The actuator disc method is an engineering approach to reduce computer resources in computational fluid dynamics(CFD)simulations of helicopter rotors or aeroplane propellers.Implementation of an actuator disc based on...The actuator disc method is an engineering approach to reduce computer resources in computational fluid dynamics(CFD)simulations of helicopter rotors or aeroplane propellers.Implementation of an actuator disc based on rotor circulation distribution allows for approximations to be made while reproducing the blade tip vortices.Radial circulation distributions can be formulated according to the nonuniform Heyson-Katzoff“typical load”in hover.In forward flight,the nonuniform disk models include“azimuthal”sin and cos terms to reproduce the blade cyclic motion.The azimuthal circulation distribution for a forward flight mode corresponds to trimmed conditions for the disk rolling and pitching moments.The amplitude of the cos harmonic is analysed and compared here with presented in references data and CFD simulations results.展开更多
A process for numerical analysis of radial circulation distribution of propeller blade is proposed and presented.It is based on the results of numerical simulation of the velocity field around propeller blades and in ...A process for numerical analysis of radial circulation distribution of propeller blade is proposed and presented.It is based on the results of numerical simulation of the velocity field around propeller blades and in the wake.The well-known traditional method using tangential velocity data in the wake and applying Stockes＇s theorem was also examined in the investigation.The results from two approaches are compared with each other.It is found that if the traditional way is utilized,in many cases an unexpected ＂hump＂ appears in the circulation distribution at certain outer radius.The authors calculated the circulations directly around blade sections,and it is referred as direct method.The unexpected hump of the circulation distribution disappears in the results of direct method.This article also discusses the reasons of the appearance of the unexpected hump in traditional approach.The direct method is proposed to have a potential in analyzing or verifying the radial road distribution for designed propeller and the numerical analysis instead of experimental validation for circulation distribution can be as a tool in the propeller design process.展开更多
The determination of the circulation for wind turbine blades is an important problem in engineering.In the present study,we develop a specific approach to evaluate the integral that represents mathematically the circu...The determination of the circulation for wind turbine blades is an important problem in engineering.In the present study,we develop a specific approach to evaluate the integral that represents mathematically the circulation.First the potentialities of the method are assessed using a two-dimensional NACA64_A17 airfoil as a testbed and evaluating the influence of different integration paths and angles of attack on the circulation value.Then the method is applied to blades with different relative heights in order to provide useful reference data to be used for the optimization and reverse design of wind turbine blades.As shown by the results,the integral value changes with the integral path,and an“optimal circle radius”exists.We calibrate the integral value by comparing its value with the lift formula.In this was we succeed in showing that there is a certain error when the radius is too small.However,the error can increase rapidly when the radius is too large.When the radius of the circle is 1–6 times the chord length,the error of all integral values is less than 5%.The optimal radius varies with the angle of attack.展开更多
The superconducting magnet of Central Solenoid（CS） model coil of China Fusion Engineering Test Reactor（CFETR） is made of Nb_3Sn/Nb Ti cable-in-conduit conductor（CICC）,and operated by forced-flow cooling with a l...The superconducting magnet of Central Solenoid（CS） model coil of China Fusion Engineering Test Reactor（CFETR） is made of Nb_3Sn/Nb Ti cable-in-conduit conductor（CICC）,and operated by forced-flow cooling with a large amount of supercritical helium.The cryogenic circulation pump is analyzed and considered to be effective in achieving the supercritical helium（SHe） circulation for the forced-flow cooled（FFC） CICC magnet.A distributed system will be constructed for cooling the CFETR CS model coil.This paper presents the design of FFC process for the CFETR CS model coil.The equipment configuration,quench protection in the magnet and the process control are presented.展开更多
Actuator Disks(AD)can provide characterizations of rotor wakes while reducing computational expense associated with modeling the fully resolved blades.This work presents an unsteady actuator disk method based on surfa...Actuator Disks(AD)can provide characterizations of rotor wakes while reducing computational expense associated with modeling the fully resolved blades.This work presents an unsteady actuator disk method based on surface circulation distribution combined with empirical data,blade element theory and rotor momentum theory.The nonuniform circulation distribution accounts for 3 D blade load effects,and in particular,tip loses.Numerical simulations were conducted for the isolated pressure sensitive paint model rotor blade in hover and forward flight using the HMB3 CFD solver of Glasgow University.Validation of CFD results in comparison with published numerical data was performed in hover,for a range of blade pitch angles using fully turbulent flow and the k-x SST model.In forward flight,the vortex structures predicted using the unsteady actuator disk model showed configurations similar to the ones obtained using fully resolved rotor blades.Despite the reduced grid cells number,the CFD results for AD models captured well the main vortical structures around the rotor disk in comparison to the fully resolved cases.展开更多
基金Work of Russian coauthors was supported by the grant"FZSU-2020-0021"(No.075-03-2020-051/3 from 09.06.2020)of the Min-istry of Education and Science of the Russian Federation.
文摘The actuator disc method is an engineering approach to reduce computer resources in computational fluid dynamics(CFD)simulations of helicopter rotors or aeroplane propellers.Implementation of an actuator disc based on rotor circulation distribution allows for approximations to be made while reproducing the blade tip vortices.Radial circulation distributions can be formulated according to the nonuniform Heyson-Katzoff“typical load”in hover.In forward flight,the nonuniform disk models include“azimuthal”sin and cos terms to reproduce the blade cyclic motion.The azimuthal circulation distribution for a forward flight mode corresponds to trimmed conditions for the disk rolling and pitching moments.The amplitude of the cos harmonic is analysed and compared here with presented in references data and CFD simulations results.
文摘A process for numerical analysis of radial circulation distribution of propeller blade is proposed and presented.It is based on the results of numerical simulation of the velocity field around propeller blades and in the wake.The well-known traditional method using tangential velocity data in the wake and applying Stockes＇s theorem was also examined in the investigation.The results from two approaches are compared with each other.It is found that if the traditional way is utilized,in many cases an unexpected ＂hump＂ appears in the circulation distribution at certain outer radius.The authors calculated the circulations directly around blade sections,and it is referred as direct method.The unexpected hump of the circulation distribution disappears in the results of direct method.This article also discusses the reasons of the appearance of the unexpected hump in traditional approach.The direct method is proposed to have a potential in analyzing or verifying the radial road distribution for designed propeller and the numerical analysis instead of experimental validation for circulation distribution can be as a tool in the propeller design process.
基金supported by the Shandong Provincial Natural Science Foundation,China(No.ZR2019QA018).
文摘The determination of the circulation for wind turbine blades is an important problem in engineering.In the present study,we develop a specific approach to evaluate the integral that represents mathematically the circulation.First the potentialities of the method are assessed using a two-dimensional NACA64_A17 airfoil as a testbed and evaluating the influence of different integration paths and angles of attack on the circulation value.Then the method is applied to blades with different relative heights in order to provide useful reference data to be used for the optimization and reverse design of wind turbine blades.As shown by the results,the integral value changes with the integral path,and an“optimal circle radius”exists.We calibrate the integral value by comparing its value with the lift formula.In this was we succeed in showing that there is a certain error when the radius is too small.However,the error can increase rapidly when the radius is too large.When the radius of the circle is 1–6 times the chord length,the error of all integral values is less than 5%.The optimal radius varies with the angle of attack.
文摘The superconducting magnet of Central Solenoid（CS） model coil of China Fusion Engineering Test Reactor（CFETR） is made of Nb_3Sn/Nb Ti cable-in-conduit conductor（CICC）,and operated by forced-flow cooling with a large amount of supercritical helium.The cryogenic circulation pump is analyzed and considered to be effective in achieving the supercritical helium（SHe） circulation for the forced-flow cooled（FFC） CICC magnet.A distributed system will be constructed for cooling the CFETR CS model coil.This paper presents the design of FFC process for the CFETR CS model coil.The equipment configuration,quench protection in the magnet and the process control are presented.
基金co-supported by the grant‘‘State task of the Education and Science Ministry of Russian Federation”agreement(No.075-03-2020-051/3 from 09.06.2020,theme No.fzsu-2020-0021)。
文摘Actuator Disks(AD)can provide characterizations of rotor wakes while reducing computational expense associated with modeling the fully resolved blades.This work presents an unsteady actuator disk method based on surface circulation distribution combined with empirical data,blade element theory and rotor momentum theory.The nonuniform circulation distribution accounts for 3 D blade load effects,and in particular,tip loses.Numerical simulations were conducted for the isolated pressure sensitive paint model rotor blade in hover and forward flight using the HMB3 CFD solver of Glasgow University.Validation of CFD results in comparison with published numerical data was performed in hover,for a range of blade pitch angles using fully turbulent flow and the k-x SST model.In forward flight,the vortex structures predicted using the unsteady actuator disk model showed configurations similar to the ones obtained using fully resolved rotor blades.Despite the reduced grid cells number,the CFD results for AD models captured well the main vortical structures around the rotor disk in comparison to the fully resolved cases.
