Distribution Of Group Feed Pressure And Its Influence On Separative Power Of A Centrifuge Cascade

Centrifugation is currently the most competitive method of uranium enrichment,and has been widely used in China’s uranium enrichment plants to produce products of different abundance.Although the state has realized the independent research,construction and operation of centrifuges and centrifuge cascades,it is still necessary to carry out more in-depth researches in the application of the theory of centrifugation to practice.At present,there is a 2~3% deviation between the actual separative power and that from a theoretical calculation.From the point of view of either accumulating theoretical experiences or improving the economic benefit of a uranium enrichment plant,this 2~3% deviation is worth further study.Improving the accuracy of the theoretical calculation model can effectively reduce the deviation.So far the theoretical calculation employs a uniform distribution model to compute feed rates in stage,which introduces a certain discrepancy compared with the actual situation and is one of the factors causing the deviation.The influences of the sizes of pipes must be investigated on the separation status of the centrifuges in a group,if the uniform distribution model is not used.This thesis uses a one-dimensional fluid network theory to calculate and study the effects of pipe size on the feed pressure distribution in a stage,and on the separative power and mixing losses,and obtains the optimal combination of pipe sizes,which provides a reference for the cascade piping design.Based on analysis on the separation status of the centrifuges in a group,also investigated are the influences of the pipes’ diameters and lengths on an assembly unit,a separated group,and a half section,leading to the following conclusions: the hydraulic parameters of the centrifuges in an assembly unit can be regarded as being identical;a matching relationship exists between the diameter and the length of a pipe.When the matching relationship is satisfied,the separation performance of the centrifuges can be fully exploited,producing a higher separative power and a lower mixing loss,and meanwhile,reducing the engineering cost.The results in the total feed flow and total separative power of a section obtained by using the uniform distribution model are compared with those obtained from the model taking into account the actual situation,and the relationships between the results of the two models are found,which provides in practice a feasible approach for a fast evaluation of the total feed rate and the total separation power of a group.