Abstract:
Transcritical methane film cooling steady flow field was calculated by numerical transfer study in the rocket engine chamber by FLUENT. Through the orthogonal methodology, cooling performance under the combined action of different diameters, axial angle, radial angle and shape of hole was simulated to choose the optimal geometric parameters. Based on the optimal geometric parameters, the optimal latin hypercube design was adopted to get sample points that can be used to establish Kriging model. Then the optimal transcritical liquid film mass flow, the partition ratio and location of cooling ring under multi-objective conditions can be calculated through genetic algorithm. The results showed that orthogonal methodology and Kriging model could resolve problems of high design cost and numerical noise in liquid rocket engine design. In the considered geometrical factors above, the significance order from big to small effects on cooling efficiency and non-uniformity degree was: shape, diameter, radial angle, axial angle; the optimal geometric parameter combination was 0.003mm diameter, 45° axial angle, 15° radial angle, and diffused shape. The Kriging model established precisely reflected the relation between objective function and the liquid film mass flow, partition ratio and location of cooling ring. The average cooling efficiency and specific impulse loss increased by 4.9% and 0.37%, respectively, and non-uniformity degree was reduced by 0.025, while the total objective function was increased by 184%. After the optimization, asymmetry of vortex pair made coolant spanwise well-distributed, while reversed vortex pair attenuated faster, and the property of liquid film attaching to the wall increased, thus improving the cooling efficiency.
