STUDY ON SEGMENT FITTING METHOD OF NUSSELT NUMBER ON THE TURBINE VANE

This study analyzes the distribution characteristics of the Nusselt number (Nu_C) on the turbine vane. Subsequently, the study proposes an original Nu segment fitting method applicable to the whole surface on the turbine vane. The flow near the leading edge can be approximated as flow around a semi-cylinder. The Nu_d in this region can be fitted using a power function of Re_d (the characteristic length is the diameter of the inner tangent circle of the leading edge) with phase correction. Due to transition is completed faster on the suction surface, Nu in the transition region is linearly related to Re (characteristic length is the arc length). In contrast, the flow in the region after the transition on the suction surface and in the region of the pressure surface is similar to the flow along a flat plate. The study proposes this segment fitting method using the experimental results on Vane A. This study also verified the feasibility of the method on Vane B and C. The error analysis presents the following conclusions: the fitting error is less than 10% for the vast majority of the regions on Vane A, while Vane B and C have an error greater than 20% only at the junction of the segments. The error is less than 10% in most regions of the vane surface.