A micro-fluidic oscillator is a device that generates an oscillating fluid jet at its two output ports. The linear tool is a linear actuator that transforms the fluidic energy into mechanical energy via a double acting piston placed in linear actuator housing. Together the two devices form a dynamic microsystem that can be used in medical application.
Since the system is influenced by the characteristics of the micro-fluidic oscillator, the parameters that affect the performance of a fluidic micro-oscillator are important in the design of the whole system. The performance factors are frequency and output pressure difference, and they depend strongly on the geometric parameters like nozzle width, splitter distance, setback distance and control port width, etc.
Considering the importance of these parameters, only four of them are chosen as design variables. And they are reduced to three dimensionless parameters using Pi theorem. An object function is output pressure difference, and the output pressure difference is chanced to pressure coefficient.
For this, computational analysis is carried out using the CFD software (Fluent 6.0). Characteristics of the fluidic oscillator are shown through the velocity distribution, pressure distribution, control pressure and output pressure. With the simulation, Pressure coefficient curves for each parameter are obtained. The pressure coefficient curves are essential for the shape optimization of oscillator because each graph is used as the object function.
There are various methods for optimization. But the pressure coefficient curves include errors because the result is fitted to polynomial curves. Therefore it is necessary to use cyclic coordinate method. The cyclic coordinate method is suitable in case the object function is unknown. As the result, we can obtain improved pressure coefficient as compared with the previous models.
Also, Frequency is the other performance factor of oscillator. The frequency of oscillation is linearly proportional to the volume flow rate through the main nozzle. In the optimized oscillator, the frequency has the wide linear range. This shows that increased pressure coefficient results in increased the linear range.
