A strange and very simple calculation problem
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This post was last edited by grechenjie on 2010-1-21 at 13:08. I used Fsplit to divide a water stream into two parts, and one of those parts was compressed using a compressor. The property method used is STEAM-TA. The conditions at the inlet are: T=105K, P=1atm, with only water vapor present. But something strange happened. After passing through this separator, the outlet temperature increased. Moreover, the degree of temperature increase after passing through the compressor is different from that obtained when simulating a single compressor alone. I don’t know what the reason is. This is part of my simulation. When I changed the property method for the separator to RKS-BM, the temperature remained unchanged, but I think the STEAM-TA property method should be used. Also, for some reason, under the same inlet conditions, the temperature at the compressor outlet is different. Is there any expert who can give some advice? Thank you.
I’ll take care of it myself. 1# grechenjie
This post was last edited by newlgt on 2010-1-10 at 14:03. I did some calculations on my own below, and the situation you described did not occur; water was separated using Fsplit, and the thermodynamic methods employed were STEAM-TA and RKS-BM. The inlet temperature was 105 K and the pressure was 1 atm. The calculation results showed that the temperature of the water was the same both at the inlet and at the outlet. Let me share my opinion: Do you understand what the conditions are like at 105K and 1 atm? ? ? 0 degrees Celsius is 275.15 K; obviously it’s in a solid state! But the software calculates the water at this point as being in a liquid state (it’s the software that decides whether it’s liquid; it cannot determine if it’s in a solid state. Is this also considered a bug in the current simulation software?) ). In other words, do the thermodynamic properties of water under these conditions still meet the application requirements of STEAM-TA and RKS-BM? It is best to check the scope of application and situations where thermodynamic equations are used; one should not make a choice based solely on intuition. I also thought you said it would be 105 degrees Celsius, so I calculated the situation at 105 degrees Celsius as well, and there was no such situation as you mentioned. If you insist on your opinion, provide an example; pictures speak louder than words. (Remove anything that is confidential). For reference only.
Thank you so much; I made a mistake – it should be 105C. I finally figured out what the reason is; it seems that the physical properties of a device located upstream of this separator have had some impact on the results produced by this separator. The problem disappeared when I interrupted the logistics in the middle. Thank you 3# newlgt