Simulation And Calculation Of Annular Gap's Leakage And Friction Based On CFD

In actual project problem, the gap is nowhere absent, for instance, the gap between piston and cylinder of the piston pump and piston motor , the gap between valve core and sleeve in spool valve subsidiary, and so on.All in all,the gap under these situations are all concentric annular gap which are made up of inner cylindrical surface and outer cylindrical surface.The leakage and friction in gap problem is inevitable .The main body of the paper is emphasized when having studied two concentric circles cylindrical surface of composition gap all moves, derivation the formula of gap leakage, the comparison between theory calculate value and simulating calculating value; and friction of two column face in the process of motion is studied; the relationship of the ratio of friction to velocity;theory value and simulating value are analyzed.The main contents of the thesis:In the first chapter, the paper's significance and purpose, related internal and overseas documents , the main job of the paper are expatiated.In the second chapter, model of the gap between inside and outside column face is built.The model setup involves geometrical model setup and laminar model setup .First of all, model is built by Pro/E and meshes are generated in gambit, then flow field inside model is simulated and results are analyzed. Calculating method , calculating equation and simulator calculating process in calculation fluid dynamics are simply presented.In the third chapter, when the two column faces of the concentric circles move, the formula of leakage is carried out And the theory value and simulated value about leakage are analyzed and compared. At the same time, the moving velocity of the two column face is difference; the velocity vector Fig and the velocity magnitude contour Fig are displayed by visualizing images.In the fourth chapter, when the column faces of the concentric circles move, the friction on the column faces are calculated in theory. The relationship of the ratio of friction to velocity is analyzed.Theory value and simulating value are analyzed and compared.In the fifth chapter, content of full text is summed up.Appendix 1, The velocity distribution of Couette.Appendix 2, The velocity distribution of Poiseuille.