|Based on experimental results on a liner of a modern direct lean injection combustion chamber using coolant ejection from both effusion cooling holes and a starter ﬁlm, a method is presented that allows the assessment of the cooling performance of the liner.|
As the main focus of the present study is a deeper understanding of the interaction of swirl ﬂow and near wall cooling ﬂow, wall pressure measurements are performed for the calculation of local blowing ratios and local coolant mass ﬂuxes. Thermal investigations allow the calculation of adiabatic ﬁlm cooling effectiveness and heat transfer coefﬁcients. The pressure drop across the effusion cooled liner is varied between 1% and 3% of the total pressure of the main ﬂow. As experiments are performed without combustion and at low temperature, the inﬂuence of radiation is neglected. Results show the impact of the swirled main ﬂow on the stability of the starter ﬁlm and on the effusion cooling performance. Stagnation areas which could be identiﬁed by wall pressure measurements are conﬁrmed by detailed PIV measurements. Thermal investigations reveal reduced cooling performance in the respective stagnation areas.
For the deﬁnition of the non dimensional cooling efﬁciency the measurement area is sub divided into rhombic sections, which are located around each effusion cooling hole. Based on the measurement results presented, heat ﬂuxes per unit area can then be calculated and put together to the cooling efﬁciency.