Pipe Unique

Posted in cigar & cigarette stuff by admin @ Sep 16, 2009

How do you determine length at which flow choking takes place?

When using the Isothermal model for compressible flow in a straight pipeline, how do you determine the length where flow choking takes place (fluid is steam entering pipe at 573K and 12bar)? All properties and variables are known at the entrance. The density, pressure, sonic velocity and linear velocity is unknown at the point of flow choking, but the Mach number is known {Ma=1/sqrt(k)}. Using substitution, the only variables needed to determine the length is pressure and length at the point of flow choking. When using Matlab and Excel, I find the values to vary - I cant find a unique solution when using solver or another iterative process for length and pressure at that point.

Try using a non dimensional correlation for the Bio number or possible Prandtl number. I can't remember off the top of my head, but one of them should relate your Mach number to pressure or viscosity allowing you to have only one unknown. Another idea would be to model the situation with a known boundary layer pattern and find where the boundary layers meet. Check the solution and see if it is reasonable.

Random pipe experiment that shows how unique pipes really are