A probability-based damage tolerance methodology has been proposed to improve the recognition of material anomalies, especially hard alpha(TiN) anomalies for aeroengine rotor disks. A key input to this method is hard ...A probability-based damage tolerance methodology has been proposed to improve the recognition of material anomalies, especially hard alpha(TiN) anomalies for aeroengine rotor disks. A key input to this method is hard alpha anomaly distribution, which reflects the occurrence rate and size of anomalies present in the finished part material of titanium rotors. Since anomalies rarely occur naturally, an experimental method is proposed to obtain the anomaly distribution for titanium alloy aeroengine disks to reflect and equivalently replace the manufacturing development in titanium industry. In general, the anomaly distribution information can be divided into two parts: the Probability of Detection(POD) curve and the detected anomaly distribution, which contains the size and frequency data of the detected anomalies. The distribution can be established based on several appropriate assumptions and derivation steps with different confidence levels of POD curves and detected anomaly distributions. In this case, the distribution can be obtained in a relatively short time as a key input to the probability-based damage tolerance methodology. Then the Probability of Failure(POF) can be calculated, and the value is found to vary with different confidence levels. On this basis, the conservative estimated POF can be obtained in conjunction with confidence levels.展开更多
Axial cyclone separator has been widely applied in chemical production as an efficient gas-liquid separation device.In this study,a new axial cyclone separator with integrated swirler and exhaust pipe is designed to a...Axial cyclone separator has been widely applied in chemical production as an efficient gas-liquid separation device.In this study,a new axial cyclone separator with integrated swirler and exhaust pipe is designed to achieve the development goal of compact structure for advanced engine,and the distribution characteristics of swirling flow patterns as well as the variation in separation characteristics are investigated under slug flow pattern.Based on flow visualizations and fluctuation characteristics of pressure signals,three typical flow patterns,namely,slug flow,swirling intermittent flow,and swirling annular flow,in the horizontal swirling separation flow are characterized.It is investigated how the inlet conditions affect the separation characteristic parameters.The separation purity and extreme points of the air separation efficiency are independent of the inlet liquid flow rate.The separation pressure drop is quadratically related to the inlet air flow rate.Based on the drift-flux model and other methods,the prediction methods for the air separation efficiency and pressure drop are proposed,and the prediction accuracy is within±20%,which may provide instructions for the practical application of axial cyclone separator.展开更多
Owing to the heterogeneity between functional units and resource scarcity,manufacturing firms have been struggling with intra-organizational coordination for productivity and innovation.Traditional organizational stru...Owing to the heterogeneity between functional units and resource scarcity,manufacturing firms have been struggling with intra-organizational coordination for productivity and innovation.Traditional organizational structures,such as linear-functional and matrix,may cause responsibility division and independent goals(Shahani,2020),and are more difficult to be adopted by large-sized innovative manufacturing firms for quantity production.This is based on a review of several new forms of organization(i.e.,network organization,multiteam system,and platform organization)compared with the traditional forms of organization(i.e.,linear,matrix,and business unit organization,among others).This study proposes a three-dimensional(3D)magic-cube organizational structure,considering the product dimensions,business,and administration.Moreover,the characteristics,propositions of system operation,system dynamic model,and working model of the 3D magic-cube organization are described.Finally,the 3D model is applied in a Chinese manufacturing firm to test its effectiveness.By redesigning the post and pay system,the pilot organization establishes a project-driven and cross-functional coordination mechanism,positively affecting the firm’s financial profit,output value,labor productivity,and income of per capita.The proposed 3D model can be adopted by large-or medium-sized manufacturing firms for product development and innovation.The implications of both practice and theory are also discussed in this study.展开更多
基金funded by the National Natural Science Foundation of China and Civil Aviation Administration of China(No.U1833109)the Innovation Team of Complex System Safety and Airworthiness of Aero Engine from the Co-Innovation Center for Advanced Aeroengine of China。
文摘A probability-based damage tolerance methodology has been proposed to improve the recognition of material anomalies, especially hard alpha(TiN) anomalies for aeroengine rotor disks. A key input to this method is hard alpha anomaly distribution, which reflects the occurrence rate and size of anomalies present in the finished part material of titanium rotors. Since anomalies rarely occur naturally, an experimental method is proposed to obtain the anomaly distribution for titanium alloy aeroengine disks to reflect and equivalently replace the manufacturing development in titanium industry. In general, the anomaly distribution information can be divided into two parts: the Probability of Detection(POD) curve and the detected anomaly distribution, which contains the size and frequency data of the detected anomalies. The distribution can be established based on several appropriate assumptions and derivation steps with different confidence levels of POD curves and detected anomaly distributions. In this case, the distribution can be obtained in a relatively short time as a key input to the probability-based damage tolerance methodology. Then the Probability of Failure(POF) can be calculated, and the value is found to vary with different confidence levels. On this basis, the conservative estimated POF can be obtained in conjunction with confidence levels.
基金supported by the National Natural Science Foundation of China(Grant Nos.51888103 and 52076175)the Fundamental Research Funds for the Central Universities。
文摘Axial cyclone separator has been widely applied in chemical production as an efficient gas-liquid separation device.In this study,a new axial cyclone separator with integrated swirler and exhaust pipe is designed to achieve the development goal of compact structure for advanced engine,and the distribution characteristics of swirling flow patterns as well as the variation in separation characteristics are investigated under slug flow pattern.Based on flow visualizations and fluctuation characteristics of pressure signals,three typical flow patterns,namely,slug flow,swirling intermittent flow,and swirling annular flow,in the horizontal swirling separation flow are characterized.It is investigated how the inlet conditions affect the separation characteristic parameters.The separation purity and extreme points of the air separation efficiency are independent of the inlet liquid flow rate.The separation pressure drop is quadratically related to the inlet air flow rate.Based on the drift-flux model and other methods,the prediction methods for the air separation efficiency and pressure drop are proposed,and the prediction accuracy is within±20%,which may provide instructions for the practical application of axial cyclone separator.
基金This study is supported by the Key Project of the National Natural ScienceFoundation of China(Grant No.72132001).
文摘Owing to the heterogeneity between functional units and resource scarcity,manufacturing firms have been struggling with intra-organizational coordination for productivity and innovation.Traditional organizational structures,such as linear-functional and matrix,may cause responsibility division and independent goals(Shahani,2020),and are more difficult to be adopted by large-sized innovative manufacturing firms for quantity production.This is based on a review of several new forms of organization(i.e.,network organization,multiteam system,and platform organization)compared with the traditional forms of organization(i.e.,linear,matrix,and business unit organization,among others).This study proposes a three-dimensional(3D)magic-cube organizational structure,considering the product dimensions,business,and administration.Moreover,the characteristics,propositions of system operation,system dynamic model,and working model of the 3D magic-cube organization are described.Finally,the 3D model is applied in a Chinese manufacturing firm to test its effectiveness.By redesigning the post and pay system,the pilot organization establishes a project-driven and cross-functional coordination mechanism,positively affecting the firm’s financial profit,output value,labor productivity,and income of per capita.The proposed 3D model can be adopted by large-or medium-sized manufacturing firms for product development and innovation.The implications of both practice and theory are also discussed in this study.