GEOMETRY AND HEAD LOSS IN VENTURI INJECTORS THROUGH COMPUTATIONAL FLUID DYNAMICS

To determine the influence of geometry on the hydrodynamic behavior of Venturi injectors, using computational fluid dynamics techniques, we studied, at the Universitat Politecnica de Valencia, Valencia, Spain, the geometric parameters that exert the most influence on head losses: the relationship between throat diameter and nozzle (beta), nozzle angle (alpha(1)) and diffuser angle (alpha(2)). In addition, three throat morphologies (B1: nozzle-throat and throat-diffuser with a sharp edge; B2: nozzle-diffuser with a zero-length, sharp-edge throat; B3: nozzle-throat and throat-diffuser with rounded edge). We analyzed their influence on the velocity distribution and differential pressure between inlet and throat (DP/gamma), throat and outlet (Delta h(v)/gamma), and outlet and throat ((P3-P2)/gamma). The development of the velocity profile from the throat is slower the greater alpha is and the lower alpha(2) is. DP/gamma decreases with beta, increases with alpha(1) and varies little with alpha(2). Delta h(v)/gamma decreases with beta and increases with alpha(1) and alpha(2). (P3-P2)/gamma decreases with beta and increases with alpha(1) and alpha(2). Geometry B3 decreases the losses and delays the onset of cavitation. Thus, the lower beta and the higher alpha(2), the greater the losses; however, the influence of alpha(1) is less clear. The rounded edges produce lower head losses.