Vapor Quality calculation

[banerjeerupak]

Water is being used as a coolant by flowing through a channel. I know the mass flow rate of water. And i know the inlet properties of water. I also know that the water is coming out of the channel at a vapor quality of 1. How do i calculate the heat flux that the water is subjected to during flowing through the channel. I need the formula or the direction in which i can think to figure out the question.

 

[Q_Goest]

Hi baner,
The easiest thing to do is just use steam tables. The heat removed is equal to the difference in enthalpy.
dQ = dH

 

[banerjeerupak]

Thank you Q,

That was helpful.

-Rupak

 

[banerjeerupak]

now there is a change in the calculations i need to perform. I have the heat flux and the mass flow rate. How should i go about calculating the vapor quality. I couldn't remember the formula, so thought of asking here.

 

[Q_Goest]

You can use the same method.
Q_in = H_out - H_in
so
H_out = Q_in - H_in
Note: the above Q_in and H have units of energy per unit time. H therefore, is the specific enthalpy (h) times mass flow rate.

Once you have h_out (units are energy per unit mass) go to your steam tables. Given the pressure on the outlet, you can determine the quality by applying the following and solving for x :
h_out = h_f + x h_fg