On the Mach Number Invariance of Gas Jets Expanding Into Hot or Cold Environments

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
R. Sambasivam ◽  
F. Durst
Keyword(s):  
Mach Number ◽  
Practical Importance ◽  
Experimental Studies ◽  
Basic Oxygen Furnace ◽  
Jet Flows ◽  
Basic Oxygen ◽  
Ambient Temperatures ◽  
Cold Environments ◽  
Gas Jets ◽  
Significant Temperature

Gas jet flows expanding into a space containing the same medium but at a significant temperature difference are of concern in many fields of engineering. One such example is the expansion of supersonic oxygen jets in the basic oxygen furnace (BOF) steelmaking process. While studying the characteristics of such gas jets, an interesting invariance of the local Mach number with the change in the surrounding temperature was found. The velocity and temperature of the jet at any given location increased with the increasing ambient temperature. However, the local Mach number remained the same for all ambient temperatures. This interesting result was further studied since there is no mention of it in any published literature. The reasons for these characteristics of the jet are analyzed in this paper. It is stressed that this finding is of practical importance and can be used in experimental studies of submerged gas jets expanding into environments with different ambient temperatures.

Synthesis and characterisation of alites from reduced basic oxygen furnace slags

2021 ◽  
Vol 147 ◽  
pp. 106518
Author(s):  
Katharina Schraut ◽  
Burkart Adamczyk ◽  
Christian Adam ◽  
Dietmar Stephan ◽  
Birgit Meng ◽  
...  
Keyword(s):  
Basic Oxygen Furnace ◽  
Basic Oxygen

scholarly journals Time-Dependent Strength Behavior, Expansion, Microstructural Properties, and Environmental Impact of Basic Oxygen Furnace Slag-Treated Marine-Dredged Clay in South Korea

2021 ◽  
Vol 13 (9) ◽  
pp. 5026
Author(s):  
Gyeong-o Kang ◽  
Jung-goo Kang ◽  
Jin-young Kim ◽  
Young-sang Kim
Keyword(s):  
Particle Size ◽  
Environmental Impact ◽  
South Korea ◽  
Mechanical Characteristics ◽  
Basic Oxygen Furnace ◽  
Microstructural Properties ◽  
Compression Tests ◽  
Basic Oxygen ◽  
Strength Behavior ◽  
Bof Slag

The aim of this study was to investigate the mechanical characteristics, microstructural properties, and environmental impact of basic oxygen furnace (BOF) slag-treated clay in South Korea. Mechanical characteristics were determined via the expansion, vane shear, and unconfined compression tests according to various curing times. Scanning electron microscopy was conducted to analyze microstructural properties. Furthermore, environmental impacts were evaluated by the leaching test and pH measurements. According to the results, at the early curing stage (within 15 h), the free lime (F-CaO) content of the BOF slag is a significant factor for developing the strength of the adopted sample. However, the particle size of the BOF slag influences the increase in the strength at subsequent curing times. It was inferred that the strength behavior of the sample exhibits three phases depending on various incremental strength ratios. The expansion magnitude of the adopted samples is influenced by the F-CaO content and also the particle size of the BOF slag. Regarding the microstructural properties, the presence of reticulation structures in the amorphous gels with intergrowths of rod-like ettringite formation was verified inside the sample. Finally, the pH values and heavy metal leachates of the samples were determined within the compatible ranges of the threshold effect levels in the marine sediments of the marine environment standard of the Republic of Korea.

scholarly journals Component Modification of Basic Oxygen Furnace Slag with C4AF as Target Mineral and Application

2021 ◽  
Vol 13 (12) ◽  
pp. 6536
Author(s):  
Yanrong Zhao ◽  
Pengliang Sun ◽  
Ping Chen ◽  
Xiaomin Guan ◽  
Yuanhao Wang ◽  
...  
Keyword(s):  
Intermediate Phase ◽  
Raw Materials ◽  
Activity Index ◽  
Basic Oxygen Furnace ◽  
Hydration Products ◽  
Basic Oxygen ◽  
Bof Slag ◽  
Mineral Compositions ◽  
Slag Component ◽  
Basic Oxygen Furnace Slag

In this paper, a new method of basic oxygen furnace (BOF) slag component modification with a regulator was studied. The main mineral was designed as C4AF, C2S and C3S in modified BOF slag, and the batching method, mineral compositions, hydration rate, activation index and capability of resisting sulfate corrode also were studied. XRD, BEI and EDS were used to characterize the mineral formation, and SEM was used to study the morphology of hydration products. The results show that most inert phase in BOF slag can be converted into active minerals of C4AF and C2S through reasonable batching calculation and the amount of regulating agent. The formation of C4AF and C2S in modified BOF slag is better, and a small amount of MgO is embedded in the white intermediate phase, but C3S is not detected. With the increase in the CaO/SiO2 ratio in raw materials, the CaO/SiO2 ratio of calcium silicate minerals in modified BOF slag increases, the contents of f-CaO are less than 1.0%, and the activity index improves. Compared with the BOF slag, the activity index and exothermic rate of modified BOF slag improved obviously, and the activity index of 90 days is close to 100%. With the increase in modified BOF slag B cement, the flexural strength decrease; however, the capability of resisting sulfate corrode is improved due to the constant formation of a short rod-like shape ettringite in Na2SO4 solution and the improvement of the structure densification of the hydration products.

Air Injection Through Microjets in Low Mach Number Turbulent Jet Flows

2007 ◽  
Author(s):  
Roberto Camussi ◽  
Giulio Guj ◽  
Francesco Tomassi ◽  
Pengyuan Yao ◽  
Aldo Pieroni ◽  
...  
Keyword(s):  
Mach Number ◽  
Air Injection ◽  
Turbulent Jet ◽  
Jet Flows ◽  
Low Mach Number

scholarly journals Simulated Experiment Study of Factors Influencing the Hydration Activity of f-CaO in Basic Oxygen Furnace Slag

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Ruiquan Jia ◽  
Jiaxiang Liu
Keyword(s):  
Solid Solutions ◽  
Volume Expansion ◽  
Basic Oxygen Furnace ◽  
Hydration Reaction ◽  
Basic Oxygen ◽  
Activity Sequence ◽  
Bof Slag ◽  
Iron Phase ◽  
Calcium Iron ◽  
Iron Manganese

The compositions and formation process of f-CaO in BOF slag were revealed and simulated to understand its expansion rules and why its hydration activity is low. BSE showed the compositions of f-CaO, which included calcium iron phase and calcium iron manganese phase, were diverse. The hydration activity sequence was Ca2Fe2O5 and Ca3Fe1.5Mn1.5O8 in tricomponent f-CaO < CaO in tricomponent f-CaO < monocomponent f-CaO; only Ca2Fe2O5 and Ca3Fe1.5Mn1.5O8 were hard to hydrate, and the volume expansion rates of the tricomponent f-CaO varied with different compositions. Inductively, in BOF slag, the hydration activity sequence was solid solutions CaO-FeOx and CaO-FeOx-MnOy in tricomponent f-CaO < CaO in tricomponent f-CaO < monocomponent f-CaO; the volume expansion rates of tricomponent f-CaO changed with different compositions, and CaO-FeOx and CaO-FeOx-MnOy were difficult to hydrate. The reason why solid solutions CaO-FeOx and CaO-FeOx-MnOy were hard to hydrate was that their hydration reaction driving force, which is the absolute value of standard molar reaction Gibbs functions, decreased.

Blood calcium for eczema

1935 ◽  
Vol 31 (6) ◽  
pp. 726-734
Author(s):  
N. N. Yasnitsky ◽  
Ts. D. Elina
Keyword(s):  
Practical Importance ◽  
Experimental Studies ◽  
Controversial Issue ◽  
Scientific Interest ◽  
Blood Calcium ◽  
Great Practical Importance

One of the urgent problems of modern dermatology, which are of deep scientific interest and are of extremely great practical importance, is the complex and controversial issue of the etiology of eczema. However, despite the colossal literature, despite a number of detailed experimental studies, the main and deep contradictions of representatives of the main dermatological schools on the nature of eczema remain unresolved.

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