Abstract:Fluctuations of the flow and pressure drops exist widely in the two phase flow, which would cause the equipment to produce severe fatigue damage and even result in malfunction. Therefore, it is necessary to control the flow and pressure drops at appropriate range in two phase flow. This paper firstly models and analyzes a hydraulic element recorded in an ancient Chinese book “Ridge outside Pickup”, the objective of which is to regulate the flow rate , only a specific pressure drop can the device release fluid flow out. A mathematical model based on Euler equation and Bernoulli equation [1] is proposed to analyze the fluid field distribution and the mechanism of the whole device, and the effect of different typical stream pattern (Laminar, Turbulent and Gasliquid flows) have been fully considered. Numerical simulation is carried out to validate the analytical solution. By optimizing diameter ratio of the device and implanting sensor part, a new valve can be designed to solve the problem of the flow fluctuation in gasliquid two phase flow.