车用小型涡轮增压器叶顶间隙可磨耗涂层控制技术研究

采用Numeca数值分析软件建立了车用小型涡轮增压器压气机端流场网格模型,并研究了不同叶顶间隙对压气机性能的影响,分析得出叶顶间隙对压气机性能影响较大,每增加0.1mm间隙后压比降低约3%,效率则降低约2%。研制了压气机叶轮叶顶间隙可磨耗涂层,减小了叶顶间隙,研究发现:压气机试验峰值效率提升了近1.5%,各转速下压比也得到了不同程度的提升,涂层在增压器高转速运转较长时间后磨耗均匀,叶轮与涂层刮擦后完好无损。研制了涡轮机叶顶间隙耐高温可磨耗涂层,经发动机匹配试验对比发现,中低速扭矩提升了2%左右,燃油消耗率在1883r/min下降低了3.5%。对蜗壳涂层开展了200h可靠性考核验证,发现涂层磨耗均匀无掉块,涡轮叶片与高温涂层刮擦后无损伤,验证了可磨耗涂层技术在车用小型涡轮增压器领域应用的可行性。

Control Technology of Abradable Coating for Blade Tip Clearance of Vehicle Small-Sized Turbocharger

The flow field grid model of compressor for a small-sized vehicle turbocharger was established by using Numeca numerical software,the effects of different blade tip clearances on the compressor performance were then studied and it was found that the blade tip clearance had great influence on compressor performance.An increase of 0.1 mm in the tip clearance led to the reduction of pressure ratio by about 3% and efficiency by about 2%.The abradable coating was developed for the blade tip clearance of compressor,which reduced the actual clearance between the blade and volute.After using the abradable coating,the test peak efficiency of compressor increased by nearly 1.5% and the pressure ratio of each speed also improved.The coating was worn evenly after a long period of operation at high speed and the compressor impeller still kept well enough after contacting with the coating.The high-temperature abradable coating was further developed for the turbine end.The comparison of engine matching test results showed that the low and middle speed torque increased by about 2% and the specific fuel consumption reduced by 3.5% at 1 883 r/min.The 200 h endurance test of turbine shell coating was carried out and it was found that the coating was worn evenly without spalling and the turbine blade is still intact after contacting with the coating,which verified that the abradable coating was feasible in the application of vehicle small-sized turbocharger.