scholarly journals Thermal-Hydraulic Analysis of Parabolic Trough Collectors Using Straight Conical Strip Inserts with Nanofluids

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 853
Author(s):  
Nabeel Abed ◽  
Imran Afgan ◽  
Hector Iacovides ◽  
Andrea Cioncolini ◽  
Ilyas Khurshid ◽  
...  
Keyword(s):  
Nusselt Number ◽  
Reynolds Numbers ◽  
Hydraulic Analysis ◽  
Uniform Heating ◽  
Parabolic Trough ◽  
Geometrical Properties ◽  
Optimum Configuration ◽  
Swirl Generator ◽  
Collector Efficiency ◽  
Thermal Hydraulic Analysis

In this study, we numerically investigated the effect of swirl inserts with and without nanofluids over a range of Reynolds numbers for parabolic trough collectors with non-uniform heating. Three approaches were utilized to enhance the thermal-hydraulic performance—the variation of geometrical properties of a single canonical insert to find the optimized shape; the use of nanofluids and analysis of the effect of both the aforementioned approaches; the use of swirl generators and nanofluids together. Results revealed that using the straight conical strips alone enhanced the Nusselt number by 47.13%. However, the use of nanofluids along with the swirl generators increased the Nusselt number by 57.48%. These improvements reduced the thermal losses by 22.3% for swirl generators with nanofluids, as opposed to a reduction of only 15.7% with nanofluids alone. The investigation of different swirl generator designs showed various levels of improvements in terms of the overall thermal efficiency and thermal exergy efficiency. The larger swirl generator (H30mm-θ30°-N4) with 6% SiO2 nanofluids was found to be the optimum configuration, which improved the overall collector efficiency and thermal exergy by 14.62% and 14.47%, respectively.

Three-Dimensional Thermal-Hydraulic Analysis in Slit Finned-Tube Heat Exchangers

2002 ◽  
Author(s):  
Jiin-Yuh Jang ◽  
Jer-Nan Yeh ◽  
Her-Chang Ay
Keyword(s):  
Nusselt Number ◽  
Numerical Study ◽  
Three Dimensional ◽  
Finned Tube ◽  
Numerical Results ◽  
Hydraulic Analysis ◽  
Tube Heat Exchanger ◽  
Flow And Heat Transfer ◽  
Fin Spacing ◽  
Thermal Hydraulic Analysis

A numerical study of laminar flow and heat transfer over a two-row and three-dimensional slit fin and tube heat exchanger is presented. The effects of two different slit numbers Sn = 2 and 4 are investigated in detail for the Reynolds number ReH (based on the fin spacing and the frontal velocity) ranging from 160 to 900. The numerical results for the velocity field, fin surface Nusselt number, Colburn and fanning factor are shown. It is found that, both the average Nusselt number and pressure drop coefficient are increased as the slit number Sn is increased. A comparison of the numerical results with the available experimental data is also presented.

Heat Transfer Enhancement in a Parabolic Trough Receiver Using Wall Detached Twisted Tape Inserts

2013 ◽  
Author(s):  
Aggrey Mwesigye ◽  
Tunde Bello-Ochende ◽  
Josua P. Meyer
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Temperature Difference ◽  
Reynolds Numbers ◽  
Heat Transfer Fluid ◽  
Twisted Tape ◽  
Parabolic Trough ◽  
Fluid Friction ◽  
Friction Performance ◽  
Volume Method

In this paper, heat transfer and fluid friction performance of a parabolic trough receiver with twisted tape inserts detached from the absorber tube’s wall is numerically studied. The numerical investigations were conducted for twist ratios in the range 0.30 ≤ ỹ ≤ 2.40, width ratios in the range 0.53 ≤ w̃ ≤ 0.91 and Reynolds numbers in the range 10,260 ≤ Re ≤ 320,000. The numerical simulations were performed using a finite volume method with the realisable k-ε turbulence model and Syltherm 800 as the heat transfer fluid. The use of twisted tape inserts shows a significant increase in the heat transfer and fluid friction performance of the receiver. The study also reveals significant reduction in absorber tube’s circumferential temperature difference due to the improved heat transfer performance. For the range of parameters considered, the Nusselt number, fluid friction and thermal enhancement factor are 1.01–3.36, 1.32–21.8, and 0.74–1.25 times those in a receiver with a plain absorber tube respectively. The absorber tube’s circumferential temperature difference reduces between 4–76% compared with a plain absorber tube. Correlations for Nusselt number and fluid friction are also reported for the range of parameters considered.

Hydrothermal characteristics of a double flow parabolic trough solar collector equipped with sinusoidal-wavy grooved absorber tube and twisted tape insert

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ali Akbar Abbasian Arani ◽  
Ali Memarzadeh
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Factor ◽  
Outer Surface ◽  
Solar Collector ◽  
Reynolds Numbers ◽  
Twisted Tape ◽  
Parabolic Trough ◽  
Content Type ◽  
Parabolic Trough Solar Collector

Purpose Present investigation conducts a study on the hydrothermal features of a double flow Parabolic Trough Solar Collector (PTSC) equipped with sinusoidal-wavy grooved absorber tube and twisted tape insert filled with nanofluid. This paper aims to present an effectual PTSC which is comprised by nanofluid numerically by means of finite volume method. Design/methodology/approach The beneficial results such as pressure drop inside the absorber tube, mean predicted friction factor, predicted average Nusselt number and hydrothermal Performance Evaluation Criteria (PEC) are evaluated and reported to present the influences of numerous factors on studied interest outcomes. Effects of different Reynolds numbers and environmental conditions are also determined in this investigation. Findings It is found that using the absorber roof (canopy) can enhance the heat transfer ratio of PTSCs significantly during all studied Reynolds numbers. Also, it is realized that the combination of inner grooved surface, outer corrugated surface and inserting turbulator can improve the thermal-hydraulic characteristics of PTSCs sharply. Originality/value Novel PTSC (N.PTSC) filling with two Heat Transfer Fluids (HTFs), inner and outer surface corrugated absorber tube, absorber roof and inserting twisted tape (N.PTSC.f) has the highest PEC values among all novel configurations along all investigated Reynolds numbers which is followed by configurations N.PTSC with two HTFs and inserting twisted tape (N.PTSC.e), N.PTSC with two HTFs and outer surface corrugated absorber tube (N.PTSC.b) and N.PTSC with two HTFs and inner surface corrugated absorber tube (N.PTSC.c), respectively. N.PTSC.f Nusselt number values can overcome the high values of friction factor, and therefore is introduced as the most efficient model in the current study.

THERMAL HYDRAULIC ANALYSIS OF SPENT FUEL SUBASSEMBLY DURING TRANSPORTATION FROM FBTR TO REPROCESSING FACILITY

Equipment ◽  
2006 ◽  
Author(s):  
D. Sujish ◽  
C. Meikandamurthy ◽  
T. R. Ellappan ◽  
M. Rajan ◽  
G. Vaidyanathan
Keyword(s):  
Spent Fuel ◽  
Hydraulic Analysis ◽  
Thermal Hydraulic Analysis

Heat transfer enhancement using second mode self-oscillating structures

2019 ◽  
Vol 30 (7) ◽  
pp. 3827-3842
Author(s):  
Samer Ali ◽  
Zein Alabidin Shami ◽  
Ali Badran ◽  
Charbel Habchi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Flow Regime ◽  
Vortex Generator ◽  
Reynolds Numbers ◽  
Content Type ◽  
Laminar Flow Regime ◽  
Second Mode

Purpose In this paper, self-sustained second mode oscillations of flexible vortex generator (FVG) are produced to enhance the heat transfer in two-dimensional laminar flow regime. The purpose of this study is to determine the critical Reynolds number at which FVG becomes more efficient than rigid vortex generators (RVGs). Design/methodology/approach Ten cases were studied with different Reynolds numbers varying from 200 to 2,000. The Nusselt number and friction coefficients of the FVG cases are compared to those of RVG and empty channel at the same Reynolds numbers. Findings For Reynolds numbers higher than 800, the FVG oscillates in the second mode causing a significant increase in the velocity gradients generating unsteady coherent flow structures. The highest performance was obtained at the maximum Reynolds number for which the global Nusselt number is improved by 35.3 and 41.4 per cent with respect to empty channel and rigid configuration, respectively. Moreover, the thermal enhancement factor corresponding to FVG is 72 per cent higher than that of RVG. Practical implications The results obtained here can help in the design of novel multifunctional heat exchangers/reactors by using flexible tabs and inserts instead of rigid ones. Originality/value The originality of this paper is the use of second mode oscillations of FVG to enhance heat transfer in laminar flow regime.

Application of the 4C code to the thermal–hydraulic analysis of the CS superconducting magnets in EAST

Cryogenics ◽  
2014 ◽  
Vol 63 ◽  
pp. 255-262 ◽  
Author(s):  
R. Zanino ◽  
R. Bonifetto ◽  
U. Bottero ◽  
J. Li ◽  
J. Qian ◽  
...  
Keyword(s):  
Superconducting Magnets ◽  
Hydraulic Analysis ◽  
Thermal Hydraulic Analysis
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