Numerical Investigation of Transcritical-T Heat-and-Mass-Transfer Dynamics in Compressible Turbulent Channel Flow

Kim, Kukjin; Hickey, Jean-Pierre; Scalo, Carlo

doi:10.2514/6.2017-1711

Cited by 4 publications

(1 citation statement)

References 1 publication

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“…Kawai et al [19,20] used a fully compressible solver to conduct a DNS of zero-pressure-gradient heated transcritical turbulent boundary layers on a flat plate at supercritical pressure conditions. Kim et al [21] carried out turbulent channel flow simulations of supercritical R-134a using Peng-Robinson equation of state to describe the thermodynamics.…”

Section: Introductionmentioning

confidence: 99%

Direct numerical simulations of turbulent channel flow under transcritical conditions

Peter

Yang

Ihme

2018

2018 AIAA Aerospace Sciences Meeting

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Turbulent flows under transcritical conditions are present in regenerative cooling systems of rocker engines and extraction processes in chemical engineering. The turbulent flows and the corresponding heat transfer phenomena in these complex processes are still not well understood experimentally and numerically. The objective of this work is to investigate the turbulent flows under transcritical conditions using DNS of turbulent channel flows. A fully compressible solver is used in conjunction with a Peng-Robinson real-fluid equation of state to describe the transcritical flows. A channel flow with two isothermal walls is simulated with one heated and one cooled boundary layers. The grid resolution adopted in this study is slightly finer than that required for DNS of incompressible channel flows. The simulations are conducted using both fully (FC) and quasi-conservative (QC) schemes to assess their performance for transcritical wall-bounded flows. The instantaneous flows and the statistics are analyzed and compared with the canonical theories.It is found that results from both FC and QC schemes qualitatively agree well with noticeable difference near the top heated wall, where spurious oscillations in velocity can be observed. Using the DNS data, we then examine the usefulness of Townsend attached eddy hypothesis in the context of flows at transcritical conditions. It is shown that the streamwise energy spectrum exhibits the inverse wavenumber scaling and that the streamwise velocity structure function follows a logarithmic scaling, thus providing support to the attached eddy model at transcritical conditions.

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Section: Introductionmentioning

confidence: 99%

Direct numerical simulations of turbulent channel flow under transcritical conditions

Peter

Yang

Ihme

2018

2018 AIAA Aerospace Sciences Meeting

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Pseudophase change effects in turbulent channel flow under transcritical temperature conditions

2019

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We have performed direct numerical simulations (DNS) of compressible turbulent channel flow at supercritical pressure with top and bottom isothermal walls kept respectively at a supercritical (T top > T pb ) and subcritical temperature (T bot < T pb ), where T pb is the pseudoboiling temperature. The DNS are conducted using a high-order discretization of the fully compressible Navier-Stokes equations in conservative form closed with the Peng-Robinsion (PR) state equation. Bulk density is adjusted to obtain a bulk pressure of approximately p b = 1.1p cr where p cr is the critical pressure of the working fluid. Top-to-bottom temperature differences investigated are ∆T = 5 K, 10 K, and 20 K, where T top/bot = T pb ± ∆T /2; buoyancy effects are neglected. Varying ∆T modifies the average location of pseudophase change from y pb /h = −0.23 (∆T = 5 K) to 0.89 (∆T = 20 K), where h is the channel half-height and y = 0 the centerline position. Real-fluid effects cause visible deviations from classical scaling laws in the mean velocity profile. Enstrophy generation due stretching and tilting decreases with ∆T . The proximity to the pseudotransitioning layer inhibits the intensity of the velocity fluctuations, while enhancing the density and temperature fluctuations. Conditional probability analysis reveals that the sheet of fluid undergoing pseudophase change is characterized by a dramatic reduction in the kurtosis of density fluctuations and becomes thinner as ∆T is increased. Instantaneous visualizations show dense fluid ejections from the pseudoliquid viscous sublayer, some reaching the channel core, causing positive values of density skewness in the respective buffer-layer region (vice versa for the top wall).

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Numerical Investigation of Transcritical Turbulent Channel Flow

Doehring

Schmidt

Adams

2018

2018 Joint Propulsion Conference

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Numerical Investigation of Transcritical-T Heat-and-Mass-Transfer Dynamics in Compressible Turbulent Channel Flow

Cited by 4 publications

References 1 publication

Direct numerical simulations of turbulent channel flow under transcritical conditions

Direct numerical simulations of turbulent channel flow under transcritical conditions

Pseudophase change effects in turbulent channel flow under transcritical temperature conditions

Numerical Investigation of Transcritical Turbulent Channel Flow

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