NEMI-SM23 evaluates piping loads on steam turbine nozzles. There are two types of force/moment allowables computed during a NEMA run:
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Individual nozzle allowables.
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Cumulative equipment allowables.
When you use Add to create a new turbine, the software creates one inlet nozzle and one outlet nozzle for the turbine.
Calculations
Each individual suction, discharge, and extraction nozzle must satisfy the equation:
3F + M < 500De
Where:
F = resultant force on the particular nozzle.
M = resultant moment on the particular nozzle.
De = effective nominal pipe size of the connection.
For cumulative equipment allowables, NEMA SM23 states that "the combined resultants of the forces and moments of the inlet, extraction, and exhaust connections resolved at the centerline of the exhaust connection", be within a certain multiple of Dc, where Dc is the diameter of an opening whose area is equal to the sum of the areas of all of the individual equipment connections. A typical turbine cumulative (summation) equipment calculation is shown below:
SFX, SFY, and SFZ are the respective components of the forces from all connections resolved at the discharge nozzle. FC(RSLT) is the result of these forces. SMX, SMY and SMZ are the respective components of the moments from all connections resolved at the discharge nozzle. Dc is the diameter of the equivalent opening as discussed above.