On engine turbocharger compressor surge Bertrand Kerres KTH Competence Center for Gas Exchange (CCGEx) Project duration: Jan 2013 β Dec 2017 (est) Motivation Engine at full load Design Line Surge ππ‘,πππ οΏ½ππ‘,ππ Const. Ξ· Const. n Choke πΜcorr β’ Downsizing to reduce friction losses β’ Surge limits the compressor operating range at low mass flows β’ Engine BMEP at low speeds can be limited by compressor surge 2014-10-09 KTH CCGEx 2 Motivation β’ Turbocharger installation differs between supplier and actual engine installation β’ This leads to different compressor characteristics Picture: Gas stand 2014-10-09 Picture: TC on engine KTH CCGEx 3 Questions β’ How do different intake geometries influence the surge margin? β’ Can we explain the differences? 2014-10-09 KTH CCGEx 4 Method β’ Cold gas stand β’ Different intake geometries: - Straight - 90 deg. bend β’ different distances bend - compressor β’ with sharp and mild curvature β’ relative angle to volute outlet β’ Glass pipe in order to visualize inlet flow field - Planned LDV - βSnuskβ 2014-10-09 KTH CCGEx 5 Preliminary results CoV = std(π2π β²)/(π1 π 2 ) β’ β’ 2014-10-09 Surge criterion: Relative pressure fluctuations at the outlet Map for sharp 90 deg. bend shows clearly different surge line than given by the supplier KTH CCGEx 6 LDV ? β’ Oil ring from compressor bearing shows swirling reverse flow during operation in or close to surge β’ Interaction with Dean vortices from the 90 deg. bend 2014-10-09 KTH CCGEx 7 Future plans β’ Switch to different compressor β’ Pressure transducers in compressor walls to detect rotating instabilities β’ On-engine validation 2014-10-09 KTH CCGEx 8
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