Second order temperature jump boundary condition for nano/microscale and hypersonic rarefied gas flow simulations

Le, Nam T. P.; Roohi, Ehsan

doi:10.1063/1.4902617

Cited by 3 publications

(14 citation statements)

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“…Non-equilibrium boundary conditions are imposed on the wall. The mesh is chosen as hexahedral with a total of 57,600 cells, as taken in the reference study (Le and Roohi, 2014) (Appendix). The free-stream Kn is 0.027.…”

Section: Resultsmentioning

confidence: 99%

“…a low Reynolds number flow. The corresponding DSMC results are obtained from White et al (2013), Le and Roohi (2014) and Wang and Li (2004). The PC3 results were run with ζ = 0 in equation (18).…”

Section: Resultsmentioning

confidence: 99%

“…Figure 3(a) and (b) shows the comparison of shear stress distribution and the slip velocity profile at the lower wall of the bend obtained from the three cases, with the DSMC results (Le and Roohi, 2014). All the three boundary condition models show nearly identical results with an overall good match with the DSMC results, properly capturing the significant jump at the bend location.…”

Section: Resultsmentioning

confidence: 99%

“…The Maxwell–Smoluchowski boundary conditions given by equations 11 and 12 are usually used with a homogeneous Neumann condition (zero normal gradient) for pressure (Le et al , 2012b; Le, 2010; Le and Roohi, 2014). The Le temperature jump condition given by equation (16) along with a homogeneous Neumann condition for pressure at the wall, however, leads to over-prediction of the pressure for different cases of hypersonic flow over a flat plate (Assam et al , 2018c).…”

Section: Non-equilibrium Boundary Conditionmentioning

confidence: 99%

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Investigation of non-equilibrium boundary conditions considering sliding friction for micro/nano flows

Assam

Kalkote

Dongari

et al. 2019

HFF

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Purpose Accurate prediction of temperature and heat is crucial for the design of various nano/micro devices in engineering. Recently, investigation has been carried out for calculating the heat flux of gas flow using the concept of sliding friction because of the slip velocity at the surface. The purpose of this study is to exetend the concept of sliding friction for various types of nano/micro flows. Design/methodology/approach A new type of Smoluchowski temperature jump considering the viscous heat generation (sliding friction) has recently been proposed (Le and Vu, 2016b) as an alternative jump condition for the prediction of the surface gas temperature at solid interfaces for high-speed non-equilibrium gas flows. This paper investigated the proposed jump condition for the nano/microflows which has not been done earlier using four cases: 90° bend microchannel pressure-driven flow, nanochannel backward facing step with a pressure-driven flow, nanoscale flat plate and NACA 0012 micro-airfoil. The results are compared with the available direct simulation Monte Carlo results. Also, this paper has demonstrated low-speed preconditioned density-based algorithm for the rarefied gas flows. The algorithm captured even very low Mach numbers of 2.12 × 10−5. Findings Based on this study, this paper concludes that the effect of inclusion of sliding friction in improving the thermodynamic prediction is case-dependent. It is shown that its performance depends not only on the slip velocity at the surface but also on the mean free path of the gas molecule and the shear stress at the surface. A pressure jump condition was used along with the new temperature jump condition and it has been found to often improve the prediction of surface flow properties significantly. Originality/value This paper extends the concept of using sliding friction at the wall for micro/nano flows. The pressure jump condition was used which has been generally ignored by researchers and has been found to often improve the prediction of surface flow properties. Different flow properties have been studied at the wall apart from only temperature and heat flux, which was not done earlier.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Non-equilibrium Boundary Conditionmentioning

confidence: 99%

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Investigation of non-equilibrium boundary conditions considering sliding friction for micro/nano flows

Assam

Kalkote

Dongari

et al. 2019

HFF

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“…It is designed to work with the continuum governing equations in the CFD method, such as the NS equations. The first order Maxwell slip condition is expressed as follows [30,31]:…”

Section: Nonequilibrium Boundary Conditionsmentioning

confidence: 99%

Effect of the sliding friction on heat transfer in high-speed rarefied gas flow simulations in CFD

Loc³

2016

International Journal of Thermal Sciences

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High-speed rarefied gas flow simulations using Quasi-Gas Dynamic equations with slip and jump boundary conditions

Le¹,

Huynh²

2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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The high-speed rarefied gas flow simulation is essential for the aerothermodynamic design of high-altitude vehicles. Recently, the Quasi-Gas Dynamic (QGD) equations have been implemented in OpenFOAM as a CFD solver named QGDFoam. In computational fluid dynamics (CFD), the accuracy of the prediction of the surface quantities depends on the slip and jump boundary conditions applied to the surfaces. In the present work, various first-order and second-order slip and jump boundary conditions have been numerically implemented into the solver QGDFoam in OpenFOAM to obtain a completed solver for simulating the rarefied gas flows. It then captures the surface quantities of the gas flows, such as the surface gas pressure, the slip velocity, and surface gas temperature. This completed solver is validated for the sharp-leading-edge wedge, the compression ramp, and the NACA 0012 micro-airfoil cases. Using the QGD model with the slip and jump conditions extends its application and enhances it to simulate high-speed rarefied gas flows. The simulation results show that the slip and jump conditions have been successfully employed with the QGD equations and give good results for predicting the surface quantities compared with the DSMC data.

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Second order temperature jump boundary condition for nano/microscale and hypersonic rarefied gas flow simulations

Cited by 3 publications

References 0 publications

Investigation of non-equilibrium boundary conditions considering sliding friction for micro/nano flows

Investigation of non-equilibrium boundary conditions considering sliding friction for micro/nano flows

Effect of the sliding friction on heat transfer in high-speed rarefied gas flow simulations in CFD

High-speed rarefied gas flow simulations using Quasi-Gas Dynamic equations with slip and jump boundary conditions

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