Transient stage oxidation of MCrAlY bond coat alloys in high temperature, high water vapor content environments

The microstructural and mechanical stabilities of a Nextel 720 (alumina+mullite) fiber-reinforced, alumina matrix composite were evaluated following exposure of the material to a high H2O pressure (to simulate a gas turbine combustor environment) in Oak Ridge National Laboratory’s (ORNL’s) high temperature, high pressure facility (Keiser Rigs). Coupons were exposed at 1135°C and 1200°C in a high-pressure (10 atm) furnace containing 10% water vapor for 1000, 2000, and 3000 h. Extensive microstructural characterization was conducted after each exposure to evaluate fiber and matrix stabilities as a function of exposure time and temperature. Retained tensile strengths were also measured and compared to baseline properties following each exposure. It was found that there was no significant change in the composite microstructure or tensile strength after long-term exposure in the Keiser Rig at 1135°C, whereas significant Nextel 720 fiber degradation (grain growth and increased surface roughness) occurred during exposure for 3000 h at 1200°C. Statistical variations in the mean strength values between the as-processed and exposed composites indicated little change in strength, however. The composite degradation was primarily thermal and the addition of H2O had little effect on changing or accelerating these effects.

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Heat and Mass Transfer from Air with HIgh Water Vapor Content (Latent Heat Recovery from Flue Gas)

JSME international journal Ser 2 Fluids engineering heat transfer power combustion thermophysical properties ◽

10.1299/jsmeb1988.31.2_299 ◽

1988 ◽

Vol 31 (2) ◽

pp. 299-305

Author(s):

Hiroshi TANIGUCHI ◽

Kazuhiko KUDO ◽

Qi-Ri HWANG ◽

Akihiro FUJII

Keyword(s):

Mass Transfer ◽

Water Vapor ◽

Heat And Mass Transfer ◽

Latent Heat ◽

Flue Gas ◽

Heat Recovery ◽

High Water ◽

Water Vapor Content

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How Do Atmospheric Rivers Form?

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-14-00031.1 ◽

2015 ◽

Vol 96 (8) ◽

pp. 1243-1255 ◽

Cited By ~ 107

Author(s):

H. F. Dacre ◽

P. A. Clark ◽

O. Martinez-Alvarado ◽

M. A. Stringer ◽

D. A. Lavers

Keyword(s):

Water Vapor ◽

Cold Front ◽

High Water ◽

Water Vapor Content ◽

Vapor Transport ◽

Water Vapor Transport ◽

Long Distance ◽

Atmospheric Rivers ◽

Atmospheric River ◽

Warm Sector

Abstract The term “atmospheric river” is used to describe corridors of strong water vapor transport in the troposphere. Filaments of enhanced water vapor, commonly observed in satellite imagery extending from the subtropics to the extratropics, are routinely used as a proxy for identifying these regions of strong water vapor transport. The precipitation associated with these filaments of enhanced water vapor can lead to high-impact flooding events. However, there remains some debate as to how these filaments form. In this paper, the authors analyze the transport of water vapor within a climatology of wintertime North Atlantic extratropical cyclones. Results show that atmospheric rivers are formed by the cold front that sweeps up water vapor in the warm sector as it catches up with the warm front. This causes a narrow band of high water vapor content to form ahead of the cold front at the base of the warm conveyor belt airflow. Thus, water vapor in the cyclone’s warm sector, not long-distance transport of water vapor from the subtropics, is responsible for the generation of filaments of high water vapor content. A continuous cycle of evaporation and moisture convergence within the cyclone replenishes water vapor lost via precipitation. Thus, rather than representing a direct and continuous feed of moist air from the subtropics into the center of a cyclone (as suggested by the term “atmospheric river”), these filaments are, in fact, the result of water vapor exported from the cyclone, and thus they represent the footprints left behind as cyclones travel poleward from the subtropics.

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Spatiotemporal changes in atmospheric water vapor content and analysis of meteorological factors over the Tibetan Plateau and its surroundings

10.21203/rs.3.rs-271320/v1 ◽

2021 ◽

Author(s):

Zhilan Wang ◽

Meiping Sun ◽

Xiaojun Yao ◽

Lei Zhang ◽

Hao Zhang

Keyword(s):

Water Vapor ◽

Tibetan Plateau ◽

Meteorological Factors ◽

Tropical Rainfall Measuring Mission ◽

High Water ◽

Water Vapor Content ◽

Radiosonde Data ◽

The Tibetan Plateau ◽

Atmospheric Infrared Sounder ◽

Increasing Trend

Abstract Based on radiosonde stations and V3.0 data, Atmospheric Infrared Sounder (AIRS)-only, Tropical Rainfall Measuring Mission satellite (TRMM) and MERRA2, and ERA-5 data, we evaluated the ability of each dataset to reproduce water vapor content and explored its relationship with precipitation and temperature over the Tibetan Plateau and its surroundings. The results showed that the southern part of the surrounding area had high water vapor content and a low water vapor content zone appeared in the inner part of the Tibetan Plateau. The largest water vapor content appeared in summer and the smallest in winter. Most of the products could capture the spatial distribution of water vapor content, ERA-5 had the smallest bias and the highest correlation coefficient with the radiosonde data. The water vapor content has shown a gradually increasing trend over the last 50 years, with the most obvious increase in summer. Several sets of products had the same fluctuation trend and value is greater than the radiosonde data. There was a significant positive correlation between air temperature and water vapor content in the Tibetan Plateau, especially in the south. As the latitude increased, the correlation between precipitation and water vapor content gradually decreased and a negative correlation appeared.

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GASDYNAMIC LASER WITH A HIGH WATER VAPOR CONTENT

Soviet Journal of Quantum Electronics ◽

10.1070/qe1972v002n03abeh004431 ◽

1972 ◽

Vol 2 (3) ◽

pp. 251-253

Author(s):

A I Demin ◽

E M Kudryavtsev ◽

N N Sobolev ◽

V N Faizulaev

Keyword(s):

Water Vapor ◽

High Water ◽

Water Vapor Content ◽

Gasdynamic Laser

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A CHEMICAL OXYGEN-IODINE LASER WITH A HIGH WATER VAPOR CONTENT

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:19917180 ◽

1991 ◽

Vol 01 (C7) ◽

pp. C7-672-C7-672 ◽

Cited By ~ 1

Author(s):

N. N. GERASIMENKO ◽

V. A. YEROSHENKO ◽

V. V. KALINOVSKI ◽

V. V. KONOVALOV ◽

I. M. KRUKOVSKI ◽

...

Keyword(s):

Water Vapor ◽

High Water ◽

Water Vapor Content ◽

Iodine Laser ◽

Chemical Oxygen Iodine Laser

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Spatial Distributions and Seasonal Variations of Tropospheric Water Vapor Content over the Tibetan Plateau

Journal of Climate ◽

10.1175/jcli-d-12-00574.1 ◽

2013 ◽

Vol 26 (15) ◽

pp. 5637-5654 ◽

Cited By ~ 23

Author(s):

Yuwei Zhang ◽

Donghai Wang ◽

Panmao Zhai ◽

Guojun Gu ◽

Jinhai He

Keyword(s):

Water Vapor ◽

Tibetan Plateau ◽

Seasonal Variations ◽

Precipitable Water ◽

High Water ◽

Water Vapor Content ◽

The Tibetan Plateau ◽

Spatial Distributions ◽

Vapor Flux ◽

Horizontal Gradients

Abstract Spatial distributions and seasonal variations of tropospheric water vapor over the Tibetan Plateau and the surrounding areas are explored by means of water vapor products from the high-resolution Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite and the NASA Water Vapor Project (NVAP). Because NVAP has a serious temporal inhomogeneity issue found in previous studies, the AIRS retrieval product is primarily applied here, though similar seasonal variations can be derived in both datasets. Intense horizontal gradients appear along the edges of the plateau in the lower-tropospheric (500–700 hPa) water vapor and columnar precipitable water, in particular over the regions along the southeastern boundary. Rich horizontal structures are also seen within the plateau, but with a weaker gradient. In the mid- to upper troposphere (300–500 hPa), horizontal gradients are relatively weak. It is shown that there is always a deep layer of high water vapor content over the plateau with a peak around 500 hPa, which can extend from the surface to roughly 300 hPa and even to 100 hPa at some locations. This layer of high water vapor content has consistent influence on precipitating processes in the downstream regions such as the valleys of the Yellow and Yangtze Rivers. Estimated vertically integrated water vapor flux and moisture divergence in the two layers (500–700 and 300–500 hPa) further confirm the effect of the Tibetan Plateau on the downstream regions. In particular, the mid- to upper-layer water vapor (300–500 hPa) tends to play an essential role during both the warm and cold seasons, confirmed by the spatial distribution of seasonal-mean precipitation.

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Interdecadal Variations in Extreme High–Temperature Events over Southern China in the Early 2000s and the Influence of the Pacific Decadal Oscillation

Atmosphere ◽

10.3390/atmos11080829 ◽

2020 ◽

Vol 11 (8) ◽

pp. 829

Author(s):

Baoyan Zhu ◽

Bo Sun ◽

Hua Li ◽

Huijun Wang

Keyword(s):

Water Vapor ◽

High Temperature ◽

Pacific Decadal Oscillation ◽

Southern China ◽

Walker Circulation ◽

Interdecadal Variation ◽

Water Vapor Content ◽

Negative Phase ◽

The Pacific ◽

Extreme High Temperature

This study documents a sudden interdecadal variation in the frequency of extreme high–temperature events (FEHE) over southern China during summer in the early 2000s, which is characterized by a relatively small (large) FEHE during 1991–2000 (2003–2018). The composite analysis on the extreme high–temperature events (EHEs) over southern China indicates that the occurrence of EHEs is mainly influenced by increased downward surface net shortwave radiation, which is induced by the cloud–forced radiation anomalies associated with reduced cloud; the reduced cloud is attributed to anomalous descent motion and decreased water vapor content in the troposphere. Compared to the situation during 1991–2000, anomalous descent motion and decreased atmospheric water vapor content occurred over southern China in summer during 2003–2018, providing a more favorable climatic condition for EHEs. This interdecadal variation is associated with the strengthened Pacific Walker circulation after 2003. The Pacific decadal oscillation (PDO) is suggested to be an important driver for the above interdecadal variation, which shifted from a positive phase towards a negative phase after 2003. Numerical experiments demonstrate that a negative phase of PDO may induce a strengthened Walker circulation and anomalous atmospheric descent motion as well as water vapor divergence over Southern China.

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