Given the existing integrated scheduling algorithms,all processes are ordered and scheduled overall,and these algorithms ignore the influence of the vertical and horizontal characteristics of the product process tree ...Given the existing integrated scheduling algorithms,all processes are ordered and scheduled overall,and these algorithms ignore the influence of the vertical and horizontal characteristics of the product process tree on the product scheduling effect.This paper presents an integrated scheduling algorithm for the same equipment process sequencing based on the Root-Subtree horizontal and vertical pre-scheduling to solve the above problem.Firstly,the tree decomposition method is used to extract the root node to split the process tree into several Root-Subtrees,and the Root-Subtree priority is set from large to small through the optimal completion time of vertical and horizontal pre-scheduling.All Root-Subtree processes on the same equipment are sorted into the stack according to the equipment process pre-start time,and the stack-top processes are combined with the schedulable process set to schedule and dispatch the stack.The start processing time of each process is determined according to the dynamic start processing time strategy of the equipment process,to complete the fusion operation of the Root-Subtree processes under the constraints of the vertical process tree and the horizontal equipment.Then,the root node is retrieved to form a substantial scheduling scheme,which realizes scheduling optimization by mining the vertical and horizontal characteristics of the process tree.Verification by examples shows that,compared with the traditional integrated scheduling algorithms that sort the scheduling processes as an overall,the integrated scheduling algorithmin this paper is better.The proposed algorithmenhances the process scheduling compactness,reduces the length of the idle time of the processing equipment,and optimizes the production scheduling target,which is of universal significance to solve the integrated scheduling problem.展开更多
Liquid bipropellant attitude control rocket engines are widely used in satellites,manned spaceships,deep space probes and other spacecraft.The performance of an attitude control engine is directly related to the lifet...Liquid bipropellant attitude control rocket engines are widely used in satellites,manned spaceships,deep space probes and other spacecraft.The performance of an attitude control engine is directly related to the lifetime,control precision and safety of a spacecraft.The study of flow characteristics of an engine transient process is important to improve its performance.In this paper,the transient flow test of a transparent test piece was carried out during the starting process of the attitude control engine.Then the transient process of the test piece was simulated and compared with the test results to verify the rationality of the simulation model.Transient flow simulation was carried out for the starting process of the real engine injector.The results show that the filling of the outer ring of the oxidant circuit is slower than that of the central collecting cavity,and the filling of the second layer of the outer ring is slower than that of the first layer.The filling process in the fuel path starts from the cooling hole near the inlet side and the fuel flows out in the circumferential direction.Installation direction has little influence on engine starting flow process in the ground state.The filling time of the engine in its vacuum state is longer than that in the ground state,the filling time of oxidizer is 31%longer than that in ground state,and the filling time of fuel is 57%longer than that in ground state.展开更多
At the end of August,Chinalco Southeast Coast Aluminum Deep Processing Base broke ground at the Fujian-Taiwan(Fuzhou)Industrial Park for Blue Economy.Based on Chilco Ruimin(an aluminum processing subsidiary of Chinalc...At the end of August,Chinalco Southeast Coast Aluminum Deep Processing Base broke ground at the Fujian-Taiwan(Fuzhou)Industrial Park for Blue Economy.Based on Chilco Ruimin(an aluminum processing subsidiary of Chinalco in Fujian Province)as the main body,Chinalco展开更多
基金supported by the National Natural Science Foundation of China[Grant No.61772160].
文摘Given the existing integrated scheduling algorithms,all processes are ordered and scheduled overall,and these algorithms ignore the influence of the vertical and horizontal characteristics of the product process tree on the product scheduling effect.This paper presents an integrated scheduling algorithm for the same equipment process sequencing based on the Root-Subtree horizontal and vertical pre-scheduling to solve the above problem.Firstly,the tree decomposition method is used to extract the root node to split the process tree into several Root-Subtrees,and the Root-Subtree priority is set from large to small through the optimal completion time of vertical and horizontal pre-scheduling.All Root-Subtree processes on the same equipment are sorted into the stack according to the equipment process pre-start time,and the stack-top processes are combined with the schedulable process set to schedule and dispatch the stack.The start processing time of each process is determined according to the dynamic start processing time strategy of the equipment process,to complete the fusion operation of the Root-Subtree processes under the constraints of the vertical process tree and the horizontal equipment.Then,the root node is retrieved to form a substantial scheduling scheme,which realizes scheduling optimization by mining the vertical and horizontal characteristics of the process tree.Verification by examples shows that,compared with the traditional integrated scheduling algorithms that sort the scheduling processes as an overall,the integrated scheduling algorithmin this paper is better.The proposed algorithmenhances the process scheduling compactness,reduces the length of the idle time of the processing equipment,and optimizes the production scheduling target,which is of universal significance to solve the integrated scheduling problem.
文摘Liquid bipropellant attitude control rocket engines are widely used in satellites,manned spaceships,deep space probes and other spacecraft.The performance of an attitude control engine is directly related to the lifetime,control precision and safety of a spacecraft.The study of flow characteristics of an engine transient process is important to improve its performance.In this paper,the transient flow test of a transparent test piece was carried out during the starting process of the attitude control engine.Then the transient process of the test piece was simulated and compared with the test results to verify the rationality of the simulation model.Transient flow simulation was carried out for the starting process of the real engine injector.The results show that the filling of the outer ring of the oxidant circuit is slower than that of the central collecting cavity,and the filling of the second layer of the outer ring is slower than that of the first layer.The filling process in the fuel path starts from the cooling hole near the inlet side and the fuel flows out in the circumferential direction.Installation direction has little influence on engine starting flow process in the ground state.The filling time of the engine in its vacuum state is longer than that in the ground state,the filling time of oxidizer is 31%longer than that in ground state,and the filling time of fuel is 57%longer than that in ground state.
文摘At the end of August,Chinalco Southeast Coast Aluminum Deep Processing Base broke ground at the Fujian-Taiwan(Fuzhou)Industrial Park for Blue Economy.Based on Chilco Ruimin(an aluminum processing subsidiary of Chinalco in Fujian Province)as the main body,Chinalco