Research On Explosive Blade-off Test In Containment Evaluation Of Aero-engines

Fan blade-off test is essential for civil aero-engines in airworthiness certification to evaluate the containment capacity.This exploratory research is focused on the explosive blade-off technology,and following works have been done.1)The contact explosion process in a hole drilled into blade,and the penetration process into blade caused by linear shaped charge(LSC)jet,were simulated on a quasi-two-dimensional basis,both blades were set up as plates.The interactions between explosion product and blades,as well as the local dynamic responses of blades in these different explosion processes,were studied and compared based on these simulations.Finally,the LSC was chosen for the subsequent research and test design.Besides,the spallation damage,as one of the most significant dynamic responses of plate subjected to impact,was clearly detected,and then explained and analysed with the theory of stress wave;2)More specifically,the penetration process caused by LSC jet into a plate and a small-scaled hollow blade were simulated on a three-dimensional basis,all the models were set up in a static state.Based on these simulations and corresponding field experiments,the macro responses of the blades were studied in detail,which were helpful to improve the configurations of LSC jet penetrating blade.Finally,the ultimate configurations for fan blade-off test were formed,the dynamic loads on the central sections of the blades in these configurations were analysed;3)Based on all the simulations done before,the explosive blade-off tests on a high-speed rotating rig were conducted,all the blades flied off successfully,the fracture processes of these blades were analysed quantitatively based on a superposition principle,and the expected objectives of these tests were achieved.Some key factors in the test design were also verified through the real tests,including the installation structure of the detonator and LSC,the reliability of the detonation form,the damage of the test rig caused by the explosion impact,the accuracy of the revolution speed when blades flied off,and the safety level of the tests.After numerous numerical simulations,field experiments and the final verification tests,a reliable technical scheme for explosive blade-off test was formed.In the foreseeable future,with some detail refinement and parameter adjustment,this scheme can be utilized in the real aero-engine rig test and finally in the airworthiness verification test.