What is Steam: Definition and 535 Discussions

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. A

    Design a condenser of a steam power plant

    This question is from my textbook: Thermodynamics an Engineering Approach 7ed SI Units, cengel. It is problem 10-129 and I can't seem to figure it out. Design the condenser of a steam power plant that has a thermal efficiency of 40 percent and generates 10 MW of net electric power. Steam...
  2. F

    Thermodynamics Steam Turbine Internal Efficiency Question

    [b]1. Steam into a steam turbine at 7 MPa and 500 deg C. The turbine has an internal efficiency of 90 %. The steam exhausts at 20 kPa. 1) What is the exhaust enthalpy? 2) What is turbine work? 3) What is the quality of the exhaust steam? This is a question I got on a 2nd class boilers...
  3. L

    Calculating Boiler Capacity and Steam Properties

    Homework Statement An electric generating plant boils water to produce high pressure steam. The steam spins a turbine that is connected to the generator. a) how many liters of water must be boiled to fill a 5.0 m^3 boiler with steam at 50 atm and 400 degrees Celsius. b) The steam has...
  4. K

    Finding the final temperature of mixed ice and steam

    Homework Statement Suppose that 20.0g of steam at 110°C is mixed with 25.0g of ice at -40°C What will the final temperature be? Ice - Specific heat capacity 2.10 J/g°C Water - Specific heat capacity 4.19 J/g°C Water - Latent heat of fusion 334 J/g Water - Latent heat of vaporization 2268...
  5. K

    Finding the final temperature when steam and ice are mixed

    Homework Statement Suppose that 20.0g of steam at 110°C is mixed with 25.0g of ice at -40°C What will the final temperature be? Ice - Specific heat capacity 2.10 J/g°C Water - Specific heat capacity 4.19 J/g°C Water - Latent heat of fusion 334 J/g Water - Latent heat of vaporization 2268 J/g...
  6. P

    Pressure and temperature of steam to produce water gas

    Can anybody inform me about the necessary pressure and temperature level of steam to produce water by reacting it with red hot coal/carbon.
  7. J

    Thermodynamics: Waste heat and total ice converted to steam

    Homework Statement A coal-fi red plant generates 600 MW of electric power. The plant uses 4:8106 kg of coal each day. The heat produced by the combustion of coal is 3:3107 J/kg. The steam that drives the turbines is at a temperature of 300C, and the exhaust water is at 37C. (a) How much...
  8. P

    Can a jet of steam be used to heat drinks quickly?

    hello..i was reading some where that a jet of steam releases latent heat when it condenses.this idea can be used to heat drinks quickly.. i understand that on condensation 1 kg of steam at 100 C should release 2300000 Joules of heat but what should be the conditions for this to happen?what...
  9. S

    A thermal physics question about steam and coffee, please could you help?

    Homework Statement A coffee machine in a café passes steam at 100°C into 0.18kg of cold coffee (s.h.c. the same as that of water(4200j/kg/K)) to warm it. If the initial temperature of the coffee is 14°C, what mass of steam must be supplied to raise the temperature of the coffee to 85°C Homework...
  10. S

    Need help on how to figure out the problems (Steam)

    Homework Statement Determine by using steamtables for 2kg of steam - Boiling point if pressure is 5MPa - pressure if the boiling point is 195°C - enthalpy of evaporation at pressure 2800kPa - total elathapy in MJ required to produce 2kg of wet steam with dryness factor of 0.7 at a pressure...
  11. dbmorpher

    Solar Driven low Resource Consuption Steam Engine Materials

    Hi I'm dbmorpher For my local History fair I am basing my report on the Indutrial Evolution and it's Inventions namely the Steam Engine. I wanted to know if there was an easy way to make a steam engine that was or had... Low cost parts No fuel such as coal or wood No need for complicated...
  12. T

    Small Steam Turbines: Impact on Efficiency

    Homework Statement Why are small steam turbine power plant more inefficient than larger ones? how does the size affect efficiency?Homework Equations - The Attempt at a Solution -
  13. S

    Seeking to maintain a steam condensation vacuum of about 0.06Bar

    Just looking for a bit of advice on a problem I am currently having. I am doing some research into the condensation characteristics of steam when under vacuum. However, I am having difficulty maintaing the desired level of vacuum of around 0.06Bar in my current system. Anytime I achieve the...
  14. X

    Work done on steam during phase change?

    Homework Statement (a) How much work is done on the steam when 3.89 mol of water at 100°C boils and becomes 3.89 mol of steam at 100°C at 1.00 atm pressure? (Assume the latent heat of vaporization of water is 2.26 106 J/kg.) (b) Assume the steam to behave as an ideal gas. Determine the...
  15. R

    Non-condensing steam recovery from exhaust gas?

    Cyclonic separators can be used to collect water in after-treatment when hydrocarbons are burnt, but (for one thing) this expends energy in cooling the walls of the cyclone. Is there a means to, say, use a similar effect of centrifugal force to concentrate the water molecules near the outer...
  16. D

    Steam Heat Exchanger Efficiency

    Heya, id like a little help calculating the efficiency of some steam heat exchangers. They are used in industrial dryers, steam goes through the radiator and then air is blowed to it in order to heat the fabric. Currently my radiators are made from carbon steel tubes and fins, it has 78 flat...
  17. B

    Determine the gas if the pressure of its saturated steam is known

    One hundred thousands denarii (or 423 kg of gold) cost a vase from mineral A in Ancient Rome. A Painter in 17th century occasionally got from it gas B and Physicist in 19th told an assumption of its composition. There are experimental data of pressure of its saturated steam and density over a...
  18. P

    Can superheating of steam increases efficiency and output of thermal power plants?

    I just want to ask a simple question to experts here. Can superheating of steam increases efficiency and output of thermal power plants?
  19. A

    How Can I Correctly Calculate Wall Temperature in an Air Cooled Steam Condenser?

    Hey my problem is related to air cooled condenser The condenser is for removing 5MW thermal power from steam at 350 C, the pressure is 170 kg/cm2. The average temperature of outside air is 95 C(inlet at 45 C and outlet at 145 C). the data is as follows: no of tubes : 182 tube od =25.4...
  20. S

    How Do You Calculate Enthalpy Using Steam Tables and Dryness Fraction?

    Homework Statement Find the enthalpy of steam at 0.4 MPa and 0.7 dryness Homework Equations The Attempt at a Solution At a pressure of 0.4MPa dry saturated steam has a total enthalpy of hg = 2,739 kj/kg. ∴ 0.7 kg of steam has an enthalpy of (0.7 x 2,739) = 1917.3 kj The...
  21. N

    Calculate Pressure of Steam in ∅12" Pipe?

    Hi, here's a problem I've recently come across, and it's bugging me that I can't wrap my mind around it. I need to calculate the pressure of steam in a ∅12" pipe. I know that the steam flows at 8700 lb/hr over a 24 minute period, and that the average steam temperature is 176°F. I also know...
  22. C

    What has more entropy out of steam, water and ice?

    I'm trying to understand entropy, because I have no clue what it is. Iv seen questions like this posted in other places on the web, but there seems to be a disagreement over the answer. Some people say it is the randomness and chaos of a system, and other people say it is how close it is to...
  23. M

    Calculating the force on a Crankshaft in a Steam Engine

    Given that I have a steam engine, and now its size, the size of the piston, the length of its stroke and the force acting on the piston at certain points, I need to calculate the force on the crankshaft. Now, I now that Fx should be the same where the piston meets the crank, and we can ignore...
  24. R

    Can Reheating Steam Locally Improve Air Outlet Temperature in Heat Exchangers?

    Our tin plating line has several of these. Original design was superheated steam to 300 degrees Celcius, but the plant reduced steam pressure and now our steam inlet temperature is much lower (less than 150 degrees Celcius). Inlet air is what we want to heat up for the drying. It comes in...
  25. X

    What are the problems with Steam Engines?

    For some reason, steam power fascinates me very much. I had a couple questions about steam power and I figured this place was the best place to ask! Would it be naive of me to believe that any engine engineered correctly can be useful? What are the advantages and disadvantages of a steam...
  26. R

    Water temperature increase in tank with steam

    Hello Everyone, I have been asked to find out what it takes to bring 775 gallons of water at 70 deg (room temperature) to a rolling boil (approx 212 deg) via 25psig steam. I have 68 square feet of heat transfer surface (stainless steel tank) with no agitation. I haven't been successful...
  27. O

    Calculating quality of steam after isentropic expansion

    Homework Statement Saturated steam with a pressure of 30 bars is isentropically expanded to a pressure of 1 bar. What is the quality (x) of the steam after expansion? Homework Equations No clue. I do have a table containing all necessary data such as temperature, specific volume...
  28. J

    Why Does My Espresso Machine Hiss When Unsealed?

    I drink a lot of espresso. From my minimal knowledge of espresso machines, I understand that the water is heated into steam which creates pressure forcing the steam through the coffee grounds. After every batch of espresso I let the machine sit overnight unplugged. Presumably, the water gas...
  29. W

    Designing of a steam power plant

    Homework Statement electric power = one million kW working fluid = steam maximum steam temperature = 550°C river mean speed = 10m/min river,8m deep,60 meter wide Homework Equations It is proposed to build a one million kW electric power plant with steam as the working fluid...
  30. G

    Build a Simple Steam Engine for Under Rs. 10

    Hello everyone this is my first steam engine made using very simple parts like cardboard, disposable syringe, straw, pen end caps and bicycle spokes. How much economical can you make your engine? Here it is costs only about Rs.10. Blowed air through mouth that's why produces lower rpm use...
  31. M

    What is the fastest way to remove all water content from steam?

    I have a tank of water of boiling water and a small tube at the top. The output is to turn a turbine or generator, but I want to remove the water soon after it leaves the tank. That way I won't need to bother with condensation/water return later. What is the fastest way to remove the water...
  32. S

    Energy required to convert ice to steam ?

    Homework Statement Find the energy required to change ' X " mass of ice at -18 degrees celcius to steam at 100 degrees celcius. Latent heat of fusion : 336 000 Lt heat of evaporaton : 2300000 SHC water : 4200 SHC ice : 2108 Homework Equations Q=mcΔθ Q=m x latent heat...
  33. S

    Steam required to boil a substance?

    Hi there, I am working on a process in which I have to melt 100 kg/h of plastic. The best way we thought of doing this was to use a boiler (steam generator) to produce sufficient heat to boil the plastics in time. I am currently trying to choose the right boiler for the system. Yet, I do not...
  34. C

    Finding the enthelpy for a sub-cooled working fluid using steam tables

    Hi guys, kind of stuck here because I either don't remember or wasn't taught this but... I'm working with refrigeration and I've come across a problem that involves a state where the fluild has been sub-cooled by 10K - Its easy enough dealing with super heated fluids but when it comes to sub...
  35. J

    San Onofre steam generator tubes leaking - why?

    Hi, San Onofre, menioned durring the Japan crisis, is leaking and corroding pipes fast: http://www.scpr.org/blogs/news/2012/03/22/5205/san-onofre-reactors-down-indefinitely/ http://sciencedude.ocregister.com/2012/02/02/nuclear-leak-damage-to-both-reactor-units/167503/ What is going on- any...
  36. M

    How to calculate steam consumption?

    there is a boiler of capacity of 150 lb/hr. steam is being consumed in multiple machines. my area of interest are three particular machines and i want to find out how much amount of steam is being used by each machine. there are no flow meters installed. all i can see is a pressure gauge at the...
  37. M

    Thermodynamics phase changes steam and water

    Homework Statement In each case, the following are mixed in a perfect calorimeter with no heat lost or gained from the system. Find the final temp in each case. 12.5 g of steam at 100C with 344 g of water at 22.2C. Homework Equations Q=Mc(Tfinal-Tinitial) M is the mass in kg C...
  38. B

    Steam generator on the exhaust pipe of the car ( cogeneration )

    I'm trying to do the concept of a turbosteamer that the bmw is workking on but I'm facing few problems : the flow rate of water will be 9 ml/s and of pressure 6 bars . based on htri xchanger program , the best design of my shell and tube heat xchanger will be of 22 cm diameter and 6.4 mm tube...
  39. M

    How to condense steam to water?

    hi I would like to know what is the easiest way to condense steam 100°C to water ?? thanks.
  40. M

    Help with Experiment of Capturing soot with steam

    Hi I'm doing an experiment to capture exhaust pipe's soot with steam. You can see in the attachment file the experiment design. So the problem is that using STEAM HEAT EXCHANGER (is it good??) in order to convert soot+steam to water+steam. What I've planed is that when the soot+steam gose...
  41. C

    Steam Table Issues: Convert m3/hr to kg/hr @14.5 barg, 1150 deg C

    Hi I'm trying to convert m3/hr to kg/hr for a steam system operating at 14.5 barg and 1150 deg C. I was planning on using steam tables to get the specific volume but anywhere i look the temperature seems too high to have any values. Any suggestions of places that do have the values I'm...
  42. S

    Steam Generator Problem: Calculating Heat Input and Fractional Usage of Heat"

    Thank you Homework Statement cold water enters a steam generator at 20°C, is vaporized at 165°C, and exits as a superheated vapor at 350°C. The steam generator, operates at constant pressure. (a) the heat input to the generator (kJ per kg of steam product); (b) the fraction of the input...
  43. P

    Thermodynamics filling steam tables for water

    Hey guys I attached the problem and the solution. I only have a question on row 4. The bolded #s are the one's we were supposed to find, but this is from the solution manual. To find h, since the given pressure is much lower than the lowest pressure value in the compressed liquid table we are...
  44. M

    Salt water steam pressure vs fresh water steam pressure

    Homework Statement My son picked a science experiment for his 5th grade project. It was supposed to be on evaporation. Basically a steam powered boat with candles heating up a cigar tube with a hole for the steam to escape and push the boat. However he got ambitious and changed the...
  45. C

    Calculate the mass of steam condensed

    A jet of steam @ 100 degrees Celsius 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 steam condensed. Specific heat capacity of water...
  46. K

    Steam engine out of coke can help

    Hi, my first post. So brief presentation, I'm an undergraduate mechanical engineer student. I hope this doesn't actually fall in homework, but it's a project that I have this semester: a steam engine car (small). I've made a bit of research and I ended up discovering the following "engine"...
  47. C

    Does steam rising in an insulated tube lose thermal energy

    I want to propose an interesting thought experiment, but don't want to A/ make a bigger fool of myself than I normally do B/ well that's about it really The premise behind my experiment is that rising steam does not lose thermal energy if we ignore thermal losses both radiative and conductive...
  48. B

    Why do steam burns cause more severe skin damage than water burns?

    Homework Statement Explain why skin burns caused by 100 degree C steam are more severe than those caused by 100 degree C water. Homework Equations 100 degree C water skin 20 degrees C 4.2 J/g so 200 J 100 degree C steam 2254 J into your arm vaporize water in cells of your arm...
  49. J

    In a vacuum: steam sinks or evenly distributes?

    Anybody know this one? I need to know for an evaporator design. Because there's no buoyancy from air, I'd think it would sink (this answer was given on Yahoo), but if it sank then there would be a low pressure area left above, and so the vapor should rise to fill it, hence evenly distributing...
  50. J

    Condensate-boiler return steam turbine

    hi. always wondered how water in a condenser is returned to the boiler. wouldnt it need to be pumped in with a high pressure pump?
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