Numerical investigation on heat transfer and pressure drop of pin-fin array under the influence of rib turbulators induced vortices

Advances in Mechanical Engineering

2020

Flow prediction, heat transfer pattern, and thermo-hydraulic efficiency in a heat exchanger tube fitted with vortex generator are chosen for the present research. The 30° inclined ring is opted to develop the performance of the heat exchanger tube. The effects of inclined ring configuration and placement in the heat exchanger tube on the patterns of flow and heat transfer are investigated. The Reynolds number (at the entry zone of the periodic model) in the range of around 100–2000 (laminar flow region) is discussed. The heat transfer ability, pressure loss, and efficiency of the heat exchanger tube fitted with 30° inclined ring are analyzed with the numerical method (finite volume method). The SIMPLE algorithm of the commercial code is picked for the present study. The simulated results in the heat exchanger tube fitted with 30° inclined ring are offered in patterns of streamlines, temperature contour, and Nusselt number contour. From the preliminary result, it is found that the creation model of the heat exchanger tube fitted with 30° inclined ring has sufficient reliance to measure flow and heat transfer profiles. The installment of the 30° inclined ring in the heat exchanger tube leads to greater heat transfer ability and thermo-hydraulic performance because of the creation of the vortex flow and thermal boundary layer disturbance on the heat exchanger tube surface. The heat transfer ability in the heat exchanger tube fitted with 30° inclined ring is found to be around 1.00–10.56 times above the plain circular tube. In addition, the installation of the 30° inclined ring in the heat exchanger tube gives the maximum thermal enhancement factor around 3.18.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Variations of heat transfer mechanism and flow structure in a heat exchanger tube fitted with 30° inclined ring

Advances in Mechanical Engineering

2020

“…Their results revealed that the averaged Nusselt number and overall Nusselt number are greater than those of the smooth channel with no rib around 2.2-2.6 and 2.9-3.3 times, respectively. Bai et al [18] simulated the pressure loss and heat transfer ability in a pin-fin array installed with rib turbulators. They summarized that the rib induces the secondary flow that is a reason for the heat transfer augmentation.…”

Section: Startmentioning

confidence: 99%

Heat Transfer Potentiality and Flow Behavior in a Square Duct Fitted with Double-Inclined Baffles: A Numerical Analysis

Modelling and Simulation in Engineering

2021

Numerical analysis of heat transfer mechanisms and flow topologies for the heat exchanger square channel (HESC) installed with the double-inclined baffles (DIB) is reported. The main objective of the present research is to study the influences of DIB height to duct height ( b / H = 0.05 – 0.30 ), DIB distance to duct height ( P / H = 1 – 1.5 ), and flow attack angle ( α = 30 ° and 45 ° ) on the flow topologies, heat transfer features, and thermal performances. The Reynolds numbers (based on the entry HESC around 100–2000) are analyzed for the present problem. The numerical models of the HESC installed with the DIB are solved with finite volume method (commercial code). The simulated results of the HESC installed with the DIB are reported in forms of flow topologies and heat transfer characteristics. The Nusselt numbers (Nu), friction factors ( f ), and thermal enhancement factors (TEF) of the HESC placed with the DIB are offered. As the numerical results, it is seen that the DIB produces the vortex streams and impinging streams in all cases. The vortex streams and impinging streams disturb the thermal boundary layer on the HESC walls that is a key motive for the growth of heat transfer rate. The best TEF of the HESC installed with the DIB is about 3.87 at P / H = 1 , α = 30 ° , Re = 2000 , and b / H = 0.15 . Additionally, the TEF contours, which help to design the HESC inserted with the DIB, are performed.

“…They concluded that the globally averaged Nusselt number and overall Nusselt number are around 2.20–2.60 and 2.90–3.30 times above the smooth channel, respectively. The numerical investigation on flow pattern and heat transfer behavior of pin-fin array with rib turbulators was reported by Bai et al 11 They found that the heat transfer rate of pin-fin array increases when installing rib turbulators. They claimed that the 90° rib provides the best overall performance.…”

Section: Introductionmentioning

confidence: 99%

Forced convective heat transfer and thermal efficiency assessment in square channel equipped with 10° wavy thin rib

Advances in Mechanical Engineering

2014

Forced convective heat transfer and thermo-hydraulic efficiency in the heat exchanger square channel (HESC) inserted with 10° wavy thin rib (WTR) are reported numerically. The effects of rib height, pitch distance and flow velocity on flow and heat transfer profiles are considered. The rib height to the channel height; e/H or HR, is varied in the range 0.05–0.30, while the rib pitch to the channel height; P/H or PR, is varied in the range 0.50–1.25. The air velocity in the HESC inserted with the WTR is considered in terms of Reynolds number. The Reynolds numbers (Re = 100–2000) for the present investigation is analyzed at the inlet condition. The finite volume method (commercial code) with SIMPLE algorithm is picked to solve the present problem. The numerical model of the HESC inserted with the WTR is validated for both grid independence and verification of the smooth HESC. The numerical results of the HESC inserted with the WTR are printed in terms of flow and heat transfer profiles. The values of Nusselt number, friction factor and thermal efficiency factor in the HESC inserted with the WTR are also plotted. As the numerical result, it is found that the WTR in the HESC can produce the vortex flow that the reason for the enhancements of heat transfer and efficiency. The increment of the heat transfer ability in the HESC is detected when increasing rib height and Reynolds number. In addition, the greatest thermal efficiency factor in the HESC inserted with the WTR is around 3.43 at HR = 0.20, PR = 1, and Re = 2000.