Computational simulation of a high efficiency nebulization method

SANTIAGO, ALFONSO; UBAL, SEBASTIAN

Mendoza

Congreso; High Performance Computer Latin America (HPCLatAm2013); 2013

Nebulization techniques have undergone great improvement in the last 100 years, when herbal cigarettes with opioid compounds were used to treat diseases such as asthma or bronchitis. Today state-of-the-art nebulizers are used to aerosolize insulin for diabetes treatment, DNA fragments for gene therapy, and drugs in a extremely fine and homogeneous mist in order to increase lung deposition. Such devices are those who work by VMT (vibrating mesh technology). These devices use a multiperforated membrane which vibrates at ultrasonic frequencies by a piezoelectric device. This operating principle result in a very sharp droplet distribution and with a nozzle design whereby to obtain drops between 1 and 5 microns, it is easy to obtain a superb aerosol for medical use. In the first pages of this work, a comparison between the different nebulization principles is performed, outstanding the ones that work by the VMT principle. After that, the process that generates the spray is modeled, explaining the governing equations and generalizing them by dimensional analysis. Afterwards, the equation system for both fluids and the interface between them is solved by FEM (Finite Element Method), previously defining the mesh, boundary conditions and domain conditions. In this work we used a fixed geometry and studied the eject regime behavior as a function of vibration frequency and amplitude. It could be easily seen that, after a short transient period, a quasi-periodic ejection regime is reached with droplets that tend to impact and coalesce. A graph that shows the critical ejection amplitude as a function of the frequency was obtained. With this tool the combination of amplitude and frequency can be picked in order to obtain atomization for the current geometry.