Computational fluid dynamics analysis of the heat transfer and pressure drop of solar air heater with conic-curve profile ribs

Ngo, Tu Thien; Phu, Nguyen Minh

doi:10.1007/s10973-019-08709-4

Cited by 42 publications

(13 citation statements)

References 37 publications

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“…Similar kind of flow behavior in the solar collector was also identified by Romdhane [43]. Ngo et al [30] also noticed the highest air temperature in the corners of collector, where air velocity was approximately zero. It is further evident from the figure that a viscous sub-layer or thermal boundary layer appeared in the contact regions with absorber plate, which grew thicker along the flow direction.…”

Section: Air Temperature-velocity Profile Inside the Fpscsupporting

confidence: 70%

“…8d, e. Therefore, it can be inferred that attachment of semicircular loops led to dissipation of heat from absorber plate to greater heights inside the duct leading to more uniform air temperature profile across the collector cross section. In contrast to it, introduction of conic curve profile ribs resulted in the increase in temperature of air only in the region located near the absorber plate [30]. The configuration 3_8_2, 3.5_7_2 and 4_6_2 exhibited 10.4 K, 8.97 K and 8.38 K, respectively, higher average air temperature at collector outlet than obtained by FPSC.…”

Section: Continuous Semicircular Loopsmentioning

confidence: 78%

“…In this regard, modeling and simulation is used for projecting the involved heat transfer phenomena and air flow pattern inside the collector under different operating conditions. Thus, it provides the opportunity of making the right decision about configuration of fin, optimization of geometrical parameters, approximation of collector performance, and scope of modification during design and development stage leading to time and resources saving [28][29][30].…”

Section: Introductionmentioning

confidence: 99%

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Heat transfer augmentation of flat plate solar collector through finite element-based parametric study

Rani

Tripathy

2020

J Therm Anal Calorim

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The introduction of fins and baffles on the absorber plate is an effective way to ameliorate the thermal performance of flat plate solar collector (FPSC), but obstructs the air passage leading to considerable pumping power penalty. In the current work, attempt is made to improve the overall performance of collector with the incorporation of hollow semicircular loop fins and rectangular baffles over the absorber plate for air mass flow rate ranging from 0.006 to 0.02 kg s −1 . A parametric study was carried out with finite element approach considering different radius (2-4 cm), pitch (6-20 cm) and number of semicircular loops per row in transverse direction (3-8 loops). Compared to intermittent loops, placement of continuous staggered semicircular loops was more effective for attaining uniform profile and higher magnitude of air temperature at collector outlet. With regard to FPSC, finned collector provided 2.64-2.95 times greater Nusselt number and 41-75% higher thermal efficiency, as well as exhibited 8.38-10.4 K higher collector outlet average air temperature. The pressure drop noted for FPSC was 0.14 Pa and increased to the range of 0.5-0.7 Pa with the addition of loops and baffles at an air mass flow rate of 0.01 kg s −1 . Collector having baffles and continuous semicircular loops of radius 3 cm, made up of 2-mm-thick wire, presented maximum thermohydraulic performance factor of 1.73 in conjunction with showing maximum magnitude and uniform profile of collector outlet temperature. The modified collector with semicircular loops along with baffles will find its application in efficient drying of agricultural commodities.

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Section: Air Temperature-velocity Profile Inside the Fpscsupporting

confidence: 70%

Section: Continuous Semicircular Loopsmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

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Heat transfer augmentation of flat plate solar collector through finite element-based parametric study

Rani

Tripathy

2020

J Therm Anal Calorim

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“…DNS and LES can provide details of turbulence statistics but are high-cost methods [19][20][21]. The RANS method is usually used for CFD simulations due to its lower computational cost [22,23], especially for turbomachinery simulation. Moreover, previous studies have confirmed that the SST γ model and SST γ − θ model are the most suitable for analysis of transitional flows [24,25].…”

Section: Governing Equations and Turbulence Modelmentioning

confidence: 99%

Effects of Leading-Edge Modification in Damaged Rotor Blades on Aerodynamic Characteristics of High-Pressure Gas Turbine

Dam

Ryu

2020

Mathematics

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The flow and heat-transfer attributes of gas turbines significantly affect the output power and overall efficiency of combined-cycle power plants. However, the high-temperature and high-pressure environment can damage the turbine blade surface, potentially resulting in failure of the power plant. Because of the elevated cost of replacing turbine blades, damaged blades are usually repaired through modification of their profile around the damage location. This study compared the effects of modifying various damage locations along the leading edge of a rotor blade on the performance of the gas turbine. We simulated five rotor blades—an undamaged blade (reference) and blades damaged on the pressure and suction sides at the top and middle. The Reynolds-averaged Navier–Stokes equation was used to investigate the compressible flow in a GE-E3 gas turbine. The results showed that the temperatures of the blade and vane surfaces with damages at the middle increased by about 0.8% and 1.2%, respectively. This causes a sudden increase in the heat transfer and thermal stress on the blade and vane surfaces, especially around the damage location. Compared with the reference case, modifications to the top-damaged blades produced a slight increase in efficiency about 2.6%, while those to the middle-damaged blades reduced the efficiency by approximately 2.2%.

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“…Due to the periodic variation in the parameters of the geometry, the pattern of the fluid movement is largely affected by the flow velocities, loss in pressure, and heat enhancements [1][2][3][4]. The wavy channels with the corrugated walls having the periodic expansion and contraction are widely studied in the many of the application like blood oxygenators [5,6], in the microfiltration cell [7], the wavy channels are also studied as the vortex generators to increase the thermal performance in solar panels [8,9]. There is a lot of work focused upon the fluid flow through sinusoidally curved wavy channels, details are given below:…”

Section: Nomenclaturementioning

confidence: 99%

Hydrodynamics and Heat Transfer Analysis of Airflow in a Sinusoidally Curved Channel

Memon¹,

Memon²,

Bhatti³

et al. 2022

Computers, Materials &Amp; Continua

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For heat transfer enhancement in heat exchangers, different types of channels are often tested. The performance of heat exchangers can be made better by considering geometry composed of sinusoidally curved walls. This research studies the modeling and simulation of airflow through a 2π units long sinusoidally curved wavy channel. For the purpose, two-dimensional Navier Stokes equations along with heat equations are under consideration. To simulate the fluid flow problem, the finite element-based software COM-SOL Multiphysics 5.4 is used. The parametric study for Reynolds number from Re = 100 to Re = 1000 and the period of vibration P from 0 to 5 are observed. The surface plots, streamline patterns, contours, and graphs are presented for the velocity field magnitude, temperature, and pressure against the Reynolds number as well as period of vibration. The results are compared with various literature. It is found that due to the creation of periodic contraction regions the velocity magnitude of the flow is continuously increasing with the increase of Reynolds number, on the contrary the pressure is decreasing from inlet to outlet of the channel. Also, a periodic variation in the pressure distribution along the vibrating boundaries has been found with an average increase of 500% for the high Reynolds number. A novel work was done by expressing the rotation rate per second in terms of local Reynolds number for the recirculating regions found due to the periodic oscillation of the boundaries. The average temperature near the outlet where a fixed temperature is imposed initially is decreasing with an increase in Reynolds number. The convection process is weakened due to an increase of periodic vibration of boundaries.

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Computational fluid dynamics analysis of the heat transfer and pressure drop of solar air heater with conic-curve profile ribs

Cited by 42 publications

References 37 publications

Heat transfer augmentation of flat plate solar collector through finite element-based parametric study

Heat transfer augmentation of flat plate solar collector through finite element-based parametric study

Effects of Leading-Edge Modification in Damaged Rotor Blades on Aerodynamic Characteristics of High-Pressure Gas Turbine

Hydrodynamics and Heat Transfer Analysis of Airflow in a Sinusoidally Curved Channel

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