Heat transfer characteristics in a rotating trailing edge internal cooling channel with two coolant inlets

摘要

Heat transfer performances in two-inlet wedge-shaped channel with side-wall coolant ejection are experimentally studied at both rotating and stationary conditions. The test section is used to model a novel turbine blade trailing edge internal cooling structure. The coolant mass flow rate ratio (MR, top-to-total coolant mass flow rate) ranges from 0 to 1.0. The major Reynolds number and rotation number are varied from 10,000 to 25,000 and 0 to 1.06, respectively. At non-rotating condition, two-inlet inflow promotes heat transfer of top-half outer region but reduces that of bottom-half channel. The MR and overall averaged Nu ratios (based on effective Reynolds number) are approximate parabolic relation, and the lowest heat transfer case is corresponding for the evenest channel heat transfer distribution. In rotating cases, the increasing MR decreases the span-wise heat transfer differences for both trailing and leading walls, and so does the trailing wall heat transfer enhancement. Also, the effect of rotation reduces and trailing-to-leading surface heat transfer difference is relatively small due to two-inlet inflow. The rotational heat transfer at low-radius half channel is dominated by bottom coolant generated radially outward flow, but high-radius half is dominated by two-inlet inflow mixing.