Simulation And Analysis Of External Helical Gear Pump Flow Field Based On Fluent

As one of the most important hydraulic power units, external gear pump with the advantages of simple structure, self-priming performance, insensitivity to oil pollution, and reliable work, has been applied in practical engineering. With the increasing demand of industrial manufacture, helical gear pump as one type of gear pump, receives more and more attention. The disadvantages of the external gear pump are great internal leakage, big radial force, wide noise and vibration caused by trapped oil phenomenon. By means of FLUENT dynamic grid technology, the present paper simulates the internal flow field of helical gear pump and analyzes the trapped oil phenomenon. At last, it sums up the characteristics of helical gear pump trapped oil and the factors which can influence it, and further analyzes the internal leakage problem.In this thesis, theoretical analysis and numerical simulation are used to analyze and calculate the radial force and trapped oil pressure of the external gear pump, and provides the appropriate numerical methods for the optimal design of external gear pump.Main contents are as follows:In Chapter1, the background and significance of this thesis are presented. It briefly introduces the current study on gear pump at home and abroad and stretches the main content of the present paper.In Chapter2, it mainly introduces the fluid dynamic equations of the gear pump, and expounds turbulence model of fluid flow. It also presents three major performance index of gear pump.In Chapter3, it presents how to construct a three-dimensional model of internal flow field inside the helical gear pump. It expounds the dynamic mesh in the software FLUENT. By comparing the trapped oil pressure phenomena of helical gear pump and straight gear pump, the transformation rules of helical gear pump trapped oil pressure can be shown.In Chapter4, it analyzes trapped oil phenomena under different conditions of distinctive helical angles and tooth widths and the transformation rules of these phenomena.In Chapter5, it analyzes the tooth surface load of gear tooth surface under the effect of high pressure oil in trapped oil field. In Chapter6, it analyzes the phenomenon of internal leakage inside the helical gear pump.At the end, some conclusions in this thesis are summarized and the future research proposals are suggested.