Ejector Dry Air Equivalent (Dae) Calculations

Ejectors have been discussed a lot on "Cheresources". In fact one of the most read posts on Cheresources relates to ejectors which also provides a workbook for ejectors by Art Montemayor the administrator of "Chereources" and a mentor to many of the younger generartion of chemical engineers. The link of that post is provided below:

http://www.cheresour...ector#entry3822

Another post related to ejectors and also widely read is provided by the link below:

http://www.cheresour...jector#entry447


Today's blog entry discusses what "Dry Air Equivalent" (DAE) is all about in ejector terminology. DAE can be defined as:

The DAE is an absolute unit that defines the performance capacity of any ejector stage. The DAE is the equivalent mass flow of 70°F dry air & is the industry standard for ejector capacity rating. The DAE is typically represented in terms of the flow capacity on the performance curve for an ejector showing suction pressure versus flow capacity.

Some further references explaining the concept of DAE for ejectors can be found at the links below:

http://www.nciweb.ne..._correction.htm

http://www.vacuum-gu...val-systems.pdf

A long time back I had prepared an excel workbook related to DAE calculations. The main feature of this workbook were the charts related to "Molecular Weight Entrainment Ratio Curve" and the "Temperature Entrainment Ratio Curve" which helps to convert the gas mixture (air + other gases) at any temperature to the DAE which is referenced at 70°F. This blog entry provides the excel workbook as an attachment for the young process engineers to determine the DAE for any gas mixture. Please note that the entire work book uses Imperial units since the curves are in Imperial Units.

The excel workbook has been converted to the Excel 2010 format since the older version had some compatibility issues. Let me know if there are any issues with the converted version.

Hoping to hear from the readers of my blog about this entry and the attached workbook. Enjoy downloading and using.

Download the MS Excel spreadsheet in the File Library

Regards,
Ankur.