A three-dimensional infrared radiation code for exhaust system was developed by the finite volume method coupled with narrow band k-distribution in non-gray absorbing-emitting media.The final infrared signature had co...A three-dimensional infrared radiation code for exhaust system was developed by the finite volume method coupled with narrow band k-distribution in non-gray absorbing-emitting media.The final infrared signature had considered the atmosphere effect,and the simulation values were favorably consistent with testing ones.The results indicate that the relative errors considering the effect of atmosphere compared with that of the contrary condition reduce by 31%,it shows that when simulating the infrared radiation of the target which is received by the infrared detectors,even the calculation band is in atmospheric windows 3～5 μm,the effect of atmospheric transmission on infrared signature of the target should not be neglected.展开更多
The finite element method (FEM) and the finite volume method (FVM) numerical simulation methods have been widely used in forging industries to improve the quality of products and reduce the costs. Because of very conc...The finite element method (FEM) and the finite volume method (FVM) numerical simulation methods have been widely used in forging industries to improve the quality of products and reduce the costs. Because of very concentrative large deformation during the aluminum extrusion processes, it is very difficult to simulate the whole forming process only by using either FEM or FVM. In order to solve this problem, an FEM and FVM compound simulation method was proposed. The theoretical equations of the compound simulation method were given and the key techniques were studied. Then, the configuration of the compound simulation system was established. The tube extrusion process was simulated successfully so as to prove the validity of this approach for aluminum extrusion processes.展开更多
A two-dimensional numerical model is proposed to simulate the thermal discharge from a power plant in Jiangsu Province. The equations in the model consist of two-dimensional non-steady shallow water equations and ther...A two-dimensional numerical model is proposed to simulate the thermal discharge from a power plant in Jiangsu Province. The equations in the model consist of two-dimensional non-steady shallow water equations and thermal waste transport equations. Finite volume method （FVM） is used to discretize the shallow water equations, and flux difference splitting （FDS） scheme is applied. The calculated area with the same temperature increment shows the effect of thermal discharge on sea water. A comparison between simulated results and the experimental data shows good agreement. It indicates that this method can give high precision in the heat transfer simulation in coastal areas.展开更多
Extrusion is the key technology to manufacture aluminum profiles and involves complicate metal deformation coupled with temperature changes. The choice of numerical technique plays an important role and is related to ...Extrusion is the key technology to manufacture aluminum profiles and involves complicate metal deformation coupled with temperature changes. The choice of numerical technique plays an important role and is related to the accuracy and effectiveness of extrusion process analyses. In this paper, the extrusion processes of two complex aluminum profiles are simulated with FEM and FVM respectively. The merit and disadvantage of these two methods are analyzed. The finite element method exhibits higher calculation efficiency in the simulation of a lock catch extrusion process. However, due to frequent rezoning in simulation of complex extrusion process, sharp distortion of finite element mesh can decrease computational accuracy. Therefore the volume loss in FEM simulation is larger than that in FVM simulation by five percent. Based on Euler description, the finite volume method employs structured element mesh covering entire material flowing area, which makes it more robust in the simulation of complicate extrusion process. The deformation configuration with FVM is much smoother than that with FEM in the extrusion simulation of a thin-walled aluminum profile, although FVM requires more computation time.展开更多
文摘A three-dimensional infrared radiation code for exhaust system was developed by the finite volume method coupled with narrow band k-distribution in non-gray absorbing-emitting media.The final infrared signature had considered the atmosphere effect,and the simulation values were favorably consistent with testing ones.The results indicate that the relative errors considering the effect of atmosphere compared with that of the contrary condition reduce by 31%,it shows that when simulating the infrared radiation of the target which is received by the infrared detectors,even the calculation band is in atmospheric windows 3～5 μm,the effect of atmospheric transmission on infrared signature of the target should not be neglected.
文摘The finite element method (FEM) and the finite volume method (FVM) numerical simulation methods have been widely used in forging industries to improve the quality of products and reduce the costs. Because of very concentrative large deformation during the aluminum extrusion processes, it is very difficult to simulate the whole forming process only by using either FEM or FVM. In order to solve this problem, an FEM and FVM compound simulation method was proposed. The theoretical equations of the compound simulation method were given and the key techniques were studied. Then, the configuration of the compound simulation system was established. The tube extrusion process was simulated successfully so as to prove the validity of this approach for aluminum extrusion processes.
文摘A two-dimensional numerical model is proposed to simulate the thermal discharge from a power plant in Jiangsu Province. The equations in the model consist of two-dimensional non-steady shallow water equations and thermal waste transport equations. Finite volume method （FVM） is used to discretize the shallow water equations, and flux difference splitting （FDS） scheme is applied. The calculated area with the same temperature increment shows the effect of thermal discharge on sea water. A comparison between simulated results and the experimental data shows good agreement. It indicates that this method can give high precision in the heat transfer simulation in coastal areas.
基金Proiects(0452nm034, 0552nm041) supported by the Science and Technology Committee of Shanghai, China
文摘Extrusion is the key technology to manufacture aluminum profiles and involves complicate metal deformation coupled with temperature changes. The choice of numerical technique plays an important role and is related to the accuracy and effectiveness of extrusion process analyses. In this paper, the extrusion processes of two complex aluminum profiles are simulated with FEM and FVM respectively. The merit and disadvantage of these two methods are analyzed. The finite element method exhibits higher calculation efficiency in the simulation of a lock catch extrusion process. However, due to frequent rezoning in simulation of complex extrusion process, sharp distortion of finite element mesh can decrease computational accuracy. Therefore the volume loss in FEM simulation is larger than that in FVM simulation by five percent. Based on Euler description, the finite volume method employs structured element mesh covering entire material flowing area, which makes it more robust in the simulation of complicate extrusion process. The deformation configuration with FVM is much smoother than that with FEM in the extrusion simulation of a thin-walled aluminum profile, although FVM requires more computation time.
