Mechanical & Fluid Systems

Two-Equation Turbulence Models for Application to Internal Flow Through Pneumatic Valves

Applications include design, analysis, and optimization of valves and pumps. John F. Kennedy Space Center, Florida Predicting turbulent flowfield and pressure drop in complex internal flows, such as valves, pumps, and turbines, is of great interest in many areas of technology. Accurate prediction of three-dimensional (3D) flowfield in complex devices is critically dependent on the accuracy of the turbulence model used to describe the turbulence energy production and dissipation processes within the flowfield region of interest.

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Swan Seal

The seal can be sized to any application while maintaining its important features. John H. Glenn Research Center, Cleveland, Ohio This seal features dual sealing capabilities: a face seal and an axial seal. The name swan seal is derived from its cross section, which resembles a swan. Most injector designs require fuel to be delivered from an inlet fitting, through a feed arm, to the injector tip. Temperature variation from the inlet to the tip, from the cool fuel to hot combustion air, and from startup to full power, often poses a challenge due to thermal growth. One of the most challenging areas is accommodating the growth differential between a hot feed arm and a cool fuel delivery tube, which is exacerbated by the relatively long distance. Several methods have been used to allow for this including coiling the fuel tube, utilizing an O-ring sliding seal, metal C-seals, or incorporating stretchable bellows. Some of the drawbacks of these methods include limited space, poor durability at high temperatures, serviceability, long lead times, and cost. The swan seal presents a compact, high-temperature, replaceable, low-cost option for this and other applications where a sliding axial seal is required.

Posted in: Briefs, TSP

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Piezoelectric Actuated Valve for Operation in Extreme Conditions

The low-power, compact valve can be used wherever valves are required in harsh environments. NASA’s Jet Propulsion Laboratory, Pasadena, California The extreme conditions on Venus (460 °C and 92 atm) prevent the use of any of the existing science instruments outside of the lander. To transfer a sample into the lander, a pneumatic mechanism was conceived that could bring sample powder into the lander. The mechanism is critically dependent on the availability of valves that can operate at the conditions on Venus. The ability to perform the sample transfer will enable the use of instruments that require direct access to the sample, but cannot sustain Venus’ ambient environment.

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A Field-Reconfigurable Manipulator for Rovers

Applications include bomb disposal, disaster recovery, search and rescue, and law enforcement. Lyndon B. Johnson Space Center, Houston, Texas, and Ames Research Center, Moffett Field, California Robotic technologies will be deeply involved in any future human mission to the Moon. Prior to human arrival, robots will survey and explore the lunar surface, establish infrastructure, and assemble and test habitat modules. Once humans have arrived, the robots must be able to assist human exploration activities. After the humans depart, robots will perform cleanup, maintenance, and documentation tasks. All these various robotic activities will require sensing and manipulation of the environment, but in quite different ways: a survey robot has very different requirements from a habitat assembly robot. It would be inefficient to launch a different robot for each task, yet a single robot capable of performing all of them would be ungainly and impractical. Instead, what is needed is a “kit” of robot parts that can be assembled into the desired robot for each task.

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Lightweight, Flexible, Freezable Heat Pump/Radiator for EVA Suits

The absorption cooling process can be used to provide portable, regenerable refrigeration and air conditioning for recreation, transportation, and medical applications. Lyndon B. Johnson Space Center, Houston, Texas For space exploration missions that may require extended stays and extensive extra-vehicular activity (EVA) operations, the temperature control system must be lightweight, rugged, non-venting, and repairable in space.

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Cryogenic Balloon End Fitting Seal

The seal does not crack or leak at cryogenic temperatures. NASA’s Jet Propulsion Laboratory, Pasadena, California Typical lighter-than-air vehicles utilizing a superpressure design such as balloons, aerostats, or blimps, have one or more fittings attached to the gas containment skin that can serve as load attachment points or inflation/vent ports. These fittings are often sealed to the skin with a silicone gasket and a room temperature vulcanizing (RTV) adhesive. This type of seal works very well over the temperature range encountered in the Earth’s atmosphere (–60 to +40 °C). However, balloons designed to operate at Titan or Mars would encounter temperatures much colder than those found on Earth, making this type of seal inadequate.

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Compact Regenerative Blower

The blower can be used to provide ventilation flow for astronauts in spacesuits, cooling for soldiers wearing body armor, or in personal cooling systems for construction work, law enforcement, or firefighting. Lyndon B. Johnson Space Center, Houston, Texas The regenerative blower provides air flow through structures or systems that have relatively high flow resistance. Specifically, the regenerative blower was designed to provide a flow of ventilation gas through a spacesuit and its portable life support system (PLSS). Since the ventilation gas is primarily oxygen, fire prevention is a critical design requirement.

Posted in: Mechanics, Briefs

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