## Fluids

#### how to input and get Relative Humidity in fluent?? – HVAC

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• aminuddin setyo
Subscriber
excuse me i wanna make fluent simulation about Greenhouse temperature and humidity

I tried to enter the air value with a temperature of 25 Celsius and 80% RH,
but, because fluent doesn't provide input for RH,
so, I use species mixture template (water-vapor and air).
the air  temperature is 25 Celsius and  teh RH is 80%,
in that condition, the air has H2O mass fraction of 0.016 (psychometric table)

then I enter the value of H2O mass fraction at the inlet and outlet

what I expect is the result of the RH contour at the end of the simulation is still the same 82%,
but why do I get an RH that is less than 82% (only 10%)..

is there a way so that I can get the RH of 82%??

thank you
• Rob
Ansys Employee

RH is a function of the temperature and partial pressure of vapour. Partial pressure is a function of the mass fraction of vapour. You can set that.  Use Search as it's been discussed several times.

Mass fraction is likely to remain constant over the domain. However, RH will vary assuming the temperature and pressure vary in the domain.

• aminuddin setyo
Subscriber

Thank you sir, I have found a way out. It turns out that when I plot the RH in solution, it shows the RH is around 70% to 100%, while in the post result it shows a value of 0.7 to 10