| With the development of modern science and technology and the continuous updating of air and sea technology and equipment,the power propulsion system based on gas turbine is also gradually improving.As the core component of gas turbine,the internal reverse pressure flow of compressor is more complex,and the multiple changes of vortex system make it more difficult to study.Moreover,the significant separation at low operating conditions and the occurrence of instability are the main problems to be solved by researchers.Under the background of the preliminary application of whale fin Bionics in the field of external flow and the gradual maturity of compressor flow control technology,it has certain research potential to explore the suppression mechanism of concave convex leading edge blades on the flow separation flow in the compressor and improve the aerodynamic performance.The purpose of this paper is to explore the modeling method of concave convex leading edge for compressor plane cascade and three-dimensional rotor blade,determine the definition of leading edge curve and 3D hybrid modeling method,and study the flow characteristics and stability expansion mechanism of concave convex leading edge blade based on wind tunnel test verification.In the compressor cascade,the local flow difference of leading edge is analyzed,and the layout scheme of concave convex leading edge is given.The results show that the angle of attack is increased,the consistency is reduced and the vortex structure is formed in the concave position of the concave and convex leading edge.The vortex structure develops downward along the radial direction and extrudes the local contraction of the flow tube at the convex position,and the separation flow is significantly inhibited due to the increase of the consistency,thus reducing the loss.The total pressure loss coefficient of wfb-3434-2-9cascade is reduced by 10.47% at 0 ° angle of attack and 12 ° angle of attack.The total pressure loss coefficient of wfb-1321-6-5 cascade is reduced by 16.13%.In addition,the vortex structure of concave convex leading edge cascade is analyzed.It is found that the special flow direction vortex and small concentrated shedding vortex structure are formed due to the difference of leading edge flow,and the channel vortex,horseshoe vortex,wall vortex,corner vortex,trailing edge shedding vortex and concentrated shedding vortex are also changed due to the reorganization of boundary layer structure.In the three-dimensional compressor rotor blade,the leading edge layout scheme is given,and the flow characteristics and low operating conditions performance of concave convex leading edge rotor blade are analyzed.The results show that the concave convex leading edge structure reduces the load on the blade tip and reduces the attack angle and strength of the leakage vortex.In addition,the concave convex structure at the tip of the blade draws the low-energy gas with radial motion at the leading edge into the downstream,and resists the low-energy gas mass moving toward the blade top under the centrifugal force at the trailing edge by contracting the high momentum flow,so as to prevent the accumulation of the two at the blade top,thus realizing the compressor stability expansion.At 80% speed,the stall boundary of BWS concave convex leading edge rotor blade moves to the left,the efficiency near the instability point is increased from 90.25% to 91.02%,and the pressure ratio is increased from 1.2595 to 1.2635.In addition,the vortex structure of concave convex leading edge rotor blade is analyzed,and the flow direction vortex structure is different from that of plane cascade structure,while horseshoe vortex,hub wall vortex,leading edge wall vortex and corner vortex in blade root part have no obvious change.Due to the optimization of flow field in blade tip region,the leading edge radial vortex,trailing edge radial shedding vortex,leakage vortex,induced vortex,tip separation vortex and pressure surface scraping are changed Cutting vortex structure. |
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