A Numerical Simulation and Comparison of Cutting Fluid Flow Characteristics through Gradual Contraction and Sudden Contraction Nozzle

Cutting fluid delivery plays an important role in every machining operation. Cutting fluid is generally delivered by a gradual converging nozzle. The present work shows an extensive numerical study on the performance of cutting fluid flow through gradual converging and sudden converging nozzles. The Nevier-Stokes and continuity equations are solved using the commercial CFD software FLUENT 6.3.26 that employs the control volume technique on a uniform staggered grid following the SIMPLE algorithm. For the sudden contraction configuration, two contraction ratios, 0.28 and 0.55, are taken. The following variables and their variations are computed for both sudden and gradual contraction: wall static pressure (WSP), wall shear stress (WSS), and centerline velocity (V_centerline). For both gradual and sudden contraction, WSP, WSS, and V_centerline increase with increases in Reynolds number. For a particular Re, the WSP decreases with increases in the length from the throat for both nozzle types. In the gradual converging nozzle, the WSS and V_centerline increase with increases in the length from the throat; in contrast, in the sudden contraction configuration, the V_centerline increases up to a few distances from the throat and afterward remains same up to the exit of the nozzle. For the same amount of increase in V_centerline, the suddenly converging nozzle requires shorter lengths than the gradually converging nozzle.