Numerical Prediction of Heat Transfer and Fluid Flow Characteristics in a Circular Microchannel with Bifurcation Plate

Valaparla Ranjith Kumar,Karthik Balasubramanian,K Kiran Kumar

doi:10.33889/ijmems.2019.4.6-109

Valaparla Ranjith Kumar, Karthik Balasubramanian + Show 1 more

Open Access

https://doi.org/10.33889/ijmems.2019.4.6-109

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Abstract

Hydrothermal characteristics in circular wavy microchannels (CWMCs) with bifurcation plate have been numerically studied and compared with hydrothermal performance of sinusoidal wavy microchannels (SWMCs). Numerical study were carried out considering the Reynolds number (Re) ranging from 100 to 300. It was observed that, as the fluid flows through CWMC, it continuously absorbs heat from the channel leading to decrease in the temperature difference between the channel and the fluid. Hence, heat dissipation along the channel length decreases. To augment the heat dissipation along the fluid flow direction in CWMC, bifurcation plate (BFP) is introduced in the middle of the channel. CWMC with bifurcation plate has shown higher Nusselt number (Nu) with pressure drop penalty. The parametric study on bifurcation plate length was also carried out to minimize the pressure drop penalty and to achieve higher Nu. It is identified that CWMC with bifurcation plate length of 12.5 mm gives higher Nu with pressure drop penalty. Nu is further enhanced by providing slots on bifurcation plate. It is concluded that CWMC with BFP(10 mm) having slots gives the highest Nu than any other designs with pressure drop penalty.

Highlights

As day to day growth of technology and modernization of electronic devices, several conventional heat dissipation technologies have not been able to meet the desired cooling effect
Span-Wise Velocity Vector Profiles and Stream-Wise Velocity Contours From Figure 4, it is observed that circular wavy microchannels (CWMCs) has more Dean vortices than sinusoidal wavy microchannels (SWMCs)
In CWMC with bifurcation plate (BFP), as slots are introduced in BFP, it leads to further thinning and re-initialization of boundary layer and augments the convective heat transfer

Summary

Introduction

As day to day growth of technology and modernization of electronic devices, several conventional heat dissipation technologies have not been able to meet the desired cooling effect. Liu and Garimella (2004) studied the heat transfer characteristics in straight microchannels in the Re range 300 to 3500 with channel width varied in the range 194 μm to 534 μm at a depth five times normal width They concluded that wide mismatches occurred between the conventional correlation and experimental values and numerical results are aligned with a deviation of 5%. Sui et al (2010) numerically investigated hydrothermal characteristics in wavy MCs by changing the relative wave length in flow direction They concluded that wavy MCs shown higher Nu than straight MCs with lesser pressure drop penalty. Chiam et al (2016) numerically studied the hydrothermal characteristics of wavy microchannels with 450 branched secondary channels They studied overall performance factor of their introduced design at full amplitude and half amplitude. FA where ‘A’ refers to reference design (SWMC) and ‘B’ refers to the present design that is compared with the reference

Experimental Validation

Results and Discussion

Heat Transfer Enhancement Figure 6 illustrates variation of Nu variation with

Temperatue Difference Between Channel Inner Surface and Fluid along Channel

Pressure Drop Penalty From

Performance Factor (Pf) Figure 9 illustrates the variation Pf with Re