Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled reactors.Compared with deterministic methods,the Monte Carlo method has more adva...Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled reactors.Compared with deterministic methods,the Monte Carlo method has more advantages in the geometric modeling of stochastic media.The explicit modeling method has high computational accuracy and high computational cost.The chord length sampling(CLS)method can improve computational efficiency by sampling the chord length during neutron transport using the matrix chord length?s probability density function.This study shows that the excluded-volume effect in realistic stochastic media can introduce certain deviations into the CLS.A chord length correction approach is proposed to obtain the chord length correction factor by developing the Particle code based on equivalent transmission probability.Through numerical analysis against reference solutions from explicit modeling in the RMC code,it was demonstrated that CLS with the proposed correction method provides good accuracy for addressing the excludedvolume effect in realistic infinite stochastic media.展开更多
This paper discusses the problem that constructing a curve to satisfy the given endpoint constraints and chord-length parameters. Based on the research of Lu, the curve construction method for the entire tangent angle...This paper discusses the problem that constructing a curve to satisfy the given endpoint constraints and chord-length parameters. Based on the research of Lu, the curve construction method for the entire tangent angles region （α0, α1）∈（-r, r）×（-r, r） is given. Firstly, to ensure the weights are always positive, the three characteristics of cubic rational Bezier curve is proved, then the segment construction idea for the other tangent angles are presented in view of the three characteristics. The curve constructed with the new method satisfies the endpoint constraint and chord-length parameters, it＇s G1 continuous in every segment curve, and the shapes of the curve are well.展开更多
The performances of turbine blades have a significant impact on the energy conversion efficiency of vertical solar power plants.In the present study,such a relationship is assessed by considering two kinds of airfoil ...The performances of turbine blades have a significant impact on the energy conversion efficiency of vertical solar power plants.In the present study,such a relationship is assessed by considering two kinds of airfoil blades,designed by using the Wilson theory.In particular,numerical simulations are conducted using the SST K−ω model and assuming a wind speed of 3–6 m/s and seven or eight blades.The two airfoils are the NACA63121(with a larger chord length)and the AMES63212;It is shown that the torsion angle of the former is smaller,and its wind drag ratio is larger;furthermore,the resistance is increased by about 66.3%on average.Within the scope of the study,the results show that the NACA63212 airfoil is better than the AMES63212 airfoil in terms of power,with an average improvement of about 2.8%.The simulation results have a certain guiding significance for selecting turbine blade airfoils and improving turbine efficiency.展开更多
文摘Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled reactors.Compared with deterministic methods,the Monte Carlo method has more advantages in the geometric modeling of stochastic media.The explicit modeling method has high computational accuracy and high computational cost.The chord length sampling(CLS)method can improve computational efficiency by sampling the chord length during neutron transport using the matrix chord length?s probability density function.This study shows that the excluded-volume effect in realistic stochastic media can introduce certain deviations into the CLS.A chord length correction approach is proposed to obtain the chord length correction factor by developing the Particle code based on equivalent transmission probability.Through numerical analysis against reference solutions from explicit modeling in the RMC code,it was demonstrated that CLS with the proposed correction method provides good accuracy for addressing the excludedvolume effect in realistic infinite stochastic media.
基金Supported by Shandong Province Higher Educational Science and Technology Program(No.J12LN34)Shandong Ji'nan College and Institute Independent Innovation Project(No.201303011,No.201303021,No.201303016)
文摘This paper discusses the problem that constructing a curve to satisfy the given endpoint constraints and chord-length parameters. Based on the research of Lu, the curve construction method for the entire tangent angles region （α0, α1）∈（-r, r）×（-r, r） is given. Firstly, to ensure the weights are always positive, the three characteristics of cubic rational Bezier curve is proved, then the segment construction idea for the other tangent angles are presented in view of the three characteristics. The curve constructed with the new method satisfies the endpoint constraint and chord-length parameters, it＇s G1 continuous in every segment curve, and the shapes of the curve are well.
文摘The performances of turbine blades have a significant impact on the energy conversion efficiency of vertical solar power plants.In the present study,such a relationship is assessed by considering two kinds of airfoil blades,designed by using the Wilson theory.In particular,numerical simulations are conducted using the SST K−ω model and assuming a wind speed of 3–6 m/s and seven or eight blades.The two airfoils are the NACA63121(with a larger chord length)and the AMES63212;It is shown that the torsion angle of the former is smaller,and its wind drag ratio is larger;furthermore,the resistance is increased by about 66.3%on average.Within the scope of the study,the results show that the NACA63212 airfoil is better than the AMES63212 airfoil in terms of power,with an average improvement of about 2.8%.The simulation results have a certain guiding significance for selecting turbine blade airfoils and improving turbine efficiency.
