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Numerical predictions of three-dimensional flow and heat transfer are presented for a rotating two-pass rectangular channel with 45° rib turbulators and channel aspect ratio of 2:1. The rib height-to-hydraulic diameter ratio (e/Dh) is 0.094 and the rib-pitch-to-height ratio (P/e) is 10. Two channel orientations are studied: β = 90° and β = 135° corresponding to the mid-portion and the trailing edge regions of a turbine blade, respectively. The focus of this study is twofold; namely, to investigate the effect of the channel aspect ratio and the channel orientation on the nature of the flow and heat transfer enhancement. A multi-block Reynolds-Averaged Navier-Stokes (RANS) method was employed in conjunction with a near-wall second-moment turbulence closure. In the present method, the convective transport equations for momentum, energy, and turbulence quantities are solved in curvilinear, body-fitted coordinates using the finite-analytic method. The numerical results compare reasonably well with experimental data for both stationary and rotating rectangular channels with rib turbulators at Reynolds number (Re) of 10,000, rotation number (Ro) of 0.11 and inlet coolant-to-wall density ratio (Δρ/ρ) of 0.115.

Computations were performed to study three-dimensional turbulent flow and heat transfer in a rotating smooth and 45° ribbed rectangular channels for which heat transfer data were available. The channel aspect ratio (AR) is 4:1, the rib height-to-hydraulic diameter ratio (e/Dh) is 0.078 and the rib-pitch-to-height ratio (P/e) is 10. The rotation number and inlet coolant-to-wall density ratios, Δρ/ρ, were varied from 0.0 to 0.28 and from 0.122 to 0.40, respectively, while the Reynolds number was fixed at 10,000. Also, two channel orientations (β − 90° and 135° from the rotation direction) were investigated with focus on the high rotation and high density ratios effects on the heat transfer characteristics of the 135° orientation. These results show that, for high rotation and high density ratio, the rotation induced secondary flow overpowered the rib induced secondary flow and thus change significantly the heat transfer characteristics compared to the low rotation low density ratio case. A multi-block Reynolds-Averaged Navier-Stokes (RANS) method was employed in conjunction with a near-wall second-moment turbulence closure. In the present method, the convective transport equations for momentum, energy, and turbulence quantities are solved in curvilinear, body-fitted coordinates using the finite-analytic method.

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Effectively converting CO2 into fuels and value-added chemicals remains a major challenge in catalysis, especially under mild conditions. In this study, we report a one-step non-thermal plasma-enabled catalytic process for...