Evolution of pressure and temperature upon sudden contact of cold water and saturated steam

2007 ◽  
Vol 5 ◽  
pp. 261-266
Author(s):  
S.I. Lezhnin ◽  
A.L. Sorokin ◽  
N.A. Pribaturin
Keyword(s):  
Wave Propagation ◽  
Rarefaction Wave ◽  
Constant Temperature ◽  
Temperature Difference ◽  
Water Surface ◽  
Cold Water ◽  
Saturated Vapor ◽  
Saturated Steam ◽  
Time Interval ◽  
Steam Condensation

The process of rarefaction wave propagation upon sudden contact of cold water and saturated vapor is studied. It is shown that the most intensive steam condensation occurs over a time interval of about 0.01 ms, during which the water surface heats up. Then a constant temperature difference of 2-3 degrees is formed between the water surface and the steam and thus the condensation intensity is reduced.

Design and implementation of automatic control for a condensation-induced depressurization system

2018 ◽  
Vol 233 (9) ◽  
pp. 1146-1158
Author(s):  
Fen Du ◽  
Bo Zhang ◽  
Chao Zhu ◽  
Zhiming Ji ◽  
Chao-Hsin Lin
Keyword(s):  
Control System ◽  
Atmospheric Pressure ◽  
Flow System ◽  
Thermodynamic Cycle ◽  
Saturated Steam ◽  
Low Grade ◽  
Steam Condensation ◽  
Open Flow ◽  
Process Characteristics ◽  
Cascade Arrangement

This study develops a control system to automate the operation of a condensation-induced depressurization technology, which is used to achieve sub-atmospheric pressure in an open-flow system on ground. The continuous depressurization is maintained via an integrated series of chambers inside which vacuum is regenerated by condensing and refilling of saturated steam. The low pressure generated inside the chambers is then used to alternatively extract the air out of a flow system for maintaining its sub-atmospheric pressure. The thermodynamic cycle in such a vacuum chamber consists of three sub-processes: air purging to ambient by steam refilling, depressurization by steam condensation, and air-extraction from a flow application. As one chamber undergoing these consecutive processes, another chamber operates in a coordinated different phase to seamlessly maintain a continuous air-extraction operation. This new system provides a quiet and efficient way of using low-grade energy to generate hypobaric environment for needed applications. A cascade arrangement of a proposed multiple-chamber operation is also illustrated. A control system is designed and implemented to realize the automatic and coordinated operation in a dual-chamber, laboratory-scaled system. Exemplified results on process characteristics such as chamber depressurization and air purging are also provided.

scholarly journals Behavior of Cold Water Mass Due to Water Surface Cooling in a Closed Water Body

10.5109/9250 ◽  
2006 ◽  
Vol 51 (2) ◽  
pp. 331-336
Author(s):  
Shinnosuke Kakizaki ◽  
Kunihiko Hamagami ◽  
Ken Mori ◽  
Yasumaru Hirai
Keyword(s):  
Water Body ◽  
Water Surface ◽  
Water Mass ◽  
Cold Water ◽  
Surface Cooling ◽  
Cold Water Mass ◽  
Closed Water

Experimental Investigation of Lab-Scale, Heat Exchanger Prototypes Designed to Provide Refugia for Trout

2021 ◽  
Author(s):  
Rajib Uddin Rony ◽  
Adam Gladen ◽  
Sarah LaVallie ◽  
Jeremy Kientz
Keyword(s):  
Heat Exchanger ◽  
Temperature Difference ◽  
Large Scale ◽  
Cold Water ◽  
Cooling System ◽  
Tube Bundle ◽  
Small Scale ◽  
Scaled Model ◽  
Average Temperature ◽  
Average Temperature Difference

Abstract In recent years Spring Creek in South Dakota, a popular fishing location, has been experiencing higher surface water temperatures, which negatively impact cold-water trout species. One potential solution is to provide localized refugia of colder water produced via active cooling. The present work focuses on the design and testing of a small-scale prototype heat exchanger, for such a cooling system. Various prototypes of the heat exchanger were tested in a 1/10th-scaled model of a section of the creek. A staggered, tube-bundle heat exchanger was used. The prototypes consisted of just the heat exchanger placed directly in the scaled-stream model and of the heat exchanger placed inside an enclosure with an aperture. The results show that, without the enclosure, the average temperature difference is 0.64 °C, with a corresponding heat transfer requirement of 1.63 kW/°C of cooling. However, with an enclosure, the average temperature difference is 1.95 °C, which required 0.59 kW/°C of cooling. Modifications to the enclosure decrease the average temperature difference but also decrease the standard deviation of the temperature difference. Thus, the cooling effect is more evenly spread throughout the water in the enclosure. This indicates that the enclosure design can be used to balance the requirements of obtaining a desired temperature difference with a relatively low spatial variation in that temperature difference. These results will be used to guide the design of the large-scale heat exchanger prototype.

In situ time-resolved X-ray diffraction of tobermorite formation process under hydrothermal condition: Influence of reactive al compound

2011 ◽  
Vol 26 (2) ◽  
pp. 134-137 ◽  
Author(s):  
K. Matsui ◽  
A. Ogawa ◽  
J. Kikuma ◽  
M. Tsunashima ◽  
T. Ishikawa ◽  
...  
Keyword(s):  
Hydrothermal Reaction ◽  
High Energy ◽  
Saturated Steam ◽  
Array Detector ◽  
Time Interval ◽  
X Rays ◽  
X Ray Diffraction ◽  
Formation Reaction ◽  
X Ray

Hydrothermal formation reaction of tobermorite in the autoclaved aerated concrete (AAC) process has been investigated by in situ X-ray diffraction. High-energy X-rays from a synchrotron radiation source in combination with a newly developed autoclave cell and a photon-counting pixel array detector were used. XRD measurements were conducted in a temperature range 100–190°C throughout 12 h of reaction time with a time interval of 4.25 min under a saturated steam pressure. To clarify the tobermorite formation mechanism in the AAC process, the effect of Al addition on the tobermorite formation reaction was studied. As intermediate phases, non-crystalline calcium silicate hydrate (C-S-H), hydroxylellestadite (HE), and katoite (KA) were clearly observed. Consequently, it was confirmed that there were two reaction pathways via C-S-H and KA in the tobermorite formation reaction of Al containing system. In addition, detailed information on the structural changes during the hydrothermal reaction was obtained.

Stability of planar rarefaction wave to the 3D bipolar Vlasov–Poisson–Boltzmann system

2019 ◽  
Vol 30 (01) ◽  
pp. 23-104 ◽  
Author(s):  
Shu Wang ◽  
Teng Wang
Keyword(s):  
Wave Propagation ◽  
Boltzmann Equation ◽  
Asymptotic Stability ◽  
Rarefaction Wave ◽  
Stability Result ◽  
Three Dimensions ◽  
Wave Patterns ◽  
Shock Profiles ◽  
Poisson Boltzmann ◽  
Math Phys

We investigate the time-asymptotic stability of planar rarefaction wave for the 3D bipolar Vlasov–Poisson Boltzmann (VPB) system, based on the micro–macro decompositions introduced in [T. P. Liu and S. H. Yu, Boltzmann equation: Micro–macro decompositions and positivity of shock profiles, Comm. Math. Phys. 246 (2004) 133–179; Energy method for the Boltzmann equation, Physica D 188 (2004) 178–192] and our new observations on the underlying wave structures of the equation to overcome the difficulties due to the wave propagation along the transverse directions and its interactions with the planar rarefaction wave. Note that this is the first stability result of basic wave patterns for bipolar VPB system in three dimensions.

Rarefaction wave propagation in a waveguide in a hydrate-containing porous medium

2019 ◽  
Author(s):  
A. A. Gubaidullin ◽  
O. Yu. Boldyreva ◽  
D. N. Dudko
Keyword(s):  
Porous Medium ◽  
Wave Propagation ◽  
Rarefaction Wave

scholarly journals The rarefaction wave propagation in transparent windows

2017 ◽  
Author(s):  
B. Glam ◽  
E. Porat ◽  
Y. Horovitz ◽  
A. Yosef-Hai
Keyword(s):  
Wave Propagation ◽  
Rarefaction Wave ◽  
Transparent Windows

Heat Transfer in the Laminar Boundary Layer Over an Impulsively Started Flat Plate

1975 ◽  
Vol 97 (3) ◽  
pp. 482-484 ◽  
Author(s):  
C. B. Watkins
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Laminar Flow ◽  
Flat Plate ◽  
Constant Temperature ◽  
Laminar Boundary Layer ◽  
Temperature Difference ◽  
Thermal Boundary Layer ◽  
Numerical Solutions ◽  
Prandtl Numbers

Numerical solutions are described for the unsteady thermal boundary layer in incompressible laminar flow over a semi-infinite flat plate set impulsively into motion, with the simultaneous imposition of a constant temperature difference between the plate and the fluid. Results are presented for several Prandtl numbers.

Confined Buckling Analysis of a Viscoelastic Ring Subjected to Constant Temperature Difference

2011 ◽  
Vol 295-297 ◽  
pp. 1804-1810 ◽  
Author(s):  
Min Yang ◽  
Shi Fu Xiao
Keyword(s):  
Galerkin Method ◽  
Critical Load ◽  
Constant Temperature ◽  
Temperature Difference ◽  
Evolutionary Trend ◽  
Buckling Behavior ◽  
Viscoelastic Theory ◽  
Confined Buckling ◽  
The Stability ◽  
Stability Of The Solution

Based on Boltzmann’s viscoelastic theory, the confined buckling behavior of a viscoelastic ring subjected to constant temperature difference is investigated by assumed modes method, Galerkin method and numeric method. The critical load and the stability of the solution are investigated. The evolutionary trend of the system is also analyzed.

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