Combined exhaust pipe for solid rocket engine

The invention discloses a combined exhaust pipe for a solid rocket engine. A Laval tube is arranged in a cavity of an exhaust pipe base, and the two ends of the Laval tube are limited by the inner end face of the exhaust pipe base and an annular gland. The annular gland is positioned through a safety pin penetrating through the exhaust pipe base and extending into the annular gland. Shearing sleeves are arranged between the safety pin and the exhaust pipe base and between the safety pin and the annular gland. Combination design is adopted for an exhaust pipe body, according to different design requirements and the exhaust pipe ablation condition, only structural parameters of the Laval tube are changed and the Laval tube is replaced so that the exhaust pipe base can still continue to be used, the exhaust pipe has certain universality and reusability, and cost is effectively used. The safety pin is used in cooperation with the inner shearing sleeve and the outer shearing sleeve, and the diameter of the safety pin, the inner diameter of the inner shearing sleeve and the inner diameter of the outer shearing sleeve can be adjusted according to design requirements; the shearing strength of the safety pin is convenient to adjust, the safety of the engine is guaranteed, and the universality of the exhaust pipe is also guaranteed.