ES_StalbeIF97 AddIn

Steam Turbine Calculation Example

The picture below shows steam turbine calculation example using ES_StableIF97_AddIn Demo software, in which steam turbine output and exhaust condition are calculated.

The Unit Legend of the calculation is located in a separate sheet named "ST Unit", as shown in the picture below.   Since the unit arguments of the functions used in the calculation are connected to the Unit Legend, the units of the calculation can be changed arbitrarily by changing the unit integer numbers in the Unit Legend.   For example, since the mass flow unit number in the Unit Legend is 1 that stands for "lb/hr", the unit of mass flow in the picture above is "lb/hr", while the all other units are SI units.

 Constant Value Input responding to Unit Legend

In the picture above, turbine inlet steam pressure of "20" bara has been input by using the ES_StableIF97_AddIn function of "=ESStb_CvtP(20,2,'ST Unit'!$C$2)", by which the turbine inlet steam pressure value responds to the pressure unit number of the Unit Legend.   

For example, if User changes the pressure unit number of the Unit Legend from "2"(bara) to "6"(psia), then the turbine inlet steam pressure value is changed from "20"(bara) to "290.0755"(psia) automatically.   If User inputs the turbine inlet steam pressure by constant value of "20" instead of using "ESStb_CvtP" function, the turbine inlet steam pressure does not change to "290.0755" and remains as "20", even though User changes the pressure unit number of the Unit Legend.

If User wants for a constant value to respond to unit number change of the Unit Legend, please use the unit conversion functions of ES_StableIF97_AddIn and input the unit number cell address of the Unit Legend to the Target Unit Number, the third argument.   In this pressure unit conversion function example, the first argument "20" is the pressure value of Source Unit, the second argument "2" is Source Unit Number(bara), and the third argument "'ST Unit'!$C$2" is Target Unit Number as the pressure unit number cell address of the Unit Legend.

Constant Value Output not responding to Unit Legend

In the picture above, the turbine output in "kW" unit has no unit conversion function in ES_StableIF97_AddIn software.   And the turbine output must not be changed and remain as it is, even though any unit number in the Unit Legend is changed.   That's because change of units means change of value expression and does not mean value itself.

This kind of work is possible by using of the unit conversion functions of ES_StableIF97_AddIn software.   In the picture above, the Inlet Flow of "50" in the cell "J10" does not change even though the mass flow unit number of the Unit Legend is changed, while the inlet flow of "396832.1" in the cell "D5" changes by the mass flow unit number change of the Unit Legend.

This is possible by using the unit conversion function of "=ESStb_CvtMFlow(D5,'ST Unit'!$C$11,2)" in the cell "J10".    It is seen in the function arguments that the cell "J10" refers to the value of the cell "D5", the first argument.   The second argument, Source Unit Number, is the mass flow unit number of the Unit Legend, "'ST Unit'!$C$11", and the third argument, Target Unit Number, is "2" representing "kg/s" unit.   This means that the unit conversion function maintains always the value in the cell "J10" in "kg/s" unit, regardless of the mass flow unit number change of the Unit Legend.

In the picture above, the equation shown in the box of "fx" is multiply of turbine inlet flow and UE(Used Energy) expressed in the unit conversion functions described above.   By this, the value of turbine output in "kW" unit does not change even though the unit numbers of the Unit Legend change.

 

 

 


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