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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Performance and Life Tests of a Regenerative Blower for EVA Suit Ventilation

Ventilation fans for future space suits must meet demanding performance specifications, satisfy stringent safety requirements for operation in an oxygen atmosphere, and be able to increase output to operate in buddy mode. A regenerative blower is an attractive choice due to its ability to meet these requirements at low operating speed. This paper describes progress in the development and testing of a regenerative blower designed to meet requirements for ventilation subsystems in future space suits. The blower includes a custom-designed motor that has significantly improved its efficiency. We have measured the blower s head/flow performance and power consumption under conditions that simulate both the normal and buddy mode operating points. We have operated the blower for TBD hours and demonstrated safe operation in an oxygen test loop at prototypical pressures. We also demonstrated operation with simulated lunar dust.

Izenson, Michael G.↗
NASA NTRS2012

Tone Noise Predictions for a Spacecraft Cabin Ventilation Fan Ingesting Distorted Inflow and the Challenges of Validation

A fan tone noise prediction code has been developed at NASA Glenn Research Center that is capable of estimating duct mode sound power levels for a fan ingesting distorted inflow. This code was used to predict the circumferential and radial mode sound power levels in the inlet and exhaust duct of an axial spacecraft cabin ventilation fan. Noise predictions at fan design rotational speed were generated. Three fan inflow conditions were studied: an undistorted inflow, a circumferentially symmetric inflow distortion pattern (cylindrical rods inserted radially into the flowpath at 15deg, 135deg, and 255deg), and a circumferentially asymmetric inflow distortion pattern (rods located at 15deg, 52deg and 173deg). Noise predictions indicate that tones are produced for the distorted inflow cases that are not present when the fan operates with an undistorted inflow. Experimental data are needed to validate these acoustic predictions, as well as the aerodynamic performance predictions. Given the aerodynamic design of the spacecraft cabin ventilation fan, a mechanical and electrical conceptual design study was conducted. Design features of a fan suitable for obtaining detailed acoustic and aerodynamic measurements needed to validate predictions are discussed.

Koch, L. Danielle↗
NASA NTRS2015

High Performance Mars Liquid Cooling and Ventilation Garment Project

EVA space suit mobility in micro-gravity is enough of a challenge and in the gravity of Mars, improvements in mobility will enable the suited crew member to efficiently complete EVA objectives. The idea proposed is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area in order to free up the arms and legs by removing the liquid tubes currently used in the ISS EVA suit in the limbs. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased to provide the entire liquid cooling requirement and increase mobility by freeing up the arms and legs. Additional potential benefits of this approach include reduced LCVG mass, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development.

Terrier, Douglas↗
NASA NTRS2017

Development Specification for the FN-323/324, Oxygen Ventilation Loop Fan Assembly

This specification establishes the requirements for design, performance, safety, and manufacture of the FN-323/324, Oxygen Ventilation Loop Fan Assembly as part of the Advanced EMU (AEMU) Portable Life Support System (PLSS). Fan development for the advanced Portable Life Support System (PLSS) began in 2009 with the development of Fan 1.0. This fan was used in PLSS 2.0 for circulation of the ventilation loop gas. Fan 2.0 was delivered in 2015 and will be used in the PLSS 2.5 Live Loads test series. This fan used the same motor as Fan 1.0, but had a larger volute and impeller in hopes of achieving lower speeds. The next iteration of the advanced PLSS fan is the subject of the requirements contained within this document, and will be used with the PLSS 2.5 -302 configuration.

Ralston, Russell↗
NASA NTRS2017

Exploration Mission Particulate Matter Filtration Technology Performance Testing in a Simulated Spacecraft Cabin Ventilation System

Human deep space exploration missions will require advances in long-life, low maintenance airborne particulate matter filtration technology. As one of the National Aeronautics and Space Administrations (NASA) developments in this area, a prototype of a new regenerable, multi-stage particulate matter filtration technology was tested in an International Space Station (ISS) module simulation facility. As previously reported, the key features of the filter system include inertial and media filtration with regeneration and in-place media replacement techniques. The testing facility can simulate aspects of the cabin environment aboard the ISS and contains flight-like cabin ventilation system components. The filtration technology test article was installed at the inlet of the central ventilation system duct and instrumented to provide performance data under nominal flow conditions. In-place regeneration operations were also evaluated. The real-time data included pressure drop across the filter stages, process air flow rate, ambient pressure, humidity and temperature. In addition, two video cameras positioned at the filtration technology test articles inlet and outlet were used to capture the mechanical performance of the filter media indexing operation under varying air flow rates. Recent test results are presented and future design recommendations are discussed.

particulate matter filtration↗
NASA NTRS2018

Development of a Multi-Stage Filter System for Cabin Ventilation Systems on the ISS and Future Deep Space Missions

The National Aeronautics and Space Administration's (NASA's) deep space exploration missions will be of significant duration requiring long-life and reliably performing spacecraft cabin ventilation filters. A particulate filter system is being developed at NASA Glenn Research Center (GRC) to meet the challenges of these remote and long duration missions. The capabilities and features of the filter system are expected to expand the life and reduce the maintenance requirements over that of the current ISS (International Space Station) filter by providing pre-filtration stages with novel self-cleaning and regenerable techniques. The filter provides two regenerable pre-filtration stages using a screen mesh media and an impactor collection system, and also provides intermediate stage filtration employing self-replacing filter media. The filter system is also designed to be compatible with the interfaces and performance requirements of the ISS distributed ventilation architecture in the US modules to facilitate testing on ISS type test or mock up platforms. Currently, a prototype of the filter system is undergoing tests in a custom configured filter test stand at the NASA GRC. The test stand provides the same range of flow rates produced on the ISS distributed architecture, and is equipped and instrumented to perform filter tests based on industrial test standards. The test stand has been used successfully to perform filter and flow performance test on returned ISS Bacterial Filter Elements. Similar test protocols were used to characterize the performance of the current filter system. Different performing grades of filter media will be installed and tested on the filter system, and different test particle standards will be used to simulate the range of particulate matter particles and debris the filter will see during a mission. This paper will present results and analysis of the test data to guide and provide input to the next generation filter system.

ISS↗
DOE OSTI2024

A methodology for selection of solid desiccants in energy recovery ventilators

Controlling indoor humidity levels is essential for maintaining acceptable indoor air quality in buildings. The use of energy recovery ventilators (ERVs) is an energy-efficient way to regulate indoor air humidity. Fixed-bed regenerators and rotary wheels are widely used ERVs because of their high sensible and latent effectiveness. These ERVs are made of desiccant-coated substrates, which enable them to transfer moisture between the supply and exhaust air streams. However, the moisture transfer ability of ERVs depends on the physiochemical and sorption properties of desiccants. Extensive, full-scale experiments are required to determine the best desiccant material for these systems. This paper presents a simplified method of selecting suitable desiccant materials for ERVs. The methodology involves important characterization methods, literature correlations for performance prediction, and cost-effective testing methods prior to full-scale testing, and full-scale test methods are discussed in detail. Furthermore, the performance of a few newly derived materials is evaluated and compared with that of conventional desiccants such as silica gel and molecular sieves. The highest latent effectiveness was obtained for composite of super absorbent polymer (SAP) with potassium formate (SAP-HCO2K-50 %), all-polymer porous solid desiccant (APPSD) and metal organic framework (MOF)–MIL–101 (Cr), followed by activated carbon fibre felt (ACFF) Silica sol-LiCl30, SAP, silica gel, MOF–303, and molecular sieve. Researchers and manufacturers would benefit from the proposed methodology and presented data in developing new desiccant materials for ERV applications.

Energy recovery↗
NASA NTRS2003

Validation of measurements of ventilation-to-perfusion ratio inequality in the lung from expired gas

The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (Va/Q) inequality in the lung. To further validate this estimate, we examined three measures of Va/Q inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions and after exposure to aerosolized methacholine. These measurements were then compared with arterial blood gases and with measurements of Va/Q inhomogeneity obtained using the multiple inert gas elimination technique. The slope of the instantaneous respiratory exchange ratio (R slope) vs. expired volume was poorly correlated with independent measures, probably because of the curvilinear nature of the relationship due to continuing gas exchange. When R was converted to the intrabreath Va/Q (iV/Q), the best index was the slope of iV/Q vs. volume over phase III (iV/Q slope). This was strongly correlated with independent measures, especially those relating to inhomogeneity of perfusion. The correlations for iV/Q slope and R slope considerably improved when only the first half of phase III was considered. We conclude that a useful noninvasive measurement of Va/Q inhomogeneity can be derived from the intrabreath respiratory exchange ratio.

NASA Discipline Cardiopulmonary↗
NASA NTRSDate not supplied

Highlights of Aeroacoustic Tests of a Metal Spacecraft Cabin Ventilation Fan Prototype

A metal spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed and tested in the NASA Glenn Research Center Acoustical Testing Laboratory. The fan design featured a low-noise blade-vane count that was chosen to reduce the rotor-stator interaction tone noise. The fan was throttled through its operating range, and results indicate that the measured aerodynamic and acoustic performance was in good agreement with predictions. Recommendations for further research of quiet high-performance fans intended to support long duration human space exploration missions are offered. This small fan aerodynamic and acoustic test rig and the NASA Glenn Acoustical Testing Laboratory are valuable resources available for supporting NASA’s aeronautics research and space exploration missions.

Fan↗
NASA NTRS2022

Highlights of Aeroacoustic Tests of a Metal Spacecraft Cabin Ventilation Fan Prototype

A metal spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed and tested in the NASA Glenn Research Center Acoustical Testing Laboratory. The fan design featured a low-noise blade-vane count that was chosen to reduce the rotor-stator interaction tone noise. The fan was throttled through its operating range, and results indicated that the measured aerodynamic and acoustic performance was in good agreement with predictions. Recommendations for further research of quiet high-performance fans intended to support long duration human space exploration missions are offered. This small fan aerodynamic and acoustic test rig and the NASA Glenn Acoustical Testing Laboratory are valuable resources available for supporting NASA’s aeronautics research and space exploration missions.

Fan, Noise, Ventilation↗
NASA NTRS2023

Quiet Spacecraft Cabin Ventilation Fan: Vibration Measurements Results

Quiet, efficient fans with minimal vibrations are needed to maximize the mechanical life of atmospheric revitalization system fans used for human life support systems for long duration space exploration missions. Several metal spacecraft cabin ventilation fan prototypes have been designed, built, and tested at the NASA Glenn Research Center Acoustical Testing Laboratory. Tests performed in 2021 of the first prototype of the metal fan measured vibrations greater than desired at design point speed and backpressure conditions. To try to reduce those vibrations, a second prototype of the fan design was developed which included a new lighter rotor with a tighter balance tolerance, a new collet to attach the rotor to the motor shaft more securely and repeatably, and a new bracket to center and hold the motor in the fan centerbody more precisely. The second prototype of the fan was tested in 2023 and the vibrations were measured with the fan operating at design point speeds in isolation but not throttled to design point back pressure conditions since it was not installed with inlet and exhaust ducting. Peak vibration was reduced from 4 mm/s to 1 mm/s. This paper is part of a series of reports documenting the performance of the prototype fan.

Fan↗
NASA NTRSDate not supplied

Spacecraft Cabin Ventilation Fan: Wake Measurements Results

Quiet, efficient fans with minimal vibrations are required for revitalization system fans used for human support system in long duration space exploration missions. A spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed in NASA Glenn research center. Two copies of the fan assembly were fabricated and tested for aerodynamic performance and acoustic levels in the NASA Glenn Research Center Acoustical Testing Laboratory. A new test rig for small axial flow fans was designed to accommodate the instrumentation and back-pressure adjustments. Measurements acquired were from: static pressures for measuring performance, a 72-channel in-duct microphone array, external microphone measurements for acoustics, and inter-stage hot-wire measurements of the fan wake. Hot-wire measurements were obtained by radially traversing a x-wire probe downstream of the rotor. This report documents the phase-locked wake velocity, flow angle and turbulence measurements from the hot-wire surveys as part of a series of reports.

Hotwire Measurement↗
NASA NTRSDate not supplied

Quiet Spacecraft Cabin Ventilation Fan: Vibration Measurements Results

The vibrations of a metal spacecraft cabin ventilation fan that tested in 2021 were greater than desired. We diagnosed the problem and modified the rotor assembly in 2022 to try and reduce those vibrations. The design changes included a new lighter rotor with a tighter balance tolerance, a new collet to attach the rotor to the motor shaft more securely and repeatably, and a new bracket to center and hold the motor a little better. The redesigned rotor was tested in 2023 and vibrations were significantly reduced. The measured peak vibration was reduced from 4 mm/s second to less than 1 mm/s, corresponding to a reduction from a balance grade G4 to a grade G 0.6.

Fan, Noise, Ventilation↗
NASA NTRS2012

Acoustic Measurements of an Uninstalled Spacecraft Cabin Ventilation Fan Prototype

Sound pressure measurements were recorded for a prototype of a spacecraft cabin ventilation fan in a test in the NASA Glenn Acoustical Testing Laboratory. The axial fan is approximately 0.089 m (3.50 in) in diameter and 0.223 m (9.00 in) long and has nine rotor blades and eleven stator vanes. At design point of 12,000 rpm, the fan was predicted to produce a flow rate of 0.0709 m3/s (150 cfm) and a total pressure rise of 925 Pa (3.72 in. of water) at 12,000 rpm. While the fan was designed to be part of a ducted atmospheric revitalization system, no attempt was made to throttle the flow or simulate the installed configuration during this test. The fan was operated at six speeds from 6,000 rpm to 13,500 rpm. A 13-microphone traversing array was used to collect sound pressure measurements along two horizontal planes parallel to the flow direction, two vertical planes upstream of the fan inlet and two vertical planes downstream of the fan exhaust. Measurements indicate that sound at blade passing frequency harmonics contribute significantly to the overall audible noise produced by the fan at free delivery conditions.

fan↗
DOE OSTI2025

Numerical Simulation Studies of Ultrasonic De-Icing for Heating, Ventilation, Air Conditioning, and Refrigeration Structures

Ice accumulation on heating, ventilation, air conditioning, and refrigeration (HVACR) structures presents significant operational challenges. These challenges include reduced efficiency, increased energy consumption, and potential damage to equipment. Traditional de-icing methods, such as chemical treatments, mechanical scraping, or heating-based techniques, are often labor-intensive, costly, and environmentally harmful. Here, this study uniquely investigates ultrasonic de-icing as an energy-efficient alternative for HVACR applications, focusing on the specific structural geometries found in these systems. A comprehensive numerical simulation framework was developed using finite element analysis to explore ultrasonic wave propagation across four distinct HVACR structures. Key parameters such as ultrasonic frequency, power levels, and the number and placement of actuators were examined for their impact on ice detachment efficiency. Results from simulations on a plate structure reveal that ultrasonic excitation can propagate effectively across large areas (at least 150 × 150 mm), enhancing the de-icing coverage. Lower frequency (e.g., 30 to 45 kHz) excitation results in greater displacement, improving de-icing performance, while increased actuator numbers with the same total power input also enhance effectiveness. Two actuators seem sufficient for the de-icing of a 300 × 300 mm plate. For tube-and-fin structures, specific high-power ultrasonic frequencies selectively excite the fin plates, demonstrating efficient ice removal when actuated on the tube. However, optimal performance requires careful design of actuator placement and vibration modes to accommodate the irregular shapes of these structures.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗