New engine trends of higher exhaust temperature driven by retarded fuel timing to reduce NOX emissions, will likely cause turbine housings to see heavier thermal transient loads and as a result, greater likelihood of cracks. Thermal cycling qualification test should be based on customers duty cycle requirements. Turbine inlet flow characteristics at both the ramp-up and cool down portions of the cycle should be accounted in the test procedure. A testing methodology that simulates the critical factors of an operating environment responsible for the rootcause of a potential failure necessary. Validation through endurance testing to replicate the future field failures with aggressive duty cycles and through a split test approach to test enhancements vs. baseline design, is an imperative process for successfully resolving problems and developing superior elegant solutions. The X-flange design reduces thermal stresses by about 46 % compared to the traditional flange designs. The articulated asymmetrical volute design reduces thermal stresses by about 43 % compared to the traditional volute design. No performance changes on the gas stand are attributed to the changes in the inlet flange X-design or the articulated volute design. The articulated asymmetrical volute design and the X-flange design for turbine housings have proved to be superior design compared to the traditional turbine housing design. The enhancement is at least 2.5 times in housing life at these locations. It is recommended that new housing design should be implemented on new future applications when thermal transient cracking is of concern and that new developed gas stand endurance test should be utilized for future turbine housing qualification. Coordination with engine manufacture at the initial stage for the design of the exhaust manifold flange and gesket is clearly called for. It should be noted that the recommended new designs could proof to be significantly beneficial to exhauts manifold life as well when implemented in future engine trends of higher exhaust temperatures.
Turbine housing design optimization and qualification rig for high temperatures
Entwurfsoptimierung von Turbinengehäusen und Testeinrichtung für hohe Temperaturen
2002
15 Seiten, 29 Bilder, 17 Quellen
Conference paper
English
Turbine Housing Design Optimization and Qualification Rig for High Temperatures
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