【正文】 pipe terminal v m3/kg media critical specific volume β media specific volume ratio at the pipe terminal and initial end β0 ratio of media critical specific volume and pipeline initial media specific volume ρ kg/m3 media density Ρ1 kg/m3 media density at the pipeline initial Ρ2 kg/m3 media density at the pipe terminal w m/s media flow velocity m kg/(m2s) media mass velocity 5 w0 m/s media critical velocity m0 kg/(m2s static pressure shall be considered。s maximal design capacity operating condition (see note). Pressure of the high temperature reheat pipe can be reduced to the undermost setpressure of the safety valve at the reheater outlet. Note: maximal design capacity operating condition of the steam turbine refers to the valve widely open condition (VWO for short) or valve widely open condition + 5% overpressure (VWO+5%OP for short) condition. (3) Steam turbine39。s pressure shall be times of the extraction pressure of the steam turbine at maximal design capacity condition, which shall be no lower than : Regulated extraction line will use its maximum operating pressure. (4) Blowdown line of the backpressure steam turbine Its maximum operating pressure shall be adopted. (5) Steam pipe behind the reliever The maximum operating pressure shall be adopted. (6) Steam water pipeline connected to the monopipe boiler starting vessel The maximum possible operating pressure in all kinds of segregator operating conditions shall be adopted. (7) High pressure feed water pipeline For nonvariable speed feed water pump outlet pipe, from fore pump to main feed pump or from the main feed pump to boiler economizer entrance, pressures for each shall take the sum of the summit value of the performance curve with fore pump or main feed pump and the pump39。 As for variable speed feed water pump outlet pipe, from the feed pump outlet to the stop valve, the design pressure shall take the sum of the rated speed performance curve summit value and the water inlet side pressure。s rated speed and design flow. (8)Above high pressure feed water pipeline pressure shall consider the amendment on pressure made by water pump inlet temperature. For the constantvoltage deoxidizing system, the sum of the desecrator rated pressure and the water column static pressure at the maximum water level shall be adopted. For sliding pressure operation of deaerator, the sum of times of the heated deaerator extraction pressure at steam turbine‘s maximal design capacity condition and the water column static pressure at the deaerator‘s maximal water level shall be taken. (9) Condensate pipe 10 For pipeline at the inlet side of the condensate pump, the water column static pressure (by this time, the pressure inside the condenser shall be taken as the air pressure) from the pump inlet center line to the turbine exhaust casing39。 For the bypath at the outlet of the single stage pump and system pump, the pressure shall take the sum of the pump lift when the outlet valve is closed and the water inlet side pressure (the aforesaid water column static pressure)。s outlet side of the twostage pump system shall adopt the same pressure as that of the corresponding single stage pump system. The pipeline at the condensate booster pump outlet side of the twostage pump system shall adopt the sum of the pump lifts of two pumps (condensate pump and condensate booster pump) when the outlet is shut down. (10) Heater39。s maximal design capacity operating condition and shall be no lower than . When the drainage static pressure inside the pipeline triggers the pressure lifting and makes it larger than 3% of the extraction pressure, the influence of the static pressure shall be taken into account. (11) Boiler water blowdown pipeline Before the boiler blowdown valve or when the pipeline after the blowdown valve is equipped with valve or closure plate that can elevate the pipe internal pressure, the design pressure for the periodic blowdown pipeline shall be no smaller than the sum of the undermost setpressure of all the safety valves on the steam drum and the water column static pressure from the steam drum39。 as for the continuous blowdown pipeline, the design pressure shall be no lower than the undermost setpressure of all the safety valves on the steam drum. If the pipe internal pressure will not go up after the boiler blow down valve, the design pressure of the blowdown line (periodic blowdown or continuous blowdown) shall be selected from Table . Table : The piping design pressure after the boiler blowdown valve [MPa (g)] Boiler pressure ~ ~ ~ ≥ Piping design pressure (12) Feedwater recirculation line When the unit system is taken, the last stop valve entering the deaerator and the previous pipeline shall take the design pressure of corresponding high pressure feed water pipe。 for the sliding pressure operation of deaerator, the design pressure shall be times of the deaerator39。 for pipeline after the restriction orifice, when no valve is installed or valve on the media double outlets cannot be closed at the same time, the deaerator39。s rated working temperature at the outlet of the boiler superheater plus the allowable temperature deviation during the boiler39。s normal operation. Suggested temperature deviation is 5℃ . Lowtemperature reheat pipe shall adopt the high pressure cylinder steam exhaust parameter under the steam turbine39。 get the isentropic corresponding temperature under the piping design pressure. If the manufacturer has special requirements, the design temperature shall take the maximal possible working temperature. (3) Steam turbine39。s maximal design capacity operating condition and calculate the corresponding temperature by constant entropy under the design pressure of the pipeline。s maximal working temperature shall