单元划分和时间步长对瞬态温度振荡的影响

分析了FEM求解温度场过程中产生温度振荡的现象和原因,讨论了不同单元划分方法和时间步长对瞬态温度振荡的影响,提出了逐层单元细分法和S型变步长计算模型.结果表明:逐层网格细分法不仅能够抑制振荡发生,满足计算精度,而且能够极大地缩短计算时间;S型变步长方法与定步长方法相比,在有效抑制振荡并保证计算精度的前提下,若其他计算条件相同,S型变步长方法计算时间缩短了十几倍.研究结果对提高计算精度和加快计算速度具有重要的理论和实际意义.

Influence of Mesh and Time-Step on Transient Temperature Oscillation

Analyzing the phenomenon and causes of transient temperature oscillation during the FEM solution to temperature field.The influences of different element meshing methods and time-step on the transient temperature oscillation were discussed.Refining the elements and S-type time-variable steps were proposed.The calculation results showed that refining the elements layer upon layer not only restrains the transient temperature oscillation so as to come to the required calculation accuracy but also reduces the calculating time.Compared to the fixed steps,the S-type time-variable steps can shorten more than 10 times the calculating time with the oscillation restrained,accuracy ensured and other conditions kept constant.The results were theoretically and practically important to improve calculation accuracy and expedite calculation speed.