Influence Of The Splitter Blade On The Centrifugal Compressor

The splitter blade was widely used in the centrifugal compressor at home and abroad. But thedesign principle of splitter blade is not mature. This paper is based on the MTE-D engine prototype,studying the flow characteristics and design technologyof the micro centrifugal compressor. Andthe einfluence of the tip clearance and the splitter blade on the centrifugal compressor are alsostudied. The main work is as follows:1. An impeller is calculated by using S-A turbulence mode when the grid density is600000,860000,1.1million,1.15million.The grid density influence on the performance and the flow fieldof the impeller is studied. The grid density of860000is suitable for numerical calculation in thispaper according the results of the analysis.2. Analyzing the splitter blade circumferential position and the tip clearance affect on theperformance of impeller. The efficiency and pressure ratio of the impeller which tip clearance is0.3mm is significantly lower than the impeller without tip clearance. Tip clearance leakage flow hasimportant influence on the performance of impeller. The tip clearance affect the flow field of theroot of impeller is smaller than the flow field of the mid-span of impeller. And the tip clearanceaffect the flow field of the tip of impeller is largest.The flow field of the impeller with0.3mm tipclearance is not same as the flow field of the impeller without tip clearance. The big loss area of theimpeller with0.3mm tip clearance is impacted by the tip clearance, and the low energy fluid isoccupying1/3of the channel. The big loss area of the impeller without tip clearance is impacted bythe boundary layer separation in the corner of the suction of blade and shroud.The emerge place anddevelopment of separated vortex in the left channel is not the same as the separated vortex in theright channel.When the tip clearance changes, the splitter blade moving from near the main blade suctionsurface to near the main blade pressure surface, the performance of the impeller are rising first thenfalling. When the left and right impeller channels entropy nearly consistent; splitter blade is in thebest circumferential position.3. Studying the splitter blade length influenced on the impeller performance and the bladenumber. The length of splitter blade changes, the quality of flow field in the root and mid-blade ofimpeller blade changes are relatively small, the change of flow field in the tip of blade larger. As thelength of splitter blade changes, the influence of splitter blade on fluid boundary layer separation inside passage and ip leakage flow are change, the flow before splitter blade and in the channels isalso changes. As the length of splitter blade changes, the friction loss in impeller different. Theperformance of the impeller will decline when the splitter blade is too long or too short. Thenumber of the impeller blades is affected the best length of splitter blade. The blade number more,the best length of the splitter blade is longer.4. Improving the MTE-D impeller. The regularity of splitter blade length and circumferentialposition are used to improving the compressor. The impeller efficiency is increased1.3%and theimpeller ratio is increased0.07compared to the prototype impeller.