Steam Definition and 535 Threads

Steam is water in the gas phase. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization. Steam that is saturated or superheated is invisible; however, "steam" often refers to wet steam, the visible mist or aerosol of water droplets formed as water vapour condenses.
Water increases in volume by 1,700 times at standard temperature and pressure; this change in volume can be converted into mechanical work by steam engines such as reciprocating piston type engines and steam turbines, which are a sub-group of steam engines. Piston type steam engines played a central role in the Industrial Revolution and modern steam turbines are used to generate more than 80% of the world's electricity. If liquid water comes in contact with a very hot surface or depressurizes quickly below its vapor pressure, it can create a steam explosion.

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  1. L

    Writing fiction, steam power, hydrogen internal combustion engine

    Question: is it possible to have any of the following - 1. Steam engine in a car 2. A steam internal combustion engine 3. A hydrogen internal combustion engine Background info Hi all, I am working on a fiction short story for fun. It is set in a parallel universe so history and a few...
  2. A

    Friction and pressure drop in a steam pipe

    Hi I am new to fluid mechanics and I wondering if anyone can explain to me in very simple terms why friction causes pressure loss when steam is moving through a pipe? I thought the friction would slow down the fluid which will lead to higher pressure but it seems its the opposite. I was trying...
  3. Hang11

    Modeling boiling in a closed container with a small hole

    I'm trying to build a mathematical model of something like Heron's Aeolipile: http://en.wikipedia.org/wiki/Aeolipile I'd like to know, based on a known heat flux, the pressure and temperature attained in the container. I assume as water boils, the control volume loses mass and energy, the...
  4. mattyboson12

    Steam Plant Cycle Performance: Analyzing Efficiency

    I am doing an experiment to determine the performance of a steam plant cycle and analyse it in comparison with the ideal rankine cycle. I have a sketch of the actual and real T-S diagram for the steam plant (See attached) I am unsure what factors cause the change in the shape of the T-S...
  5. S

    Steam Turbine Design for Waste Heat Recovery Plant

    i need the design data of a reaction steam turbine in order to complete my project..My project is about waste heat recovery plant..
  6. P

    How can I remove steam from exhaust gases?

    hello I have hot gases with steam (water) inside how do I separate it ? without cooling it magnetic field can help? ultrasound? something else? thanks!
  7. N

    Electronic Steam Tables Programs

    Hi all, Been a while since I posted in these forums. Looking for advice on steam table software package. I am looking for a relatively simple software package to look up steam properties. Preferably compatible with Excel. It at least has to be able to compute SH steam enthalpy as a function of...
  8. W

    Internal combustion hybrid Steam engine

    Would it be possible to build an engine that runs primarily off a petrol but has a steam engine that captures all the heat lost from the combustion (70%) and applies it towards powering the engine? Looking for ideas, opinions and attitudes on whether or not it is a practical idea.
  9. Dennis C

    What Happens to Steam Temperature After Throttling at 170 PSI?

    Upstream Conditions: Saturated steam, 230 PSI, 399 degree F. Downstream conditions: 170 PSI Assume 98% quality steam We throttle steam to our distribution system for use by hospitals for sterilization, heating and autoclaves. I have a theory of what is happening after throttling and would like...
  10. anthonyk2013

    Troubleshooting Steam Plant Output: Tips for Evening Class Assignment

    Im attempting this question for an evening class I am attending. hope I am posting in the right place. I'm not sure where I have gone wrong think its where I rearranged my formula to find steam output. Question attached below
  11. J

    Does steam flow from top to bottom or bottom to top

    does steam flow from top to bottom or bottom to top in a heat exchanger
  12. C

    Thermodynamics throttling device

    Homework Statement Steam at 550 bar and 475 °C undergoes a throttling expansion to 1 bar in a steady-state process. What will be the temperature of the steam after the expansion? Calculate the internal energy of the fluid. Homework Equations h2 = h1 The Attempt at a Solution the temperature...
  13. Amr Ali 33

    Regeneration in steam cycle (feed water heaters)

    i know that regeneration is heating the feed water by the bled steam from the turbine to reduce the sensible heat addition by the boiler but doesn't that also causes a reduction in the steam turbine work because we've taken some steam from it . can anyone explain please i'may have some...
  14. voltech444

    Oxygen Enriched Internal Steam Compression Ignition Engine (OEISCIE)

    Hello PF members and guests, I have been working on this concept for 2 years and I wanted to get some input from this forum. I have done a lot of research on oxygen enriched combustion and water injection. Both of these concepts have been tested and proven in experiments and the real world. My...
  15. R

    Calculating Dryness fraction of steam

    Hi guys I am trying to calculate athe dryness fraction of wet steam at a pressure of 0.5Bar has a specific volume of 1.75m3/kg. can someone walk me through it? much appreciated!
  16. M

    Steam produced heat transfer heat exchangers

    Homework Statement Dry saturated steam at a temperature of 180oC is to be produced in a fire tube boiler from the cooling of 50 000 kg h–1 of flue gases from a pressurised combustion process. The gases enter the tubes of the boiler at 1600oC and leave at 200oC. The feed water is externally...
  17. snowwhite

    Work problem -- Steam piston volume and work length

    Homework Statement Steam is raised as saturated steam at 6 bar (g) and supplied to the first ( high pressure ) piston. The steam then exhausts from piston 1 at 3 bar (g). The steam is thought to expand adiabatically in accordance with PV^( 135 .1)= Constant Given the initial volume is...
  18. snowwhite

    Thermo question -- volumetric flows of dry steam and liquid water

    1. Homework Statement Given the rate of pipe= 100 kg/s The steam flow has quality x= 80% = 0.8, pressure= 90 atm Find the volumetric flows of dry steam and liquid water 2. Relevant equations...
  19. B

    Calculating Steam Production in Fire Tube Boiler | 180ºC Dry Saturated Steam

    Homework Statement Dry saturated steam at a temperature of 180ºC is to be produced in a fire tube boiler from cooling of 50000 kg/h of flue gases from a pressurised combustion process. The gases enter the tubes of the boiler at 1500ºC and leave at 100ºC. The feed water is externally preheated...
  20. D

    Exploring Pressure Changes When Mixing Hot Air and Steam in a Sealed Cylinder

    Hi, everyone! I have a question: if we quickly fill a cylinder with steam from one end and with hot air from another end, both at atmospheric pressure and equal volume, with hot air 4 times hotter than steam, and then immediately seal that cylinder -- will pressure change as steam and hot air...
  21. C

    Thermodynamics Steam Turbine Specific Entropy

    Homework Statement The mass flow rate through a steam turbine operating under steady conditions is 100 kg/s. Steam enters the turbine at 12 MPa and 400oC. A mixture of vapour and liquid water exits the turbine at 10 kPa. At the exit state 93% of the mass of the water is in vapour form. The...
  22. C

    How to calculate the power generated by a turbine (steam)?

    Firstly, let's assume the expansion is isentropic. An example I found: Mass flow = 0.5kg/s Pi = 6000 kPa Ti = 500 Celcius Pf = 30kPa From this, how do we find the power generated and final steam quality? Do we look at steam tables, W = m(flow) (h_1 - h_2) --- is that helpful?
  23. T

    How to Calculate Steam Engine Efficiency and Water Usage in a Power Plant

    Homework Statement At a steam power plant, steam engines work in pairs, the heat output of the first one being the approximate heat input of the second. The operating temperatures of the first are 718∘C and 427∘C, and of the second 419∘C and 270∘C. A) If the heat of combustion of coal is...
  24. P

    Design Steam Turbine for Solar Energy: Math Help Needed

    im designing a steam turbine and boiler for a solar energy project but i can't figure out the math and have had trouble looking it up the only thing that is definite about the turbine (other than that its a tesla turbine) is that the thermal wattage is 5,855 watts or 1,434.72 calories per second...
  25. Amr Ali 33

    Hey i need some help in calculating the thermal efficiency of steam turbine

    guys i just wanted to know the formula by which i can calculate the thermal efficiency of a pass out steam turbine( a steam turbine with an extraction for process ) I've attached a simple diagram explaining my problem can anyone please help !
  26. C

    Energy released by condensing steam back to liquid water

    Homework Statement vaporized 19 kg of water and did not capture and condense it. It took 42.9 MJ to vaporize the water, how much energy did I lose from not condensing the steam? Homework Equations Latent Heat of Water = 2260kJ/kg The Attempt at a Solution Would the energy lost to not...
  27. David Carroll

    Results of steam bubbles in the reactor

    When I was in the Navy, we were told of the immense importance of maintaining pressure inside the reactor (all the reactors in the Navy use a hydrogen moderator via water). My teacher discussed that one of the results of loss of pressure could be the formation of steam bubbles collecting on the...
  28. S

    Heating steam, not water, with microwave energy

    I see a lot of information posted on the inefficiencies of heating water to steam with microwave energy. I was wondering if anybody has thoughts on super heating steam with microwave energy? For example, could you run steam through a turbine at 300 psi (417 degrees F), return steam at 100 psi...
  29. bozone

    Just signed up for steam - game recommendations please

    Hi everyone. I've just signed up for and downloaded Steam as I'm new to the whole RPG thing I was hoping people might be able to recommend their favourite MMO RPG games. I'd prefer f2p ones to start as I'm totally new to it. Which games do you guys love and what are good games for beginners like...
  30. W

    Pressure, temp, volume change of water vapor, and steam table clarity

    Homework Statement Two pounds of water vapor at 30 psia fill the 4ft^3 left chamber of a partitioned system. The right chamber has twice the volume of the left and is initially evacuated. Determine the pressure of the water after the partition has been removed and enough heat has been...
  31. X

    How Does Recirculation Work in Steam Engines?

    I am very fascinated by steam engines. When I took my thermodynamics course a few years back, I remember learning that the steam is recirculated after it does work. I am confused on how this happens. After the steam is used to do work, it is expelled at a lower pressure than it started...
  32. Y

    Can Superheated Steam Reach 1000°C?

    Is it possible to heat steam to a 1000°C at sufficiently high pressures? If yes, what is the best way to do it?
  33. S

    Variation in tube wall temperature as steam condenses to form liquid

    I'm having a bit of difficulty conceptually understanding a problem. Hoping someone here can clear it up for me. In a simple circular condenser tube (which is cooled by water or air) what happens the tube wall temperature as the steam inside is condensed? Intuitively I would have thought that...
  34. Soumalya

    Steam Power Plants and the Second Law of Thermodynamics

    We know that a steam power plant is basically a heat engine with steam as the working fluid. According to the second law of thermodynamics a heat engine must operate between two thermal energy reservoirs one at a higher temperature(source) than the other(sink) to produce net work in a...
  35. E

    Choosing the Right Compressor for Low Pressure Steam Applications

    Does anyone know what types of compressors/vacuum pumps can be used with low pressure steam at lab scale? I'm interested in a mechanical vapor compression system like this one used for large scale desalination and industrial processes. I think these use centrifugal compressors but I know...
  36. Manraj singh

    Shadow of Steam: Seeing the Unseen

    My mother was ironing clothes a few days ago, and the iron was really hot. It was giving out steam, i couldn't see it, but i could see its shadow on the wall. How so?
  37. S

    Why Are Liquid Properties in Steam Tables Labeled with an 'f' Subscript?

    I'm curious as to why steam tables typically present liquid properties with an "f" subscript, such as ρf.The gas properties use a "g" subscript, so I would expect the liquid properties to use "l". My first guess at the meaning of the "f" would be that it means "fluid", but this wouldn't make...
  38. I

    Steam turbine performance witr reduction in inlet pressure

    Dear All, I am estimating a future problem while still in erection phase for 60 MW steam turbine. I may need your help to estimate a solution. Due to some reason my process heater is not able to generate steam at the desired pressure (other parameters including Temperature and Flow rate...
  39. J

    Modelling Steam generator with P controller and 4-20mA signal to valve

    Hi . I am modeling a sodium steam generator in Octave. I build a set of differential equations and solve them with Octave DAE solver. My model works just fine. Now i would like to start implementing controls but I am quite confused with P conroler output signal and with what it actually...
  40. R

    Does steam deaeration involve Henry's Law?

    On many boiler feed-water systems there are deaerators which essentially sparge steam through the water. Why does steam deaerate water? Is this simply a temperature effect on gas solubility? Or something else?
  41. M

    Can a Self-Feeding Steam Turbine Recycle Its Own Water?

    I'm trying to design or find a design for a steam turbine that recycles it's water, or at least a large percentage of it, to prevent refilling of a boiler tank. My thoughts; The turbine will be powered by steam heated through copper tubing which is fed from a large unheated, (or partially...
  42. A

    Steam evolved during pressurized experiment

    I'm developing an experiment where an exothermic reaction will evolve water as an unavoidable byproduct, and for containment purposes I'll be using a sealed 25cc steel reaction vessel for initial testing. The question I'm posting here is for the purposes of safety and control, acknowledging...
  43. N

    Advice request - design a toy steam engine and do a pull event

    Advice request -- design a toy steam engine and do a pull event Hello, Please do forgive me if this is inappropriate use of this sight, I'm looking for general advice, any suggestions as to where I could get information and thoughts on the subject are welcome. I've taken a challenge to...
  44. P

    How much energy is consumed in reality in steam compression?

    I want to know how much energy REAL steam compressors consume in compressing steam @ 1 kg/sec from 2.56 kPa to 1 bar. Theoretically (with `100% efficiency) it's 141 kW for making 1 kg/sec steam flow assuming that the temperature doesn't decrease due to loss of heat as latent heat of...
  45. C

    Efficient Laser Steam Generation for High Pressure Vessels: Expert Suggestions

    I am working on a new concept design and would like some suggestions on which Lasers(s) would be most appropriate for heating a high pressure vessel for producing steam. The concept requires very quick steam generation but heat can not be excessive enough to harm the vessel being heated. As a...
  46. Soumalya

    Law of expansion for super heated steam

    Ideal gas behavior of super heated steam Why is super heated steam said to exhibit ideal gas behavior?
  47. M

    Thermodynamics of Steam Homework

    Here is the question in my homework, but my response does not correspond with the answer given, even though I worked out the answer that was given backwards and it still does not work: Determine the quantity of heat required, to raise 7.7 kg of water at 90°C, to saturated steam at 1300 kPa...
  48. A

    How to generate 2 bar pressure of steam economically?

    I am in a need to generate steam of 2 bar pressure, 403 K temperature and a mass flow rate of 0.0123 kg/s. Its just needed for my project work. Kindly suggest some ways to generate it economically. Thanks in advance.
  49. S

    Problem Solving - Calculate the mass of steam condensed

    Problem Solving -- Calculate the mass of steam condensed 1 ) A jet of steam at 100°C is directed into a hole in a large block of ice. After the steam has switched off, the condensed steam and melted ice are both a 0 degrees Celsius. The mass of water collected is 206 g. Calculate the mass of...
  50. N

    Thermodynamics: Air and Steam Mixtures

    Homework Statement A vessel of 0.3m3 capacity contains a mixture of air and steam which is 0.75 dry. If the pressure is 7 bar and temperature is 116.9 degree Celsius, find: Mass of water present, mass of dry saturated vapour, mass of air. Answer key: 0.102kg, 0.307kg, 1.394kgHomework Equations...
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