정적 작동환경에 따른 항공기용 열교환기의 구조설계에 관한 연구

Abstract

The objective of this study is to predict structural characteristics of a heat exchanger mounted on aircraft engine using a finite element analysis. The plastic fracture and life on the heat exchanger are estimated by thermo-mechanical analysis.

The mechanical properties of Inconel 625 refer to SPECIAL METALS which is Inconel manufacturer. Also, the mechanical properties of Inconel tube refer to tensile test result at PNU-RRUTC(Pusan National University- Rolls Royce University Technology Center). The yield strength shows 308 MPa and tensile strength shows 640 MPa at 1000 K.

To assess the structural characteristics of heat exchanger, the full and part models for the aircraft engine are employed under static operating conditions given by thermo-mechanical and inertia load.

The components of aircraft engine should have high stiffness body with light weight and small volume. Therefore, parametric study is performed to determine the basic dimensions of major parts.

Heat exchanger is mounted on the gas turbine engine of aircraft with mounting component which has structural safety. The mounting component design is performed to determine the major dimensions. And it is employed to heat exchanger for structural analysis.

Also, heat exchanger is required installation study according to the arrangement of mounting component considering high temperature and locations.

When the full model of heat exchanger is performed to the structural analysis under thermo-mechanical and inertia load, the stress result of whole load show a strong dependence to the thermal load which causes large thermal deformation.

To perform transient analysis under thermo-mechanical load, heat exchanger is employed ligament efficiency refer to ASME code. When checking stress results of the equivalent model, thermal load has large difference from base model more than 70%. So, it need to consider additional conditions for thermal load in the future work.

As a result of static load on the major parts, such as, the case, tubesheet, flange and mounting component have reasonable safety margin to allowable stress assumed the fatigue strength of Inconel 625 at 10000 cycle and 1000 K.