Thermodynamic Characteristic Study of a High-temperature Flow-rate Control Valve for Fuel Supply of Scramjet Engines

Thermodynamic characteristics are of great importance for the performance of a high-temperature flow-rate control valve,as high-temperature environment may bring problems,such as blocking of spool and increasing of leakage,to the valve.In this paper,a high-temperature flow-rate control valve,pilot-controlled by a pneumatic servo system is developed to control the fuel supply for scramjet engines.After introducing the construction and working principle,the thermodynamic mathematical models of the valve are built based on the heat transfer methods inside the valve.By using different boundary conditions,different methods of simulations are carried out and compared.The steady-state and transient temperature field distribution inside the valve body are predicted and temperatures at five interested points are measured.By comparing the simulation and experimental results,a reasonable 3D finite element analysis method is suggested to predict the thermodynamic characteristics of the high-temperature flow-rate control valve.

Supply Chain Engineering in China's Retailing Industry: A Case of Meiyijia

This paper addresses the supply chain engineering and its application in China’s retailing industry. Based on the approaches of systems engineering, we propose the concept of supply chain engineering, which applies the idea of supply chain management to the engineering practices through the advanced information and management technology, to integrate the supply chain system and optimize its operations. We then illustrate the application of the supply chain engineering in China’s retailing industry. In such practices, we developed the virtual retailing enterprise mode and the FROM-SCM system, and designed the sales assistant etc. Such theory and practices are successfully applied in Meiyijia, which has transformed Meiyijia from a traditional retailer to a modern service enterprise, and the profits are resulted from the service fees rather than the traditional surplus between buying and selling prices. Now Meiyijia has built an ecosystem with the retailer in the core, the headquarter as the service platform. The success of Meiyijia in recent years shows the effectiveness of the supply chain engineering.

Importance Analysis of a Multi-state System Based on Direct Partial Logic Derivatives and Multi-valued Decision Diagrams

Importance analysis quantifies the critical degree of individual component. Compared with the traditional binary state system,importance analysis of the multi-state system is more aligned with the practice. Because the multi-valued decision diagram( MDD) can reflect the relationship between the components and the system state bilaterally, it was introduced into the reliability calculation of the multi-state system( MSS). The building method,simplified criteria,and path search and probability algorithm of MSS structure function MDD were given,and the reliability of the system was calculated. The computing methods of importance based on MDD and direct partial logic derivatives( DPLD) were presented. The diesel engine fuel supply system was taken as an example to illustrate the proposed method. The results show that not only the probability of the system in each state can be easily obtained,but also the influence degree of each component and its state on the system reliability can be obtained,which is conducive to the condition monitoring and structure optimization of the system.