How does a high density ratio affect the near- and intermediate-field of high-Re hydrogen jets?

Bonelli, Francesco; Viggiano, Annarita; Magi, Vinicio

doi:10.1016/j.ijhydene.2016.06.174

Cited by 18 publications

(14 citation statements)

References 69 publications

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“…sound, and is known to follow the −7 power law [17]. It can be found from Figure 15 that, in both Region 1 and Region 2, the inertial subrange exists in the region between 100 Hz and 1000 Hz, and a dissipation range exists in the frequency region higher than 1000 Hz.…”

Section: Wavenumber-frequency Analysismentioning

confidence: 96%

Development of High-Fidelity Numerical Methodology Based on Wavenumber-Frequency Transform for Quantifying Internal Aerodynamic Noise in Critical Nozzle

Lee

Cheong

et al. 2019

Applied Sciences

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In industrial fields dealing with high-temperature and high-pressure gas such as chemical, petrochemical, and offshore oil production plants, piping systems with valves are frequently used to protect the relevant system and equipment from being damaged by such gases. However, excessive noise is sometimes generated by the valve flow in the piping system, causing so-called acoustic induced vibration in the pipe wall. Therefore, it is of great importance to design the related system to avoid this phenomenon. In this study, a high-fidelity numerical procedure is proposed to assess the acoustic power generated by pressure relief devices in a pipe. The method consists of three sequential steps: high accuracy large eddy simulation, wavenumber-frequency transform, and duct acoustic theory. The critical nozzle is selected as a target system since it is commonly used as a flowmeter and thus there are a lot of relevant data for comparison. First, the steady Reynold-Averaged Navier–Stokes (RANS) solver is used to predict the flow rate of the two-dimensional axisymmetric critical nozzles, and its validity is confirmed by comparing the predicted results with the measured ones. There is good agreement between the two results. Then, a high accuracy Large Eddy Simulation (LES) technique is performed on the three-dimensional critical nozzle, and the steady-state RANS result is used as the initial condition to accelerate the convergence of the unsteady simulation. The validity of the unsteady LES results is also confirmed by comparing them with measured surface pressure data. The wavenumber-frequency transform is taken on the LES results, and the compressible surface pressure components matching the acoustical duct modes are identified in the wavenumber-frequency pressure diagram. The inverse wavenumber-frequency transform taken on the compressible pressure components leads to the acoustic power spectrum. These results reveal that the current numerical procedure can be used to more accurately predict the acoustic power generated by pressure relief device in the piping system.

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Section: Wavenumber-frequency Analysismentioning

confidence: 96%

Development of High-Fidelity Numerical Methodology Based on Wavenumber-Frequency Transform for Quantifying Internal Aerodynamic Noise in Critical Nozzle

Lee

Cheong

et al. 2019

Applied Sciences

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“…Kim et al [12] studied the effects of initial momentum thickness and Reynolds number on the free jet flow in circular holes by large eddy simulation (LES), and found that the flow characteristics of free jet are closely related to initial momentum thickness and Reynolds number. Bonelli et al [13] carried out a comprehensive investigation of mixing properties in near-and intermediate-fields by LES. A qualitative view of the jet coherent structures and a quantitative analysis of the turbulence scales are also provided.…”

Section: Flow Configurationmentioning

confidence: 99%

“…Coherent structure is the key mechanism that turbulent flow generates and maintains, which has been used to analyze jets flow in recent years [13]. Q criterion is one of the vortex criterion under Euler system defined as Q = 1/2(|Ω| 2 − |S| 2 ), Ω is vorticity tensor, reflecting the rotation effect; S is strain rate tensor, reflecting the deformation effect.…”

Section: Coherent Structurementioning

confidence: 99%

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Large Eddy Simulation of Self-Excited Oscillation Pulsed Jet (SEOPJ) Induced by a Helmholtz Oscillator in Underground Mining

Fang

Zhang

et al. 2019

Energies

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Pulsed waterjet can break rocks effectively by taking advantage of the water hammer effect, and is thus widely used in mining, petroleum, and natural gas fields. With the aim to further clarify the flow field characteristics of pulsed jets induced by a Helmholtz oscillator, large eddy simulation was conducted under different operating pressures. The velocity distribution, mean flow field, and the coherent structure were examined using the oscillators of different cavity lengths and diameters. The results clearly showed that the major frequency of jet pulsation gradually increased with the increase of operating pressure. A stable periodic velocity core was formed at the outlet of the Helmholtz oscillator, while the external flow field was subjected to periodic impact. As a result, the ambient fluid was strongly entrained into the jet beam. With the increase of the cavity length, the length of the core segment decreased while the energy loss caused by the cavity increased, which was also accompanied by a rapid attenuation of the axial velocity at the jet outlet. The coherent structure of the jet in the oscillator with small cavity diameter was more disordered near the nozzle outlet, and the vortex scale was larger. The effect of cavity diameter can be reflected in the feedback modulation of the jet in the cavity. Compared with the conical nozzle, the length of the core section of the jet was shorter, but the jet had better bunching, a smaller diffusion angle, and better mixing performance. These results provide a further understanding of the characteristics of pulsed water jet for better utilizations in the fields of energy exploitation. a self-propelled water-jet drilling nozzle to drill three-type boreholes to improve gas extraction and drilling experiments were conducted to optimize the nozzle configuration. As a generator of SEOPJ, attention has been paid to the Helmholtz oscillator and extensive research has been done by . The unsteady flow phenomenon in SEOPJ is combined with various theories such as fluid dynamics, fluid resonance, and hydroelasticity, which makes it difficult to measure the flow patterns and vortex structures. In particular, an experimental study was conducted to characterize the discrete model by the change of cavity length and to give stable working regions under various parameters [7]. The identification of the complex mechanism responsible for this phenomenon is difficult because it is the result of multiple factors and data acquisition of all the instantaneous fields simultaneously is unavailable under the existing measurement techniques [8].Energies 2019, 12, x FOR PEER REVIEW 3 of 21 be distinguished. The research results can be used as the theoretical basis for selection and design of SEOPJ nozzles in underground mining.

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“…Research work on this subject is carried out by other authors, because the quantification of the dissipative properties of different numerical schemes is at the centre of interest in the field of computational physics and engineering sciences. Bonelli et al [9] carried out a comprehensive investigation of how a high density ratio does affect the near-and intermediate-field of hydrogen jets at high Reynolds numbers. They developed a novel Localized Artificial Diffusivity (LAD) model to take into account all unresolved sub-grid scales and avoid numerical instabilities of the LES approach.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Numerical Dissipation in Classical and Implicit Large Eddy Simulations

2017

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Abstract:The quantitative measure of dissipative properties of different numerical schemes is crucial to computational methods in the field of aerospace applications. Therefore, the objective of the present study is to examine the resolving power of Monotonic Upwind Scheme for Conservation Laws (MUSCL) scheme with three different slope limiters: one second-order and two third-order used within the framework of Implicit Large Eddy Simulations (ILES). The performance of the dynamic Smagorinsky subgrid-scale model used in the classical Large Eddy Simulation (LES) approach is examined. The assessment of these schemes is of significant importance to understand the numerical dissipation that could affect the accuracy of the numerical solution. A modified equation analysis has been employed to the convective term of the fully-compressible Navier-Stokes equations to formulate an analytical expression of truncation error for the second-order upwind scheme. The contribution of second-order partial derivatives in the expression of truncation error showed that the effect of this numerical error could not be neglected compared to the total kinetic energy dissipation rate. Transitions from laminar to turbulent flow are visualized considering the inviscid Taylor-Green Vortex (TGV) test-case. The evolution in time of volumetrically-averaged kinetic energy and kinetic energy dissipation rate have been monitored for all numerical schemes and all grid levels. The dissipation mechanism has been compared to Direct Numerical Simulation (DNS) data found in the literature at different Reynolds numbers. We found that the resolving power and the symmetry breaking property are enhanced with finer grid resolutions. The production of vorticity has been observed in terms of enstrophy and effective viscosity. The instantaneous kinetic energy spectrum has been computed using a three-dimensional Fast Fourier Transform (FFT). All combinations of numerical methods produce a k −4 spectrum at t * = 4, and near the dissipation peak, all methods were capable of predicting the k −5/3 slope accurately when refining the mesh.

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How does a high density ratio affect the near- and intermediate-field of high-Re hydrogen jets?

Cited by 18 publications

References 69 publications

Development of High-Fidelity Numerical Methodology Based on Wavenumber-Frequency Transform for Quantifying Internal Aerodynamic Noise in Critical Nozzle

Development of High-Fidelity Numerical Methodology Based on Wavenumber-Frequency Transform for Quantifying Internal Aerodynamic Noise in Critical Nozzle

Large Eddy Simulation of Self-Excited Oscillation Pulsed Jet (SEOPJ) Induced by a Helmholtz Oscillator in Underground Mining

Investigation of Numerical Dissipation in Classical and Implicit Large Eddy Simulations

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