This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFD) software code CFX was used for the computation. RNG k...This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFD) software code CFX was used for the computation. RNG k-ε two equation turbulence model was used to simulate the model with unstructured mesh. Sliding mesh interface was used at the interface between the rotating and stationary domains to capture the unsteady interactions. An accurate assessment of the present investigation is made by comparing various parameters with the available experimental data. Three impeller geometries with different blade angles and radius ratio are used in the present study. Maximum energy transfer through the impeller takes place in the region where the flow follows the blade curvature. Radial velocity is not uniform through blade channels. Some blades work in turbine mode at very low flow coefficients. Static pressure is always negative in and around the impeller region.展开更多
This paper investigates the relations between the fluctuating pressure and velocity of the source by means of nu- merical method and sound pressure in the far field obtained with an noise experiment for a novel cross ...This paper investigates the relations between the fluctuating pressure and velocity of the source by means of nu- merical method and sound pressure in the far field obtained with an noise experiment for a novel cross flow fan. The frequency characteristics of the fluctuating pressure and velocity in a cross flow fan are analyzed by means of spectral analysis and wavelet transform. The fluctuating pressures obtained by large eddy simulation on the casing wall are compared with that of experiments and show good agreement. From the spectral analysis of sound source, it is found that the pressure fluctuating peak is correspond with the sound pressure in the far field.展开更多
A numerical analytic process is suggested combining direct boundary element methodwith discrete vortex method and internal flow in cross-flow fan calculated. The process considersnot only function of impeller, but als...A numerical analytic process is suggested combining direct boundary element methodwith discrete vortex method and internal flow in cross-flow fan calculated. The process considersnot only function of impeller, but also effect of volute casing. Internal flow field of cross-flow fan ispractically measured, and results compared with that from calculation. It shows that the process isexpected to be used in predicting performances of fluid machinery.展开更多
A numerical analysis method has been developed for the prediction of the flow in across-flow fan with a casing. The method has no simplifying assumptions regarding the geometryof both the impeller blades and the casin...A numerical analysis method has been developed for the prediction of the flow in across-flow fan with a casing. The method has no simplifying assumptions regarding the geometryof both the impeller blades and the casing Taking into consideration the effect of the boundarylayer on the upper wall surface of the casing, the internal flow is analyzed using both the directboundary element method and the discrete vortex method by assuming that the flow istwo-dimensional. inviscid and incomtressible. In order to satisfy Kelven's theorem, vorticity is sh-ed at the trailing edges of each impeller blade, then the discrete vortex method is used to approxi-mate the convection of the free vorticity. Results are giver for the cross-flow fan with two differ-ent configurations of the casing with an dentical impeller.展开更多
为实现贯流式风机叶轮结构时变可靠性的快速准确评估,利用概率密度演化理论(Probability Density Evolution Theory,PDEM),考虑了叶轮结构和运行环境的随机性,并结合有限元分析模型,建立了叶轮结构极值应力的概率密度函数分析方法,给出...为实现贯流式风机叶轮结构时变可靠性的快速准确评估,利用概率密度演化理论(Probability Density Evolution Theory,PDEM),考虑了叶轮结构和运行环境的随机性,并结合有限元分析模型,建立了叶轮结构极值应力的概率密度函数分析方法,给出了服役期内叶轮结构在不同运行时间的失效概率和时变可靠度。对Abaqus有限元分析软件进行了二次开发,通过Matlab和Abaqus的联合模拟,实现了模型建立、应力分析、结果提取和概率密度演化的全流程批量仿真分析。通过与代理模型法和蒙特卡洛模拟法的对比,从计算效率和结果精度两方面验证了概率密度演化理论的准确性和高效性。展开更多
文摘This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFD) software code CFX was used for the computation. RNG k-ε two equation turbulence model was used to simulate the model with unstructured mesh. Sliding mesh interface was used at the interface between the rotating and stationary domains to capture the unsteady interactions. An accurate assessment of the present investigation is made by comparing various parameters with the available experimental data. Three impeller geometries with different blade angles and radius ratio are used in the present study. Maximum energy transfer through the impeller takes place in the region where the flow follows the blade curvature. Radial velocity is not uniform through blade channels. Some blades work in turbine mode at very low flow coefficients. Static pressure is always negative in and around the impeller region.
基金a Grant-in-Aid for Scientific Research through grant number 50676035 from National Natural Science Foundation of China
文摘This paper investigates the relations between the fluctuating pressure and velocity of the source by means of nu- merical method and sound pressure in the far field obtained with an noise experiment for a novel cross flow fan. The frequency characteristics of the fluctuating pressure and velocity in a cross flow fan are analyzed by means of spectral analysis and wavelet transform. The fluctuating pressures obtained by large eddy simulation on the casing wall are compared with that of experiments and show good agreement. From the spectral analysis of sound source, it is found that the pressure fluctuating peak is correspond with the sound pressure in the far field.
文摘A numerical analytic process is suggested combining direct boundary element methodwith discrete vortex method and internal flow in cross-flow fan calculated. The process considersnot only function of impeller, but also effect of volute casing. Internal flow field of cross-flow fan ispractically measured, and results compared with that from calculation. It shows that the process isexpected to be used in predicting performances of fluid machinery.
文摘A numerical analysis method has been developed for the prediction of the flow in across-flow fan with a casing. The method has no simplifying assumptions regarding the geometryof both the impeller blades and the casing Taking into consideration the effect of the boundarylayer on the upper wall surface of the casing, the internal flow is analyzed using both the directboundary element method and the discrete vortex method by assuming that the flow istwo-dimensional. inviscid and incomtressible. In order to satisfy Kelven's theorem, vorticity is sh-ed at the trailing edges of each impeller blade, then the discrete vortex method is used to approxi-mate the convection of the free vorticity. Results are giver for the cross-flow fan with two differ-ent configurations of the casing with an dentical impeller.
文摘为实现贯流式风机叶轮结构时变可靠性的快速准确评估,利用概率密度演化理论(Probability Density Evolution Theory,PDEM),考虑了叶轮结构和运行环境的随机性,并结合有限元分析模型,建立了叶轮结构极值应力的概率密度函数分析方法,给出了服役期内叶轮结构在不同运行时间的失效概率和时变可靠度。对Abaqus有限元分析软件进行了二次开发,通过Matlab和Abaqus的联合模拟,实现了模型建立、应力分析、结果提取和概率密度演化的全流程批量仿真分析。通过与代理模型法和蒙特卡洛模拟法的对比,从计算效率和结果精度两方面验证了概率密度演化理论的准确性和高效性。
