Mechanical Engineering Department, National Research Centre Mechanical Engineering Department, National Research Centre
Thesis Title
| SPRAY DYNAMICS UNDER THE EFFECT OF ACOUSTIC WAVES |
Awarding University and Year
| Faculty of Engineering – Cairo University – 2001 |
Abstract
| An experimental Study is conducted to characterize the turbulent flow structure of isothermal sprays subjected to an acoustic field excitation. The spray is produced by high shear atomizer .The acoustic ideal axisymmetric acoustic waves. The speakers are connected to an amplifier and an audio generator to obtain different sound pressure levels and frequencies .
The spray parameters are measured by using a phase Doppler particle analyzer. The droplets sauter mean diameter (SMD) , droplets mean velocities and droplets number densities, Liquid volume flux, and root mean square velocities are measured at several and axial Locations. Also the cone angle is measured by direct photography method. With and without excitation under the same operating conditions. Five liquid flow rates are considered; 2.5, 3 38, 4.34, 6. 18 and 7.5 g/sreaspectively Five air flow rates are used; 1.49,2.024,2.6,2.88 and 3.2 g/s. the experimental program cover a Strophe number ranges from 0.15 to 0.75. This range represents the fundamental mode as well as the subharmonic modes. The obtained results cover different sound pressure levels ranges from 95 to 110 dBA. The results indicate that the spray characteristic parameters are almost symmetric about the spray axis. At each axial spray cross section, the SMD has a minimum value at the spray centerline has a more comlex variation in the downstream direction because of the secondary atomization at high air velocity near the nozzle exit and droplet . |