Pressure-swirl spray in a low-turbulence cross-flow

Description of Study Test Case

The conical liquid sheet produced by water spraying from a PSA was investigated in cross-flow of non-heated, non-pressurised air. See Figure 1b, which shows the atomizer in the test section. The atomizer was operated continuously in cold-flow (non-reacting) conditions. It generated a water spray at inlet pressure, $p_{\text{in}}$ , of 0.5 MPa. The flow conditions of the atomizer are described by Reynolds number:

Re_{\text{in}}=\rho _{\text{in}}u_{\text{in}}D_{\text{in}}/\mu

(14)

where $\rho _{l}$ is the liquid density, $u_{\text{in}}=Q_{\text{l}}/A_{\text{in}}$ is the liquid velocity at inlet ports and $D_{\text{in}}={\sqrt {4A_{\text{in}}/\pi }}$ is the hydraulic diameter of the inlet ports (for atomizer details see Figure 7 and corresponding text in section Experimental Set Up). The $Re_{\text{in}}=1330$ . The presented case is one of three inlet pressure cases ( $p_{\text{in }}=\mathrm {0} .25,0.5,1$ $\mathrm {MPa}$ ) measured and studied in ^[1]. The interaction of the spray with the cross-flowing air is controlled by the ratio of the momentum of liquid to the air momentum, $q$ (see Equation 10) and by the Weber number which relies on the surface tension forces of the liquid film with the drag forces of the airflow, $We_{a}$ (Equation 11) or $We_{r}$ (Equation 12). $We$ and $q$ values for the experimental regimes are given in Table 2.