Structural and flow relationship of microfluidics pulsating high and low frequency jets

Synthetic jets are being investigated last several years. Researchers have been interested in its unique applications for a wide range of flow control to thermal management of electronics applications. Synthetic jets are made up of actuators such as piezoelectric, magnetic, or linear piston technology etc. Piezoelectric synthetic jets are investigated and found relationship between its structural and flow parameter like deflection, frequency and resonance with velocity and heat transfer enhancement. In order to find a relationship some numerical and experimental techniques are being used. For experimental result and fully-automated experimental setup made using high end equipment like Laser Vibrometer, Hotwire anemometer and 3D robot. Four different type of measurement were made on synthetic jet actuators deflection, heat transfer, velocity measurements and power consumption. The heat transfer enhancement factor of each of these jets with respect to natural convection is measured over a 25.4x25.4 (mm) vertical heater. Finally, power consumption of the low and high frequency synthetic jets were measured and compared. It is found that disk deflection and operating frequency are directly related to heat transfer enhancement factor, if the Helmholtz frequency of a cavity has no effect on the performance of a jet. For numerical analysis commercially available software are used like Ansys and Comsol. Eigen frequency and transient deflection is modeled using Comsol 4.0 and different mode shapes and deflection measurements using PZD module of Comsol. A 3-D computational fluid dynamics model was constructed using Ansys CFX to determine the flow and temperature fields of a meso-scale central orifice synthetic jet at a nozzle-to-target surface spacing of y/d = 2, ReDj = 1400 and f = 500 Hz. Unlike the majority of previous computational studies, rather than specifying the boundary conditions at the nozzle, the flow inside the synthetic jet device was solved by specifying the time dependent boundary conditions on the vibrating diaphragm and utilizing the moving mesh technique. Local surface pressure and heat transfer coefficient distributions were determined and discussed. It was found that the pulsating flow at the nozzle exit for a round jet generates vortex rings and these rings seem to have some considerable effects on the target surface profiles. Finally figure out the design parameters for Synthetic jet actuator for the optimum performance.