annular clearance meaning in English

环空间隙
环形间隙

The derivation of the leakage flow rate formula of the special annular clearance between the piston and cylinder under condition of variable viscosity in the axial piston pumps was carried out . at same time , considering the questions of the eccentricity and the variable sealing length of piston friction pair , the modified coefficient of the calculation formula of the flow - rate of the leakage was given
在变粘度、柱塞偏心以及变密封长度条件下，对轴向柱塞泵中柱塞与缸孔之间的特殊圆环缝隙的泄漏流量公式进行推导，得到了该计算公式的修正系数； 6