Condensation with decreasing temperature

- October 31, 2023 at 9:53 am
  
  Erik Gerlings
  Subscriber
  
  Hi,
  I am trying to make a multiphase model which involves the condensation of n-heptane.
  An issue that I run into in this case is that even for the simplest mass transfer mechanism (constant rate), the temperature of the fluid decreases. My from fluid is the liquid heptane and to liquid is heptane vapor.
  Could someone please explain why the temperature decreases while for condensation the temperature should increase? And how can I resolve this problem?
  
  Kind regards,
  Erik
- October 31, 2023 at 3:43 pm
  
  Rob
  Forum Moderator
  
  If the gas is condensing, what density model did you use? Ie where does the extra volume come from if the system is sealed?
- November 1, 2023 at 1:04 am
  
  Erik Gerlings
  Subscriber
  
  Thank you for your fast response.
  It is an open system, the inflow is 3 kg/s (left) and the outlet is a pressure outlet (right).
- November 1, 2023 at 1:42 am
  
  Erik Gerlings
  Subscriber
  
  I found that the standard state enthalpy for heptane vapour is -1.878e+08 j/kmol which causes the temperature decrease. Thanks for you attention.