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在确立高温叶片冷却过程辐射和对流边界换热系数的基础上,依据有限元理论对In718高温镍基合金末级叶片终锻后的冷却过程进行了热-力耦合三维数值模拟。研究了叶片冷却过程中的温度、应力和应变分布及变形规律。结果表明:初始时刻叶片表面和环境温差较大,温降较快,随着冷却过程进行,温降速度变缓;叶片形状复杂,非均匀的热传导和换热作用使等效应力和应变分布不均匀,从而产生附加内应力,榫头与叶身交接处应力最大,易于产生裂纹;叶片在冷却时发生了严重翘曲,叶尖部分的翘曲明显。
On the basis of establishing the radiation and convective boundary heat transfer coefficients during the high-temperature blade cooling process, the thermo-mechanical coupling numerical simulation of the cooling process of the final-stage forged In718 high temperature nickel-base alloy blade was performed according to the finite element theory. The temperature, stress and strain distribution and deformation of the blade during cooling were studied. The results show that the temperature difference between the surface of the blade and the environment is larger at the initial time, and the temperature drop is faster. As the cooling process proceeds, the temperature drop slows down. The shape and complexity of the blade, the non-uniform heat conduction and heat transfer make the equivalent stress and strain distribution not Uniform, resulting in additional internal stress, tenon and leaf body junction of the maximum stress, easy to produce cracks; leaf blade in the cooling of a serious warp, tip part of the warp obvious.