The effects of root fillet on the flow behavior of high loading compressor rotor tends to be much more crucial in practice,and it’s necessary to explore the internal relations between the geometric effects of root fi...The effects of root fillet on the flow behavior of high loading compressor rotor tends to be much more crucial in practice,and it’s necessary to explore the internal relations between the geometric effects of root fillet and the flow behaviors of rotor blade.Therefore,eight types of root fillet with different radius were designed and installed around the blade root of NASA Rotor67.With the aids of fillet,the corner separation near suction side of blade root has been suppressed significantly in that the root fillet reconstructs the circumferential bending distributon of the suction-side curve from leading edge to trailing edge,and reduces the genmetric turning angle in the latter part of root section near trailing edge.However,apart from the improvement of corner flow characteristic caused by root fillet,both the tip flow deterioration and the decrease of stall margin occur in the new rotors,which indicates an indirect correlation between tip flow characteristic and root fillet exists indeed in the three-dimensional flowfields of transonic rotor.Actually,by means of the new radial pressure equilibrium affected by root fillet,a larger radius of root fillet contributes to much larger blade loading and stronger leakage flow in tip region of compressor rotor.As a result,a monotonic decrease of stall margin was present in the transonic rotor with increase of the root fillet radius.Subsequently,the positive bending of blade tip was introduced to deal with the negative effect caused by the root fillet indirectly.Combined with the effects of root fillet and positive tip-bending on the radial pressure equilibrium existing in channels,both the radial and streamwise loading distributions tend to be much more reasonable in new rotors,and the static pressure difference in former 1/3 chord of blade tip has decreased clearly which benefits to reduce the strength of leakage flow in tip region.Therefore,the flow deterioration in tip region of transonic rotor induced by root fillet has been well suppressed,with an obvious improvement of overall performance occurring in new rotors.展开更多
Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was propos...Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was proposed.The software ANSYS Maxwell was used to simulate the effect of different pole orientation arrangements on the magnetic field distribution.A comparison of polishing effect was made between elastic and inelastic magnetic pole carriers.The processing parameters of the elastic magnetic tool polishing for the blade root were optimized by orthogonal experiment(Taguchi)method.Results show that compared with the inelastic magnetic polishing tool,the elastic magnetic polishing tool with polyurethane as the pole carrier can effectively improve the surface quality of the polished workpiece.Under the optimal processing parameters(rotational speed=900 r/min,feeding rate=6 mm/min,machining gap=1.5 mm and abrasive size=10‒14μm),the original milling marks at the blade root are effectively removed and the average surface roughness Ra is dropped from 0.95μm to 0.12μm,which verifies the feasibility of the elastic magnetic polishing tool in the surface finishing of the titanium alloy blade root.展开更多
基金This research work was sponsored by the Youth Fund of National Natural Science Foundation of China(Grant No.51906243)the General Program of National Natural Science Foundation of China(Grant No.52076124)the General Program of Natural Science Foundation of Shandong Province(Grant No.ZR2020ME173).
文摘The effects of root fillet on the flow behavior of high loading compressor rotor tends to be much more crucial in practice,and it’s necessary to explore the internal relations between the geometric effects of root fillet and the flow behaviors of rotor blade.Therefore,eight types of root fillet with different radius were designed and installed around the blade root of NASA Rotor67.With the aids of fillet,the corner separation near suction side of blade root has been suppressed significantly in that the root fillet reconstructs the circumferential bending distributon of the suction-side curve from leading edge to trailing edge,and reduces the genmetric turning angle in the latter part of root section near trailing edge.However,apart from the improvement of corner flow characteristic caused by root fillet,both the tip flow deterioration and the decrease of stall margin occur in the new rotors,which indicates an indirect correlation between tip flow characteristic and root fillet exists indeed in the three-dimensional flowfields of transonic rotor.Actually,by means of the new radial pressure equilibrium affected by root fillet,a larger radius of root fillet contributes to much larger blade loading and stronger leakage flow in tip region of compressor rotor.As a result,a monotonic decrease of stall margin was present in the transonic rotor with increase of the root fillet radius.Subsequently,the positive bending of blade tip was introduced to deal with the negative effect caused by the root fillet indirectly.Combined with the effects of root fillet and positive tip-bending on the radial pressure equilibrium existing in channels,both the radial and streamwise loading distributions tend to be much more reasonable in new rotors,and the static pressure difference in former 1/3 chord of blade tip has decreased clearly which benefits to reduce the strength of leakage flow in tip region.Therefore,the flow deterioration in tip region of transonic rotor induced by root fillet has been well suppressed,with an obvious improvement of overall performance occurring in new rotors.
基金Joint Funds of the National Natural Science Foundation of China(U20A20293)。
文摘Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was proposed.The software ANSYS Maxwell was used to simulate the effect of different pole orientation arrangements on the magnetic field distribution.A comparison of polishing effect was made between elastic and inelastic magnetic pole carriers.The processing parameters of the elastic magnetic tool polishing for the blade root were optimized by orthogonal experiment(Taguchi)method.Results show that compared with the inelastic magnetic polishing tool,the elastic magnetic polishing tool with polyurethane as the pole carrier can effectively improve the surface quality of the polished workpiece.Under the optimal processing parameters(rotational speed=900 r/min,feeding rate=6 mm/min,machining gap=1.5 mm and abrasive size=10‒14μm),the original milling marks at the blade root are effectively removed and the average surface roughness Ra is dropped from 0.95μm to 0.12μm,which verifies the feasibility of the elastic magnetic polishing tool in the surface finishing of the titanium alloy blade root.
