Home

Airfoil-Shaped Fluid Flow Tool for Use in Making Differential Measurements

Researchers at NASA’s Marshall Space Flight Center have developed a suite of adaptable flow measurement devices that can be easily installed without compromising the structural integrity of existing conduits. With their simple installation procedures, the devices can be removed or exchanged without difficulty, allowing for temporary or extended use. The design is in-situ and self-contained, taking measurements from within the conduit, thereby offering more accuracy and allowing for opportunities to modify system operating parameters. Some of the designs can be used to mix the flow or inject a second fluid into the stream.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

Read More >>

Piezo-Actuated, Fast-Acting Control Valve

The ability of this valve to throttle makes it suitable for regulators and cold gas thrusters.High-power electric propulsion systems have the potential to revolutionize space propulsion due to their extremely high performance. This can result in significant propellant savings on space vehicles, allowing the overall mass to shrink for launch on a less expensive vehicle, or to allow the space vehicle to carry more payload at the same weight. Many electrical propulsion systems operate in pulse mode, pulsing hundreds or thousands of times per second. Creating reliable valves that can operate in pulse mode for extremely long periods and at low power is critical in these applications. Current solenoid valves have difficulty achieving the life requirements. In addition, a valve with the ability to throttle has the potential to simplify the entire propulsion system by eliminating the need for pressure regulators or latching valves.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

Read More >>

Interface Between STAR-CCM+ and 42 for Enhanced Fuel Slosh Analysis

Fuel slosh is excited during spacecraft maneuvers. The forces and torques exerted on the spacecraft by the slosh must be controlled by the attitude control system to maintain correct pointing and spacecraft orbit. In some rare cases, the attitude control system may excite the slosh and cause a loss of control of the spacecraft, or the expected spacecraft motion from a certain control command will be different enough from the control command to adversely affect the mission. By linking the computational fluid dynamics (CFD) and the flight simulation software, the fuel slosh can be modeled at high fidelity by the CFD software, while receiving and passing information to and from the flight simulation software, thus increasing the fidelity of both models. In the past, fuel slosh has either been modeled with an equivalent mechanical model, such as a pendulum, or with a standalone CFD simulation.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

Read More >>

Mechanisms for Achieving Non-Sinusoidal Waveforms on Stirling Engines

The current state-of-the-art Stirling engines use sinusoidal piston and displacer motion to drive the thermodynamic cycle and produce power. Research performed at NASA Glenn has shown that non-sinusoidal waveforms have the potential to increase Stirling engine power density, and could possibly be used to tailor engine performance to the needs of a specific application. However, the state-of-the-art Stirling engine design uses gas springs or planar springs that are very nearly linear, resulting in a system that resonates at a single frequency. This means that imposing non-sinusoidal waveforms, consisting of multiple frequencies, requires large forces from the drive mechanism (either the alternator or the crank shaft). These large forces increase losses, and increase the size and requirements of the control system. This innovation aims to reduce the external forcing requirements by introducing internal mechanical components that provide the forces necessary to achieve the desired waveforms.

Posted in: Briefs, Mechanical Components, Mechanics, Motion Control

Read More >>

RFID Cavity

Potential applications include inventory tracking for containers such as waste receptacles or storage containers.This technology provides a method for interrogating collections of items with radio-frequency identification (RFID) tags. It increases the read accuracy, meaning that more of the item tags will be successfully read. It also permits smaller tag antennas than would otherwise be necessary.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

Read More >>

Method for Asteroid Volatile Extraction in Space

The method would support human missions to Mars or other distant objects.Some meteorites representative of certain classes of asteroids are 25% or more water by weight. This is consistent with infrared spectra of some asteroids, indicating hydrated minerals are abundant in some varieties of carbonaceous chondrite asteroids. Since water is very valuable in space, it would be desirable to be able to process asteroids to recover this water and other volatiles. The Asteroid Redirect Mission concept has formulated a method for returning asteroids of 1,000-ton mass into the Earth-Moon system orbit using only ~10 tons of propellant. If ~25% of that returned asteroid mass were recovered as volatiles and solar power used to make those volatiles into propellant, then the overall system would generate approximately 25 times as much propellant as it uses. This could be used to make sustainable human missions to Mars or otherwise spread humanity into the solar system.

Posted in: Briefs, Aerospace, Mechanical Components, Mechanics, Fluid Handling

Read More >>

Improving Stirling Engine Performance Through Optimized Piston and Displacer Motion

Stirling engines typically achieve high efficiency, but lack power density. Low power density prevents them from being used in many applications where internal combustion engines are viable competitors, and increases system costs in applications that require Stirling engines. This limits their operating envelope in both terrestrial and space applications. Sinusoidal piston and displacer motion is one of the causes of low power density. Previous work proposed solving this problem by replacing sinusoidal waveforms with waveforms that more closely approximate those of the ideal Stirling cycle. However, when working with real engines, imposing ideal waveforms has been shown to reduce power density and efficiency due to increased pressure drop through the regenerator and heat exchangers.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling, Motors & Drives

Read More >>

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.