Heat transfer characteristic and optimization design of alter diameter array impingement cooling structure

Abstract

The fine design of blade cooling is one of the leading directions in the development for blade manufacturing technology, attaining optimal and consistent cooling efficiency is the common research concern in the field of fine design. In the current work, the alter diameter hole arrays are applied to reasonably regulate the distribution of cold air flow, which aims to achieve uniform cooling performance of impinging cooling technology. Experiment involving temperature sensitive paint technology and simulation based on SST k-w turbulence model are conducted. Subsequently, the mechanism of cooling performance increasement is investigated; the impact of structural elements on the heat transfer properties is discussed. Moreover, the correlation between the Nu number of the target surface and the comprehensive influence factors was fitted based on response surface method; the optimal structure in the range of the structural parameters is calculated based on NSGA-II and TOPSIS method. The results reveal that the influence of d and x on average surface Nusselt number is remarkable. In addition, the response surface model fitting model is accurate to predict the structure parameter effect on cooling performance of alter impingement cooling, with the prediction error less than 2.67 %. Compared with the basic EDI, the Nu of the ADI structure with ∇T constraint is increased by 5.2 %, the temperature inhomogeneity is reduced by 53.4 %. The significant improvement of temperature inhomogeneity indicates the practicality of ADI structure and optimized procedure used in improving impingement cooling efficiency which shows promising performance increasement.