Numerical study of thermohydraulic performance of solar air heater duct equipped with novel continuous rectangular baffles with high aspect ratio

Menasria, Fouad; Zedairia, Merouane; Moummi, Abdelhafid

doi:10.1016/j.energy.2017.05.002

Cited by 89 publications

(30 citation statements)

References 36 publications

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“…In Eqs, (8)(9)(10)(11), Re, Da and Pr represent Reynolds, Darcy and Prandtl numbers, which are defined as…”

Section: Non-dimensional Governing Equationsmentioning

confidence: 99%

“…Over the last two decades the field of heat transfer enhancement has experienced significant advancements. There are now a number of methods that take advantage of rough surfaces [2,3], porous material with high thermal conductivity [4], nanofluids [5,6,7], mounting twisted tape inserts or baffles [8,9] and wavy walls [10], as means of heat transfer enhancement. These are at different stages of maturation.…”

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confidence: 99%

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First and second laws of thermodynamics analysis of nanofluid flow inside a heat exchanger duct with wavy walls and a porous insert

Akbarzadeh

Rashidi

Karimi

et al. 2018

J Therm Anal Calorim

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This paper investigates the combined effects of using nanofluid, a porous insert and corrugated walls on heat transfer, pressure drop and entropy generation inside a heat exchanger duct. A series of numerical simulations are conducted for a number of pertinent parameters. It is shown that the waviness of the wall destructively affects the heat transfer process at low wave amplitudes and that it can improve heat convection only after exceeding a certain amplitude. Further, the pressure drop in the duct is found to be strongly influenced by the wave amplitude in a highly non-uniform way. The results, also, show that the second law and heat transfer performances of the system improve considerably by thickening the porous insert and decreasing its permeability. Yet, this is associated with higher pressure drops. It is argued that the hydraulic, thermal and entropic behaviours of the system are closely related to the interactions between a vortex formation near the wavy walls and nanofluid flow through the porous insert. Viscous irreversibilities are shown to be dominant in the core region of duct where the porous insert is placed. However, in the regions closer to the wavy walls, thermal entropy generation is the main source of irreversibility. A number of design recommendations are made on the basis of the findings of this study.

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“…In Eqs, (8)(9)(10)(11), Re, Da and Pr represent Reynolds, Darcy and Prandtl numbers, which are defined as…”

Section: Non-dimensional Governing Equationsmentioning

confidence: 99%

mentioning

confidence: 99%

First and second laws of thermodynamics analysis of nanofluid flow inside a heat exchanger duct with wavy walls and a porous insert

Akbarzadeh

Rashidi

Karimi

et al. 2018

J Therm Anal Calorim

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“…In addition, helical vortex flows generate through the multi V‐shaped ribs, which helped for mixing the fluid between the colder and the warmer mainstream near the absorber wall. Numerical study of thermohydraulic performance of solar air heater duct armed with novel continuous rectangular baffles studied by Menasria et al 50 The effect of four baffle‐pitch spacing ratios, ( PR = 2, 4, 6, 8) and four baffle blockage ratios, ( BR = 0.7, 0.82, 0.92, 0.98) in 16 configurations were acknowledged. The result shows that the suggestion of baffles on the bottom wall of ducts is an effective technique to improve the heat exchange despite their advantages in terms of pressure loss.…”

Section: Introductionmentioning

confidence: 99%

Numerical evaluation of the thermal performance of a solar air heater equipped with two different types of baffles

2020

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In the present study, the effect of utilizing two different types of baffles in the channel of the solar air heater is investigated numerically. The studied baffles include angled rectangular baffles and angled V-shaped baffles, which are mounted on the bottom and top walls of the duct, respectively. Both considered baffles were evaluated separately which the studied parameter in each section was the angular position of baffles. Finally, the best-obtained results of both sections were compared to each other. The results indicated that in the rectangular model by comparison between 90°model and no baffle, it was found that the pressure drop and average Nusselt number increase 316.67% and 148.15%, respectively at Reynolds number (Re) = 2000. Also, in V-shaped angled baffles, the thermal efficiency of β = 90°, 60°, 45°, and 30°are 27%, 18%, 13% higher than no baffle channel at Re = 2000, respectively. Furthermore, at low Re (about Re below 300), utilizing baffles into the channel had no effect on the thermal efficiency of the system compared to the no baffle channel. However, at high Re, it was found that the highest thermal efficiency occurred in the model of rectangular baffles with an angle of 90°. K E Y W O R D S baffle, heat-transfer enhancement, numerical simulation, solar air heater

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“…is apply us in industrial domain including cooling of electronic circuit [1], thermal performance of energy efficiency [2], flow and heat transfer in solar collectors [3], lubrication technologies [4], geothermal heat exchangers [5][6][7][8] and many others. In the literature, numerous analytical models, numerical and experimental researches have done on the mixed convection heat transfer in different geometries [9,10].…”

Section: Introductionmentioning

confidence: 99%

Combined Heat and Mass Transfer of Fluid Flowing through Horizontal Channel by Turbulent Forced Convection

Salhi

Amghar

Bouali³

et al. 2020

Modelling and Simulation in Engineering

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In the present paper, we report a numerical study of dynamic and thermal behavior of the incompressible turbulent air flow by forced convection in a two-dimensional horizontal channel. This one contains the complicated form of the deflector which has been studied by varying the inclination angle from φ = 40°, φ = 55° to φ = 65°. The baffles are mounted on lower and upper walls of the channel. The walls are maintained at a constant temperature (375 K), the inlet velocity of air is Uint = 7.8 m/s, and the Reynolds number Re = 8.73 × 104. A specifically developed numerical model was based on the finite-volume method to solve the coupled governing equations and the SIMPLE (Semi Implicit Method for Pressure Linked Equation) algorithm for the treatment of velocity-pressure coupling. For Pr = 0.71, the results obtained show that (i) the streamlines and isotherms are strongly affected by the inclinations angles at Re = 8.73 × 104, (ii) the friction coefficient near the baffles increases under the angle exchange effect, and (iii) for a constant Re, the local Nusselt number at the walls of the channel varies with increasing the inclination angle of the deflector. Furthermore, the deflectors are generally used to change the direction of the structure of flow and also to increase the turbulence levels. We can conclude that the contribution of inclined baffles improves the increase of heat and mass transfer in which the Nusselt number at a certain angle increases noticeably.

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Numerical study of thermohydraulic performance of solar air heater duct equipped with novel continuous rectangular baffles with high aspect ratio

Cited by 89 publications

References 36 publications

First and second laws of thermodynamics analysis of nanofluid flow inside a heat exchanger duct with wavy walls and a porous insert

First and second laws of thermodynamics analysis of nanofluid flow inside a heat exchanger duct with wavy walls and a porous insert

Numerical evaluation of the thermal performance of a solar air heater equipped with two different types of baffles

Combined Heat and Mass Transfer of Fluid Flowing through Horizontal Channel by Turbulent Forced Convection

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