An experimental study of flow and heat transfer performance of a longitudinal corrugated liner for a combustion chamber

Abstract

Experiments are conducted to investigate the flow and heat transfer performance of a longitudinal corrugated liner for a combustion chamber. The effect of cooling air passage height and blockage ratio on the heat transfer performance of the liner has been studied. In addition, the friction factors in cooling air passages are also presented and the test results are compared with previously reported studies. In the experiments, the pressure fields having the same conditions as that present in the real engine are established. The detailed temperature distributions on the hot side of the liner are measured by using the infrared imaging technique. Local film cooling effects are calculated from these temperature distributions. A range of parameter combinations of interest in cooled liner practice is covered, including combinations of variations in Reynolds number of cooling air passage, passage height and blockage ratio. The results indicate that the blockages in the cooling air passage are not beneficial for obtaining a high film cooling effect and for the uniform distribution of film cooling effect in the streamwise direction. The cooling air flow will be disturbed by the blockages located in the cooling air passage which weakens the effect of dynamic pressure on cooling air injection. The local and downstream film cooling effect will be significantly influenced. The friction factor increases with the increase of bolckage ratio. Compared with previous works, the friction factors in the present conditions are much higher (at least by 133%) than that for parallel plat passage and pipes with rough walls. As the passage height increases, the film cooling effect increases first and then decreases. However, the relative deviation decreases first and then increases. That means there is an optimum passage height for a higher film cooling effect and a uniform distribution. The passage height has an significant effect on the momentum of cooling air injection and the distribution of cooling air flow rate through the windward side of the crest and the leeward side of the crest. The effect of passage height on the friction factor is slight. The f-Re correlations are proposed based on the present experimental data.