High-Speed Droplet Generator

NASA's miniaturized electrosprayer offers a new technology that may support the next generation of portable and/or of precise electrosprayers. Developed for applying water to plants in space where gravimetric methods do not apply, this sprayer may also enable the delivery of a precise liquid for terrestrial uses without relying on pressurized air. Electrospraying (aka electrostatic spraying) is a technique where droplets are charged to enhance surface adhesion and coverage efficiency. Various electrospray variants are used in a host of industries to coat auto parts, apply pesticides and nutrients to crops, and more. Commercially-available electrosprayers are generally large, air-assisted devices that traverse up to 20 feet in the air and require large amounts of liquid and electrical power. NASA's miniaturized electrosprayer system does not require compressed air, uses far less liquid, and concentrates the mist in an area less than 2 feet away. The system only needs enough power to charge the droplets at the spray nozzle, so it may use small batteries (e.g., AAA batteries). The new electrosprayer implements a unique nozzle design that imparts a high charge-to-mass ratio on the spray and increases coverage efficiency. Thus, the miniaturized electrosprayer can be placed inside a portable, handheld sprayer or be used as a stationary device for a wide range of uses, particularly when spraying expensive chemicals (e.g., plant nutrients) and when precise, efficient spraying is required (e.g., industrial coatings, disinfectants, etc.).

Both oscillators are flow control devices based on novel geometric designs. They have no moving parts and produce spatially oscillating jets. Each was designed to address a particular limitation of current oscillators. Gaining control authority by decoupling frequency and amplitude: Existing oscillators are limited in that the frequency of oscillation is controlled by input pressure or mass flow rate--the frequency and amplitude (mass flow rate) are coupled, limiting control authority over the oscillators. The new oscillator design decouples the frequency from the amplitude by employing a novel design featuring a main oscillator that controls the amplitude and a small oscillator that controls the frequency of the oscillations (see Figure 1). The decoupled oscillator delivers high (or low) mass flow rates without changing the frequency and vice versa. Gaining control authority by synchronizing the entire oscillator jet array: Existing oscillators in an array oscillate randomly. While this is useful for mixing enhancement, synchronized flow may be more beneficial for active flow control applications. The simple design of the new Langley synchronized oscillator achieves synchronization without having electro/mechanical or any other moving parts. The new oscillator enables synchronization of an entire array by properly designing the feedback loops to have one unique feedback signal to each actuator. Once each actuator has the same feedback signal, each main jet attaches to one side of the Coanda surface at the same time, allowing synchronized oscillation, as shown in Figure 2.

This durable, transparent, nano-textured coating can be applied via a wet chemistry process to variety of rigid and flexible surfaces by spin coating, brush application, or spray application, making it applicable for many purposes beyond space flight and aeronautical applications. The coatings unique nano-textured surface and overcoat reduces surface energy and contact surface area, giving the coating anti-contamination and self cleaning properties that minimize dust, liquid, and ice accumulation on its surface, similar to a leaf on the Lotus plant. The coating is low outgassing, stable in vacuum, and can survive harsh spaceflight environments. Depending on requirements, the Lotus Coating can be tailored to fit the specific needs of a project or customer. This customization makes the Lotus system far more adaptive, allowing for a more diverse range of applications.

Storage and transfer of fluid commodities such as oxygen, hydrogen, natural gas, nitrogen, argon, etc. is an absolute necessity in virtually every industry on Earth. These fluids are typically contained in one of two ways; as low pressure, cryogenic liquids, or as a high pressure gases. Energy storage is not useful unless the energy can be practically obtained ("un-stored") as needed. Here the goal is to store as many fluid molecules as possible in the smallest, lightest weight volume possible; and to supply ("un-store") those molecules on demand as needed in the end-use application. The CFC concept addresses this dual storage/usage problem with an elegant charging/discharging design approach. The CFC's packaging is ingeniously designed, tightly packing aerogel composite materials within a container allows for a greater amount of storage media to be packed densely and strategically. An integrated conductive membrane also acts as a highly effective heat exchanger that easily distributes heat through the entire container to discharge the CFC quickly, it can also be interfaced to a cooling source for convenient system charging; this feature also allows the fluid to easily saturate the container for fast charging. Additionally, the unit can be charged either with cryogenic liquid or from an ambient temperature gas supply, depending on the desired manner of refrigeration. Finally, the heater integration system offers two promising methods, both of which have been fabricated and tested, to evenly distribute heat throughout the entire core, both axially and radially.

While HEPA filter elements can last for years without intervention, pre-filtering systems that remove larger particles before they reach the HEPA filter need to be treated (most often by cleaning or replacement) as often as once a week. These treatments can be resource-intensive and expensive, especially in extreme environments. Glenn's innovative system combines a pre-filtration impactor and a scroll filter that reduces the need to replace the more sensitive or expensive filters, extending the system's working life. The system uses an endless belt system to provide the impaction surface. A thin layer of low-toxicity grease is applied to the impaction surface to increase particle adhesion. A high flow turning angle near the impaction surface causes relatively large particles to impact and stick to the surface while smaller particles stay within the air flow. When the surface is covered with particles - or if a layer of particles has grown to a thickness that impairs adhesion - the surface is regenerated. The band is rotated so that the loaded surface passes by a scrapper, removing the layer of particles and a clean segment of the band revolves to become the new impaction surface. A further innovation is the scroll filter which allows the filtration media to be rotated out of the airflow when fully loaded, providing multiple changes of the filter through a motorized scrolling or indexing mechanism. When nearly fully loaded with dust particles, the exposed media is mechanically rolled up on one side of the filter to both contain and compactly store the dust. The spools that hold the clean and spent filter media are mounted on roller bearings to facilitate the scrolling operation and reduce motor power requirements. Nearly any grade of filter media can be used to meet the desired filtration specification. Additional media rolls can be added after the original roll is spent to further increase filter life.