Endwall Heat Transfer in a Vane Cascade Passage and in a Curved Duct
Measurements of endwall heat transfer coefficient have been made for flow through a vane cascade passage and a similarly shaped duct. The purpose of this work is to evaluate the usefulness of the duct shape for modelling cascade endwall heat transfer. The Reynolds number for the cascade experiment is 5.4 × 105 based on chord. For the duct geometry the inlet velocity is adjusted in order to match the Reynolds number based on the pitch dimension. Thin stainless steel strips mounted on the endwall make up a large flat resistance heater. The temperature distribution over the heater surface is measured with 156 resistance temperature sensors. Surface heat transfer coefficient is obtained in the vicinity of each sensor by a local energy balance. The results are presented so as to show clearly the effect of secondary flow on endwall heat transfer. Except in the entrance plane region, the qualities of the cascade endwall Stanton number distribution compare well with the duct endwall measurements. The duct endwall heat transfer coefficients are everywhere greater than for the cascade passage endwall. The effect of a counter-clockwise rotating vortex in the suction side corner is shown clearly for both geometries.