Working out steam velocity with only pressure difference

In summary, the conversation discusses the relationship between pressure and velocity in a steam turbine. The pressure differential is caused by the blades and rotors of the turbine, which create internal resistance to the flow of steam. Theoretically, if there was no resistance, the maximum velocity could be calculated by considering the specific volume and pressure changes. However, in a real turbine, the conditions of steam can vary, resulting in a variable speed for each cross-section.
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jacob1
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I am currently doing an assignment on nuclear power and in the turbine, the steam is moving from pressure of 6Mpa to 0.008 Mpa. is there any way to work out the velocity of the steam when moving between these pressure differences?
 
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  • #2
Welcome! :)
The main reason you have that pressure differential is the blades and rotors of the steam turbine, which are stealing energy from the steam flow: therefore, that steam velocity at each section depends on that internal resistance to the flow.
 
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  • #3
Lnewqban said:
Welcome! :)
The main reason you have that pressure differential is the blades and rotors of the steam turbine, which are stealing energy from the steam flow: therefore, that steam velocity at each section depends on that internal resistance to the flow.
Thanks for your response!
How about if the system was treated as having no resistance to flow to work out a theoretical maximum velocity would there be a way to do this?
 
  • #4
A change of pressure is involved for the mass of steam going through certain cross section; therefore, the specific volume at each section should be considered.
The conditions of steam could go from over-heated steam (turbine inlet) to sub-cooled condensate (turbine outlet) in a real turbine.
In your hypotetic case, the sudden pressure reduction could imply a sudden adiabatic increase of volume; resulting in a variable speed of steam for each cross-section of what would now be a duct rather than a entalphy degrading machine.
 

What is steam velocity and why is it important to calculate?

Steam velocity refers to the speed at which steam flows through a system. It is important to calculate because it can affect the efficiency and safety of steam-powered equipment.

Can steam velocity be accurately determined with only pressure difference?

Yes, steam velocity can be accurately determined with only pressure difference. This is because pressure and velocity are directly related in a closed system, so knowing one value allows you to calculate the other.

What factors can affect the accuracy of calculating steam velocity with only pressure difference?

The accuracy of calculating steam velocity with only pressure difference can be affected by factors such as the type of steam (saturated or superheated), the size and shape of the pipe, and any obstructions or changes in the flow path.

Is there a specific formula for calculating steam velocity with only pressure difference?

Yes, there is a specific formula for calculating steam velocity with only pressure difference. It is known as the Bernoulli's equation and takes into account the pressure difference, density of steam, and the area of the pipe.

Are there any limitations to using pressure difference to determine steam velocity?

Yes, there are limitations to using pressure difference to determine steam velocity. This method assumes that the steam is in a steady flow and that there are no significant changes in the flow path. It also does not take into account any heat loss or gain in the system, which can affect the accuracy of the calculation.

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