Two methods for vibration characteristic investigation of the counter-rotating dual-rotors in an aero-en- gine are put forward. The two methods use DAMP tool on the MSC. NASTRAN platform and develope the re- solving s...Two methods for vibration characteristic investigation of the counter-rotating dual-rotors in an aero-en- gine are put forward. The two methods use DAMP tool on the MSC. NASTRAN platform and develope the re- solving sequence. Vibration characteristics of a turbofan engine are analyzed by using the two methods. Com- pared with results calculated using transfer matrix method and test results, the two methods are valuable and have great potential in practical applications for vibration characteristic investigation of aero-engines with high thrust-weight ratio.展开更多
This paper describes the redesign of a high pressure rotor (with exit Mach number around 1.5) for the vaneless counter-rotating turbine by choosing adequate exit-to-throat width ratio. Based on the previous design ana...This paper describes the redesign of a high pressure rotor (with exit Mach number around 1.5) for the vaneless counter-rotating turbine by choosing adequate exit-to-throat width ratio. Based on the previous design analysis and test results, effects of the exit-to-throat width ratio on the performance of the transonic turbine cascade were proposed. In order to investigate the influence of the exit-to-throat width ratio on the performance of the turbine cascade, a flow model of the convergent-divergent turbine cascade was constructed by using the theory of Laval nozzle. Then a method on how to choose the adequate exit-to-throat width ratio for the turbine cascade was proposed. To validate the method, it was used to calculate the adequate exit-to-throat width ratio for the high pressure rotor of the vaneless counter-rotating turbine. The high pressure turbine rotor was redesigned with the new exit-to-throat width ratio. Numerical simulation results show that the isentropic efficiency of the redesigned vaneless counter-rotating turbine under the design condition has increased by 0.9% and the efficiencies under the off-design conditions are also improved significantly. On the original design, a group of compressional waves are created from the suction surface after about 60% axial chord in the high pressure turbine rotor. While on the new design the compressional waves are eliminated. Furthermore, on the original design, the inner-extending waves first impinge on the next high pressure turbine rotor suction surface. Its reflection is strong enough and cannot be neglected. However on the new design the inner-extending waves are weakened or even eliminated. Another main progress is that the redesigned high pressure turbine rotor is of practical significance. In the original rotor, a part of the blade (from 60% axial chord to the trailing edge) is thin leading to the intensity problem and difficult arrangement of the cooling system. In the new design, however, the thickness distribution of the rotor airfoil along the chord is relatively reasonable. The intensity of the rotor is enhanced. It is possible to arrange the cooling system reasonably.展开更多
The authors had invented the unique wind power unit composed of the large-sized front wind rotor,the small-sized rear wind rotor and the peculiar generator with the inner and the outer rotational armatures without the...The authors had invented the unique wind power unit composed of the large-sized front wind rotor,the small-sized rear wind rotor and the peculiar generator with the inner and the outer rotational armatures without the conventional stator.This unit is called "Intelligent Wind Power Unit" by the authors.The front and the rear wind rotors drive the inner and the outer armatures,respectively,while the rotational torque is counter-balanced between both armatures/wind rotors.This paper discusses experimentally the acoustic noise from the front and the rear wind rotors.The acoustic noise,in the counter-rotating operation,is induced mainly from the flow interaction between both rotors,and has the dominant power spectrum density at the frequency of the blade passing interaction.The noise is caused mainly from the turbulent fluctuation due to the flow separation on the blade,when the rear wind rotor stops or rotates in the same direction as the front wind rotor.展开更多
文摘Two methods for vibration characteristic investigation of the counter-rotating dual-rotors in an aero-en- gine are put forward. The two methods use DAMP tool on the MSC. NASTRAN platform and develope the re- solving sequence. Vibration characteristics of a turbofan engine are analyzed by using the two methods. Com- pared with results calculated using transfer matrix method and test results, the two methods are valuable and have great potential in practical applications for vibration characteristic investigation of aero-engines with high thrust-weight ratio.
基金supported by the National Natural Science Foundation of China (Grant No. 90718025)the National Basic Research Program of China ("973" Program) (Grant No. 2010CB227302)
文摘This paper describes the redesign of a high pressure rotor (with exit Mach number around 1.5) for the vaneless counter-rotating turbine by choosing adequate exit-to-throat width ratio. Based on the previous design analysis and test results, effects of the exit-to-throat width ratio on the performance of the transonic turbine cascade were proposed. In order to investigate the influence of the exit-to-throat width ratio on the performance of the turbine cascade, a flow model of the convergent-divergent turbine cascade was constructed by using the theory of Laval nozzle. Then a method on how to choose the adequate exit-to-throat width ratio for the turbine cascade was proposed. To validate the method, it was used to calculate the adequate exit-to-throat width ratio for the high pressure rotor of the vaneless counter-rotating turbine. The high pressure turbine rotor was redesigned with the new exit-to-throat width ratio. Numerical simulation results show that the isentropic efficiency of the redesigned vaneless counter-rotating turbine under the design condition has increased by 0.9% and the efficiencies under the off-design conditions are also improved significantly. On the original design, a group of compressional waves are created from the suction surface after about 60% axial chord in the high pressure turbine rotor. While on the new design the compressional waves are eliminated. Furthermore, on the original design, the inner-extending waves first impinge on the next high pressure turbine rotor suction surface. Its reflection is strong enough and cannot be neglected. However on the new design the inner-extending waves are weakened or even eliminated. Another main progress is that the redesigned high pressure turbine rotor is of practical significance. In the original rotor, a part of the blade (from 60% axial chord to the trailing edge) is thin leading to the intensity problem and difficult arrangement of the cooling system. In the new design, however, the thickness distribution of the rotor airfoil along the chord is relatively reasonable. The intensity of the rotor is enhanced. It is possible to arrange the cooling system reasonably.
基金co-sponsored by Research Project 2007 "Grand-in-aid for Scientific Research (c) (2) in Japan" and Research project:Grant-in-aid for JSPS fellow
文摘The authors had invented the unique wind power unit composed of the large-sized front wind rotor,the small-sized rear wind rotor and the peculiar generator with the inner and the outer rotational armatures without the conventional stator.This unit is called "Intelligent Wind Power Unit" by the authors.The front and the rear wind rotors drive the inner and the outer armatures,respectively,while the rotational torque is counter-balanced between both armatures/wind rotors.This paper discusses experimentally the acoustic noise from the front and the rear wind rotors.The acoustic noise,in the counter-rotating operation,is induced mainly from the flow interaction between both rotors,and has the dominant power spectrum density at the frequency of the blade passing interaction.The noise is caused mainly from the turbulent fluctuation due to the flow separation on the blade,when the rear wind rotor stops or rotates in the same direction as the front wind rotor.
