Flow induced vibration investigation of a main steam pipe suffering from high temperature steam flow

2022 ◽  
Vol 143 ◽  
pp. 104040
Author(s):  
Yu Zhang ◽  
Lei Sun ◽  
Chao He
Author(s):  
Bo Yang ◽  
Yi-chang Huang ◽  
Xiao-ying Tang ◽  
Yu-hui Huang

Main steam pipelines work in the environment of high temperature and pressure steam and withstand double damage between oxidation and creep load for a long time. Creep-oxidation interrupt tests were used in high temperature steam conditions at different stress load to get P92 steel mechanochemical behavior date in the present study. Weight gain method was used to get the oxidation kinetics under different applied loading. Scanning electron microscopy (SEM) micro observation techniques was applied to obtain growth characteristic in the interaction between steam oxidation and creep loading.


Author(s):  
Gregory Zysk ◽  
Michael Oliver

Piping vibration had been observed in the Farley Unit 2 main steam system since plant start-up. Hanger damage occurred in several portions of the system, including inside containment, in the Main Steam Valve Room (MSVR), and in the turbine building. A program was undertaken to determine the cause of the failures in the main steam supports. This program included the installation of diagnostic equipment, data analysis, and acoustic and structural modeling in an effort to determine the root cause of the piping vibration. The program also addressed a modified system support scheme, which included the addition of vibration absorbing and dampening devices. Recommendations were also provided to resolve the vibration issue.


2006 ◽  
Vol 326-328 ◽  
pp. 1129-1132
Author(s):  
C.S. Jeong ◽  
Bum Joon Kim ◽  
Byeong Soo Lim

The initiation and growth of micro-defects such as micro cracks and voids usually causes the failure of long term operated structural components at high temperature. In this study, the creep characteristics and void nucleation and growth characteristics of P92 steel which is used as main steam pipe material in power plant were investigated at several temperatures and loading conditions. The area fraction of void increased with increase of test temperature, stress, and load holding time. In case of internal defect presence, micro-voids initiated in the early stage of loading period and resulted in the increased load line displacement and crack growth rate. The microvoids were found to form along the prior austenite grain boundaries and at the martensite packet boundaries.


Author(s):  
Qiang Liu ◽  
Sheng-yin Song ◽  
Yao-rong Feng ◽  
Bo Duan

The high temperature steam pipe used in one heavy oil well in China burst. This failure pipe was investigated and analyzed by macroscopic analysis, material tests (including chemical composition, metallurgical analysis & mechanical property) and fracture surface scanning electronic microscopy (SEM) analysis. Then it can be concluded that the mechanical properties of the burst pipe accord with related standards, and that the fracture surface is a typical brittle fracture. The herringbone stripes were found on the fracture surfaces and pointed to a fracture source where there were over 1.6mm deep mechanical damages on the pipe surface. After micro hardness testing near mechanical damage area and the nearby substrate, it was found that the toughness of mechanical damage area was low. The expanding diameter of the burst pipe was also investigated. Because the residual water in the pipe was pushed by high temperature steam when the steam was turned on, the speed of water was very fast, and the stress caused by water hammer were higher than yield pressure of the pipe, which is the internal pressure in the pipe and which could produces a maximum hoop stress in the pipe equal to the yield strength of the pipe material, the pipe would be expanded. The fracture surface is a typical brittle fracture. There are two mechanical damages on the fracture source, and the pipe burst because of the mechanical damages and huge impact of water hammer.


Author(s):  
Branko Stankovic

This concept shows that an efficient combined cycle, comprising topping & bottoming cycle, does not have to be privilege of gas turbine plants only, but could also be achieved with steam turbine plants. An efficient power-producing concept of a combined steam-turbine cycle with addition of a recirculating steam compressor is disclosed. Topping part of such a combined steam-turbine cycle operates at elevated steam turbine inlet temperature and pressure, while its “waste heat” is recovered by the bottoming part of the combined cycle in a heat-recovery boiler (steam heat exchanger). The recirculating steam compressor pumps the cooled majority of the entire steam flow to the maximum cycle pressure, while smaller steam flow fraction continues its full expansion to some low pressure in a condenser. The cycle waste heat could be transferred to the bottoming part of the combined cycle in a variety of modalities, depending on the chosen main high-temperature steam-turbine inlet temperature and inlet pressure (supercritical/subcritical). At an assumed constant steam-turbine inlet temperature of 900°C (∼300 bar), a very high gross cycle thermal efficiency could potentially be achieved, ranging from 56 to 62% with the high-temperature steam-turbine pressure ranging from subcritical (30 bar) to supercritical (300 bar). Such a combined steam-turbine cycle seems to be a suitable energy conversion concept that could be applied in classic thermal power plants powered by coal, but also seems as an ideal option for application in the new generation of gas-cooled nuclear rectors, where the gaseous reactor coolant, heated up to 1000°C, would indirectly transfer its heat content to working fluid (superheated steam) of the topping part of the combined steam-turbine cycle. Alternatively, the proposed concept may be combined with renewable energy sources of a sufficient temperature level.


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