风扇叶片爆炸飞断等效试验与分析方法

Equivalent Test and Analysis Method for Explosive Releasing of Fan Blade

关键词:  航空发动机  风扇叶片  爆炸飞断  等效试验  数值仿真

Key words:  Aero engine  Fan blade  Explosive releasing  Equivalent test  Numerical simulation

摘要:

针对航空发动机风扇叶片爆炸飞断试验难度大、成本高的问题，在发动机研制初期，通过等效平板试验件爆炸损伤机理试验，模拟风扇叶片实际损伤与飞断过程。基于包容性试验对叶片爆炸飞断位置、转速、时间和额外动能的要求，以飞断质量、动能和损伤截面积等效为准则，首先，根据飞断截面平均应力进行等效平板和爆炸结构设计。然后，采用显式动力学数值仿真方法对等效平板爆炸损伤和飞断过程进行模拟，评估飞断时间和飞断动能，并根据仿真结果对试验方案进行优化。最后，通过平板等效试验和真实风扇叶片试验对优化后的爆炸飞断方案进行验证。经评估，风扇叶片爆炸飞断位置准确，飞断转速误差控制在［0%，+1%］之内，符合适航规章的要求，且爆炸未对飞断碎片施加额外动能。采用爆炸飞断等效试验与分析方法，能够有效提高真实风扇叶片包容试验的成功率，具备工程应用的可行性。

Abstract:

Aiming at the difficulty and high cost of the explosive releasing test of aero engine fan blade， it is proposed that the explosion damage mechanism test of equivalent plate test piece is used to simulate the actual damage and released process of fan blade at the early stage of engine development. Based on the requirements of the containment test for the released location， rotating speed， breaking duration and additional kinetic energy of the blade， the equivalent of the mass， kinetic energy and damage cross section are taken as the criteria. Firstly， the equivalent plate and explosion structures are designed according to the mean stress of the released section. Then， the explosive damage and released process of the equivalent plate were simulated by explicit dynamic numerical simulation method， and the duration of the released process and kinetic energy of the plate were evaluated. The test scheme was optimized according to the simulation results. At last， the explosion scheme is verified by plate equivalent test and actual fan blade test. It is assessed that the released location of the blade is accurate， and the error of the fan blade’s rotating speed is within the range ［0， +1%］， which comply with the airworthiness regulations. At the same time， the explosion did not apply additional kinetic energy to the released debris. The using of the equivalent test and analysis method of the explosive releasing can effectively improve the success rate of the real fan blade containment test， which has the feasibility of engineering application.