某型大功率柴油机活塞热机耦合研究

Coupled Thermal and Mechanical Load Analysis in a Certain Type High Power Diesel Engine Piston

利用AVL-BOOST软件对某型柴油机缸内工作过程进行计算分析,结合经验半经验公式得到了活塞的热边界条件,进而采用有限元方法计算了活塞的温度场。然后利用ADAMS软件对曲柄连杆机构进行了多体动力学分析,得到活塞的往复惯性力、侧推力等机械边界条件,在此基础上,计算了活塞在热负荷-机械负荷耦合下的应力及变形,最后利用NCODE软件计算了活塞稳定工况下的高频疲劳寿命。结果表明,活塞的最高温度为305℃,位于头部喉口处;最大应力为456 MPa,出现在第一环槽内壁过渡圆弧处;最大变形量为0.47 mm,位于活塞火力岸;最小疲劳寿命为1.04×1010,位于裙内销座上方。

Utilizing AVL-BOOST software to analyze diesel with empirical and semi-empirical formulas, piston thermal temperature was calculated by the means of finite element method to analyze crank and connecting rod mechanism, the engine in-cylinder working process, combined boundary conditions were gained, and piston method. Making use of multi-body dynamic mechanical boundary conditions of reciprocating inertia forces and lateral force were obtained. On this basis, piston stress and deformation are calculated under the conditions of thermal-mechanical coupling load. Finally, the high frequency fatigue life of the piston is obtained by NCODE software. The results showed that,its maximum temperature is 305℃, occurring on first ring groove inner wall transition arc; and its maximum deformation is 0.47mm, occurring on top land; its minimum fatigue life is 1.04×10^10, occurring on the inboard of piston skirt above pin-seat.