Measurements on Water Spray for Suction Air Cooling System along Flow Direction

Abstract

Water spray characteristics are evaluated by a phase Doppler anemometer (PDA). PDA can provide the spray velocity and its diameter. The spray is tested in a wind tunnel which has 1m square plane and 2.5 m in length. The surround air conditions are 2.0 m/s of mean diameter, 33 degree Celsius of mean temperature and 60 % of humidity. The measurement planes are 100 mm and 600 mm from nozzle exit. A pin jet type nozzle which has a pin near the nozzle outlet hole is tested. One dimensional PDA system is applied for making measurements. Spray is spreading with the distance from the nozzle exit and then the data rate is decreasing from upstream to downstream. Mean velocities in the upstream is larger than that of downstream. In the downstream, the mean velocity profile becomes flat shape and it becomes almost the same as the air mean velocity. There is no clear tendency in the mean diameter and the Sauter mean diameter distributions. Differences in all data profiles for both vertical and horizontal directions are observed. This is caused by the unsteady and uneven spatial droplets distribution of the present spray.