Numerical simulation of viscoelastic flow using flux difference splitting at moderate Reynolds numbers

Abstract The results of numerical simulation of the separation flow in matrix channels by the RANS method are presented. The simulation is performed at the Reynolds number Re = 12600, determined by the mass-average velocity and the height of the channel. The distribution of the local Nusselt number is obtained for various Reynolds numbers in the range of 5÷15⋅103 and several rib angles. It is shown that the temperature distribution on the surface is highly nonuniform; in particular, the maximum heat transfer value is observed near the upper edge facets, in the vicinity of which the greatest velocity gradient is observed.

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Numerical Simulation Around Airfoil with High Resolution in High Reynolds Numbers

45th AIAA Aerospace Sciences Meeting and Exhibit ◽

10.2514/6.2007-720 ◽

2007 ◽

Cited By ~ 1

Author(s):

Takuji Kurotaki ◽

Takahiro Sumi ◽

Takashi Atobe ◽

Jun Hiyama

Keyword(s):

Numerical Simulation ◽

High Resolution ◽

Reynolds Numbers ◽

High Reynolds Numbers ◽

High Reynolds

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A NOVEL 3D MICROMIXER WITH QUARTIC KOCH CURVE FRACTAL

Surface Review and Letters ◽

10.1142/s0218625x21500499 ◽

2021 ◽

pp. 2150049

Author(s):

SIYUE XIONG ◽

XUEYE CHEN

Keyword(s):

Numerical Simulation ◽

Deflection Angle ◽

Reynolds Numbers ◽

Mixing Efficiency ◽

Flow State ◽

Koch Curve ◽

Mixing Performance ◽

Chaotic Convection ◽

The Deflection Angle ◽

High Application

In this paper, we mainly study the mixing performance of the micromixer with quartic Koch curve fractal (MQKCF) by numerical simulation. Changing the structure of the microchannel based on the fractal principle can significantly improve the fluid flow state in the microchannel and improve the mixing efficiency of the micromixer. This paper discussed the effects of different fractal deflection angles, microchannel heights and different fractal times on the mixing efficiency under four different Reynolds numbers (Re). It is found that changing the deflection angle of the fractal can bring extremely high benefits, which makes the fluid deflect and fold in the microchannel, enhancing the chaotic convection in the microchannel, and improve the mixing efficiency of the fluid. Under the reasonable arrangement of the quartic Koch curve fractal principle, it can give the micro-mixture more than 99% mixing efficiency. Based on the excellent mixing performance of MQKCF, it also has extremely high application value in the biochemical neighborhood.

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Numerical Simulation of Pressure Loss and Heat Transfer Characteristics for Additively Manufactured Channels

Volume 2C: Turbomachinery ◽

10.1115/gt2020-14803 ◽

2020 ◽

Author(s):

Bryan Arko ◽

Chad Iverson ◽

Nicholas Staudigel

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Surface Roughness ◽

Nusselt Number ◽

Pressure Loss ◽

Reynolds Numbers ◽

Measured Data ◽

Transfer Effects ◽

Micro Channels ◽

Heat Transfer Effects

Abstract This body of work provides an initial study of modeling both surface roughness and heat transfer concurrently in a numerical simulation of micro-channels representative of those that might be found in a turbine cooling application. Increased use of additive manufacturing (AM) or 3D printing techniques for turbomachinery components enable the manufacture of complex features to achieve higher operational performance. Accurate modeling of flow losses and heat transfer effects are critical to designing parts which achieve optimal efficiency paired with durability. Surface finish is rougher with AM compared to more traditional manufacturing techniques; therefore enhancing the pressure loss and heat transfer effects. Proper implementation of surface roughness within the computational model and correct modeling of the near wall boundary mesh must be maintained to produce accurate results. This study focuses on the comparison of near wall mesh treatment coupled with surface roughness to determine a practice for obtaining accurate pressure loss and heat transfer within a cooling passage, as compared to measurements. Steady-state computational fluid dynamics (CFD) models consisting of a wind tunnel inlet nozzle and outlet diffuser, along with internal cooling passages represented using micro-channels, has been run for a range of Reynolds numbers and simulated roughness levels. Analysis of a baseline configuration with aerodynamically smooth walls is first compared to the measured data to verify the assumption of aerodynamically smooth walls. Surface roughness is then added to the channel walls, from published test coupon measurements, and compared to published experimental data for a range of Reynolds numbers. The metal surrounding the passages is also included as a conjugate heat transfer model providing heat addition to the fluid. Pressure loss and heat transfer is compared to the measured data as a friction factor and Nusselt number for the range of Reynolds numbers. Since surface roughness units and measurements vary, an effect of surface roughness values on pressure loss and heat transfer will also be investigated to determine the importance of using and converting to the correct units for the numerical model. This serves as a starting point for a guideline that will help when both heat transfer and surface roughness are included in a CFD model. Further study is recommended to understand the diminishing levels of increase in friction factor and Nusselt number observed as surface roughness was continually increased in the numerical simulation.

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Numerical Simulation of the Separated Fluid Flows at Large Reynolds Numbers

Separated Flows and Jets ◽

10.1007/978-3-642-84447-8_16 ◽

1991 ◽

pp. 129-132

Author(s):

V. A. Gushchin ◽

V. N. Konshin

Keyword(s):

Numerical Simulation ◽

Fluid Flows ◽

Reynolds Numbers

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