An orifice is used widely as a flow meter or a contraction device in pipeline systems in hydro-power plants, thermal power plants, and chemical plants because of its simple construction, high reliability, and low cost...An orifice is used widely as a flow meter or a contraction device in pipeline systems in hydro-power plants, thermal power plants, and chemical plants because of its simple construction, high reliability, and low cost. However, it is well known that flow-accelerated corrosion (FAC) occurs on the pipe wall downstream of the orifice. Some of the authors have examined FAC through experimental and numerical analyses and have reported that one of the major governing parameters of FAC for single-phase water flow is the pressure fluctuation p’ on the pipe wall, and also that pipe wall thinning rate TR can be estimated by p’. In addition, they have presented the effects of the ori-fice geometry on p’ or TR, and have described a method for suppressing p’ or TR. In the present study, FAC for a two-phase air-water bubble flow is examined and compared with the single-phase water flow experimentally. Further, it is shown that because p’ is also considered a governing parameter of FAC for a two-phase air-water bubble flow, TR can be estimated using p’. It is also indicated that, by using a downstream pipe with a smaller diameter than that of the upstream pipe, p’ or TR can be suppressed.展开更多
To reduce the time of getting an ideal elliptical heat used in power station through repairing and testing a die repeatedly according to experience,finite element software Deform-3D was used to research the simulation...To reduce the time of getting an ideal elliptical heat used in power station through repairing and testing a die repeatedly according to experience,finite element software Deform-3D was used to research the simulation of deformation-heat transfer coupling in hot forming process of elliptical head with the size of Φ1200 mm ×100 mm. The variations of stress,stain,temperature,thickness and strain rate in forming process were gotten,and the forming quality was evaluated from roundness,thinning rate and thermal contraction. The results show that the maximum thinning rate of the elliptical head is 7. 31% ,it is close to the orthographic place; and the inner diam- eter obtained from simulation is 1200. 6 - 1202. 977 mm,it is in the range of inner diameter tolerance required; all the data fit well with the practical dimension data of processing head.展开更多
文摘An orifice is used widely as a flow meter or a contraction device in pipeline systems in hydro-power plants, thermal power plants, and chemical plants because of its simple construction, high reliability, and low cost. However, it is well known that flow-accelerated corrosion (FAC) occurs on the pipe wall downstream of the orifice. Some of the authors have examined FAC through experimental and numerical analyses and have reported that one of the major governing parameters of FAC for single-phase water flow is the pressure fluctuation p’ on the pipe wall, and also that pipe wall thinning rate TR can be estimated by p’. In addition, they have presented the effects of the ori-fice geometry on p’ or TR, and have described a method for suppressing p’ or TR. In the present study, FAC for a two-phase air-water bubble flow is examined and compared with the single-phase water flow experimentally. Further, it is shown that because p’ is also considered a governing parameter of FAC for a two-phase air-water bubble flow, TR can be estimated using p’. It is also indicated that, by using a downstream pipe with a smaller diameter than that of the upstream pipe, p’ or TR can be suppressed.
基金Sponsored by the Heilongjiang Provincial Public Relation Project (Grant No.GC06A515)
文摘To reduce the time of getting an ideal elliptical heat used in power station through repairing and testing a die repeatedly according to experience,finite element software Deform-3D was used to research the simulation of deformation-heat transfer coupling in hot forming process of elliptical head with the size of Φ1200 mm ×100 mm. The variations of stress,stain,temperature,thickness and strain rate in forming process were gotten,and the forming quality was evaluated from roundness,thinning rate and thermal contraction. The results show that the maximum thinning rate of the elliptical head is 7. 31% ,it is close to the orthographic place; and the inner diam- eter obtained from simulation is 1200. 6 - 1202. 977 mm,it is in the range of inner diameter tolerance required; all the data fit well with the practical dimension data of processing head.
