Effect of viscosity and wall heat conduction on shock attenuation in narrow channels

Deshpande, Arvind; Puranik, B. P.

doi:10.1007/s00193-015-0556-5

Cited by 11 publications

(7 citation statements)

References 15 publications

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“…The Knudsen number for our experimental conditions is in the range Kn 0.001 0.01 < < for the smallest tube with D=50 μm, because 68 nm L » for atmospheric conditions [33]. The Kn here is also comparable with the one in the theoretical work [34]. Therefore, as we will see, although LIMS in the current work is different than macro shock waves due to dissipative effects, continuum mechanics still applies here.…”

Section: Introductionsupporting

confidence: 65%

Laser-plasma induced shock waves in micro shock tubes

et al. 2017

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Shock wave generation with help of lasers or shock tubes, for example, is a common subject at macroscopic scale. On the other hand, the current tendency towards smaller scales becomes more and more important. In particular, shock waves in small channels or tubes with sub-mm or micron-sized diameter have attracted much interest within the last years. But downscaling of shock wave effects such as pressure decrease and Mach number attenuation during propagation, viscous and heat effects, laminar and turbulent flow is not necessarily straightforward from macro to micro or even nano range. Although several theoretical investigations are available in this new field, there is a strong demand on experiments, which are mostly missing due to the lack of suitable methods. The present work introduces a novel method for the generation of shock waves at microscale, namely laserinduced micro shock waves (LIMS). The LIMS method applies a femtosecond laser to induce an optical breakdown in a thin aluminum target located at the entrance of a micro tube. Subsequently, a shock wave is launched by the high pressure aluminum plasma and starts propagating into the tube. The topical work presents, for the first time, experimental investigations on direct micro shock wave generation and propagation at well-defined conditions in micron-sized tubes. They are performed for different conditions and tubes down to 50 μm diameter. Different from previous shock wave investigations in the mm-diameter range that involve pressure transducers, the present work applies non-contact measurements by optical methods. The experiments are supported by additional simulations. A one-dimensional numerical hydrocode is applied to simulate the shock wave generation process. Further propagation of the shock in a micro tube is analyzed by solving twodimensional Navier-Stokes equations. Both simulations agree well with the experimental results. Nomenclature L t laser pulse duration (fs-laser) E L laser pulse energy (fs-laser)

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Section: Introductionsupporting

confidence: 65%

Laser-plasma induced shock waves in micro shock tubes

et al. 2017

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“…Since we consider noticeably short periods of time on the level of several milliseconds, the assumption on the isothermal wall looks reasonable: the characteristic time of heat transfer through the walls of waveguide tubes is usually much longer. 30 Three approaches to solving the problem are considered. The first is based on the application of the Euler equations (inviscid flow, Case 1).…”

Section: Statement Of the Problemmentioning

confidence: 99%

“…A two-dimensional viscous shock tube configuration was simulated numerically in Ref. 30. Because the thermal penetration depths in the tube wall for different values of wall conductivity and thickness were negligibly small for the times of interest (about 1 ms), the assumption of an isothermal tube wall was shown to be adequate for taking the wall heat conduction into account.…”

Section: Introductionmentioning

confidence: 99%

“…Various correlations supported by experimental data for the shock Mach number attenuation along a tube were also suggested in the literature (e.g., Refs. [30][31][32]. Using the Withem's assumption that all changes in the shock wave velocity are caused by the interaction between the leading shock front and tube walls, Gelfand et al 31 suggested a simple correlation for the shock wave Mach number, including the initial Mach number, local drag coefficient, and dimensionless propagation distance.…”

Section: Introductionmentioning

confidence: 99%

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Pressure measurements in detonation engines

Иванов

Фролов

Sergeev

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The influence of waveguide tubes on the signals received by remote pressure sensors measuring pressure histories in pulsed detonation engines (PDEs) and rotating detonation engines (RDEs) is studied computationally. Two types of pressure sensors are considered: low-frequency static pressure sensors and high-frequency sensors of pressure pulsations. Three approaches to solving the problem are used: based on Euler (inviscid flow), Navier–Stokes (laminar flow), and unsteady Reynolds-averaged Navier–Stokes (turbulent flow) equations. The approaches based on the inviscid and laminar flow models are shown to provide the best predictive capability. The laminar flow model is applied to analyzing the readings of pressure sensors installed remotely in the waveguide tubes attached to the hydrogen-fueled PDE, RDE, and detonation ramjet (DR). It is shown that the measurements of static pressure and pressure pulsations by remote pressure sensors do not correspond to the time-averaged mean and local instantaneous values of pressure in the combustors. The pressure time histories can be recovered based on the measurements and computational fluid dynamics calculations of the operation process. The latter is demonstrated by analyzing the results of test fires with a dual-duct DR model.

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“…Гидравлические удары, колебания и пульсации давления, повышенная вибрация трубопроводов многократно повышают скорость внутренних коррозионных процессов, способствуют накоплению усталостных микротрещин в металле, особенно в местах концентрации напряжений (сварные швы, царапины, заводские дефекты и др.) и являются основным фоном возникновения аварийных ситуаций [4,5].…”

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