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Steam Problems

  • Thread starter FrankPais
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1.I am currently working through some steam questions and I am struggling with this problem. I am using "Thermodynamic and Transport Properties of Fluids byG.F.C Rogers and Y.R Mayhew

Here are my questions as it is written:

"(A) Steam at 30 bar, 375 degrees C flows through a cooling coil with a negligible change in velocity and pressure, such that the exit dryness fraction is 0.5.

Calculate the heat transfer per kg of water substance."

I have worked this out by using the steady flow equation, linear interpolation and the unknown which was the "h2" value using h=(1-x)hf+xhg. (Obviously not in that order)

Here is my issue below...

One kg of steam at 30 bar, 375 degrees C, is contained in a rigid container and is cooled until the pressure is 13 bar.

Calculate the final dryness fraction and the heat transfer

Now I have been given a data sheet with the equation for x (dryness fraction) which is x= mass of saturated steam/total mass but I am still unsure how to calculate the dryness fraction from the information from the Steam Tables as I can not get the value of -966kJ

So I am asking for your help with this please.

I also have many more problems as well I need help with.

Many thanks

Scott


2. x (dryness fraction) which is x= mass of saturated steam/total mass

I believe once I have calculated the dryness fraction I need to use the steady flow equation of Q=m(h2-h1) to calculate the work done [I have disregarded the other values as they state that they are negligible]




3. I can not continue this until I know how to work out the dryness fraction correctly. As I have obviously not worked out the dryness fraction correctly I can not seem to get the correct answer.

PLEASE HELP

1. Homework Statement



2. Homework Equations



3. The Attempt at a Solution
 

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