A plane-symmetric inhomogeneous cosmological model of perfect fluid distribution with electro-magnetic field is obtained. F12 is the non-vanishing component of electromagnetic field tensor. To get a deterministic solu...A plane-symmetric inhomogeneous cosmological model of perfect fluid distribution with electro-magnetic field is obtained. F12 is the non-vanishing component of electromagnetic field tensor. To get a deterministic solution, we assume the free gravitational field is Petrov type-Ⅱ non-degenerate. Some physical and geometric properties of the model are also discussed.展开更多
The inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet structures were studied in numerical method,mainly focused on three issues including the amounts and difference...The inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet structures were studied in numerical method,mainly focused on three issues including the amounts and differences of the inlet recirculation in different working conditions,the circumferential non-uniform distributions of the inlet recirculation,the recirculation velocity distributions of the upstream slot of the rear impeller.The results show that there are some differences between the recirculation of the front impeller and that of the rear impeller in whole working conditions..In design speed,the recirculation flow rate of the rear impeller is larger than that of the front impeller in the large flow range,but in the small flow range,the recirculation flow rate of the rear impeller is smaller than that of the front impeller.In different working conditions,the recirculation velocity distributions of the front and rear impeller are non-uniform along the circumferential direction and their non-uniform extents are quite different.The circumferential non-uniform extent of the recirculation velocity varies with the working conditions change.The circumferential non-uniform extent of the recirculation velocity of front impeller and its distribution are determined by the static pressure distribution of the front impeller,but that of the rear impeller is decided by the coupling effects of the inlet flow distortion of the rear impeller,the circumferential unsymmetrical distribution of the upstream slot and the asymmetric structure of the volute.In the design flow and small flow conditions,the recirculation velocities at different circumferential positions of the mean line of the upstream slot cross-section of the rear impeller are quite different,and the recirculation velocities distribution forms at both sides of the mean line are different.The recirculation velocity distributions in the cross-section of the upstream slot depend on the static pressure distributions in the intake duct.展开更多
文摘A plane-symmetric inhomogeneous cosmological model of perfect fluid distribution with electro-magnetic field is obtained. F12 is the non-vanishing component of electromagnetic field tensor. To get a deterministic solution, we assume the free gravitational field is Petrov type-Ⅱ non-degenerate. Some physical and geometric properties of the model are also discussed.
基金funded by the National Natural Science Foundation of China(No.51276017)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20131101110015),China
文摘The inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet structures were studied in numerical method,mainly focused on three issues including the amounts and differences of the inlet recirculation in different working conditions,the circumferential non-uniform distributions of the inlet recirculation,the recirculation velocity distributions of the upstream slot of the rear impeller.The results show that there are some differences between the recirculation of the front impeller and that of the rear impeller in whole working conditions..In design speed,the recirculation flow rate of the rear impeller is larger than that of the front impeller in the large flow range,but in the small flow range,the recirculation flow rate of the rear impeller is smaller than that of the front impeller.In different working conditions,the recirculation velocity distributions of the front and rear impeller are non-uniform along the circumferential direction and their non-uniform extents are quite different.The circumferential non-uniform extent of the recirculation velocity varies with the working conditions change.The circumferential non-uniform extent of the recirculation velocity of front impeller and its distribution are determined by the static pressure distribution of the front impeller,but that of the rear impeller is decided by the coupling effects of the inlet flow distortion of the rear impeller,the circumferential unsymmetrical distribution of the upstream slot and the asymmetric structure of the volute.In the design flow and small flow conditions,the recirculation velocities at different circumferential positions of the mean line of the upstream slot cross-section of the rear impeller are quite different,and the recirculation velocities distribution forms at both sides of the mean line are different.The recirculation velocity distributions in the cross-section of the upstream slot depend on the static pressure distributions in the intake duct.
