A Study on Oxygen Leak-Diffusion Process and Environmental Influence of High-Pressure Liquid of Spherical Tank

2014 ◽  
Vol 1073-1076 ◽  
pp. 1574-1578
Author(s):  
Jia Wei Chen ◽  
Jue Ding ◽  
Pei Fen Weng

Numerical prediction can analyze the cause and process of the accident comprehensively with the application of mathematical models. The computed results are more reliable and intuitive compared with the qualitative analysis results. Therefore, based on the Computational Fluid Dynamics (CFD) and the related theory of safety system science, leak and diffusion processes of high pressure liquid oxygen in spherical tank area, and the subsequent potential oxygen poisoning was analyzed by accident consequence assessment method. The given poisoning area and damage situation provide a reference for the safety analysis of oxygen storage and transportation.

Author(s):  
N. C. Hallett ◽  
H. W. Altman ◽  
M. L. Yeager ◽  
C. L. Newton

2019 ◽  
Vol 9 (3) ◽  
pp. 510
Author(s):  
Ming-Hong Chen ◽  
Yau-Pin Chyou ◽  
Ting Wang

The objective of this study is to implement a tar condensation and re-vaporization sub-model in a previously established Computational Fluid Dynamics (CFD) model for the Entrained Slagging Transport Reactor (E-STR) gasifier, modified from the existing E-Gasifier simulation models in previous studies. The major modifications in E-STR, compared to the existing E-GasTM design, include higher operating pressure and lower temperature, with the aim of achieving a higher H2/CO ratio of syngas, which is more favorable for synthetic natural gas (SNG) production. In this study, the aforementioned sub-model is described by the UDF (User-Defined Function) and incorporated in a previously developed computational model for entrained-flow gasification process, to study the syngas composition without implementing a tars-cracking catalyst in the E-STR gasifier. The results show that incorporating the tar condensation model leads to a formation of approximately 6.47% liquid volatiles and an exit temperature increase about 135 K, due to the release of latent heat. These sub-models have been successfully implemented and will be useful in the condition that the gasifier temperature is intentionally kept low, just as the E-STR gasifier. The results indicate that high pressure and less oxygen feed produce a higher H2/CO ratio, more favorable for SNG production.


2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Dengji Zhou ◽  
Tingting Wei ◽  
Dawen Huang ◽  
Maozong Liang ◽  
Huisheng Zhang ◽  
...  

Abstract Compressor units used for long-distance transportation natural gas pipeline pressurization have high-pressure and high-risk characteristics. Hence, the scientific reliability assessment is important for high-pressure compressor units, to evaluate the reliability standard, find the performance deficiency, and provide references for operation and maintenance. The classical reliability assessment method is not suitable for the complex and high-reliability equipment, like high-pressure compressor units and pipelines. The reliability assessment of the high-reliability equipment is faced with the challenge of the multisource information. A reliability assessment method based on the multisource information fusion is proposed in this work. The fusion resources consist of design information, component test information, and trial operation information. The reliability of high-pressure compressor units can be assessed by fusing the characteristic parameters, from component-based assessment, function-based assessment, quality evaluation, and life model, by D–S evidence theory. A case study is conducted to verify the proposed reliability assessment method in a 20 MW-class high-pressure compressor. There are four information resources in the case, i.e., component test data, design information, operation data, and simulation data. The compressor reliability is assessed as 99.32%, validated by the statistical assessment result based on long-term shutdown reports. This application points out the existing weakness in the high-pressure compressor units and indicates the directions for improving the design, analysis, operation, and failure prevention technologies. It reveals that the reliability assessment based on multisource information can provide a guarantee for the operation and maintenance of high-pressure compressor units. Meanwhile, the proposed method has good expansibility, which may be used in more fields.


2014 ◽  
Vol 922 ◽  
pp. 801-806
Author(s):  
Robert Watson ◽  
Tayeb Zeguer ◽  
Simon Ruffle ◽  
William D. Griffiths

Aluminium High Pressure Die Castings are economical to produce in high volumes. However, as greater structural demands are placed on such castings, a more detailed understanding is required of the defects which limit their strength. The process is prone to high levels of surface turbulence and fluid break-up, resulting in the entrainment of air into the liquid metal, which may manifest as trapped air porosity or bifilm defects in the finished part. A novel algorithm was developed and integrated into a commercial computational fluid dynamics (CFD) package, to model mould filling, and the formation and transport of such entrainment defects. A commercial High Pressure Die Casting was simulated using this algorithm, to illustrate its application. Castings were also produced, and the results of tensile testing were summarised in the form of Weibull statistics. It was found that where the algorithm predicted a greater quantity of entrained surface film, a reduction in UTS of about 10% was also observed.


Solid Earth ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 167-189 ◽  
Author(s):  
Francesco Giuntoli ◽  
Pierre Lanari ◽  
Martin Engi

Abstract. Contiguous continental high-pressure terranes in orogens offer insight into deep recycling and transformation processes that occur in subduction zones. These remain poorly understood, and currently debated ideas need testing. The approach we chose is to investigate, in detail, the record in suitable rock samples that preserve textures and robust mineral assemblages that withstood overprinting during exhumation. We document complex garnet zoning in eclogitic mica schists from the Sesia Zone (western Italian Alps). These retain evidence of two orogenic cycles and provide detailed insight into resorption, growth, and diffusion processes induced by fluid pulses in high-pressure conditions. We analysed local textures and garnet compositional patterns, which turned out remarkably complex. By combining these with thermodynamic modelling, we could unravel and quantify repeated fluid–rock interaction processes. Garnet shows low-Ca porphyroclastic cores that were stable under (Permian) granulite facies conditions. The series of rims that surround these cores provide insight into the subsequent evolution: the first garnet rim that surrounds the pre-Alpine granulite facies core in one sample indicates that pre-Alpine amphibolite facies metamorphism followed the granulite facies event. In all samples documented, cores show lobate edges and preserve inner fractures, which are sealed by high-Ca garnet that reflects high-pressure Alpine conditions. These observations suggest that during early stages of subduction, before hydration of the granulites, brittle failure of garnet occurred, indicating high strain rates that may be due to seismic failure. Several Alpine rims show conspicuous textures indicative of interaction with hydrous fluid: (a) resorption-dominated textures produced lobate edges, at the expense of the outer part of the granulite core; (b) peninsulas and atoll garnet are the result of replacement reactions; and (c) spatially limited resorption and enhanced transport of elements due to the fluid phase are evident along brittle fractures and in their immediate proximity. Thermodynamic modelling shows that all of these Alpine rims formed under eclogite facies conditions. Structurally controlled samples allow these fluid–garnet interaction phenomena to be traced across a portion of the Sesia Zone, with a general decrease in fluid–garnet interaction observed towards the external, structurally lower parts of the terrane. Replacement of the Permian HT assemblages by hydrate-rich Alpine assemblages can reach nearly 100 % of the rock volume. Since we found no clear relationship between discrete deformation structures (e.g. shear zones) observed in the field and the fluid pulses that triggered the transformation to eclogite facies assemblages, we conclude that disperse fluid flow was responsible for the hydration.


1988 ◽  
Vol 31 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Mamoru Oike ◽  
Masataka Nosaka ◽  
Yoshiaki Watanabe ◽  
Masataka Kikuchi ◽  
Kenjiro Kamijo

1992 ◽  
Author(s):  
Y. T. Lee ◽  
J. Feng ◽  
M. E. Slipper ◽  
C. L. Merkle

An advanced computational fluid dynamics (CFD) modelling design method using a numerical viscous/inviscid coupling procedure has been developed. The method is employed to analytically evaluate the performance of various combinations of high pressure vaneaxial fan rotor, stator and diffuser geometries. The procedures used in the CFD design method ensure a free-vortex blading, a separation-free profile, and a configuration with optimum rotor-stator interaction. Two test fans which have aerodynamic performance and geometrical characteristics close to the desired fan operating range are used to provide code verification and empirical information for the total design effort. A design example is presented. Aerodynamic and aeroacoustic test data will be presented in a later paper.


Author(s):  
D.I. Suslov ◽  
J.S. Hardi ◽  
B. Knapp ◽  
M. Oschwald

Injector behavior is of utmost importance for the performance and stability of liquid rocket engines (LREs). A major problem is getting a highly efficient homogeneous mixture and effective chemical reaction of fuels at minimum chamber length. Despite substantial progress in numerical simulations, a need for experimental data at representative conditions for development and validation of numerical design tools still exists. Therefore, in the framework of the DLR-project “ProTau,” the authors have performed tests to create an extended data base for numerical tool validation for high-pressure liquid oxygen (LOx) / hydrogen combustion. During the experimental investigations, a windowed DLR subscale thrust chamber model “C” (designated BKC) has been operated over a broad range of conditions at reduced pressures of approximately 0.8 (4 MPa), 1 (5 MPa), and 1.2 (6 MPa) with respect to the thermodynamic critical pressure of oxygen. Liquid oxygen and gaseous hydrogen (GH2) have been injected through a single coaxial injector element at temperatures of ~ 120 and ~ 130 K, respectively. High-speed optical diagnostics have been implemented, including imaging of OH* emission and shadowgraph imaging at frequencies from 8 up to 10 kHz to visualize the flow field.


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