steam

  1. P

    Electricity production from steam - help

    First topic here in the forum, thanks for having me! Recently i've developed some curiousity over how steam based electricity is produced. and i have some questions i'm hoping to help me understand the mechanims of it. My physics backround is dull because i had hard time with it in school...
  2. B

    Steam saturation in a wood-fired bread oven

    Good morning, We are trying to apply some sound science to the age old problem of steaming a wood-fired bread oven. When baking most breads you need to have as much steam as possible at the initial stage of baking to allow the bread to expand by keeping the crust moist and soft and also to...
  3. Z

    Heat absorption in reversible isothermal expansion

    2kgs (total mass) of steam goes through a revesible isothermal expansion at 500 degrees celcius. During the expansion the pressure drops from 300 kpa to 200 kpa What is the heat absorbed by the steam during this process? I guess that steam cannot be assumed to be ideal which makes the...
  4. J

    Please Help - Calculate Steam Flow Rate

    Hi, I'm sure I'm missing something here. I have a small steam vessel (internal volume 380mL) with an inlet pressure of 55psig (380 kPa) and existing to atmospheric with no change in elevation. I believe that Bernoulli states that velocity is the pressure change over density times volume...
  5. T

    Time for steam to fill a certain volume

    Hi, I'm new to thermodynamics. I am trying to find how long it will take a cavity of 2' x 4' x 4' to reach 211 F with a steamer with an output of 35 g/m @ 211 C. At some point I need to take into account the heat loss through the walls but for now I think I need to just find the time...
  6. P

    Steam Turbines..

    Steam is expanded from 90 bar, 412°C to 4.5 bar saturation in a high pressure turbine, after-which a certain percentage of the steam is bled off to a feed heater. The remaining steam is then expanded through a low pressure turbine to 1.0 bar and dryness fraction of 0.93. All ‘steam’ entering the...
  7. B

    Steam Turbine power output?

    Hi, I've got a problem finding the power output of a steam turbine and have come up with a negative answer which can't be correct... Steam turbine takes in steam with specific enthalpy of 3210 kJ/kg at a rate of 85 kg/minute. The steam exits with a specific enthalpy of 2650 kJ/kg. Heat...
  8. W

    Enthalpy / Internal Energy in steam turbine

    Hello :) Okay, so I'm studying for a thermodynamics exam which is due in two days. In the book (Fundamentals of Engineering Thermodynamics 6th edition by Moran and Shapiro, p 156) they offer an example on how to use Control Volume analysis in transient states. They provide the following...
  9. R

    Convert steam to water

    I know how to convert water to steam but I'm not sure what to do with the other way around. Will the signs change or something? So for example, how much heat is required to condense 120kg of steam at 110 degree celcius? What I did is this 120 (0.5) (110-100) + 120 (540) = 65400 Kcal Is that...
  10. J

    Need help calculating steam pressure...

    Hello all. I haven't done any steam calculations for many, many years and am in need of some help. WIthout going into too much detail, I need to know how much pressure is generated by heating a confined volume of water to the point of boiling/evaporating. For example, if I expose 1 confined...
  11. P

    Steam turbine help please!

    2. A steam turbine receives a steam flow of 5000 kg/h and its power output is 500 KW. Neglect any heat loss from the turbine. Find the change in specific enthalpy of the steam flowing through the turbine if a) if the entrance and exit are at the same elevation and entry and exit velocities are...
  12. S

    Steam throttling & mixing

    Hi, I am trying to follow a worked example & i can not work out where a number comes from. You will possibly need steam tables in front of you for this. "steam at a pressure of 15bar & 250 deg C, flowing at a rate of 1.5 kg/s is throttled to a pressure of 7 bar and then is mixed with steam at...
  13. J

    steam tables phases

    hi, i understand how to use steam tables, but my problem is i cannot tell which phase the water is currently in. i do all the calculations, but how do i choose which phase? i ask because one of my questions asks for phase difference. many thanks jared james