Research on Fluid Transmission Performance of Propellant Acquisition Vane Under Microgravity Environment

2015 ◽  
Author(s):  
Qi Hu ◽  
Xianwu Luo
Keyword(s):  
Fluid Management ◽  
Separation Distance ◽  
Test System ◽  
Space Environment ◽  
Lateral Acceleration ◽  
Microgravity Environment ◽  
Optimized Design ◽  
Transmission Performance ◽  
Transmission Velocity ◽  
Section Form

Propellant acquisition vane (PAV) is a key part of vane type surface tension tank (STT) and is mostly used to transmit fluid under microgravity environment, its transmission performance will determine fluid management of STT. In present paper, a ribbon type PAV with hems on both sides is conceptually designed, and its transmission performance has been analyzed based on four configuration parameters of its section form, which are flat part breadth, hems’ height, hems’ angle and separation distance between PAV and inner wall of STT. The laws of the effects of four configuration parameters on PAV’s transmission performance have been obtained and a set of most optimized configuration parameters has been given. Then transmission performance of the PAV whose configuration parameters of section form are the set of optimized parameters has been studied in-depth. Our results revealed that the optimized PAV is able to meet orbital demand of gas-free propellant completely during the end of STT’s life under harsh microgravity environment. On the basis of analyzed laws, microgravity environment has been conducted by the hundred meters drop tower tests, so the model test system with PAV is established and the campaigns have as objective to test the PAV’s fluid transmission performance under axial and lateral acceleration conditions. All these analyses and tests have been successfully conducted to demonstrate fluid transmission performance of such a PAV. According to present research, PAV with different section forms influences fluid transmission performance of STT remarkably. Thus, it is an effective way to control liquid transmission velocity by reasonably design of section form of PAV. Present research can not only provide a guideline for optimized design of new-style vane type fluid management assembly, but also present a new way for liquid control in space environment.

Experiment Investigation on Fluid Storage Characteristic and Transportation Performance of Propellant Refillable Reservoir in Microgravity Environment

2013 ◽  
Vol 390 ◽  
pp. 91-95 ◽  
Author(s):  
Bao Tang Zhuang ◽  
Yong Li ◽  
Ha Lin Pan ◽  
Qi Hu
Keyword(s):  
Surface Tension ◽  
Rational Design ◽  
Storage Capacity ◽  
Fluid Management ◽  
Test System ◽  
Space Environment ◽  
Lateral Acceleration ◽  
Microgravity Environment ◽  
Test Results ◽  
Liquid Storage

Satellites store and manage propellant by surface tension. A surface tension propellant management device (PMD) consists of a propellant refillable reservoir (PRR) for propellant storage and propellant acquisition vanes (PAVs) for propellant transportation. PRR is a key part of vane type surface tension tank (STT), and its storage performance determines the fluid management of vane type STT. In the present paper, a model test system was established and microgravity drop tower tests conducted based on experimental study of fluid storage and transportation behavior of PRR. Laws of fluid storage and transportation of PRR in microgravity environment were obtained. The test results show that two types of PRR both have good liquid storage capacity, and the double cone PRR exhibits good liquid storage capacity in lateral acceleration. A rational design of PRR can effectively store liquid and control liquid transportation velocity. The test results offer a guideline for optimization of new-style vane type PMD, and also provide a new method for fluid control in space environment.

Exploration of Unsteady Spray Cooling for High Power Electronics at Microgravity Using NASA Glenn’s Drop Tower

2005 ◽  
Author(s):  
Eric L. Golliher ◽  
Chad P. Zivich ◽  
S. C. Yao
Keyword(s):  
High Power ◽  
High Speed ◽  
Fluid Management ◽  
Thermal Response ◽  
Spray Cooling ◽  
High Heat ◽  
Drop Tower ◽  
Space Environment ◽  
Microgravity Environment ◽  
High Heat Flux

At present, there is little understanding of the application of spray cooling to electronics in the microgravity environment. Typically in closed cycle terrestrial spray cooling systems, since not all of the liquid impinging on a hot substrate is evaporated, some residual liquid is separated from its vapor component by gravity and returned to the pump. This technique of phase separation is not available to spacecraft designers. Methods to predict spray cooling performance for ground systems do exist, but they are absent for the space environment. Particularly for NASA spacecraft, there is a need to design spacecraft that use high power laser systems and other systems that use evaporative spray cooling in microgravity. Such knowledge is very important for the performance and life of the device. Reliable analytical methods of predicting thermal response of a spray cooled substrate when considering a transient heat load, such as that found during start up and shut down of a space-based laser or other high heat flux electronics, do not exist. Our goal was to use NASA Glenn’s 2.2 second drop tower to investigate unsteady heat transfer at low Bond numbers and residual fluid behavior in spray cooling. The work contrasts other experiments aboard the NASA Glenn KC-135 low gravity aircraft [1]. Our future plans are to continue the experimental work and include the use of the NASA Glenn 5 second drop tower. This paper will report on some preliminary results of an interesting experimental study performed at NASA Glenn in the summer of 2004. The high speed camera and specially-designed “S.L.O.B.” drop rig provided video and data to assess the fluid management problems that arise in a microgravity spray environment, for both heated and unheated cases. The data show unexpected residual fluid management issues, such as the development of multiple spherical liquid globs, with apparent ordered and repeatable geometry, at the point of impact. The results of these experiments provide direction for further investigation in the future.

A Comprehensive Test System for Precision Transmission Performance of CORT Reducer

2013 ◽  
Vol 333-335 ◽  
pp. 2448-2451
Author(s):  
Yong Li ◽  
Guang Ma ◽  
Yun De Shen ◽  
Tai Hong Cheng ◽  
Zhen Zhe Li ◽  
...  
Keyword(s):  
Performance Test ◽  
Velocity Ratio ◽  
Test System ◽  
Test Method ◽  
Transmission Performance ◽  
Test Bed ◽  
Comprehensive Test ◽  
Return Difference ◽  
And Control ◽  
Torque Angle

To meet the needs of test for compound oscillatory roller transmission (CORT) reducer, A comprehensive test system for precision transmission performance was designed, the test-bed structure and control principal of which were introduced. First, a transmission performance test method was proposed and focused on the transmission performance of velocity ratio, accuracy, and efficiency. Then, user interface based on LabVIEW program was designed, and the transmission performance of torque, angle, velocity, velocity ratio, return difference, efficiency could be displayed. Finally, measurement example on an E80 type CORT reducer has been made, and shows that the proposed test system is suitable for test for these reducers of high-precision drive, high stiffness, high load characteristics.

Investigation into Damage of Stainless Steel Mesh/ALPlate Multi-Shock Shield under Hypervelocity AL-Spheres Impact

2012 ◽  
Vol 525-526 ◽  
pp. 397-400
Author(s):  
Gong Shun Guan ◽  
Dong Dong Pu ◽  
Yue Ha
Keyword(s):  
Stainless Steel ◽  
Impact Angle ◽  
Separation Distance ◽  
Hypervelocity Impact ◽  
Aluminum Plate ◽  
Optimized Design ◽  
Stainless Steel Mesh ◽  
Steel Mesh ◽  
Gas Gun ◽  
The Impact

A series of hypervelocity impact tests on stainless steel mesh/aluminum plate multi-shock shield were practiced with a two-stage light gas gun facility. Impact velocity was approximately 4km/s. The diameter of projectiles was 6.4mm. The impact angle was 0°. The fragmentation and dispersal of hypervelocity particle against stainless steel mesh bumper varying with mesh opening size and the wire diameter were investigated. It was found that the mesh wall position, diameter of wire, separation distance arrangement and mesh opening had high influence on the hypervelocity impact characteristic of stainless steel mesh/aluminum plate multi-shock shields. When the stainless steel mesh wall was located in the first wall site of the bumper it did not help comminuting and decelerating projectile. When the stainless steel mesh wall was located in the last wall site of the bumper, it could help dispersing debris clouds, reducing the damage of the rear wall. Optimized design idea of stainless steel mesh/aluminum plate multi-shock shields was suggested.

PVAT - a Posture Video Analysis Tool

1993 ◽  
Vol 37 (15) ◽  
pp. 1045-1045
Author(s):  
Darlene Merced-Moore ◽  
Susan C. Adam
Keyword(s):  
Video Analysis ◽  
Human Performance ◽  
Body Movement ◽  
Body Part ◽  
Space Environment ◽  
Microgravity Environment ◽  
Analysis Tool ◽  
Video Footage ◽  
Input Parameters ◽  
Data Collection Technique

The Posture Video Analysis Tool (PVAT) has been developed to meet the special needs of ergonomist and human factors analyst at NASA Johnson Space Center. Often times these specialist must attempt to evaluate microgravity working posture from video footage not specifically recorded for the purposes of quantitative analysis. The purpose for developing PVAT was to provide a structured methodology in which these specialists could optimize the data collection technique. The PVAT is designed such that microgravity postures can be documented while systematically observing footage of astronauts working in a space environment. PVAT is an interactive Macintosh menu and button driven SupercardTM prototype. Users are provided with a set of input parameters related to the microgravity environment and human performance issues. The primary inputs are: subject code, body orientation, targeted body part, camera view (given subject location), body movement, and rating level. A secondary set of inputs is available for users wishing to document extraneous behaviors or activities such as bending, reaching, interruptions, etc. These secondary behaviors may be documented as part of the primary inputs or independently. Each entry is time stamped and stored automatically. Provisions are made that allow users to pause, tag incorrect selections, enter an “unsure” response and user comments. Data output is saved as a “text file” using tab delimiters for easy importation into programs such as Micrsoft EXCELTM. Future PVAT modifications will include adding more input parameters, data reduction capabilities, control of the video deck from the application, and an animated postural glossary.

Effects of Traditional Chinese Medicines on Murine Bone Metabolism in a Microgravity Environment

2003 ◽  
Vol 31 (05) ◽  
pp. 739-749 ◽  
Author(s):  
Qing-Hua Song ◽  
Takao Kobayashi ◽  
Takayuki Hosoi ◽  
Jong-Chol Cyong
Keyword(s):  
Alkaline Phosphatase ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Bone Metabolism ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Space Environment ◽  
Microgravity Environment ◽  
Traditional Chinese Medicines ◽  
Chinese Medicines

We investigated the effects of three traditional Chinese medicine prescriptions on changes of bone metabolism in mice, using a gravity device to produce a microgravity environment. We found that Hochu-ekki-to (TJ-41) and Hachimi-jio-gan (TJ-7) suppress the increase in the ratio of serum Ca/P and the increase of calcium in urine. Moreover, TJ-41 and Shin-bu-to (TJ-30) reversed the increase of alkaline phosphatase activity (ALP), and TJ-41 also reversed the decrease of estradiol in the serum. The mechanism may be that the traditional Chinese medicines increased estradiol, causing the decrease of ALP, which induced the changes of Ca and P in serum, leading to a decreased excretion of Ca in urine. In this study, TJ-41 was effective in every parameter while TJ-7 and TJ-30 was effective on some parameters, showing that traditional Chinese medicines have specificities in the space environment. In conclusion, this study suggests that some traditional Chinese medicines may be beneficial for adaptation to a space environment.

scholarly journals Decreased biofilm formation in Proteus mirabilis after short-term exposure to a simulated microgravity environment

2021 ◽  
Author(s):  
Dapeng Wang ◽  
Po Bai ◽  
Bin Zhang ◽  
Xiaolei Su ◽  
Xuege Jiang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Proteus Mirabilis ◽  
Biofilm Formation ◽  
Simulated Microgravity ◽  
Microgravity Condition ◽  
Biological Characteristics ◽  
Space Environment ◽  
Microgravity Environment ◽  
Constructive Method ◽  
Short Term Exposure

Abstract Background Microbes threaten human health in space exploration. Studies have shown that Proteus mirabilis has been found in human space habitats. In addition, the biological characteristics of P. mirabilis in space have been studied unconditionally. The simulated microgravity environment provides a platform for understanding the changes in the biological characteristics of P. mirabilis. Objective This study intends to explore the effect of simulated microgravity on P. mirabilis, the formation of P. mirabilis biofilm, and its related mechanism. Methods The strange deformable rods were cultured continuously for 14 days under microgravity simulated in high-aspect rotating vessels (HARVs). The morphology, growth rate, metabolism, and biofilm formation of the strain were measured, and the phenotypic changes of P. mirabilis were evaluated. Transcriptome sequencing was used to detect differentially expressed genes under simulated microgravity and compared with phenotype. Results The growth rate, metabolic ability, and biofilm forming ability of P. mirabilis were lower than those of normal gravity culture under the condition of simulated microgravity. Further analysis showed that the decrease of growth rate, metabolic ability, and biofilm forming ability may be caused by the downregulation of related genes (pstS, sodB, and fumC). Conclusion The simulated microgravity condition enables us to explore the potential relationship between bacterial phenotype and molecular biology, thus opening up a suitable and constructive method for medical fields that have not been explored before. It provides a certain strategy for the treatment of P. mirabilis infectious diseases in space environment by exploring the microgravity of P. mirabilis.

Mitigating Crew Health Degradation During Long-Term Exposure to Microgravity Through Countermeasure System Implementation

2004 ◽  
Author(s):  
Jeremy M. Gernand
Keyword(s):  
Space Station ◽  
Microgravity Environment ◽  
Optimized Design ◽  
Mineral Density ◽  
Operational Risks ◽  
Performance Requirements ◽  
Failure Tolerance ◽  
Increased Risk ◽  
Requirements Development

Experience with the International Space Station (ISS) program demonstrates the degree to which engineering design and operational solutions must protect crewmembers from health risks due to long-term exposure to the microgravity environment. Risks to safety and health due to degradation in the microgravity environment include crew inability to complete emergency or nominal activities, increased risk of injury, and inability to complete safe return to the ground due to reduced strength or embrittled bones. These risks without controls slowly increase in probability for the length of the mission and become more significant for increasing mission durations. Countermeasures to microgravity include hardware systems that place a crewmember’s body under elevated stress to produce an effect similar to daily exposure to gravity. The ISS countermeasure system is predominately composed of customized exercise machines. Historical treatment of microgravity countermeasure systems as medical research experiments unintentionally reduced the foreseen importance and therefore the capability of the systems to function in a long-term operational role. Long-term hazardous effects and steadily increasing operational risks due to non-functional countermeasure equipment require a more rigorous design approach and incorporation of redundancy into seemingly nonmission-critical hardware systems. Variations in the rate of health degradation and responsiveness to countermeasures among the crew population drastically increase the challenge for design requirements development and verification of the appropriate risk control strategy. The long-term nature of the hazards and severe limits on logistical re-supply mass, volume and frequency complicates assessment of hardware availability and verification of an adequate maintenance and sparing plan. Design achievement of medically defined performance requirements by microgravity countermeasure systems and incorporation of adequate failure tolerance significantly reduces these risks. Future implementation of on-site monitoring hardware for critical health parameters such as bone mineral density would allow greater responsiveness, efficiency, and optimized design of the countermeasures system.

Experimental study on transmission performance of harmonic drive under multifactor interaction

2019 ◽  
Vol 20 (6) ◽  
pp. 614
Author(s):  
Guangwu Zhou ◽  
Zhenhua Zhang ◽  
Hua Zhang
Keyword(s):  
Working Conditions ◽  
High Performance ◽  
Interaction Analysis ◽  
Space Environment ◽  
Mechanism Analysis ◽  
Harmonic Drive ◽  
Analysis Method ◽  
Transmission Performance ◽  
Traditional Performance ◽  
Starting Torque

In space environment and complex working conditions, the harmonic drive is prone to performance degradation. The traditional performance analysis method cannot reveal the interaction among the factors. In this paper, a mathematical model of multifactor interaction analysis is built to analyze transmission performance of efficiency, stiffness, and starting torque in various temperature, vacuum, speed and torque. And the high performance gear transmission platform is independently designed and developed. The experimental research and mechanism analysis are carried out on the starting torque, stiffness and efficiency of the harmonic drive. Research shows that the multifactor interaction has an important impact on the transmission performance of harmonic drive. The approach provides some guidance for the application of harmonic drive in space.

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