Hydrothermal performance analysis of various surface roughness configurations in trapezoidal microchannels at slip flow regime

Toghraie, Davood; Mashayekhi, Ramin; Niknejadi, Mohammadreza; Arasteh, Hossein

doi:10.1016/j.cjche.2020.03.028

Cited by 10 publications

(3 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Toghraie et al [19] investigated the effect of surface roughness to pressure drop in a triangle, rectangular, and trapezoidal cross-section microchannel with number roughness of 3, 6 in the Reynolds number of 5, 10, 15, and 20. They concluded that escalating roughness number would escalate the pressure drop in consequence stagnation effect.…”

Section: A Surface Roughnessmentioning

confidence: 99%

A review of single-phase pressure drop characteristics microchannels with bends

Junianto

Hendrarsakti

2021

J. Mechatron. Electr. Power Veh. Technol.

View full text Add to dashboard Cite

Microfluidic use in various innovative research, many fields aimed at developing an application device related to handling fluid flows in miniature scale systems. On the other hand, on the use of micro-devices for fluid flow the existence of bends cannot be avoided. This research aims to make a comprehensive study of fluid flow characteristics through a microchannel with several possible bends. This study was conducted by comparing Reynolds number versus pressure drop in a serpentine microchannel to gain bends loss coefficient. The result showed that the fluid flow with Re 100 did not affect the pressure drop, but on the Reynolds number above that, the pressure drop was increased along with the appears of vortices in the outer and inner walls around the channel bends which causes an increase in an additional pressure drop. The other finding shows that the reduction in diameter bend tube can increase the pressure drop.

show abstract

Section: A Surface Roughnessmentioning

confidence: 99%

A review of single-phase pressure drop characteristics microchannels with bends

Junianto

Hendrarsakti

2021

J. Mechatron. Electr. Power Veh. Technol.

View full text Add to dashboard Cite

show abstract

“…Since heat exchangers are commonly used in almost all areas of industrial activities, including fuel cells [1], electronic device cooling [2], solar air collectors [3], aerospace engineering [4], flame stabilization [5], refrigeration [6], electric vehicles [7], natural gas liquefaction [8], air dehumidification [9] and so forth, increasing the thermal performance is of vital importance. To satisfy such a need, in the last two decades, researchers have proposed different passive techniques for heat transfer augmentation, including roughness elements [10], twisted tapes [11] and wires inserts [12]. Such equipment modifies heat transfer using a higher heat transfer surface, generating a swirl flow, as well as disturbing hydrodynamic and thermal boundary layers of the fluid inside the tube, which directly improves the heat transfer coefficient.…”

Section: Introductionmentioning

confidence: 99%

Thermo-Hydraulic Performance Analysis on the Effects of Truncated Twisted Tape Inserts in a Tube Heat Exchanger

Ghalambaz

Mashayekhi²,

Arasteh

et al. 2020

Symmetry

Self Cite

View full text Add to dashboard Cite

This paper investigates the convective heat transfer in a heat exchanger equipped with twisted tape elements to examine effects of the twisted tape truncation percentage, pitch value, position and Reynolds number using 3D numerical simulation. A symmetric heat flux is applied around the tube as the studied heat exchanger. Based on the influences in both heat transfer enhancement and pressure drop, the performance evaluation criterion (PEC) is utilized. Inserting twisted tape elements and reducing the pitch value significantly augment the Nusselt number, friction coefficient and PEC number compared to the plain tube. For the best case with a Reynolds number of 1000, the average Nusselt number increases by almost 151%, which is the case of fully fitted twisted tape at a pitch value of L/4. Moreover, increasing the twisted tape truncation percentage reduces both heat transfer and pressure drop. Furthermore, the highest heat transfer rate is achieved when the truncated twisted tape is located at the entrance of the tube. Finally, it is concluded that for P = L, L/2, L/3 and L/4, the optimum cases from the viewpoint of energy conservation are twisted tapes with truncation percentages of 75, 50, 50 and 0%, in which the related PEC numbers at a Reynolds number of 1000 are almost equal to 1.08, 1.24, 1.4 and 1.76, respectively.

show abstract

“…The result shows that the Reynolds number has a dominant impact on the flow velocity. The trapezoidal microchannel has been examined by Toghraie et al 31 The influence of geometrical properties of roughness of surface on the heat transfer of slip flow was presented. They found that the increase in roughness leads to an increase in the pressure drop.…”

Section: Introductionmentioning

confidence: 99%