Internal Flow of an Inscribed Trochoid Gear Pump at Low Reynolds Numbers (Evaluation of Pumping Characteristics with 3-D Numerical Simulation):Evaluation of Pumping Characteristics with 3-D Numerical Simulation

The pumping characteristics and the internal flow structure of an inscribed trochoid gear pump are investigated by means of three-dimensional numerical simulation. Cartesian grid system is employed to calculate the fluid flow while the boundary conditions on rigidly rotating gear surface is expressed with Lagrangian markers. The results reveal that the flow rate and the pressure rise obtained by the pump become the highest at Re=10 when the clearance between the two gears is considered. At lower Re numbers, the shear stress transfer on the gear surface fluctuates significantly resulting into lower performance. For higher Re numbers, backward induced jet flow through the clearance makes the internal flow complicated due to non-uniform centrifugal acceleration.