Features of convective heat transfer in heated helium channel flow

Gordeev, S.; Heinzel, V.; Slobodtchouk, V.

doi:10.1016/j.ijheatmasstransfer.2005.02.023

Cited by 11 publications

(6 citation statements)

References 12 publications

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“…It is straightforward to notice that most of the studies focus on imposed heat flux [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] whereas Dirichlet boundary conditions types are very scant [26,27]. Cylindrical pipes are the most frequently encountered geometry [7, 9-12, 14-16, 18, 20-23, 25] while channels are scarcer [6,8,13,17,26,27]. This scarcity obviously creates an impetus for the analysis of laminarization in turbulent channel flows with imposed temperature at the walls.…”

Section: Literature Reviewmentioning

confidence: 99%

Asymmetric reverse transition phenomenon in internal turbulent channel flows due to temperature gradients

Serra

Franquet

Boutrouche

et al. 2021

International Journal of Thermal Sciences

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Laminarization of a turbulent flow due to wall heating has been known for more than 50 years, to the point that it is sometimes used as means of reducing friction. However this phenomenon has been mainly studied for cylindrical pipes and with imposed heat flux but not for channel flows and with imposed temperature boundary conditions, especially with asymmetric ones (that is to say in presence of a transverse thermal gradient). Based on the recent success of some Reynolds-averaged Navier-Stokes (RANS) models to correctly describe the influence of a strong transverse temperature gradient on turbulent Poiseuille flows, when compared to similar direct numerical simulations (DNS) or large eddy simulations (LES) results, these approaches are used here to investigate reverse transition. Since the choice of turbulence model has a non-negligible influence on the results, however, it is necessary to use different models to get an indication of the uncertainty associated with them. The proposed methodology is based on the use of RANS closures that do not involve any wall functions due to the strong gradient in the wall layer that has to be modeled. Thus, two first-moment closures and a second-moment closure are considered: the k − ω − SST and the k − ε − v 2 /k, and the EB-RSM. The latter two rely on an elliptic blending. The turbulent heat flux is modeled with a simple gradient diffusion hypothesis (SGDH) and a generalized gradient diffusion hypothesis (GGDH) for the first-moment and second-moment closures respectively. In summary, more than 800 calculations are performed for the above three models in order to analyze the reverse transition, and to open room for debate on the possibility for such approaches to correctly reproduce the experimentally observed behavior.

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Section: Literature Reviewmentioning

confidence: 99%

Asymmetric reverse transition phenomenon in internal turbulent channel flows due to temperature gradients

Serra

Franquet

Boutrouche

et al. 2021

International Journal of Thermal Sciences

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“…DTHT is also a direct result of decrements of turbulent heat flux caused by decreases in turbulent kinetic energy, reductions in momentum exchange near the wall, and gas property variations [9]. This would lead to a substantial reduction in the heat transfer coefficient (HTC) and an increase in wall temperature [10].…”

Section: Introductionmentioning

confidence: 99%

“…Additional influences of rapid flow acceleration on turbulence include increments in viscous shear stress near the wall due to an amplified axial velocity gradient. The turbulence dissipation rate would surpass the turbulence production rate initiating a turbulence decay and a reduction in the Reynolds stress [10,14]. These conditions are accompanied by the growth of a thermal boundary layer [7], which would lead to readjustment of any previously fully developed turbulent velocity profile.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Convection Heat Transfer in High Pressure and High Temperature Gas Flows

Valentin

Anderson

Kawaji

2017

Journal of Heat Transfer

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This work focuses on an experimental investigation of convection heat transfer to a gas in a vertical tube under strongly heated conditions at high temperatures and pressures up to 943 K and 65 bar. A unique test facility for convection heat transfer experiments has been constructed, and used to obtain experimental data useful for better understanding and validation of numerical simulation models. This test facility consists of a single flow channel in a 2.7 m long, 0.11 m diameter graphite column with four 2.3 kW heaters placed symmetrically around the 16.8 mm diameter flow channel. Upward flow convection experiments with air and nitrogen were conducted for inlet Reynolds numbers from 1300 to 60,000, thus covering laminar, transition, and fully turbulent flow regimes. Experiments were performed at different flow rates (3.8 Â 10 À4 to 1.5 Â 10 À2 kg/s) and heater power up to 6 kW. Importantly, the data analysis considered the thermophysical properties of the gas and graphite changing with temperature and pressure. Nusselt number results are further compared to existing correlations. The effect of pressure and heater power on degraded heat transfer is examined. The analyses of the experimental data showed significant reductions in Reynolds number of up to 50% and Nusselt numbers of up to 90% between the gas inlet and outlet.

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“…With the improvement of computer performance, the computational fluid dynamic (CFD) tool began to be applied for the Experimental and numerical study of transient heat transfer for forced convection flow of helium gas over a twisted plate numerical analysis of the transient heat transfer process. Gordeev et al (2005) simulated steady state convective heat transfer in heated helium channel flow at the flow Reynolds number below 10,000 by the commercial STAR-CD code. Chen et al (2012) tried transient simulation for helium cooled IFMIF (The International Fusion Materials Irradiation Facility) high flux test module by ANSYS CFX and Star-CD code and qualified the CFX k-ε model.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study of transient heat transfer for forced convection flow of helium gas over a twisted plate

Wang

Liu

Fukuda

2016

JTST

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This study was conducted to investigate the transient heat transfer process between the solid surface and the coolant (helium gas) in Very High Temperature Reactor (VHTR). Forced convection transient heat transfer for helium gas flowing over a twisted plate was experimentally and theoretically studied. The heat generation rate of the twisted plate was increased with a function of / (where t is time, τ is period). Experiment was carried out at various periods ranged from 35 ms to 14 s and gas temperature of 303 K under 500 kPa. The flow velocities ranged from 4 m/s to 10 m/s. Platinum plates with a thickness of 0.1 mm and width of 4 mm were used as the test heaters. The plate was 180ºtwisted with a pitch of 20 mm. Based on the experimental data, it was found that the average heat transfer coefficient approaches the quasi-steady-state value when the dimensionless period τ* (τ* = τU/L, U is flow velocity, and L is effective length) is larger than about 300 and it becomes higher when τ* is small. Three dimensional numerical study were conducted and the results of three typical turbulence models were compared with experimental data. Numerical simulation results were obtained for average surface temperature difference, heat flux and heat transfer coefficient of the twisted plate and showed reasonable agreement with experimental data. Based on the numerical simulation, mechanism of local heat transfer coefficient distribution was clarified. A comparison of the twisted plate and flat plate was conducted to show the difference in heat transfer coefficient distribution.

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Features of convective heat transfer in heated helium channel flow

Cited by 11 publications

References 12 publications

Asymmetric reverse transition phenomenon in internal turbulent channel flows due to temperature gradients

Asymmetric reverse transition phenomenon in internal turbulent channel flows due to temperature gradients

Experimental Investigation of Convection Heat Transfer in High Pressure and High Temperature Gas Flows

Experimental and numerical study of transient heat transfer for forced convection flow of helium gas over a twisted plate

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