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

In summary, the problem involves finding the volumetric flows of dry steam and liquid water in a steam flow with a rate of 100 kg/s, a quality of 80%, and a pressure of 90 atm. This can be solved using the relevant equations and steam tables to determine the specific volumes of saturated steam and liquid water at 90 atm. Linear interpolation may be necessary. Then, using the quality and specific volumes, the total volume of the 100 kg mixture can be calculated.
  • #1
snowwhite
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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.

https://www.physicsforums.com/file:///C:\Users\Toshiba\AppData\Local\Temp\msohtmlclip1\01\clip_image001.gif Volumetric flow= Area * v where v is the rate of pipe 100 k/s

3. The attempt at a solution

Volumetric flow= Av= (1metre square)(100kg/s)= (100metres square)8kg)/s

The part that is confusing me is the steam quality. What for I need the steam quality in the problem? Is there any formula that relates the steam quality and rate of the pipe to calculate the volumetric flow of dry steam and liquid water?

I don’t know what the problem is giving me the quality and pressure?
 
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  • #2
Do you know the definition of steam quality? If so, let's hear it.

Do you know how to determine the temperature?

I assume you are using the steam tables to solve this. Correct?

What is the specific volume of the liquid water and the specific volume of the vapor under these conditions?

Chet
P.S., this has nothing to do with the area of the pipe.
 
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  • #3
No. I don´t know how to find the temperature of both. Looking at the pressure 90 atm for the liquid water and vapor, I will find the temperature of both.Then I will determine the specific volume of both?
Yes, exactly, I´m using the steam tables.
 
  • #4
Steam flows down a pipe at a rate of 100kg/s. The steam flow has a quality of
80% at 90 atm. Determine the volumetric flows of dry steam and liquid water.
 
  • #5
By the way, I always do everything different from everybody else that why I´m different
 
  • #6
snowwhite said:
No. I don´t know how to find the temperature of both. Looking at the pressure 90 atm for the liquid water and vapor, I will find the temperature of both.Then I will determine the specific volume of both?
Yes, exactly, I´m using the steam tables.
If water vapor and liquid water are present together in the flow stream, then the temperature is (a) the saturation temperature (and they are at the same temperature) or (b) not the saturation temperature?

Chet
 
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  • #7
The problem doesn´t mention if dry stream and liquid water are present together.

The problem only provides me rate of pipe 100kg/s. The quality x=80 % =0.80
and the pressure= 90 atm. Determine the volumetric flows of dry steam and liquid water.

do u know any formula to find the volumetric flow of dry steam and liquid water ?
 
  • #8
snowwhite said:
The problem doesn´t mention if dry stream and liquid water are present together.
If they are in the same pipe, they must be present together, correct? Hint: they are at the saturation temperature at 90 atm.
The problem only provides me rate of pipe 100kg/s. The quality x=80 % =0.80
and the pressure= 90 atm. Determine the volumetric flows of dry steam and liquid water.
If the quality is 80%, it means that 80% of the mass flow rate is steam and 20% of the mass flow rate is water.

From your steam tables, what is the specific volume of saturated steam at 90 atm, and what is the specific volume of saturated liquid water at 90 atm?

Chet
 
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  • #9
First, I convert the pressure given to bar.

so: 9 atmx (1.01325bar)/1atm = 91.1925 bar

I look these temperature in the steam table for specific volume of saturated steam and saturated liquid water, and these temperature does not appear.

so I need to interpolate.How can I do it?
 
  • #10
snowwhite said:
First, I convert the pressure given to bar.

so: 9 atmx (1.01325bar)/1atm = 91.1925 bar

I look these temperature in the steam table for specific volume of saturated steam and saturated liquid water, and these temperature does not appear.

so I need to interpolate.How can I do it?
Linearly interpolate. That's good enough.

Chet
 
  • #11
looking at the steam tables:

at 90 atm= 9MPA specific saturated steam volume is =0.001418metres cube/kg

In my steam tables does not appear saturated liquid water volme. How can I find it?
 
  • #12
snowwhite said:
looking at the steam tables:

at 90 atm= 9MPA specific saturated steam volume is =0.001418metres cube/kg

In my steam tables does not appear saturated liquid water volme. How can I find it?
Look harder. It should be there. See the table Further Properties of Water and Steam.

Chet
 
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  • #13
can u please provide me a web page to look at the specific volume of saturated liquid water at 9 MPa? or a good steam tables web page to look at it?

I have books with steam tables, steam tables in pdf and really DOES NOT APPEAR LIQUID WATER.

WHAT APPEARS ITS COMPRESSED WATER.?IS THAT IT?
 
  • #14
snowwhite said:
can u please provide me a web page to look at the specific volume of saturated liquid water at 9 MPa? or a good steam tables web page to look at it?

I have books with steam tables, steam tables in pdf and really DOES NOT APPEAR LIQUID WATER.

WHAT APPEARS ITS COMPRESSED WATER.?IS THAT IT?
Probably, but in the tables you linked in one of your posts, the relevant section is Further Properties of Water and Steam
 
  • #15
Does this question only require you to find Vf and Vg?
 
  • #16
DownShift said:
Does this question only require you to find Vf and Vg?
No. Suppose you have 100 kg of this mixture. We want to find the volume of this 100 kg of mixture. Knowing the quality, how many kg of vapor are there? How many kg of liquid are there? Knowing Vf and Vg, how many cubic meters of vapor are there. How many cubic meters of liquid are there? What's the total volume of the 100 kg mixture?

Chet
 
  • #17
Chestermiller said:
No. Suppose you have 100 kg of this mixture. We want to find the volume of this 100 kg of mixture. Knowing the quality, how many kg of vapor are there? How many kg of liquid are there? Knowing Vf and Vg, how many cubic meters of vapor are there. How many cubic meters of liquid are there? What's the total volume of the 100 kg mixture?

Chet

Thanks
 

1. What is the difference between dry steam and liquid water?

Dry steam is a vaporized form of water that contains no liquid droplets, while liquid water is the liquid form of water that contains no vapor. Dry steam has a higher temperature and energy content compared to liquid water.

2. How do you calculate the volumetric flow of dry steam and liquid water?

The volumetric flow of dry steam can be calculated by multiplying the mass flow rate by the specific volume of dry steam. The volumetric flow of liquid water can be calculated by dividing the mass flow rate by the density of liquid water.

3. What factors affect the volumetric flow of dry steam and liquid water?

The volumetric flow of dry steam and liquid water is affected by temperature, pressure, and flow rate. Higher temperatures and pressures result in higher volumetric flows, while higher flow rates result in higher volumetric flows for liquid water only.

4. How does the volumetric flow of dry steam and liquid water impact thermodynamic processes?

The volumetric flow of dry steam and liquid water is an important factor in determining the efficiency and performance of thermodynamic processes. It affects heat transfer, work output, and overall system efficiency.

5. Can the volumetric flow of dry steam and liquid water be controlled?

Yes, the volumetric flow of dry steam and liquid water can be controlled through various methods such as adjusting the temperature, pressure, and flow rate. In industrial processes, flow controllers and valves are often used to regulate the volumetric flow of these fluids.

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