The pressure calculation formula of the anticorrosive spiral steel tube for hydropower station
The diameter of the anticorrosive spiral steel tube is a very important design parameter.Generally, the economic diameter is chosen first, and then the water hammer pressure is checked.The specification stipulates that the economic diameter should be selected by technical and economic comparison.When estimating, the economic section and diameter of the anticorrosive spiral steel tube are calculated by dividing the maximum flow rate of the turbine Qmax by the economic flow rate V.According to domestic experience, the economic flow rate is as follows: 4 ~ 6 m/s for the open-pit anti-corrosion spiral steel pipe V, 5 ~ 6 m/s for the buried pipe V in the dam, and 3 ~ 4.5 m/s for the buried pipe V.The technical and economic comparison and demonstration are needed for the economical diameter of the large and important hydro-electric power station.It should be pointed out that in different countries in different periods, with the change of the economic comparison criterion of kinetic energy, especially the change of various economic indicators and material price, the economic diameter of the selected pressure anticorrosive spiral steel pipe should be different.In the 1950s and 1960s, China always adopted the former Soviet union's economic comparison criterion of "offset years" to choose the economic diameter of the pressure anticorrosive spiral steel pipe.After the reform and opening up, China's water conservancy and hydropower construction projects are included in the time value of funds, the use of dynamic economic criteria for program comparison.The interim provisions on economic evaluation of hydroelectric projects (1983) of hydropower station, the comparison is one of the economic principles of construction project schemes: keep all the benefits of the package (such as electricity, electricity) or equal basic equal conditions, the total cost present value or total cost present value conversion into equal year period of n years of economic operation cost minimum value of NF.
Where, Z is the original value of investment converted in each year within the construction period (m years) to the converted investment at the end of construction;R0 refers to the rated rate of return on investment of power construction projects. Currently, China stipulates that r0=0.1.Kt is the original value of investment in the t year during the construction period. In this paper, the original value of total investment, K, is initially calculated according to the uniform annual investment in the m year during the construction period. Kt=K/m;N is the economic operation period of power station construction, n= 50a for hydropower station, and n= 25a for thermal power station.U is the annual operating cost (excluding depreciation) of the power station during the economic operation period, and coal consumption is also included in the thermal power station.The derivation principle of general calculation formula of economic diameterThe diameter D of the anticorrosive spiral steel pipe is taken as the variable. The larger the diameter D of the anticorrosive spiral steel pipe is, the more steel is used and the more investment is made.However, a large D means a small head loss and a small power loss. In order to keep the total power of the system equal, the annual cost of the alternative thermal power station NF fire is also small.If the annual cost of hydropower station NF water and the annual cost of alternative thermal power station NF fire are added, it can be written as a power function of diameter D, and then set its first derivative equal to 0, to find the minimum value, as shown in equation
Cangzhou Steel Pipe Group (CSPG) Co., Ltd
Cangzhou Steel Pipe Group (CSPG) Co., Ltd. is a large-sized, key metallurgic enterprise of Hebei Province in North China, whose history dates back to 1994. CSPG currently em/paces six member companies with products varying from SSAW, LSAW, ERW, seamless steel pipes to 3PE pipes, galvanized pipes, casing pipes, etc. A Joint-stock corporation, CSPG occupies an area of 600,000 square meters with a total asset of $530 million.
Specialized in the production of straight welded pipe spiral pipe galvanized pipe 3PE/3PP/FBE/TPEP internal and external epoxy powder internal and external epoxy resin cement mortar two cloth three oil buried pipeline IPN8710 non-toxic drinking water internal and external plastic coated lining plastic and other anti-corrosion pipe fittings for oil and gas pipeline water conservancy projects
Executive standard :DIN30670 DIN30678 CSA Z245 AFNOR nf49-710/711 NACE rp0394/0490 AWWAC 210/C213GB/T9711 API 5L ISO 3183Material: Q235B/Q355BGR A GR B x42-x80 l245-l555
Business scope: 21.3mm-3620mmLSAW submerged arc welded pipe 325-2020mmERW straight welded pipe 6mm-711mmSMLS seamless tube 10-1120mmSSAW spiral steel tube 219-3620mmDemand for quality suppliers and partners