Performance comparison of the conical and contoured nozzle in the HEG

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[唯一标识符]:CDSITC.AEROSPACE.A98-32751
[文献来源]:美国航空航天数据库(aerospace);美国航空航天学会会议(AIAA)
[资源原始索取号]:A1998-32751; Reference AN: A98-32751
[标题]:Performance comparison of the conical and contoured nozzle in the HEG
[作者]:Eitelberg G; Beck W H; Schneider M; Chue R; Widdecke N
[来源]:AIAA-Advanced-Measurement-and-Ground-Testing-Technology-Conference-20th-Albuquerque-NM-June-15-18-1998
[文摘]:The HEG facility was built to provide a test bed in which to test various models to elucidate non-equilibrium flow dynamics. Considering the somewhat lacking flow uniformity due to wave focusing effects in the contoured nozzle, a conical nozzle was installed in the HEG. This was done in the expectation that reduced nonuniformity and better flow quality can be achieved. The design parameters of the conical nozzle are given. The calibration status obtained within the framework of the ESA-sponsored MSTP program and additional DLR work is described. It is shown that a good spatial and temporal uniformity of the higher enthalpy flow is obtained for all tested conditions. This is a significant improvement over the original commissioning status of the wind tunnel. (Author)
[关键词]:CONICAL NOZZLES; TEST FACILITIES; NOZZLE GEOMETRY; NONEQUILIBRIUM FLOW; GAS DYNAMICS; FLOW CHARACTERISTICS; TEST EQUIPMENT; PERFORMANCE ASSESSMENT; GERMANY
[出版年份]:1998
[专业领域]:RESEARCH AND SUPPORT FACILITIES AIR
[馆藏索取号]:A9832751
[总页数]:13


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[文献类型]:科技报告
[标题]:Evaluation of R-22 Alternatives for Heat Pumps.
[作者]:hwang, y. judge, j. f. radermacher, r.
[机构]:Maryland Univ.,College Park. Center for Environmental Energy Engineering.*Environmental Protection Agency,Research Triangle Park,NC. Air Pollution Prevention and Control Div.
[关键词]:heat pumps,environmental chemical substitutes,halohydrocarbons,material substitution,retrofitting,alternatives,heat exchangers,heating systems,heat recovery,energy efficiency,refrigerants,chlorofluorocarbons,air pollution abatement,performance evaluation,reprints,r-22,r-407c
[出版年份]:1996
[报告时间]:1996,
[页码]:10p
[馆藏索取号]:PB96143466
[总页数]:0


[唯一标识符]:CDSITC.AEROSPACE.N89-18300
[文献来源]:美国航空航天数据库(aerospace)
[资源原始索取号]:N1989-18300; Reference AN: N89-18300
[标题]:Sulfide mineralization: Its role in chemical weathering of Mars
[作者]:BURNS ROGER G
[书名]:IN: Lunar and Planetary Inst., Workshop on Mars Sample Return Science p 48-50 (SEE N1989-18288 10-91)
[来源]:In Lunar and Planetary Inst. Workshop on Mars Sample Return Science p 48 50 (SEE N1989 18288 10 91)
[文摘]:Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produced degradation products in the Martian regolith. By analogy with terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato- and hydroxo-complex ions and sols formed gossans above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite) and silica (opal). Underlying groundwater, now permafrost, contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, etc., which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates and phyllosilicates during dust storms on Mars. (Author)
[关键词]:IGNEOUS ROCKS; MARS SURFACE; MARS VOLCANOES; PERMAFROST ; REGOLITH ; SULFIDES ; WEATHERING ; DUST STORMS; FELDSPARS ; GROUND WATER; IRON ; MARS PLANET; NICKEL
[出版年份]:1988
[专业领域]:LUNAR AND PLANETARY EXPLORATION