StressReversal
Mechanical
Hello Everybody,
I have a very interesting problem I need your help on. I'll try to make it as short as possible.
While stress analyzing the Main Steam and Cold Reheat lines for a 650 MW plant, I proposed to relocate the HP-Bypass valve away from the turbine (by about 14 [m]/45 [ft]) because it reduces the loads on the turbine significantly. However, this will also mean a longer warm-up period for the turbine (whose inlet lines are being warmed up through 2'' drains). We do not want that to be too long because the Owner is not going to like it and it may cause operational problems. So, I am trying to work out a quick and simplified calculation to determine the time required to heat up the pipe to a predetermined temperature for steam admission to an HP-start turbine (average value).
The following parameters are known and available:
-Upstream Steam Pressure
-Downstream Steam/Condensate Pressure (Condenser Pressure, vacuum @ 0.1 bara/1.45 psia)
-Other Steam Properties (Specific Volume, Initial Enthalpy @ Bypass Conditions, Final Enthalpy assumed @ saturation conditions)
-Pipe Properties (Size, Thickness)
-Material Properties (Thermal Conductivity, Specific Heat, Density)
-Pipe Geometry: 3 lines connected in series (24'' common header followed by a wye splitting the header into two identical/symmetrical 18'' legs followed by a 2'' drain (on each leg) into the Condenser)
My question: Can somebody help me out with a formula to calculate the mass flowrate for steam (obviously treated as a compressible fluid) because that will be my starting point to calculating the heat transfer that will take place between the steam and the pipe)?
If you need more specifics, please let me know.
Thanks in advance for your time and help.
I have a very interesting problem I need your help on. I'll try to make it as short as possible.
While stress analyzing the Main Steam and Cold Reheat lines for a 650 MW plant, I proposed to relocate the HP-Bypass valve away from the turbine (by about 14 [m]/45 [ft]) because it reduces the loads on the turbine significantly. However, this will also mean a longer warm-up period for the turbine (whose inlet lines are being warmed up through 2'' drains). We do not want that to be too long because the Owner is not going to like it and it may cause operational problems. So, I am trying to work out a quick and simplified calculation to determine the time required to heat up the pipe to a predetermined temperature for steam admission to an HP-start turbine (average value).
The following parameters are known and available:
-Upstream Steam Pressure
-Downstream Steam/Condensate Pressure (Condenser Pressure, vacuum @ 0.1 bara/1.45 psia)
-Other Steam Properties (Specific Volume, Initial Enthalpy @ Bypass Conditions, Final Enthalpy assumed @ saturation conditions)
-Pipe Properties (Size, Thickness)
-Material Properties (Thermal Conductivity, Specific Heat, Density)
-Pipe Geometry: 3 lines connected in series (24'' common header followed by a wye splitting the header into two identical/symmetrical 18'' legs followed by a 2'' drain (on each leg) into the Condenser)
My question: Can somebody help me out with a formula to calculate the mass flowrate for steam (obviously treated as a compressible fluid) because that will be my starting point to calculating the heat transfer that will take place between the steam and the pipe)?
If you need more specifics, please let me know.
Thanks in advance for your time and help.
