Study On The Containment Criterion About Double-layer Casing Of Aeroengine

The design and evaluation on the containment problem of aeroengine casing are important in the research of aeroengine.There are increasingly applications of double-layer casing in aeroengine,so that it is important to find a set of containment criterion for double-layer casing in order to reduce the costs of test research.The research of containment criterion is of great value to the design and evaluation of aeroengine casing.This paper makes a systematic study of the containment problem,including theoretical analysis,numerical simulation and test verification.Based on the adiabatic shear theory,a new method of the ballistic limit calculation for double-layer casing with no space was proposed,the parameter in which was modified by numerical simulation results.The ballistic limit model of double metal casing with no space is possible to calculate the ballistic limit of double layer mental casing under any thickness ratio of inner and outer layer.This method can be used as one of the criteria for the containment of double-layer casing.In this paper,the containment process of double-layer metal casing was modeled theoretically,which simplified as the impacting test model.A new ballistic limit calculation model of the double layer metal casing with no space was established through theoretical deduction,then a series of numerical simulations and experimental research were conducted by using TC4 material.The results are as follows:A method for calculating the effect coefficient of blades of arbitrarily shaped is proposed,and the range of the effect coefficient is perfected.The ballistic limit model of the double layer metal plate with no space is modified by numerical simulation result,and the range of parameters is obtained.Analyzing the impact resistance of double layer metal target with no space,it is found that the impact resistance of the double layer TC4 plate increases first,then decreases while the increase of the thickness of the inner plate.The calculated results of the ballistic limit model with parameter modified are in good agreement with the numerical simulation and experimental results,which can accurately predict the ballistic limit of the double layer TC4 no-space plate.Analyzing the impact resistance of double layer metal target with space,the results show that there are no monotonous relevance between impact resistance and space.Aiming at the optimal design for real engine test,this paper also studied the blade out method.After evaluating the current method and combining the mechalism of the jet flow erosion,linear shaped charge cutter were used to cut the TC4 plate.It is found that the cuneiform shaped charge performs better than the conical shape charge since the faster jet flow speed and higher energy it has.A series of numerical simulations were done to analyze the jet metal flow striking the target plates.These numerical simulations were conducted to studied the influence of the half cone angle by changing which of the linear shaped charge cutter,the results show that linear shaped charge cutter can be a priority alternative in the test research since its advantages.