Active control of sprays using a single synthetic jet actuator

LEM Characterization of Synthetic Jet Actuators Driven by Piezoelectric Element: A Review

“…By using Equation (10), it can be shown that this term is proportional to 1 2 (p i 2 (T) − p i 2 (0)) and, therefore, it does not give any contribution because p i assumes the same value at the beginning and end of each cycle. One can reach the same result by observing that the pressure work is conservative by definition.…”

“…These devices are able to manipulate the flow, to modify its structure and allow a favorable variation of the aerodynamic forces on aircrafts (Glezer and Amitay [1], Cattafesta and Sheplak [2], Smith and Glezer [3]). Their application field is extremely wide, including flow control (e.g., Glezer [4] and, more recently, Van Buren et al [5]), mixing enhancement (Wang and Menon [6], Tamburello and Amitay [7]), heat transfer from small surfaces (Pavlova and Amitay [8], Chaudari et al [9]), spray vectoring (Pavlova et al [10], Marchitto et al [11]), micropropulsion (Finley and Mohseni [12], Parviz et al [13]), active control for MAV (Otani et al. [14]), and many others.…”

Active performance enhancement of spray cooling

“…Thus, a precise control of the amount of water siphoned, for a given air flow rate, was enabled. Note that the water flow rate through the spray nozzle depended on two parameters: the water intake level elevation L w , and the air flow rate (the relationship between the water flow rate and the air flow rate was presented in our previous papers, Pavlova et al, 2007Pavlova et al, , 2008. Water was pumped from a 37.9 l container, equipped with a water level meter and a type-T thermocouple, by a diaphragm pump through a closed 7.6 l pressure vessel, which was used to damp out the unsteadiness associated with the pump.…”

“…Shadowgraphy measurements were acquired at 45 locations in the spray, such that the effect of active flow control could be determined for the entire three-dimensional spray. In the present paper, only data along the centerline of the spray are presented for brevity [for more details about the Shadowgraphy technique, including a complete description of droplet sizing and velocity measurements, as well as for the full 3D field, see previous work by Pavlova et al (2007Pavlova et al ( , 2008]. In these measurements, the resulting uncertainty in the velocity is ±0.1 m/s and ±0.5 lm in the droplet diameter.…”

“…When the synthetic jet is activated, there is a small effect near the orifice, while the spreading of the spray is significantly enhanced farther downstream. For detailed information on the behavior of the spray when a single synthetic jet is used for flow control, as described above, refer to (Pavlova et al, 2008).…”