Abstract: A spiral sealed liquid capacity model was established for fluid motion under laminar flow conditions. Using the CFD method， the stress distribution of the seal material and sealing medium speed differential force distribution under the pressure gradient force were analyzed， and thus to obtain pumping rate and the annular lower leakage flow along the helical groove and differential pressure pumping gap leakage. According to the flow equilibrium theory， the sealing parameters were obtained and the spiral sealing structure parameters were optimized. The sealing capacity is strongest in the case of the ratio of tooth top width and space width， gullet depth and gap as well as the angle of helix are 1， 2.61 and 15.6°， respectively. Reference was provided for the selection of spiral seal structure parameters under laminar flow conditions.

Key words: flow balance, screw seal, sealed liquid capacity, parameter optimization