Aerodynamic device

G. J. Green, F. Takahashi, D. E. Walsh, and F. L. Dryer Aerodynamic device for generating mono-disperse fuel droplets. Review of Scientific histraments, 60(4), 646-652 (1989). 

Air Brake Aerodynamic device used to slow a wind-turbine rotor in strong winds, important to prevent damage. 

Another concept considered for noise reduction in jet engines for civil aircraft are aerodynamic devices called chevrons, which are placed along the trailing edges of a jet engine primary and secondary exhaust nozzle. These chevrons need to be fine tuned between noise-benefit and thrust-loss, where a solution has been proposed by using SMA actuators to position the chevron in accordance to the on-ground and cruise level temperatures [47]. 

Ventilation for buildings - Air terminal devices - Aerodynamic testing of dampers and valves. Superseded BS 6821 1988... 

EN. 17.51, Ventilation for buildings—Air terminal devices—Aerodynamic testing of clampers and valves. 

Aerodynamic drag has also been used to capture energy from the wind. Drag mechanisms consist of flat or cup-shaped devices that turn the rotor. The wind simply pushes the device around the main shaft. Anemometers used to measure wind speed are often drag devices, as are traditional farm windmills. 

Studies have shown that in order to clear the oropharyngeal impaction barrier (comprising the mouth, throat, and pharynx), particles with aerodynamic diameters smaller than 5 pm are required [3,4]. Only particles with aerodynamic diameters less than 3 pm reach the terminal bronchi and the alveoli in significant numbers [5]. Therefore, the particle diameter required to be produced by the delivery system depends to a great extent on the intended target lung tissue. Lung deposition is also affected substantially by the specific inhalation dynamics of the patient, which in turn are influenced by the delivery device. This article addresses various attributes of the dry powder inhalation product, from intrinsic material properties to final product performance. 

As described in Section 3.3 in more detah, particles in the aerosol cloud should preferably have an aerodynamic diameter between 0.5 and 7.5 pm. Currently three different types of devices are used to generate aerosol clouds for inhalation nebulizers (jet or ultrasonic), (pressurized) metered dose inhalers (pMDIs) and dry powder inhalers (DPIs). The basic function of these three completely different devices is to generate a drug-containing aerosol cloud that contains the highest possible fraction of particles in the desired size range. 

The device resembles a cylindrical differential mobility analyzer (DMA) in that a sample flow is introduced around the periphery of the annulus between two concentric cylinders, and charged particles migrate inward towards the inner cylinder in the presence of a radial electric field. Instead of being transmitted to an outlet flow, the sample is collected onto a Nichrome filament located on the inner cylinder. The primary benefit of this mode of size-resolved sampling, as opposed to aerodynamic separation into a vacuum, is that chemical ionization of the vapor molecules is feasible. Because there is no outlet aerosol flow, the collection efficiency is determined by desorption of the particles from the filament, chemical ionization of the vapor, separation in a mobility drift cell, and continuous measurement of the current produced when the ions impinge on a Faraday plate. 

Air classifiers may have external or internal aerodynamic cycles. The former devices are constructed independently of dust collectors and fans and connected to them via pipelines. The internal-cycle (recirculating-air) devices contain these elements in a single unit, and hence need less production area and normally require lower investments. They have several technical shortcomings outlined in subsection 3.5. 

Separation in these devices known as winnowing machines [3], is achieved due to the difference between trajectories of coarse and fine particles in the separation zone (Fig. lb). Their operation and efficiency are strongly affected by the stochastic factors of the process, in particular by uncertainties in feeding and particles aerodynamic interactions. In most cases coarse particles prevent proper classification of fines. Separation efficiency of these devices is usually low. They are normally used for separation of solid particles according to densities (e.g. grain from peel), rather than by size. Sometimes crossflow separation in horizontal streams is used in combination with other separation principles. 

---