Can anyone recommend measured performance data from the Trilateral Flash Cycle ?
- The use of Screw Expanders is interesting ,but also measured performance data from other types of expanders are interesting.
Kind regards,
Bo
www.bosangfors.se
According to my calculations the Trilateral Flash method not work at all.
Now, I expect to see practical measurements that show that I am completely wrong. I will not change my opinion until I have seen convincing practical measurements.
See attached figure.
This might be something also. In this data set the steam mass flow is constant. As you can see the Power decreases when the x-value decreases. These calculations are made with built-in volume ratio =1, which means that flashing/condensation takes place after the opening of the control volume.
I think the paper "Experimental and modeling study on adiabatic two-phase expansion in a Cylinder" by Hiroshi Kanno and Naoki Shikazono" also is worth to study when we talk about two-phase expansion. The time factor is interesting.
Comments?
Kind regards,
Bo
Of course you get a torque because of the pressure difference over the expander.
What I mean with "does not work at all" is that the control of the operation is very difficult. Hitherto what I have seen there is a spread of measuring point when the media quality is close to zero.
May I also say that what I have understand as "Trilateral Flash Circle" is expansion from quality x=0. I have seen calculations with x=1 and they have also been called "Trilateral Flash Cycle"!!??
I think the paper "Experimental and modeling study on adiabatic two-phase expansion in a Cylinder" by Hiroshi Kanno and Naoki Shikazono" also is worth to study when we talk about two-phase expansion.
The time factor is interesting.
Comments?
Kind regards,
Bo
Another way to investigate the influence of the R245fa quality is to look at the case when the adiabatic efficiency is 100 %.
I.e. we have no leakage, mechanical losses, flow losses, perfect build-in volume ratio…..
As can be seen from the graph shaft power per kg/s R245fa flow rate decreases when the R245fa quality decreases.
All data in the graph are calculated with REFPROP.
May I also point out that the inlet mass flow can be constant by changing the rotor tip speed or change of built-in volume ratio.
I think the following approx. calculations can wake up some thoughts about trilateral flasing.
Kind regards
Bo Sångfors
May I also point out the data sheet "Easy method to predict effect of R245fa inlet quality. on th..." is when flashing is 100 %. I.e. immediate. In practice the flashing is not so immediate. It is time dependent, which will reduce the efficiency.
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