AFT Arrow can be used to model various types of choking such as restriction choking, endpoint choking, and expansion choking. A useful parameter in AFT Arrow’s output is the “Sonic Flow Area” and this is the flow area in which sonic choking will occur. Comparing the sonic flow area to the actual flow area can help determine the margin between not choking and choking.
The figure below provides a conceptual understanding of comparing various sonic areas to the actual flow area of a compressible system. If one defines their system such that the sonic area (ASonic,1) is less than the flow area, the portion of the system will not choke. If the sonic area (ASonic,2) is greater than the flow area, then there will be choking.
In summary, to avoid choking, adjust the flow area such that it is greater than the sonic area.
Ben is AFT's Technical Sales Manager. He can be found teaching many of AFT's technical seminars, stopping over for lunch and learns with our customers and managing the AFT booth at trade shows. Prior to joining AFT, Ben worked as a contract engineer for Eaton Corporation and WellbornYX Corporation. He holds a Bachelor's of Science in Chemical Engineering (2009) from Colorado School of Mines.