| Popis: |
Focused research and development of pin fin geometry in the trailing edge as turbulators in turbine blades has been a subject thoroughly researched for the past several decades. Highly efficient turbomachinery requires higher inlet temperatures, introducing the need for these internal cooling channel features to increase the heat removal of the blades and prevent material failure. Turbomachinery commonly uses air cycles to operate, but recently there has been a shift towards supercritical carbon dioxide (sCO2) power cycles. Promising higher cycle efficiency and smaller footprints, sCO2 has become an attractive alternative to the well-established turbomachinery cycles used presently. This alternative introduces the need to re-visit the local heat transfer of these internal cooling solutions with the incorporation of sCO2 as the cooling fluid. The first objective of this paper is to study the conjugate heat transfer characteristics of sCO2 as the secondary internal cooling fluid, operating at temperature and pressure conditions significantly above the critical point. A new heat transfer correlation is proposed for sCO2 in a staggered pin fin array. Secondly, the resulting sCO2 cases are compared to air cases in a matching staggered pin fin array to investigate the differences and similarities between both working fluids. The steady RANS conjugate heat transfer study was carried out with the commercial computational software STARCCM+ for the sCO2 and air cases. Finally, this study will validate a future experimental rig with matching geometry. |
