Evaluation of mass injection cooling on flow and heat transfer characteristics for high-temperature inlet air in a MIPCC engine

Abstract

Thermal management on high-temperature inlet air cooling is one crucial factor to improve the aero-engine performance. In this study, Mass Injection and Pre-compressor Cooling (MIPCC) technology is applied to a problem-solving way to reduce inlet air temperature. Numerical simulations are employed to investigate and predict the relationship between flow field characteristics and mass injection cooling at high altitude simulated pre-compressor section of MIPCC engine, which is based on the regression orthogonal analysis. The solution accuracy of numerical procedure is qualified with the experimental data. Results show that the flow loss and temperature reduction in the pre-compressor section are of non-linear and linear relationships with spray cooling conditions, respectively. Then, the dominant factors of influencing on the temperature reduction are droplet size and spray flow rate, and that of influencing on total-pressure reduction is droplet size. Especially, the effect of each spray factor on the flow field characteristics is of independence. According to the characteristic prediction in given spray conditions, the total-temperature drop and total-pressure drop coefficients after mist injection cooling are 1.57–29.13% and 0.461–1.683%, respectively. These observations signify that, by comparison with the dry air condition, a reduction of the temperature and flow loss in the pre-compressor section are correspondingly in the range of 7.3–135.5 K and 33.3–81.73% after mist injection. Thus, an appropriate mist injection condition can improve flow field characteristics at the most extent, and then heat management of inlet air can be controlled within a certain range.