Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the b...Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the blade, while some only consider the whirl of the rotor, neglecting its spin. To address these limitations, this paper proposes a dynamic model with large rotation for the SDBC system. The model incorporates the spin and whirl of the rotor, enabling the realistic reproduction of multiblade rubbing faults. To verify the accuracy of the SDBC model with large rotation and demonstrate its capability to effectively consider the rotational effects such as the centrifugal stiffening and gyroscopic effects, the natural characteristics and dynamic responses of the proposed model are compared with those obtained from reported research and experimental results. Furthermore, the effects of the rotating speed, contact stiffness,and blade number on the dynamic characteristics of the SDBC system with multi-blade rubbing are investigated. The results indicate that the phase angle between the rotor deflection and the unbalance excitation force increases with the increasing rotating speed,which significantly influences the rubbing penetration of each blade. The natural frequency of the SDBC system with rubbing constrain can be observed in the acceleration response of the casing and the torsional response of the shaft, and the frequency is related to the contact stiffness. Moreover, the vibration amplitude increases significantly with the product of the blade number under rubbing, and the rotating frequency approaches the natural frequency of the SDBC system. The proposed model can provide valuable insight for the fault diagnosis of rubbing in bladed rotating machinery.展开更多
A large gas field with reserves of nearly 200 billion m^(3)dBZ19-6dwas discovered in the Bozhong Depression in the Bohai Bay Basin in 2018.There is a considerable difference between the amount of natural gas that woul...A large gas field with reserves of nearly 200 billion m^(3)dBZ19-6dwas discovered in the Bozhong Depression in the Bohai Bay Basin in 2018.There is a considerable difference between the amount of natural gas that would traditionally be expected to be generated by the thermal degradation of low-mature kerogens and the resources that have been confirmed by exploration.Therefore,the geochemical characteristics and the genesis of gas have become crucial aspects of investigating deep natural gas in the Bozhong Depression.The deep gas in the depression is predominantly methane.Its dry coefficient(C_(1)/C_(1-5))ranges from 0.73 to 0.94,which is generally characterized as wet gas.The main nonhydrocarbon gases are CO_(2)(1.26%-52.00%)and N_(2)(0.1%-0.74%),with traces of H_(2)S(10.44×10^(-6)-36.63×10^(-6) ppm).The natural gases are thermogenic oil-type gases from the Shahejie and Dongying Formations.The deep natural gas in the Bozhong Depression is mainly derived from kerogen degradation,with contributions from oil cracking gas in the BZ1/19 and BZ2/3 structures.Complex carbon isotopic reversals are caused by the filling and mixing of natural gas with different maturities from the same source,evaporative fractionation due to the filling of late-stage high-mature natural gas,and Rayleigh fractionation under deep exogenous temperatures in the presence of transition metals.Combining the analysis of the fluid properties of natural gas,the evaluation of the performance of the migration system,and the understanding of the accumulation background indicates a high possibility that the gas was supplied from multiple hydrocarbon sources over long distances in the late stage.Thus,advantageous traps with high temperatures,close proximity to source kitchens,and favorable migration conditions are the preferred targets for future natural gas exploration in the Bozhong Depression.展开更多
基金Project supported by the National Science and Technology Major Project of China (No. 2017-V-0009)the National Natural Science Foundation of China (Nos. 12032015 and 12121002)the National Funding Program for Postdoctoral Researchers of China (No. GZC20231586)。
文摘Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the blade, while some only consider the whirl of the rotor, neglecting its spin. To address these limitations, this paper proposes a dynamic model with large rotation for the SDBC system. The model incorporates the spin and whirl of the rotor, enabling the realistic reproduction of multiblade rubbing faults. To verify the accuracy of the SDBC model with large rotation and demonstrate its capability to effectively consider the rotational effects such as the centrifugal stiffening and gyroscopic effects, the natural characteristics and dynamic responses of the proposed model are compared with those obtained from reported research and experimental results. Furthermore, the effects of the rotating speed, contact stiffness,and blade number on the dynamic characteristics of the SDBC system with multi-blade rubbing are investigated. The results indicate that the phase angle between the rotor deflection and the unbalance excitation force increases with the increasing rotating speed,which significantly influences the rubbing penetration of each blade. The natural frequency of the SDBC system with rubbing constrain can be observed in the acceleration response of the casing and the torsional response of the shaft, and the frequency is related to the contact stiffness. Moreover, the vibration amplitude increases significantly with the product of the blade number under rubbing, and the rotating frequency approaches the natural frequency of the SDBC system. The proposed model can provide valuable insight for the fault diagnosis of rubbing in bladed rotating machinery.
文摘A large gas field with reserves of nearly 200 billion m^(3)dBZ19-6dwas discovered in the Bozhong Depression in the Bohai Bay Basin in 2018.There is a considerable difference between the amount of natural gas that would traditionally be expected to be generated by the thermal degradation of low-mature kerogens and the resources that have been confirmed by exploration.Therefore,the geochemical characteristics and the genesis of gas have become crucial aspects of investigating deep natural gas in the Bozhong Depression.The deep gas in the depression is predominantly methane.Its dry coefficient(C_(1)/C_(1-5))ranges from 0.73 to 0.94,which is generally characterized as wet gas.The main nonhydrocarbon gases are CO_(2)(1.26%-52.00%)and N_(2)(0.1%-0.74%),with traces of H_(2)S(10.44×10^(-6)-36.63×10^(-6) ppm).The natural gases are thermogenic oil-type gases from the Shahejie and Dongying Formations.The deep natural gas in the Bozhong Depression is mainly derived from kerogen degradation,with contributions from oil cracking gas in the BZ1/19 and BZ2/3 structures.Complex carbon isotopic reversals are caused by the filling and mixing of natural gas with different maturities from the same source,evaporative fractionation due to the filling of late-stage high-mature natural gas,and Rayleigh fractionation under deep exogenous temperatures in the presence of transition metals.Combining the analysis of the fluid properties of natural gas,the evaluation of the performance of the migration system,and the understanding of the accumulation background indicates a high possibility that the gas was supplied from multiple hydrocarbon sources over long distances in the late stage.Thus,advantageous traps with high temperatures,close proximity to source kitchens,and favorable migration conditions are the preferred targets for future natural gas exploration in the Bozhong Depression.
