment were designed were i. combustor test rig and ii. acoustics-vibration box. The former includes complete ancillary equipment combustion equipment and measuring system. The latter is a secondary research which will assist the former on acoustics-vibration coupling.Finally, by using standard k-? turbulence model and non-premixed combustion model the preliminary data were obtained by simulation on the combustor under 40 KW and 60 KW thermal power with one-way Fluid-Structure Interaction method.