TY - JOUR
T1 - Numerical study of phantom cooling on rotor blade and endwalls from nozzle trailing edge discharge
AU - Zhang, Shenghui
AU - Ding, Shuiting
AU - Qiu, Tian
AU - Liu, Chuangkai
AU - Yang, Xiaojun
AU - Yang, Guan
N1 - Publisher Copyright:
© 2026 Elsevier Masson SAS.
PY - 2026/11
Y1 - 2026/11
N2 - Phantom cooling refers to the cooling effect on unintended region resulting from turbine airfoil coolant discharge and leakage. In this study, the phantom cooling effect on high pressure turbine rotor blade and endwalls, induced by nozzle guide vane (NGV) trailing edge discharge, was numerically investigated. Simulations were conducted for three mass flow ratios (MFR) including 1.41%, 2.82% (design condition) and 4.23% with the identical NGV trailing edge slot geometry. The migration of NGV coolant within rotor passage and its effect on the phantom cooling over rotor walls were examined. Results indicate that at midspan, NGV coolant exhibits a preferential migration toward suction side (SS). Whereas within endwall, except for the preferential migration effect, the interaction between incoming NGV vortex and the pressure side leg of rotor horseshoe vortex (PS_HV) causes coolant to feed into PS_HV, deflects towards SS and subsequently migrates with rotor passage vortex (PV) toward midspan. The preferential migration effect, combined with unsteady vortex-induced transport effect, leads to more pronounced phantom cooling effect on SS compared with PS and generates a triangular region of high phantom cooling effectiveness on hub. Resulting from the comparable transport mechanisms, a similar distribution of phantom cooling effectiveness is observed on shroud. However, unlike hub, this region is additionally affected by rotor tip leakage flow. With respect to the effect of MFR, phantom cooling increases nearly linearly with MFR across the 20%-80% span regions where preferential migration effect predominates. On SS endwall, however, this trend is suppressed by the vortex-driven coolant migration, where a 50% increase in MFR yields only a 36.8% improvement. The phantom cooling effectiveness exhibits notable fluctuation. At mid-to-high span, the intermittent sweep of coolant on leading edge causes the peak fluctuation amplitude to exceed 280% of mean value, while at low span, unsteady vortex transport effect shifts the maximum variation to SS mid-chord, where the amplitude surpasses 230%.
AB - Phantom cooling refers to the cooling effect on unintended region resulting from turbine airfoil coolant discharge and leakage. In this study, the phantom cooling effect on high pressure turbine rotor blade and endwalls, induced by nozzle guide vane (NGV) trailing edge discharge, was numerically investigated. Simulations were conducted for three mass flow ratios (MFR) including 1.41%, 2.82% (design condition) and 4.23% with the identical NGV trailing edge slot geometry. The migration of NGV coolant within rotor passage and its effect on the phantom cooling over rotor walls were examined. Results indicate that at midspan, NGV coolant exhibits a preferential migration toward suction side (SS). Whereas within endwall, except for the preferential migration effect, the interaction between incoming NGV vortex and the pressure side leg of rotor horseshoe vortex (PS_HV) causes coolant to feed into PS_HV, deflects towards SS and subsequently migrates with rotor passage vortex (PV) toward midspan. The preferential migration effect, combined with unsteady vortex-induced transport effect, leads to more pronounced phantom cooling effect on SS compared with PS and generates a triangular region of high phantom cooling effectiveness on hub. Resulting from the comparable transport mechanisms, a similar distribution of phantom cooling effectiveness is observed on shroud. However, unlike hub, this region is additionally affected by rotor tip leakage flow. With respect to the effect of MFR, phantom cooling increases nearly linearly with MFR across the 20%-80% span regions where preferential migration effect predominates. On SS endwall, however, this trend is suppressed by the vortex-driven coolant migration, where a 50% increase in MFR yields only a 36.8% improvement. The phantom cooling effectiveness exhibits notable fluctuation. At mid-to-high span, the intermittent sweep of coolant on leading edge causes the peak fluctuation amplitude to exceed 280% of mean value, while at low span, unsteady vortex transport effect shifts the maximum variation to SS mid-chord, where the amplitude surpasses 230%.
KW - Endwall
KW - High pressure turbine
KW - Mass flow ratio
KW - Phantom cooling
KW - Rotor blade
UR - https://www.scopus.com/pages/publications/105044145030
U2 - 10.1016/j.ast.2026.113157
DO - 10.1016/j.ast.2026.113157
M3 - 文章
AN - SCOPUS:105044145030
SN - 1270-9638
VL - 178
JO - Aerospace Science and Technology
JF - Aerospace Science and Technology
M1 - 113157
ER -