annular gap meaning in English

环形间隙
环形模隙
环形隙

So it should be pointed out from the above analysis that to make the module operate better , it is the better choice to ensure the flow in the annular gap of it to be a turbulent flow
同时也需指出的是，为使外旋流的方式较好地达到强化微滤的目的，建议采用一定流量下的湍流方式较为合适。
In this paper , the characteristics and details of the laminar flow fields in the annular gap of the modules were theoretically studied by numerical simulation method first time . the mechanism of the microfiltration with outside helical flow was analyzed . its results were compared with the former experimental results and those of outside axial flow mf and would provide the theoretical basis for optimization design
本文采用数值计算的方法首次对层流范围内膜器环隙内的流场进行数值模拟，从理论的角度分析其流场分布的细节和特点，与前人的实验研究结果和外轴向流微滤进行比较，分析外旋流强化微滤的机理，对膜器优化设计提供理论依据。