Mechanical and Fluid Systems
Mechanical and Fluid Systems
The development of devices controlled or operated by or as if by a machine, machinery or human via the influence of physical forces or substances capable of flowing and changing shape at a steady rate when acted upon by a force so as to automatically execute human tasks.
Cryogenic Cam Butterfly Valve
A globe valve controls flow by translating a disc over an opening. A butterfly valve controls flow by rotating a disc in an opening. The disc and seat of a butterfly valve have to create a tight seal exactly when the disc meets the 90 degree mark. If additional torque (energy) is added to the actuator of a butterfly valve, the disc will rotate past 90 degrees and the valve will open again. Therefore, with a standard butterfly valve, additional actuator energy cannot be added to reduce or minimize seat leakage, like with a globe valve. The novel Cryogenic Cam Butterfly Valve (CCBV) design functions like a typical butterfly valve, rotated to open or close the valve. However, unlike a typical butterfly valve disc that can only rotate, the CCBV can be translated and rotated to control flow. The main parts of the CCBV include a body, disc, cam shaft, torsion spring and 180 degree actuator. In the full open position, disc rotation is 0 degrees and the disc is approximately perpendicular to the valve body to enable maximum flow. However, unlike a typical butterfly valve where the disc is not pinned to the shaft, the CCBV has a preloaded torsion spring mounted concentrically on the shaft with the spring legs against the disc, and a pin to keep the disc coupled to the shaft. The torsion spring is preloaded with sufficient torque so that the disc/shaft assembly acts like the disc is rigidly pinned to the shaft. The first 90 degrees of the actuator and shaft rotation rotates the disc, just like a typical butterfly valve; however, at approximately 90 degrees, one edge of the disc makes contact with the body seat, while the opposite edge is slightly off of the body seat. At this point, the disc can no longer rotate. The cam shaft then converts rotatory motion into translational motion. Because of the cam shaft lobes, as the actuator continues to rotate the shaft, the disc can now translate towards the body, and enables more of the disc to seal against the body seat. Therefore, all actuator and shaft rotation beyond 90 degrees translates the disc towards the body seat to create a tighter seal, similar to how globe valve functions. When the valve is in this position, seat leakage will be reduced and with additional actuator rotation, stopped. Eventually, a tight seal is formed in the full closed position. Then, with opposite shaft rotation, the valve will open. The CCBV incorporated the advantages of a globe to achieve tight seals from ambient to cryogenic temperatures.
Fluid Structure Coupling Technology
FSC is a passive technology that can operate in different modes to control vibration: Harmonic absorber mode: The fluid can be leveraged to act like a classic harmonic absorber to control low-frequency vibrations. This mode leverages already existing system mass to decouple a structural resonance from a discrete frequency forcing function or to provide a highly damped dead zone for responses across a frequency range. Shell mode: The FSC device can couple itself into the shell mode and act as an additional spring in a series, making the entire system appear dynamically softer and reducing the frequency of the shell mode. This ability to control the mode without having to make changes to the primary structure enables the primary structure to retain its load-carrying capability. Tuned mass damper mode: A small modification to a geometric feature allows the device to act like an optimized, classic tuned mass damper.
Freeze-Resistant Hydration System
Even when a water conformal fluid reservoir and drink straw are zipped into a down suit, water freezes under extreme conditions. This poses a health hazard, particularly to high-altitude climbers who mouth-breathe, as mouth-breathing causes substantial fluid loss (in exhaled breaths). Climbers of 8,000-meter peaks get only 1 liter or less of fluid on summit days because their drink bottles freeze so quickly. The High Altitude Hydration System keeps water from freezing in three different ways. First, the system has passive thermal control that uses aerogel insulation on the outside of the conformal fluid reservoir and around the drinking straw to protect the contents from the cold. The container is placed within an inner layer of clothing, and the insulated straw is pulled out from underneath the suit for sips. Second, the system has a braided copper wire placed around the exterior of the drinking straw and another heat-collecting surface about the container wall to transfer body-generated heat to the fluid reservoir and straw during use. Third, the system uses a microcontroller and tape heater powered by a battery to keep the straw warm and free of ice crystals.
Cryogenic Hydraulically Actuated Isolation Valve
NASA's cryogenic isolation valve technology uses solenoid valves powered by direct current (DC) electrical energy to control and redirect the energy stored in the upstream line pressure. Powering the solenoid valves only requires a DC power source capable of supplying 22 watts that can be distributed and controlled in an on/off manner. By achieving actuation using only upstream line pressure and a 22-watt DC power source, many additional support systems that are required for electromechanical and pneumatic actuation are eliminated. This reduction of parts results in several benefits, including reduced footprint, weight, and potential cost of the valve in addition to lower energy consumption. NASA fabricated several operational prototype valves using this technology for a rocket company. The table below shows the results of tests performed on these valves under cryogenic conditions. Please contact the NASA MSFC Technology Transfer Office for additional information.
3D-Printed Injector for Cryogenic Fluid Management
NASA's TVS Augmented Injector includes an internal heat exchanger, a fluid injector spray head, and an external surface condensation heat exchanger - all combined with multiple intertwined flow paths containing liquid, two-phase, and gaseous working fluid. The TVS provides a source of coolant to the injector, which chills the incoming fluid flow. This cooled flow promotes condensation of the tank ullage dropping pressure and maintains incoming fluid flow. The system eliminates the potential for a stalled fill condition and reduces tank pressure during cryogenic fluid transfer. During fill operations, the tank vent can be closed early in the process before fluid is introduced, and, in some cases, the tank vent may not even need to be opened. Furthermore, the TVS Augmented Injector can remove sufficient thermal energy to reach a 100% liquid level in the receiver tank. A cryo-cooler can be used in place the TVS flow circuit for a zero-loss system. The TVS Augmented Injector couples internal fluid flow cooling and external surface ullage gas condensation into a single, compact package that can be mounted to small tank flanges for minimal impact insertion into any vessel. The injector is printed as one part using additive manufacturing, resulting in part count reduction, improved reproducibility, shorter lead times, and reduced cost compared to conventional approaches. The injector may be of particular interest in applications where cryogenic fluid is expensive, fluid loss through vents is problematic, and/or achieving high filling levels would be helpful. The injector can benefit typical cryogenic fluid transfer between containers or, alternatively, can serve as a tank pressure control device for long-term storage using a fluid recirculation system that pumps fluid through the injector and sprays cooled liquid back into the tank. Additionally, where ISRU processes are employed, the injector can be used to liquefy incoming propellant streams.
Normally-closed (NC) Zero Leak Valve
The valve consists of two major sub-assemblies: the actuator and the flow cavity. The actuator is preloaded to 1,250 N by adjusting the preload bolt, pressing the Terfenol-D against the now-deflected belleville springs. When actuation is needed, either solenoid coil is charged in a pulsed mode, causing magnetostriction or elongation in the Terfenol-D which deflects the belleville spring stack, supplying an increasing load to the stem until the parent metal seal is fractured. Once fractured, the spring inside the bellows drives the bellows base downward, onto a raised boss at the top of the fracture plate. When fracture has occurred, the stem and its spring stack is left, separated from the actuator column. The Terfenol-D is unloaded and returns to its original length. The valve remains open due to the spring inside the bellows.
Fluid Flow Metering and Mixing Technologies
The suite of innovations includes: a fluid-mixing plug with metering capabilities; an unbalanced-flow, fluid-mixing plug with metering capabilities; a flow meter plug with length-to-hole size uniformity; and an eddy-current-minimized flow plug for use in flow conditioning and flow metering. How it works: The innovations included in this technology suite are variations of the same base innovation, which typically consists of a fluid plate or plug of varying thickness. The device is simple to install and can be mounted between two flanges in a fluid-flow conduit, or it can be threaded or welded into the conduit. In some curved-pipe applications, the device can be integrated into a pipe fitting, bend, elbow, or tee. The face of the plug features several ports through which fluid flows. The orientation and position of these ports vary, depending on the needs of a specific application. The design balances fluid flow and kinetic energy across the plug face to create the desired flow effect. The device can smooth the fluid flow for superior conditioning, decrease turbulence for highly accurate metering, or increase turbulence to enhance fluid mixing. For example, discrete openings parallel to the fluid flow will decrease turbulence for accurate metering and conditioning. Other shapes of fluid openings can be introduced to change flow velocity or energy. The openings can also contain tapers and/or be directed along an unparallel path to the flow conduit to induce fluid mixing. In addition, the open flow area of the plug can be more heavily weighted on one side to amplify or offset the fluid effects around bends. Why it is better: The base for Marshall's suite of flow metering, mixing, and conditioning technologies is a unique innovation that offers improved performance in a wide range of applications. It is the only small, easy-to-install device of its kind that provides the ability to control turbulence, improve metering accuracy, or encourage thorough mixing. The innovation also facilitates rapid recovery of fluid pressure, helping to decrease power requirements and their associated costs.
Harsh Environment Protective Housings
These connectors are designed to be used in harsh environments and to withstand rough handling, such as being stepped on or rolled over by wheelbarrows or light vehicles. If the demated connectors are dropped or placed on the ground, the end caps will shield them from damage and contaminants. When mated, the seal between the housings and end caps keeps contaminants out. The end caps are latched to the housings so that the caps cannot be unintentionally opened; this latch can be opened only by depressing the levers. The spring used to open or close the cap is constructed of a shape memory alloy, allowing the cap to be opened and closed an almost infinite number of times. The cap actuation levers are designed so that only a 3/4-inch pull is needed to open the cap a full 190 degrees. The housings can accept most commercial-off-the-shelf electrical or fluid connectors (including those designed for cryogenics), thus eliminating the need for specialized connectors in hostile environments. The housings can also be grounded and scaled up or down to accommodate connectors of different sizes. The housings can be constructed of steel, aluminum, composites, or even plastic, depending on the environment in which they will be used and material cost constraints.
Multi-Stage Filtration System
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.
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