关键词: 冲压发动机;前缘体;拉压不同模量;热应力;二次开发;温度场

Abstract: In order to study the thermal stress of the front body of the ramjet intake port with different modulus in tension and compression (Here in after is referred to as bi-modulus), a module which can analyze the stress of materials with bi-modulus was obtained by secondary development which is based on Ansys. Taking the ZrB₂ which is the part of engine that is made of ZrB₂-SiC as research object, since the Mach number is 6.0, the total temperature is 1660K, and the total pressure is 2.85MPa, the internal uneven temperature field of the front body was calculated by flow field and heat conduction. The tensile and compressive modulus of ZrB₂ at different temperatures were measured experimentally, and the compressive modulus was twice the tensile modulus. The tensile and compressive elastic modulus and the calculated temperature field were imported into the developed stress module to obtain the thermal stress of the ZrB₂. These results were compared with the thermal stress distribution curves obtained by flow-solid-thermal coupling without considering the bi-modulus. The results show that the maximum error of thermal stress of ZrB₂ which don’t consider property of bi-modulus is higher than 300%, which is seriously beyond the engineering requirements. The results illustrate the importance of different modulus theory and demonstrate the engineering practical value of the developed stress modulus for bi-modulus materials.

Key words: Ramjet;Front body;Bi-modulus;Thermal stress;Secondary development;Temperature field