Numerical investigation of a high pressure hydrogen jet of 82 MPa with adaptive mesh refinement: The starting transient evolution and Mach disk stabilization

Tang, Xinmeng; Asahara, Makoto; Hayashi, A. Koichi; Tsuboi, Nobuyuki

doi:10.1016/j.ijhydene.2017.01.016

Cited by 28 publications

(9 citation statements)

References 36 publications

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“…The Figure 9, Figure 10, Figure 12 and Figure 13 show respectively the error behavior for each numerical value against measurements based on the parameters of and for the profiles upstream and downstream of the Mach disk, the quantitative results were satisfactory, as they had an average error for each of the parameters in the respective profiles of , , and . It can be observed by Figure 8 and Figure 11 that the greatest transverse velocity occurs at the midpoint in terms of the profile upstream of the Mach disk and gradually decreases after approximately , as for the profile downstream, it can be seen that the velocity is relatively low in the middle position thus respecting the physics of the problem with the barrelshaped regions [13] and also the transition region called Mach disk [14] in addition to qualitative and quantitative validations.…”

Section: (31)mentioning

confidence: 69%

“…Cheks by the Figure 4 and Figure 5 that the velocity is around at the exit of the tube, with a gradual increase with the distance until reaching the peak (about ) around . After that, the velocity drops significantly and then drops marginally with distance, furthermore, the formation of the barrelshaped region where Mach [13] and also the transition boundary region called "Mach disk" [14] respecting the physics of the problem.…”

Section: Resultsmentioning

confidence: 99%

“…As boundary conditions for each of the regions shown by Figure 2 Some of the considerations used were that the system is in steady state, since the stabilization of the jet occurs in approximately [13], it was also considered that air entry and viscous forces in the expansion zone are negligible [20].…”

Section: Boundary Conditions and Solution Methodsmentioning

confidence: 99%

“…Expanding (illustrated in Figure 1) stands out among the phenomena presented in this article. It is a very important study as it is a type of flow that involves compressibility effects, high gradients of velocity, temperature, and pressure; in addition, there is the formation of the barrel-shaped region (where Mach ) [13] and the transition boundary region called "Mach disk" [14]. These sub-regions and the characteristics of the expansion phenomenon, as well as the maximum leak velocity and the Mach disk position, are parameters that are difficult to obtain precisely.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

CFD Verification through comparison with LDP measurements of underexpanded gas leak.

Santolin¹,

Martins²,

Martins³

et al. 2023

Proceedings of the 19th International Flow Measurement Conference 2022 on Flow Measurement - FLOMEKO 2022

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A numerical model was performed to represent the expansion phenomenon resulting from the leakage of pressurized gases in a pipe using the Ansys Fluent 2021 R1 software. The free underexpanded jet was produced by a nozzle with an outlet diameter of operating at a stagnation pressure and temperature respectively equal to and , being compared with the experiment conducted by Eggins and Jackson (1974) for qualitative (visual analysis) and quantitative validation requirements (through the statistical model proposed by Hanna (1993)). After the validation of the proposed numerical model, some important results can be highlighted, such as the temperature, pressure and velocity profiles, showing important regions, such as the barrel-shaped shock and the transition limit region from Mach to Mach denominated "Mach disk", other important results obtained such as a peak velocity of approximately , the Mach disk position obtained at , a position necessary for the correct plotting of the upstream and downstream velocity profile graphs of the Mach disk. In general, the numerical model managed to meet expectations very well, agreeing with the experiment, it had excellent results for the expected velocity profiles, obtaining maximum average error for each of the compared cases of , and for the worst case, thus validating the proposed numerical model clearly showing the main characteristics of an underexpanded free jet so necessary for leak analysis of pressurized gases.

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Section: (31)mentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Boundary Conditions and Solution Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

CFD Verification through comparison with LDP measurements of underexpanded gas leak.

Santolin¹,

Martins²,

Martins³

et al. 2023

Proceedings of the 19th International Flow Measurement Conference 2022 on Flow Measurement - FLOMEKO 2022

View full text Add to dashboard Cite

show abstract

“…Because of the supersonic velocity, the flow is compressible as Ma ≫ 0.3 (Munson et al , 2010) and inertia dominated, therefore, buoyancy forces are negligible. The time scales involved are of the order of approximately 10 µs, that is, the time necessary for the Mach disk complete development (Tang et al , 2017).…”

Section: Introductionmentioning

confidence: 99%

Scaling procedure for designing accidental gas release experiment

Moscatello

Uggenti

Iuso

et al. 2020

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Purpose The purpose of this paper is to present a procedure to design an experimental setup meant to validate an innovative approach for simulating, via computational fluid dynamics, a high-pressure gas release from a rupture (e.g. on an offshore oil and gas platform). The design is based on a series of scaling exercises, some of which are anything but trivial. Design/methodology/approach The experimental setup is composed of a wind tunnel, the instrumented scaled (1:10) mock-up of an offshore platform and a gas release system. A correct scaling approach is necessary to define the reference speed in the wind tunnel and the conditions of the gas release to maintain similarity with respect to the real-size phenomena. The scaling of the wind velocity and the scaling of the gas release were inspired by the approach proposed by Hall et al. (1997): a dimensionless group was chosen to link release parameters, wind velocity and geometric scaling factor. Findings The theoretical scaling approaches for each different part of the setup were applied to the design of the experiment and some criticalities were identified, such as the existence of a set of case studies with some release parameters laying outside the applicability range of the developed scaling methodology, which will be further discussed. Originality/value The resulting procedure is one of a kind because it involves a multi-scaling approach because of the different aspects of the design. Literature supports for the different scaling theories but, to the best of the authors’ knowledge, fails to provide an integrated approach that considers the combined effects of scaling.

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Experimental and computational studies of concentration and flow field variation of syngas released

Li,

Wang,

Yin

et al. 2023

Env Prog and Sustain Energy

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Syngas is an important chemical energy source with broad application prospects. The main problem with using syngas is its hazards, such as high storage pressure, high dispersion, low mass density, explosive, and toxic. The aim of this article is to find the key factors for the diffusion of syngas leakage and analyze the distribution of the dangerous concentration range from the diffusion behavior and hazard range characteristics of syngas leakage under complex working conditions. Therefore, a syngas leakage experimental bench is established, and a three‐dimensional simulation of syngas leakage was modeled. The results show that the initial pressure is the most critical factor, and the concentration distribution under different initial pressures is significantly different. The time required for carbon monoxide (CO) and hydrogen (H2) to reach their maximum concentration increased as the initial pressure or temperature decreased. The volume ratio had little effect on the time when CO and H2 reached the maximum concentration. In the horizontal direction, CO diffused further than H2 in the buoyant jet. The max volume fraction of H2 and CO did not exceed 1% and 2.5%, respectively. The research results are expected to give guidelines for the safety protection and standard improvement of syngas leakage.

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Numerical investigation of a high pressure hydrogen jet of 82 MPa with adaptive mesh refinement: The starting transient evolution and Mach disk stabilization

Cited by 28 publications

References 36 publications

CFD Verification through comparison with LDP measurements of underexpanded gas leak.

CFD Verification through comparison with LDP measurements of underexpanded gas leak.

Scaling procedure for designing accidental gas release experiment

Experimental and computational studies of concentration and flow field variation of syngas released

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