Steam turbine Performance Modeling

[thermalarchitect]

I have some fairly good heat balance software for predicting power outputs from steam turbines under various throttle/admission/extraction and exhaust conditions. I also get steam maps from manufacturers that predict performance based on a combination of these variables. I would like to marry the two for performance predicting and modeling.

Usually a steam map will have several lines of constant extraction or intermediate admission flow with throttle flow and power as the two axis. After the power is found from these maps, a separate condenser or exhaust pressure correction factor or curve is utilized to correct for back pressure.

Unfortunately, a steam turbine in operation will spend little of its time exactly on these constant extraction or admission lines.

All the prefacing behind now, how do I develop a single algorithm that will calculate the power at any extraction/admission flow against throttle flow? I think it is a calculus question that deals with three dimensional mapping and the end result should be something that can interpolate between the various extraction lines of constant flow. Once I have that result, applying the pressure correction factor is easy. And inserting this algorithm back in the modeling software isn't hard either.

20 years removed from differential equations, I could use some help or even some links to the math processes to do this.

It is very important that I get this right.

Thanks

 

[stgrme]

thermalarchitect,

You say that you have good software to predict steam turbine output. If this is so, you should model a particular steam turbine in that software, including schedules or families of performance/correction curves. Then, you should only have to run the software to get results. If your software is not capable of doing this, you might want to consider another piece of software. If your software runs, but your results do not agree with reality, you may need to "tune" your model.

Best of luck!

stgrme