Hello,I am looking into improving heat transfer in a vertical pipe, where hot product is being cooled by a cryogenic liquid injected(liquid-liquid contact). The cryogen boils and bubble flow is obtained but not long enough to allow appropriate temperature drop.Measuring temperature in two phase flow can be quite tricky in a vertical pipe and was looking for suggestions on best way to see an improvement(pressure drop measurement vs. temperature measurement).The purpose is to reduce the hot media in the pipe roughly 130 degrees F delta. Thus far, we have looked at pipe diameter change(currently 4") versus increase pipe length to improve residence time of the bubbles(nucleation boiling). I do not wish to decrease the flow rate of the hot product as this would impact throughput in the plant.If anyone has any history or good references to look at it would be much appreciated.
How is the cryogen being injected? Smaller bubbles would take longer to rise and provide more heat transfer area. If you used a spray nozzle to inject the cold liquid you should get smaller bubbles and better cooling.
Harold Reed, M.S.
Sirius Technical Services Contract Engineer
For Evonik Corporation
Process Technology and Engineering, Americas
Phone +1 251 443 2428
Mobile +1 251 802 7518
Fax +1 251 443 4078
Here are a couple of very good reference books, old, but theory has not changed:
Jimmy D Kumana
Kumana & Associates
Houston, Texas, USA
Tel. +1 (281) 437-5906, Cel. +1 (646) 546-2484
If you think that it is expensive to hire an expert to do the job, wait until you find out how much more it will cost you to hire an amateur. ― Paul N. "Red" Adair, 1915-2004