Determining parameters for trapped air in contact with water.

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SUMMARY

This discussion focuses on evaluating the heat capacity, density, and thermal conductivity of humid air in contact with water at a temperature of 39°C (312K). The user seeks to determine the proportion of water vapor in the air, which is essential for accurate calculations. They have identified a formula for calculating the density of water vapor using pressures and specific constants, but require validation of their calculations and assistance in determining humidity levels. The user has not found adequate tools to assist with their needs.

PREREQUISITES
  • Understanding of thermodynamic properties such as heat capacity and thermal conductivity.
  • Familiarity with the ideal gas law and its application in calculating density.
  • Knowledge of humidity measurement techniques and tools.
  • Experience with pressure and temperature relationships in gases.
NEXT STEPS
  • Research methods for measuring humidity in air, such as hygrometers or psychrometers.
  • Learn about the calculation of thermal properties for humid air using empirical formulas.
  • Explore the use of software tools for thermodynamic property calculations, such as REFPROP or CoolProp.
  • Investigate the impact of humidity on the thermal conductivity of air and water vapor.
USEFUL FOR

This discussion is beneficial for engineers, physicists, and researchers involved in thermodynamics, HVAC systems, or any field requiring precise calculations of humid air properties.

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Hi everyone,

I need to evaluate parameters (heat capacity, density and thermal conductivity) for some very humid air.
I know the parameters for both dry air and water vapor. So I suppose the parameters I need will just be a linear combination of the other parameters, with a coefficient corresponding to the percentage of water in the air.
Problem is I do not know what is the proportion of water inside my air.

I have a 12cm wide layer of air in contact with plenty of water at a temperature of 39°C (312K) the contact area is about 5.46m². The air is trapped, I believe there are a few leaks keeping a balance in the air but that is not important for now.

Could someone validate my (basic) calculation, and overall could someone help me as to how figure out the humidity of the air.
I browsed a few tool boxes and did not find the parameters I need, if someone knows about that it would also be very welcomed.

Thank you for your times and your answers.
Have a good day.
 
Chemistry news on Phys.org
Already found out that the density of water vapor is definitely not calculated as I thought.

But like that :
rho = p1/(R1*T) + p2/(R2*T)
Where p are the pressions, R are some specific constants and T the temperature.

So I am wondering if I am not wrong for the other 2 parameters.
 

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