The hybrid flow shop scheduling problem with unrelated parallel machine is a typical NP-hard combinatorial optimization problem, and it exists widely in chemical, manufacturing and pharmaceutical industry. In this wor...The hybrid flow shop scheduling problem with unrelated parallel machine is a typical NP-hard combinatorial optimization problem, and it exists widely in chemical, manufacturing and pharmaceutical industry. In this work, a novel mathematic model for the hybrid flow shop scheduling problem with unrelated parallel machine(HFSPUPM) was proposed. Additionally, an effective hybrid estimation of distribution algorithm was proposed to solve the HFSPUPM, taking advantage of the features in the mathematic model. In the optimization algorithm, a new individual representation method was adopted. The(EDA) structure was used for global search while the teaching learning based optimization(TLBO) strategy was used for local search. Based on the structure of the HFSPUPM, this work presents a series of discrete operations. Simulation results show the effectiveness of the proposed hybrid algorithm compared with other algorithms.展开更多
With the growing energetic need present in the world, it is increasingly necessary for the researches and facilities to seek a better use of renewable natural resources. This paper is applied in the study of the perfo...With the growing energetic need present in the world, it is increasingly necessary for the researches and facilities to seek a better use of renewable natural resources. This paper is applied in the study of the performance of the aeration system of the Francis turbines present in Itaipu Hydroelectric Power Plant. When a Francis turbine operates off its optimal conditions, a vortex is formed inside the draft tube that, besides produces cavitation and pressure fluctuations, can pulse at frequencies with risk of resonance with hydraulic system, producing efforts and vibrations that may cause structural failures in the turbines, generators and civil parts of the power house. These damaging effects can be reduced using atmospheric aeration of the turbines. Because of this, the availability and effectively of the aeration system is fundamental to smooth the behavior of the turbines, helping preserve the health of the power plant. An analysis of the performance of the aeration system will be done using maintenance records and disturbances analysis reports （RAP）, allowing verification of the operating conditions of the turbine and fatality of water inlet in air pipes. Through the improvements detected, it is possible to reduce machine stoppages by tripping, thus increasing the availability of the turbines.展开更多
The flow rate measurements are the most difficult part of efficiency tests on prototype hydraulic turbines.Among the numerous flow rate measurement methods,the Winter Kennedy method is preferred for measuring turbine ...The flow rate measurements are the most difficult part of efficiency tests on prototype hydraulic turbines.Among the numerous flow rate measurement methods,the Winter Kennedy method is preferred for measuring turbine flow rates,since it is convenient,practical and economical.This paper describes efficiency tests on a large 300 MW Francis turbine,with the flow rate measured using the Winter Kennedy method and the Winter Kennedy flow rate coefficient calibrated using the Gibson method.The measured turbine efficiency curve is then compared with the curve provided by the manufacturer.The CFD calculations including the spiral case are then used to analyze the influence with the coefficient K and index n in the Winter Kennedy flow rate formula on the flow rate measurement.The uncertainty values of n and K are a key reason for the differences between the curves obtained from the efficiency test and the curves provided by the manufacturer.展开更多
基金Projects(61573144,61773165,61673175,61174040)supported by the National Natural Science Foundation of ChinaProject(222201717006)supported by the Fundamental Research Funds for the Central Universities,China
文摘The hybrid flow shop scheduling problem with unrelated parallel machine is a typical NP-hard combinatorial optimization problem, and it exists widely in chemical, manufacturing and pharmaceutical industry. In this work, a novel mathematic model for the hybrid flow shop scheduling problem with unrelated parallel machine(HFSPUPM) was proposed. Additionally, an effective hybrid estimation of distribution algorithm was proposed to solve the HFSPUPM, taking advantage of the features in the mathematic model. In the optimization algorithm, a new individual representation method was adopted. The(EDA) structure was used for global search while the teaching learning based optimization(TLBO) strategy was used for local search. Based on the structure of the HFSPUPM, this work presents a series of discrete operations. Simulation results show the effectiveness of the proposed hybrid algorithm compared with other algorithms.
文摘With the growing energetic need present in the world, it is increasingly necessary for the researches and facilities to seek a better use of renewable natural resources. This paper is applied in the study of the performance of the aeration system of the Francis turbines present in Itaipu Hydroelectric Power Plant. When a Francis turbine operates off its optimal conditions, a vortex is formed inside the draft tube that, besides produces cavitation and pressure fluctuations, can pulse at frequencies with risk of resonance with hydraulic system, producing efforts and vibrations that may cause structural failures in the turbines, generators and civil parts of the power house. These damaging effects can be reduced using atmospheric aeration of the turbines. Because of this, the availability and effectively of the aeration system is fundamental to smooth the behavior of the turbines, helping preserve the health of the power plant. An analysis of the performance of the aeration system will be done using maintenance records and disturbances analysis reports （RAP）, allowing verification of the operating conditions of the turbine and fatality of water inlet in air pipes. Through the improvements detected, it is possible to reduce machine stoppages by tripping, thus increasing the availability of the turbines.
基金supported by the National Natural Science Foundation of China (Grant No.50979044)State Key Laboratory of Hydroscience and Engineering of China (Grant No. 2009T3)
文摘The flow rate measurements are the most difficult part of efficiency tests on prototype hydraulic turbines.Among the numerous flow rate measurement methods,the Winter Kennedy method is preferred for measuring turbine flow rates,since it is convenient,practical and economical.This paper describes efficiency tests on a large 300 MW Francis turbine,with the flow rate measured using the Winter Kennedy method and the Winter Kennedy flow rate coefficient calibrated using the Gibson method.The measured turbine efficiency curve is then compared with the curve provided by the manufacturer.The CFD calculations including the spiral case are then used to analyze the influence with the coefficient K and index n in the Winter Kennedy flow rate formula on the flow rate measurement.The uncertainty values of n and K are a key reason for the differences between the curves obtained from the efficiency test and the curves provided by the manufacturer.
