Application of pipeline network algorithm in turbine inner cooling blade heat transfer calculation

Based on the concept of pipeline network algorithm, the calculation procedure applicable to inner cooling channel heat exchange has been developed. Coupled with external flow field solver HIT3D, the Mark II blades condition 5411 test results were used to verify the validity of pipeline network procedure, showing that heat transfer coefficient and temperature had good agreement with the test values. On this basis, for the complex inner cooling channel flow paths of a certain type of high-pressure turbine rotor blade, a fluid network computing model was established. An exhaust film hole was added to the suction side of blade tip, and the two groups of adjacent passages of the front and rear serpentine channels were connected with three through tubes separately to balance the pressure. Retrofit design and prototype employed pipeline network procedure to calculate flow and heat transfer parameters. Results show that, under the same inlet boundary conditions of cooling air, the maximum temperature and the average temperature have decreased more than 10K as compared with prototype, and adverse conditions such as concentration of local high temperature on suction side have been improved. The improvement effect has been confirmed through full three-dimensional CFX simulation.