An analytical approach is described for the axisymmetric flow through a permeable near-sphere with a modification to boundary conditions in order to account permeability. The Stokes equation was solved by a regular pe...An analytical approach is described for the axisymmetric flow through a permeable near-sphere with a modification to boundary conditions in order to account permeability. The Stokes equation was solved by a regular perturbation technique up to the second order correction in epsilon representing the deviation from the radius of nondeformed sphere. The drag and the flow rate were calculated and the results were evaluated from the point of geometry and the permeability of the surface. An attempt also was made to apply the theory to the filter feeding problem. The filter appendages of small ecologically important aquatic organisms were modeled as axisymmetric permeable bodies, therefore a rough model for this problem was considered here as an oblate spheroid or near-sphere.展开更多
In a Zippe-type 3-pole gas centrifuge, feed gas is introduced through a sonic nozzle into the rarefied region in the rotor. Introduction of the nonrotating feed gas will slow the whirl flow and introduce a secondary r...In a Zippe-type 3-pole gas centrifuge, feed gas is introduced through a sonic nozzle into the rarefied region in the rotor. Introduction of the nonrotating feed gas will slow the whirl flow and introduce a secondary recirculating flow in the meridian plane. The effects of feed gas on the output of a gas centrifuge are investigated. The non-linear. axisymmetric N-S equations are used to calculate the secondary flow induced by the feed gas. Three types of numerical schemes. an implicit scheme similar to the Beam-Warming scheme. an implicit unfactorized scheme and an improved Newton-Raphson scheme are used. The Cohen separation theory with axial variation is used forcalculating the isotope concentration. Optimization of the output is achieved by automatic variation of the weighting factors for a number of linear flow solutions which can be superimposed. A Rome type centrifuge is analyzed as an example. Results show the recirculating flow caused by the feed gas. especially the acceleration loss. has an important effect on the output of a gas centrifuge.展开更多
文摘An analytical approach is described for the axisymmetric flow through a permeable near-sphere with a modification to boundary conditions in order to account permeability. The Stokes equation was solved by a regular perturbation technique up to the second order correction in epsilon representing the deviation from the radius of nondeformed sphere. The drag and the flow rate were calculated and the results were evaluated from the point of geometry and the permeability of the surface. An attempt also was made to apply the theory to the filter feeding problem. The filter appendages of small ecologically important aquatic organisms were modeled as axisymmetric permeable bodies, therefore a rough model for this problem was considered here as an oblate spheroid or near-sphere.
文摘In a Zippe-type 3-pole gas centrifuge, feed gas is introduced through a sonic nozzle into the rarefied region in the rotor. Introduction of the nonrotating feed gas will slow the whirl flow and introduce a secondary recirculating flow in the meridian plane. The effects of feed gas on the output of a gas centrifuge are investigated. The non-linear. axisymmetric N-S equations are used to calculate the secondary flow induced by the feed gas. Three types of numerical schemes. an implicit scheme similar to the Beam-Warming scheme. an implicit unfactorized scheme and an improved Newton-Raphson scheme are used. The Cohen separation theory with axial variation is used forcalculating the isotope concentration. Optimization of the output is achieved by automatic variation of the weighting factors for a number of linear flow solutions which can be superimposed. A Rome type centrifuge is analyzed as an example. Results show the recirculating flow caused by the feed gas. especially the acceleration loss. has an important effect on the output of a gas centrifuge.
