The Water Membrane Evaporator for Space Shuttle Heat Rejection: Membrane Performance and Plans for Pre-Prototype Testing

2000 ◽  
Author(s):  
Eugene K. Ungar ◽  
Jay C. Almlie
Keyword(s):  
Space Shuttle ◽  
Waste Heat ◽  
Membrane Technology ◽  
Performance Tests ◽  
Heat Rejection ◽  
Membrane Performance ◽  
The Us ◽  
Coolant Loop ◽  
Pass Through ◽  
Hydrophilic Membrane

Abstract The US Space Shuttle on-orbit waste heat rejection is currently accomplished through a combination of radiators and a Flash Evaporator System (FES). Three of the FES units have been rebuilt to date because of corrosion problems. In addition, the FES has experienced freeze-ups on-orbit. As part of NASA’s Orbiter Upgrade Program, a Water Membrane Evaporator (WME) is being developed as a replacement for the FES. The WME will use hydrophobic micropore membrane technology to passively control a water liquid/vapor interface. Waste heat acquired from the Orbiter Freon-21 coolant loop will evaporate water at the interface. The water vapor will pass through the membrane and be vented to space. The WME program takes advantage of the recent advances in hydrophobic micropore membrane technology to provide a simpler and more robust heat rejection device than the current FES. The WME design uses a hydrophobic and hydrophilic membrane layup over 60 rectangular stainless steel Freon-21 tubes in each of 80 small cores to perform the same function as the FES. The mass and volume of the WME design is comparable to that of the FES. In the present work, the results of membrane performance tests are presented, the membrane physics are explored, and a membrane performance prediction is developed. The WME design is described in detail and the predicted performance of the WME design is compared to that of the FES.

ON PRICE DYNAMICS WITH SEARCH AND BARGAINING IN THE PRODUCT MARKET

2020 ◽  
pp. 1-34
Author(s):  
Mirko Abbritti ◽  
Tommaso Trani
Keyword(s):  
Equilibrium Analysis ◽  
Intermediate Goods ◽  
Price Dynamics ◽  
Producer Price ◽  
Second Moments ◽  
Sensitivity Tests ◽  
The Us ◽  
B2b Relationships ◽  
Pass Through

We introduce business-to-business (B2B) relationships into an otherwise standard model to revisit two aspects of price dynamics in a unified analysis. On one side, the pass-through of cost shocks to prices is empirically incomplete. On the other side, the literature contains conjectures that long-term relationships may reduce the allocative role of price changes. After a partial equilibrium analysis of these aspects, we consider the general equilibrium effects. The formation of B2B relationships implies that the trade of intermediate goods depends on search, bargaining, and the adjustment along the intensive margin as opposed to the extensive margin. We find that, when this adjustment is costly, retailers have a relatively high bargaining power, and mismatch shocks are possible, the model can account for the second moments of the US producer price index and other variables. In this case, although its allocative role is low, the intermediate goods price affects the allocation of goods through the search externalities and is sufficiently volatile. The analysis includes several sensitivity tests and comparisons.

Thermal Performance Model for Spacesuit Waste Heat Rejection Using Water Membrane Evaporators

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
Y. Janeborvorn ◽  
T. P. Filburn ◽  
C. C. Yavuzturk ◽  
E. K. Ungar
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Waste Heat ◽  
Water Channel ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Performance Model ◽  
Heat Transfer Analysis ◽  
Water Evaporation ◽  
Heat Rejection

Hydrophobic, micropore membrane evaporators are studied for use in waste heat rejection in new generation spacesuits developed by the U.S. National Aeronautics and Space Administration (NASA). The waste heat rejection is accomplished via evaporation of liquid water through membrane pores, whereby the hydrophobic membrane allows only water vapor to pass through and retains the liquid phase inside the membrane water channel, allowing the waste heat rejection through the proposed spacesuit water membrane evaporator (SWME) system to be significantly less sensitive to contamination while improving the overall contaminant and system control. Although SWME uses the same heat transport loop as used in current NASA sublimator systems, thus eliminating the need for a separate feedwater system, it permits the system configuration to be simpler and more compact while also eliminating corrosion problems and reducing system freeze-up potential. An improved thermal performance model based on membrane segment energy balances is presented, which is a spacesuit water membrane evaporator for a single circular annulus water channel bounded by two annular vapor channels. The model allows for the investigation of the local heat transfer characteristics along the annulus including temperature gradients in the membrane wall and the water channel using a steady-state approach. The model also accounts for the effects of thermal and hydraulic entry lengths, far field radiation, and energy carried away by the mass of water evaporation. The local heat transfer analysis enables the straightforward calculation of the overall magnitude of heat transfer from the SWME. A model validation is presented via the sum of the squares error analyses between the model predictions and the experimental results.

Seismic Requirements for the Welding and Inspection of the K-Area in Hot Rolled Products to AS/NZS 3679.1

2018 ◽  
Vol 763 ◽  
pp. 197-206
Author(s):  
Michail Karpenko ◽  
Alan McClintock ◽  
Marlon Helms ◽  
Holger Heinzel
Keyword(s):  
New Zealand ◽  
Strain Hardening ◽  
Notch Toughness ◽  
Performance Tests ◽  
Test Setup ◽  
The Us ◽  
And Performance ◽  
Flange Beams ◽  
Susceptibility Tests ◽  
Hot Rolled

Hot-rolled products such as beams are usually subject to rotary straightening as a last step in the manufacturing process. This operation may change the properties of the plastically deformed area by strain hardening. The affected regions of the beam are referred to as the “k-area”, as shown in Figure 1. Strain hardening reduces the ductility and notch toughness of the steel and can potentially lead to cracking in the k-area when welding is carried out in restrained conditions e.g. addition of stiffeners by welding. The phenomenon was reported for wide flange beams in the US literature in the 1990s. Welding limitations and increased inspection requirements in these areas were introduced to AISC and AWS D1.8 codes [1]. Similar requirements can be found in New Zealand Standard NZS 3404.1 [2]. However, it is unclear if steel products used in New Zealand are affected by this phenomenon. A series of welding and performance tests were carried out at HERA using hot rolled products UB610, UC310, UB310 and UC200 of material grade 300S0 to AS/NZS 3679.1 [3]. The material is commonly used in New Zealand for seismic construction. Welded test specimens were subject to a range of testing, including mechanical and cold cracking susceptibility tests. Test setup and results are reported in the paper. The authors present recommendations for future standard developments.

scholarly journals A Review of Membrane Distillation Process: Before, During and After Testing

2019 ◽  
Vol 6 (1) ◽  
pp. 62-81
Author(s):  
N.A.S. Muhamad ◽  
Nadzirah Mohd Mokhtar ◽  
R. Naim ◽  
W.J. Lau ◽  
A.F. Ismail
Keyword(s):  
Membrane Fouling ◽  
Treatment Process ◽  
Membrane Distillation ◽  
Separation And Purification ◽  
Hydrophobic Membrane ◽  
Major Drawback ◽  
Membrane Performance ◽  
Membrane Surfaces ◽  
Thermally Driven ◽  
Pass Through

Membrane Distillation (MD) is a promising technology for separation and purification processes. It is a thermally-driven separation process which allow only vapour molecules are to pass through a porous hydrophobic membrane. MD separation is driven by the vapour pressure difference existing between the porous hydrophobic membrane surfaces unlike normal membrane processes which operate on temperature difference. This paper focus on the expectation of MD treatment process primarily for the readers who have no idea about this membrane process A brief overview is given of MD before treatment process which includes membrane materials, membrane preparation techniques, membrane characteristics, module and configuration. Membrane performance during treatment process will be highlighted. Membrane fouling which is one of the major drawback of MD will be also discussed.

scholarly journals Prototypical thermoelectric generator for waste heat conversion from combustion engines

2013 ◽  
Vol 154 (3) ◽  
pp. 60-71
Author(s):  
Krzysztof WOJCIECHOWSKI ◽  
Jerzy MERKISZ ◽  
Paweł FUĆ ◽  
Joanna TOMANKIEWICZ ◽  
Rafał ZYBAŁA ◽  
...  
Keyword(s):  
Flow Resistance ◽  
Thermoelectric Generator ◽  
Waste Heat ◽  
Theoretical Calculations ◽  
Exhaust System ◽  
Combustion Engines ◽  
Performance Tests ◽  
System Efficiency ◽  
Maximal Power ◽  
Powertrain System

The work presents experimental results of performance tests and theoretical calculations for the thermoelectric generator TEG fitted in the exhaust system of a 1.3 dm3 JTD engine. Benchmark studies were carried out to analyze the performance of the thermoelectric modules and total TEG efficiency. Additionally the investigation of combustion engine’s power drop casued by exhaust gasesflow resistance is presented. The detailed studies were performed using a new prototype of the thermoelectric generator TEG equipped with 24 BiTe/SbTe modules with the total nominal power of 168 W. The prototypical device generates maximal power of200 Wfor the exhaus gases massflow rate of 170 kg-h-1 and temperature of280 oC. Power drop caused by the flow resistance of gases ranges between 15 and 35 mbarfor mass flow rate 100-180 kg-h-1. We predict that the application of the new thermoelectric materials recently developed at AGH would increase the TEG power by up to 1 kW, would allow the increase of the powertrain system efficiency by about 5 %, and a corresponding reduction of C02 emission.

scholarly journals Testing at the U.S. Navy’s Gas Turbine Systems Engineering Complex: Part II

1991 ◽  
Author(s):  
John H. Preisel
Keyword(s):  
Control System ◽  
Gas Turbine ◽  
Systems Engineering ◽  
Waste Heat ◽  
Exhaust System ◽  
Full Scale ◽  
Electrical System ◽  
The Us ◽  
The Future ◽  
Electrical Generation

Full-scale testing has continued at the US Navy’s Gas Turbine Systems Engineering Complex. The test complex, which is based on the US Navy’s DDG-51 class propulsion plant, has fully transitioned from the construction phase to the testing phase. A complete LM 2500-based propulsion train exists, as well as an electrical generation, distribution and control system. The purpose of this paper is to provide an update to last year’s test report, and to document the new tests and systems integration tasks that have taken place. Particular areas to be discussed include: - electrical system design, installation and testing - crew training and integrated plant operations - full-scale casualty control exercises - integration and testing of an Auxiliary Power Unit - control system upgrades and communication testing At the time that this paper is being written, final design approval has been given to move a second 2500 kW gas turbine generator to the test site. This will be a cogeneration system, since it has a waste heat recovery system installed in the exhaust system. The paper describes the plans for integrating this system into the gas turbine complex. The proposed electrical system test plan is also discussed. The paper concludes by outlining the component and system testing programs that are planned for the future. The future tests represent a continuing commitment to land based test sites and full scale integration testing.

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