Study On Power Distribution Of High And Low Pressure Cylinder Of Marine Puopulsion Steam Turbine

Marine steam power plant has many advantages such as high power,long life,high reliability and easy operation.Researchers not only pay attention to the index parameters of steam turbine under full speed condition,but also pay attention to its operation under low speed condition in the research and development design,.In this paper,the output power ratio of high and low pressure cylinders of marine double cylinder steam turbine at low speed is taken as the goal,and how to redistribute the power ratio at low speed is studied.The research content of this paper is mainly divided into the following three aspects:First of all,the basic structure,operation characteristics and main design parameters of the target steam turbine are described and analyzed preliminarily,and the five schemes,i.e.the adjustment of the flow passage stages of the high and low pressure cylinders,the setting of partial admission stages of the low pressure cylinder,the adjustment of the steam distribution law,the extraction of steam from the high pressure cylinder to supplement the low pressure cylinder and the supplement of waste steam from the system to the low pressure cylinder,are explained and one-dimensional thermal calculation are carried out respectively.Through the comparison of the calculation results The advantages and disadvantages of each scheme and its influence on marine propulsion steam turbine unit or active force system are analyzed.The results show that each scheme has its advantages and disadvantages.The scheme with ideal thermal power may have structural problems,and the scheme with easy structure has certain limitations in thermal power.Secondly,according to the results of one-dimensional calculation,the design scheme of adjusting and distributing steam which is easy to be applied in engineering practice and the design scheme of system waste steam feeding into low pressure cylinder are selected for test design and verification.In the first scheme,two groups of test piece cams are made,and in the second scheme,two kinds of steam filling pipes with diameter of DN100 and DN150 are set.Through the analysis and processing of the test results,the reliability of one-dimensional thermal design is verified,and the two schemes above are proved to have strong engineering feasibility and meet the design requirements.At last,this paper puts forward a research scheme that can be applied to operation,that is to reduce the power capacity of low-pressure steam turbine by means of "return steam".Because the scheme can not carry out one-dimensional thermal calculation,three-dimensional numerical simulation is carried out for it,and four comparable operation conditions are set up in the calculation.From the calculation results,this method makes the reverse stage consume the output power of the low-pressure turbine,and the steam entering the reverse stage is done by the reverse rotating blades.Through one-dimensional thermal calculation,whole machine test and three-dimensional simulation calculation,this paper designs and verifies the feasibility of several schemes proposed to optimize the power ratio of high and low pressure cylinders under low-speed condition of main steam turbine.If there is such demand in the development and design of domestic marine double cylinder main steam turbine unit in the future,this paper can provide valuable reference for relevant issues.