Due to the important role of the unsteady heat transfer process of packed beds in industrial production,the construction of the transient heat transfer model is of great significance for the operation and optimization...Due to the important role of the unsteady heat transfer process of packed beds in industrial production,the construction of the transient heat transfer model is of great significance for the operation and optimization.The present study performs a transient thermal analysis of packed bed,in which the convective heat transfer and conductive thermal resistance within the particles are considered simultaneously.A mathematical model is established of the total entropy generations(0-t)contributed by viscous dissipation and heat transfer;the influence of particle diameter,air flow rate,and pressure drop,is then investigated.Because of the time cost,these results present some different trends from the steady-state process.Furthermore,for a laboratory heat transfer system,with the aid of the genetic algorithm we adopt a multi-objective genetic algorithm model and modified expressions of the entropy generations are set as objective functions.Finally,optimal operational and structural parameters are obtained for different fan power settings.When the fan power is 300 W,the optimal particle diameter and inlet wind speed are 14 mm and 2.4 m/s,respectively.The results also suggest that the time cost is reduced with increasing fan power consumption.展开更多
Time-cost trade off problem (TCTP), known in the literature as project crashing problem (PCP) and project speeding up problem (PSP) is a part of project management in planning phase. In this problem, determining the o...Time-cost trade off problem (TCTP), known in the literature as project crashing problem (PCP) and project speeding up problem (PSP) is a part of project management in planning phase. In this problem, determining the optimal levels of activity durations and activity costs which satisfy the project goal(s), leads to a balance between the project completion time and the project total cost. A large amount of literature has studied this problem under various behavior of cost function. But, in all of them, influence of discount has not been in-vestigated. Hence, in this paper, TCTP would be studied considering the influence of discount on the re-source price, using genetic algorithm (GA). The performance of proposed idea has been tested on a medium scale test problem and several computational experiments have been conducted to investigate the appropriate levels of proposed GA considering accuracy and computational time.展开更多
基金supported by the Shandong Provincial Natural Science Foundation (Grant No. ZR2019QEE016)
文摘Due to the important role of the unsteady heat transfer process of packed beds in industrial production,the construction of the transient heat transfer model is of great significance for the operation and optimization.The present study performs a transient thermal analysis of packed bed,in which the convective heat transfer and conductive thermal resistance within the particles are considered simultaneously.A mathematical model is established of the total entropy generations(0-t)contributed by viscous dissipation and heat transfer;the influence of particle diameter,air flow rate,and pressure drop,is then investigated.Because of the time cost,these results present some different trends from the steady-state process.Furthermore,for a laboratory heat transfer system,with the aid of the genetic algorithm we adopt a multi-objective genetic algorithm model and modified expressions of the entropy generations are set as objective functions.Finally,optimal operational and structural parameters are obtained for different fan power settings.When the fan power is 300 W,the optimal particle diameter and inlet wind speed are 14 mm and 2.4 m/s,respectively.The results also suggest that the time cost is reduced with increasing fan power consumption.
基金supported by the national social science fund in China (No. 15BTJ024)the planning fund project of humanities and social science research in Chinese Ministry of Education (No. 14YJAZH040)+1 种基金the NSF of China (No.11401247)the NSF of Guangdong province in China (No.2015A030313674)
文摘Time-cost trade off problem (TCTP), known in the literature as project crashing problem (PCP) and project speeding up problem (PSP) is a part of project management in planning phase. In this problem, determining the optimal levels of activity durations and activity costs which satisfy the project goal(s), leads to a balance between the project completion time and the project total cost. A large amount of literature has studied this problem under various behavior of cost function. But, in all of them, influence of discount has not been in-vestigated. Hence, in this paper, TCTP would be studied considering the influence of discount on the re-source price, using genetic algorithm (GA). The performance of proposed idea has been tested on a medium scale test problem and several computational experiments have been conducted to investigate the appropriate levels of proposed GA considering accuracy and computational time.
