Abstract:In order to reduce the impact of high velocity fluid in high temperature and under high pressure on thermowells, to suppress the fluidexcited vibration, to elaborate the mechanism of the structure vibration resulted from fluidexcited vortex shedding, and to analyze the reasons that caused the fracture of thermowells, a new design scheme, setting up a streamlined block in front of the thermowell to protect the thermowell from fracture, was proposed. Large eddy simulation (LES) technique was utilized to numerically simulate the unsteady flowfields around the specified thermowells with and without the streamlined block respectively. The contours of the total pressures, averaged forces and the pressure fluctuations in time domain and frequency domain on the surface of the thermowell and the streamlined block under the two conditions were obtained. The simulated results show that, the streamlined block can significantly reduce the resultant force acting on the thermowell, suppress the vibration and make the thermowell more reliable. The research provides a new way for optimized structure design of thermowells.
[1]孟丹, 郭海燕, 徐思朋. 输流管道的流体诱发振动稳定分析[J]. 振动与冲击, 2010, 29(6): 80-83.Meng Dan, Guo Haiyan, Xu Sipeng. Stability analysis on flowinduced vibration of fluidconveying pipes[J]. Journal of Vibration and Shock, 2010, 29(6): 80-83.(in Chinese)[2]祝立群, 贡学钢, 常广东. 热电偶套管开裂失效分析[J].炼油与化工, 2011,22(5):60-61.Zhu Liqun, Gong Xuegang, Chang Guangdong. Failure analysis on cracking of thermowell[J]. Refining and Chemical Industry, 2011, 22(5):60-61.(in Chinese)[3]于洪波, 李霞. 热电偶套管断裂的原因分析及预防措施[J]. 石油化工自动化, 2008, 44(2): 86-87.Yu Hongbo, Li Xia. Analysis of thermowell fracture and the prevention measures[J]. Automation in Petrochemical Industry, 2008, 44(2): 86-87.(in Chinese)[4]夏明六, 师红旗, 丁毅, 等. 加氢装置热电偶套管断裂失效分析[J]. 压力容器, 2010, 27(7): 52-55.Xia Mingliu, Shi Hongqi, Ding Yi,et al. Failure on fracture of thermowell in hydrogenation unit[J]. Pressure Vessel Technology, 2010, 27(7): 52-55.(in Chinese)[5]张阿漫, 戴绍仕. 流固耦合动力学[M]. 北京: 国防工业出版社, 2011.[6]Aoi H, Zhao Y, Hayase T. Improvement of the damaged thermowell of the monju fastbreeder reactor based on vibration analysis[J]. Simulation, 2002, 78(8): 504-511.[7]Haslinger K H. Flowinduced vibration testing of replacement thermowell designs[J]. Journal of Fluids and Structures, 2003, 18(3/4): 425-440.[8]Belver A V, Iban A L, Lavin Martin C E. Coupling between structural and fluid dynamic problems applied to vortex shedding in a 90 m steel chimney[J]. Journal of Wind Engineering and Industrial Aerodynamics, 2012, 100(1): 30-37.[9]蔡杰, 尤云祥, 李巍,等. 均匀来流中大长径比深海立管涡激振动特性[J]. 水动力学研究与进展:A辑, 2010, 25(1): 50-58.Cai Jie, You Yunxiang, Li Wei, et al. The VIV characteristics of deepsea risers with high aspect ratio in a uniform current profile [J]. Chinese Journal of Hydrodynamics: Ser A, 2010, 25(1): 50-58.(in Chinese)[10]王春林, 吴志旺, 司艳雷,等. 旋流自吸泵气液两相流数值模拟[J]. 排灌机械, 2009, 27(3): 163-167.Wang Chunlin, Wu Zhiwang, Si Yanlei,et al. Gasliquid twophase flow numerical simulation of a vortex flow selfpriming pump[J]. Drainage and Irrigation Machinery, 2009, 27(3): 163-167.(in Chinese)