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.
Hi
I need to perform a material selection case on the rotor of a steam turbine. Both material selection as process selection have to be made.
Since my background is rather chemical than mechanical or material engineering I've encountered some difficulties. I hope you can help me with them.
For...
hello everybody, I'm new here and i have this homework which i don't know how to solve it, please help me:
Design the thickness of insulation for steam pipe of:
-Pipe diameter 2 in.
-Pipe length 200 m.
-Saturated steam pressure 10 bar.
-Ambient temperature 30°C.
-Steam cost $4.5/MMbtu
i...
Hello All,
I'm working on a project and one of the main parts is this pressure vessel that is sealed air tight that has 2 tubes coming out. One is straight and the other is a U tube. I have a 2.5 KW heater coil in the water to boil the water in order to create steam to raise pressure and move...
Hello!
I'm trying to build simulation of steam generation process
My problem is this:
I want to know how to calculate pressure in the following problem-
closed container, V=1 litres
121 C water, 1 g
121 C saturated steam 1.129 g
p = 1 bar
if container valve opens shortly and...
Homework Statement
Suppose that 1 kg of water, initially at 350 K, is turned into steam at 373 K. What is the change in entropy? (Lv = 2.26 x 106 J/kg; cwater = 4186 J/(kg Co)
a. 6060 J/K
b. 6070 J/K
c. 6320 J/K
d. 6330 J/K
Homework Equations
ΔS=ΔQ/T
Q=mcΔT
Q=mL
The Attempt...
1. Homework Statement
Calculate the heat energy required to convert 0.10 kg of ice at -10 degrees Celcius into steam at 100 degrees Celcius.
2. Homework Equations
E = m c dt (1)
where
E = heat energy (kJ)
m = unit mass (kg)
c = specific...
Hi all!
i'm trying to figure out what method would be the cheapest to create steam at high pressure with.
ideally, the source of energy for the process would be electricity, as the facility is not intended to have it's own power generation capabilities.
the mechanical use of the steam will be to...
hi, if you had a litre container full of water with negligible air and nothing else and heated it at a linear rate from 50 degrees centigrade upto 200 degrees centigrade does the steam pressure rise linearly or exponentially?
the measurements are plucked from the air, its the rate of steam...
Hi,
I'm have big problems calculating the Isentropic Effeciencies of steam turbines. There is a HP, IP and LP turbine in the system. I know the calculation is (h1 - h2)/(h1 - h2'), i have the temperatures and pressures in and out for the first two turbines so i can easily get h1 and h2 from the...
Why is this done? Wikipedia says that condensing the steam makes the cycle 'more efficient.' How is it more efficient? Why can't the de-energized steam be transferred to the boiler without condensing it?
All the time I hear how steam is an excellent way of transferring and storing energy, but I'm questioning it at this point. Consider a Coal-powered electric generating station. Enormous amounts of heat are produced by the coal to heat water in pipes that is transformed into steam. This steam...
Homework Statement
http://img140.imageshack.us/img140/2963/isobaricsteam.jpg
P1 and P2 are 1 bar. V2 4.812 and V2 specific volume is 2.406
X1=0.6
Homework Equations
v=vf+x(vf-vg)
W=-P(v2-v1)
Q=(u2+pv2)-(u1+pv1)
The Attempt at a Solution
Hi guys first timer here...
Hi i am a brand new member to this forum i am studying to be a power engineer and thermodynamics is one of the courses I need to succeed. If i could get help with this problem it would be much appreciated.
Homework Statement
A perfectly insulated box contains 3.50kg of dry saturated steam...
hi all!
i'm trying to figure out how much water i need to heat and to what temperature, to end up with 1 cubic meter of steam at 70atm.
i used the calculator found here:
http://www.efunda.com/materials/water/steamtable_sat.cfm
i punched in 70atm, and got the following data:
Temperature...
Homework Statement
In a steam engine the pressure and volume of steam satisfy the equation PV1.4=k, where k is a constant. Calculate the work done by the engine (in ft/lbs) during a cycle when the steam starts at a pressure of 100 lb/in2 and a volume of 400in3 and expands to a volume of...
Hi, I've recently gotten some simple plans to build a hobby kit steam engine running on 2 pistons that drives a crankshaft. It runs on saturated steam instead of superheated steam. One can attach a small generator to the end of the crankshaft to generate some power. Looking at these plans, I...
Homework Statement
I have a problem which I will attach a picture of, regarding a system composing of a heat recovery steam generator and a turbine. I have to work out the power output of the turbine, which I think I will be fine with. What I would like to know is, how does the combustion...
Homework Statement
Long steam pipes often have a section in the shape of a \bigcup. Why?Homework Equations
None.The Attempt at a Solution
I'm at a loss. It might be because of some sort of volume expansion, but I'm not entirely sure why...
Homework Statement
If we have a containment sprayed by a subcooled water to condense the steam, the pressure decreased from 5 bar to 4 bar, calculate the amount of sprayed water required as a minimum to decrease this pressure?
Heat of vaporization 2550 kJ/Kg, steam at saturated condition...
Homework Statement
A copper calorimeter can with mass 0.466kg contains 00950kg of ice. The system is initially at 0.0C. If 0.0350kg of steam at 100C and 1atm pressure is added to the can, what is the final temperature of the calorimeter can and its contents?
Homework Equations
Q=mL
Q=mcΔT...
Homework Statement
A vessel whose walls are thermally insulated contains 2.40kg of water and 0.450kg of ice, all at a temperature of 0.0 C. The outlet of a tube leading from a boiler in which water is boiling at atmospheric pressure is inserted into the water. How many grams of steam must...
Hi All,
I am designing a vertical venturi tube to be inserted into a 18" piece of ductwork in order to pull steam generated in a 12'' perpendicular duct. I would like to reduce the diameter from 18'' to 6'' at which point i will tie in the 12'' perpendicular duct (nozzled down in size) in...
I recently bought one of those model steam engines, which came with a box of fuel tablets which I can't figure out how to light. I've put them over my cigarette lighter until they snap, crackle, and pop but they just won't catch and my engine won't go.
How do you light these things?
The box...
Problem:
If 5.0 g of steam at 100 deg C interacts with 20 g of ice at 0 deg C, what is the final temperature of the resulting 25 g of water?
My thinking on the solution:
I figure I can use the equation
delta Q = mC(delta T)
to calculate the final temperature, where m = 25 g...
Hello all,
I've got a question for folks who have taken the FE exam. I've been doing some thermo prep questions, and I've come across several sample questions (Non-NCEES written) that give properties of steam at odd points, say 1.8 MPa. In the reference handbook I'm using (2008; the 2011 PDF...
Homework Statement
i need to calculate steam required to remove moisture content from the paper .
low pressure steam: 2.7kg/cm2
i have calculated total water to be evaporated : 3500kg/hr
machine speed is 335 mt/min
gsm of paper:64gsm
deckle width;310 cm
Homework Equations
Q=ML
Q...
The idea I have is that on a multi fuel stove I could have a boiler attached to it to heat water for the purpose of steam, then the steam in turn to drive a small steam turbine to produce electricity and the steam then to condense and return to water. Thus allowing the process to start again...
Ok here's an idea that isn't a perpetual motion machine (it's no more perpetual than solar cells):
Using a big magnifying lens or parabolic mirrors, what are the formulas when either of them are used to evaporate water into water vapor steam to move a turbine to power an electric generator?
Hello,I'm attempting to come up with the best method to achieve maximum condensation (air dryness).
In the system an exhaust fan will draw in steam (212F) and pass it through a 90 degree pipe (~12-14 inches) before it enters an area where it needs to be cooled for the purpose of removing the...
Homework Statement
A steam driven turbine generates 200 MW of mechanical power at tan eficiency of 32%. The temperature of the steam at the input is 500 C, and at the output it is 200C
a: How much power is input as heat to run this turbine?
b: How much power is lost in hear to the...
Hello,
i would like to do structural analysis for low pressure spindle blades in Ansys apdl.. but i couldn't do it coz of lack of knowledge about it.. Can anybody explain me where to apply force/ pressure and constraints and how to do it to find stress, strain and deformation in it.. please i...
Homework Statement
How much energy is required to change one-quarter of 8.0kg of water at 25 C into steam?
The way I see it, the entirety of the 8.0kg of water must be brought from 25 C to 100 C, then only 2.0kg is changed to steam so...
Specific heat capacity (of water) = 4200 J / kg...
For water separation purposes, what's the difference between steam and fully saturated air? I was looking at a certain product:
http://www.nciweb.net/combinat.htm
And I'm not sure if such a thing would be suitable for separating the water from a fully saturated air stream at about 60degC...
Hey guys, I'm an engineer working on the design of a small start up solar power plant. The solar power plant will operate using "solar troughs" instead of the traditional photovoltaic cells. In these systems water is the working fluid and sunlight is focused from a solar reflector onto a pipe...
Homework Statement
A transparent rigid container is filled with 2 gallons of water. Initially the pressure is
measured to be 10.2 psig, using a gage attached to the container. The local atmospheric pressure is 14.8 psia. It is observed that the liquid water in the container occupies two...
Question:
http://i1179.photobucket.com/albums/x393/mariaschiffer/img017.jpg
Can anyone please check whether this answer is right.Thanks in advance
Answer:
Pressure of the closed feed water heaterP4=1MPa
Take the extracted pressure from the second turbine P11=0.3MPa
Operating pressure...
Question :
http://i1179.photobucket.com/albums/x393/mariaschiffer/img017.jpg
Can anyone please double check if this answer is right. Thanks in advance.
Answer :
Pressure of the closed feed water heaterP4=1MPa
Take the extracted pressure from the second turbine P11=0.3MPa
Operating...
Homework Statement
Steam is passing a pipe that has cold water flowing through. I need to find the change in temperature from when the water enters the pipe to when it leaves the pipe.
Homework Equations
First i found the total thermal resistance using...
Hey everyone,
I'm a bit confused with the meanings of f, g, and fg subscripts in the thermo steam tables (e.g. hf, hfg, hg). If there is saturated steam, part of the enthalpy is in liquid, hf, part is encapsulated in the vapour, hg, but what is hfg? Also h = hf + (x)hfg. h here is the total...
Let's say we have a room in which it is around 20° C and at normal pressure.
There is a substance that is a liquid, but when the temperature increases to 25° C or so, it rapidly expands, whether that is by boiling (conversion to gas), or just by expanding as a liquid.
First question: does...
I have to do a paper ( kind of project ) for 4-6 page on Thermodynamics description of a watt steam engine. i have no idea where to start.
It is for a Thermodynamics 1 class.
Thanks in advance.
Hi,
Can someone please explain this to me:
Looking at the steam tables, if I have steam at 40bar and 350C then the specific volume is ~66.4 m^3/kg and enthalpy is 3095 kJ/kg.
If I halve the pressure to 20bar (still at 350C), thus 'doubling' the specific volume to 138.56 m^3/kg, the...
I have an assignment and don't even know where to start so that's y am asking the experts on here to give me an idea how to go about this:
In a company factory, a steam line has been identified as loosing too much heat. The steam line has a diameter of 254mm ( it may be considered to be thin...