Investigation And Application Of Endwall-modified Technique On Compressor

Compressor is the main part of the aero/ground/marine gas turbine andvehicle/marine turbocharger, which performance directly determines the level of theefficiency of national economy and the advance of the defense equipment and which is onesymbol of the strength of science and technology on the world. To improve the efficiency,develop the load capacity and widen the operating margin is the consistent trend of thecompressor development. The strong three-dimensional and unstready complex turbulentflow occupying about30%of the flow loss on compressor endwall is the key factor ofdeteriorating the performance and inhibiting the load ability promotion. One of themaximizing the compressor load capacity researchs is to suppress, weaken or eveneliminate the corner separation through controlling and organizing the endwall flow.Aiming at the situation of the limited measures of controlling the flow oncompressor endwall, the two types causes of inducing the separation on turbomachineryendwall area are obtained，one is the intersection flow with the second-flow in boundarylayer between the blade side and endwall, especially on the condition of inverse pressure incompressor; The other is the second-flow on endwall upstream, the tangential velocitydifference in the relative coordinate by the relative motion of the solid wall and the endwallflow distortion (at large incidence angle) caused by the leakage flow between rotor andstator. The main researchs are as following:Firstly, the paper described the new methods of solving the endwall twisted flow incompressor, which are Leading Edge Stake Blade and Blended Blade and End Wall, andthen developed the programs aiming for axial compressor and centrifugal tcompressor soon with the Fortran language program.Secondly, on the foundation of the confirmation of the test data of cascade to thesimulation precision of CFD and the master of using experience, CFX was used for thenumerical simulation of the LESB design schemes and the NACA65protype on thecondition of-5degree,0degree and5degree incidence angle with the endwall boundarylayer twisted flow. It has found that LESB could efficiently organize the endwall fieldstructure and improve the performance of compressor, while there aslo exist the twoappropriate values of the height and length of LESB design and the value of height shouldbe more than the thickness of the stream twisted boundary layer. Thirdly, aiming at the BBEW design schemles, Numeca software is used for thenumerical simulation of the LESB design schemle and the NACA65protype at thecondition of-10degree,0degree and5degree incidence angle without the endwallboundary layer twisted flow. It has found that BBEW could reduce the corner separation onthe suction side and improve the aerodynamic performance of the compressor cascade withthe good adaptability to the variable conditions.Then, aiming at the numerical simulation of the centrifugal impeller in basis ofcarrying out different BBEW design on the leading edge structure of the impeller blade, thesuction/pressure side of the main blade and the suction/pressure side of the splitter blade, Ithas found that BBEW applied on the leading edge structure of the impeller blade couldimprove the adiabatic efficiency nearly0.4%in the base of the exist of the conventionalengineering fillet while the influence of the spanwise amplitude could reach20%, andBBEW applied on the reasonable area side of the main/splitter blades could improve theadiabatic efficiency nearly0.4%while the total pressure ratio increases by0.06.Finally, the paper presented the numerical simulation of a high pressure ratiocentrifugal compressor on turbocharger in basis of applying different end-modified methodson the vane diffuser. The BBEW method applied on the suction blade of the vane diffuserindicated that the corner separation was delayed and weakened in one certain extent withthe peak efficiency improving about0.4%, the choke stall point increasing nearly0.7%andthe pressure ratio rising slightly without effect on the surge margin. Then the BBEWmethod applied on the shroud of leading edge structure revealed to further enhance theaerodynamic performance of the blade near stall side. At last, the reasons of improving theperformance were presented in the basis of the comparison and analysis of the BBEWmethod impact on the field structure.