Analytical Design Of Turboprop S-Duct Intake

Since the 70's of last century, interest in aircraft turboprop propulsion concepts has increased because of high efficiency and pot entially large reductions in fuel usage. For tractor configurations, these inlets become complex three-dimensional geometries because of com patibility requirements. The particularity of the structure and the effect of propeller slipstream make duct flow field more complex, so the research of how to design turboprop inlet with good performance rapidly is important.The lip thickness is designed varying from crown to keel;the duct design is based on the method of circular cross section;the distribution of the geometry parameters along the duct was designed,a “S” curve distribution formula was improved for the central line,and the spread angle distribution was design as N urbs curve.According to the single-scoop inlet design algorithm, the visu al modeling software of Turbo-Prop-Inlet is developed by programming under the Nussyppag System.The single-scoop inlets with design Maher 0.5 were E stablished in order to simulate the influence of geometric parameters on the single inlet performance numerically, the main conclusions are as follows: the impact of the keel contraction ratio on the lip design performance is greater than the crown contraction ratio; the higher inlet offset or the larger throat spread angle will increase the total pressure distortion index of the AIP(aerodynamic interface plane); the main channel with expansion and contraction mode can largely reduce the total pressure distortion index of the AIP.The optimum model has a good design performance,the total pressure recovery coefficient of the AIP is 0.9865,and the total pressure distortion index is only 0.0912. The optimum model performs good in large flow range and fligh speed range;the inlet performance falls not too much under 15 deg angle of attack and side slip?The conclusion of the above research has some guidance for the analytic design of the turboprop intake.Finally, based on the sliding mesh technology, the article made a study of the influence of slipstream on turboprop inlet performance at take-off condition, the research of the slipstream on the inlet performance influence laid a certain foundation for later research.