针对在柴油机运转工况下排气门处于高温腐蚀环境，较易发生断裂、弯曲、烧蚀等现象，采用Ansys软件对耐高温合金材料排气门进行温度场数值模拟。采用某型船用柴油机的额定工况，结合试验所得耐高温合金材料不同温度下的物性参数分析排气门的等效热边界载荷对气阀的影响，结果表明仿真温度场与失效气阀试件的特征相符合，气阀盘底中心为第一热点且变形量最大，盘底烧蚀现象明显，若存在晶粒大小分布不均或裂纹易发生阀面断裂；气阀颈部被废气冲刷产生第二热点发生颈部弯曲现象；锥面处热应力集中极易发生烧蚀。最后采用整体硬度法对仿真温度场进行验证，得出结果证明模拟具有真实可靠性，可以对气阀疲劳分析和气阀选型提供参考。
In view of the fact that the exhaust valve is in a high-temperature corrosion environment under diesel engine operating conditions, which is more prone to fracture, bending, and ablation, Ansys software is used to numerically simulate the temperature field of the high-temperature alloy exhaust valve. Using the rated working conditions of diesel engine, combined with the physical properties of the high temperature alloy material obtained at the test at different temperatures, the effect of the equivalent thermal boundary load of the exhaust valve on the gas valve was analyzed. The results showed that the simulated temperature field and the failure of the gas valve specimen The characteristics are consistent, the center of the bottom of the valve disc is the first hot spot and the amount of deformation is the largest. The phenomenon of ablation of the disc bottom is obvious. If there is uneven grain size distribution or cracks, it is prone to face fracture; the neck of the valve is washed by exhaust gas to produce the second neck bending occurs at the hot spot; the thermal stress concentration at the cone surface is extremely prone to ablation. Finally, the overall hardness method is used to verify the simulation temperature field, and the results show that the simulation has real reliability, which can provide reference for the fatigue analysis of the gas valve and the selection of the gas valve.
2022,44(2): 140-144 收稿日期：2020-08-14
DOI：10.3404/j.issn.1672-7649.2022.02.025
分类号：TK428
基金项目：基于有限元法的船用柴油机气阀关键技术及智能制造示范应用课题（KY19ZG12）
作者简介：杨兴林(1964-)，男，博士，教授，研究方向为现代工业工程、现代集成制造系统、现代造船模式等
参考文献：
[1] 肖晓玲, 况敏, 乐有树. 柴油机排气阀盘面断裂的失效分析[J]. 材料研究与应用, 2012, 6(4): 271–275
[2] 傅达, 崔毅, 阎心怡, 等. 活塞换热边界自动标定方法研究[J]. 内燃机工程, 2018, 39(5): 66–72
FU D, CUI Y, YAN X Y, et al. Research on automatic calibration of piston heat exchange boundary[J]. Chinese Internal Combustion Engine Engineering, 2018, 39(5): 66–72
[3] 黄凤琴, 李双清, 王伟民, 等. 基于Abaqus的汽油发动机排气门温度场模拟分析和试验[J]. 计算机辅助工程, 2013, 22(z2): 48–51
[4] 林凤功, 林华, 程永强. 发动机排气门瞬态温度场数值模拟分析[J]. 农业装备与车辆工程, 2009(10): 30–33
[5] 张艳辉, 杜辉, 孙传红. 基于数值模拟的某柴油机燃烧室优化研究[J]. 内燃机工程, 2018, 39(2): 87–92
ZHANG Y H, DU H, SUN C H. A study on optimization of diesel engine combustion chamber based on numerical simulation[J]. Chinese Internal Combustion Engine Engineering, 2018, 39(2): 87–92
[6] 吴玥明, 曾攀, 方刚, 等. 排气阀热边界条件分析及温度场有限元计算[J]. 柴油机, 2009, 31(4): 33–38
[7] 丁宁, 徐政, 陈明, 等. 基于缸内燃烧分析的发动机金属温度场计算方法[J]. 内燃机工程, 2017, 38(5): 127–132
DING N, XU Z, CHEN M, et al. Engine metal thermal analysis method based on in-cylinder combustion analysis[J]. Chinese Internal Combustion Engine Engineering, 2017, 38(5): 127–132
[8] P. HAHN, M. SCHWIENHEER, C. KONTERMANN, et al. Modeling of creep and stress relaxation of the nickel-base alloy NiCr20TiAl at isothermal and non‐isothermal loading conditions[J]. Materialwissenschaft und Werkstofftechnik, 2017, 48(11): 1070–1081
[9] 许勇静, 张智. 柴油机气门温度的实验测量[J]. 船海工程, 2007, 36(4): 79–82
[10] WEI R, WU H Y, ZHANG Q Q, et al. The microstructure and mechanical properties of heat treated NiCr20TiAl superalloy[J]. Materials Science Forum, 2016, 4327(1698): 531−536.
