SpinOffs

Most turbomachines need to operate across a range of fluid flow rates and speeds. This is obvious in transportation applications where gas turbine engines and turbochargers need to operate at all of the speeds, altitudes and temperatures that the vehicles they power will encounter. In industrial and refrigeration applications, turbomachines need to have a wide operating range to make them appealing to end users who want efficiency under many operating conditions.

The 2018 ASME Turbo Expo in Lillestrøm, Norway was, as always,  a smorgasbord of papers and presentations on the latest and greatest ideas in turbomachinery and gas turbines. Two of our favorites were from Mark R. Anderson and Felipe F. Favaretto, Concepts NREC employees. Coincidence? I think not. Felipe presented, “Development of a Meanline Model for Preliminary Design of Recirculating Casing Treatment In Turbocharger Compressors”:

Can you really get something for nearly nothing? In many cases, a properly-designed compressor casing treatment can extend compressor operating range without having to pay an appreciable efficiency penalty. Major automotive turbocharger OEMs have been leading this design effort for years and have successfully gained compressor operating range increase on both sides of the compressor (pressure versus flow) map. In most cases, the range increase has outweighed any efficiency penalty and best of all, these so-called “ported shroud” designs are naturally uncomplicated to implement, meaning that incremental cost is low.