Mass Flow Turbine Optimization

The answer lies with the difference in enthalpy between start conditions and end conditions of the two fluids <...air...steam...> multiplied, in the case of each fluid, by the flowrate and the efficiency of the setup.

Given the temperatures, pressures and a set of tables for the thermodynamic properties of each fluid at those conditions, and the flowrates, the rest is simple arithmetic using either a pocket calculator, a slide rule, log tables or indeed, subtraction and multiplication by hand.

You are not looking at the change of enthalpy in a thermodynamic system.

Water is the superior working fluid

Did you miss those Thermo 101 classes at University??

https://en.wikipedia.org/wiki/Enthalpy%E2%80%93entropy_chart

https://en.wikipedia.org/wiki/Rankine_cycle

However water is lighter than air, so how can that be better in a "mass flow" turbine? We are not talking steam turbine here, we are talking about Open cycle Brayton turbine.

you must check specific heat capacity of air and steam.

I don't want to.

I wonder what turbine that is handling 2 phase air and steam.

Quiet day, huh?

Yep. Mainly, this is about how far the evaporative cooling moisture loading can go before it starts to degrade, rather than enhance gas turbine output.

We normally run within one or two degrees F of the wet bulb temperature. Forget reaching dew point. I am looking at watering the grass with the blow-down from the intake cooler for the area surrounding the gas turbine to see if we get any additional cooling, but I expect the flow and evaporation rates are what they are, and we will not see anything other than green grass.