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Article
Publication date: 24 October 2022

Babak Lotfi and Bengt Ake Sunden

This study aims to computational numerical simulations to clarify and explore the influences of periodic cellular lattice (PCL) morphological parameters – such as lattice…

1128

Abstract

Purpose

This study aims to computational numerical simulations to clarify and explore the influences of periodic cellular lattice (PCL) morphological parameters – such as lattice structure topology (simple cubic, body-centered cubic, z-reinforced body-centered cubic [BCCZ], face-centered cubic and z-reinforced face-centered cubic [FCCZ] lattice structures) and porosity value ( ) – on the thermal-hydraulic characteristics of the novel trussed fin-and-elliptical tube heat exchanger (FETHX), which has led to a deeper understanding of the superior heat transfer enhancement ability of the PCL structure.

Design/methodology/approach

A three-dimensional computational fluid dynamics (CFD) model is proposed in this paper to provide better understanding of the fluid flow and heat transfer behavior of the PCL structures in the trussed FETHXs associated with different structure topologies and high-porosities. The flow governing equations of the trussed FETHX are solved by the CFD software ANSYS CFX® and use the Menter SST turbulence model to accurately predict flow characteristics in the fluid flow region.

Findings

The thermal-hydraulic performance benchmarks analysis – such as field synergy performance and performance evaluation criteria – conducted during this research successfully identified demonstrates that if the high porosity of all PCL structures decrease to 92%, the best thermal-hydraulic performance is provided. Overall, according to the obtained outcomes, the trussed FETHX with the advantages of using BCCZ lattice structure at 92% porosity presents good thermal-hydraulic performance enhancement among all the investigated PCL structures.

Originality/value

To the best of the authors’ knowledge, this paper is one of the first in the literature that provides thorough thermal-hydraulic characteristics of a novel trussed FETHX with high-porosity PCL structures.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 29 May 2019

Guanglin Shi and Haiji Wang

This paper aims to carry out a thermal-hydraulic simulation model for pump and hydraulic system to predict the temperature increasing and pump performance. Based on the model, how…

Abstract

Purpose

This paper aims to carry out a thermal-hydraulic simulation model for pump and hydraulic system to predict the temperature increasing and pump performance. Based on the model, how to alleviate the temperature is introduced. Besides, the optimization of piston is carried out.

Design/methodology/approach

This paper analyzes the heat generation in lubricating interfaces of the pump with energy conversion theory. The heat transfer inside the pump is analyzed with the control volume method. The simulation model is constructed in AMESim because of its operating friendly nature. The experiment is carried out to prove the validity and accuracy of the simulation model.

Findings

Temperature has less effect on the mechanical loss of pump. However, it has a great impact on volumetric efficiency. To reduce the temperature on the piston surface, the size of the piston should be optimized.

Originality/value

This paper fulfills a novel thermal-hydraulic model to evaluate the temperature of the pump. Based on the model, the performance of the pump is determined and optimization is carried out.

Details

Industrial Lubrication and Tribology, vol. 71 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 25 November 2021

Carolina P. Naveira-Cotta, Jian Su, Paulo Lucena Kreppel Paes, Philippe R. Egmont, Rodrigo P.M. Moreira, Gabriel Caetano G.R. da Silva and André Sampaio Monteiro

The purpose of this paper is to investigate the impact of semi-circular zigzag-channel printed circuit heat exchanger (PCHE) design parameters on heat transfer and pressure drop…

Abstract

Purpose

The purpose of this paper is to investigate the impact of semi-circular zigzag-channel printed circuit heat exchanger (PCHE) design parameters on heat transfer and pressure drop of flows under high Reynolds numbers and provide new thermal-hydraulic correlations relevant to conditions encountered in natural gas processing plants.

Design/methodology/approach

The correlations were developed using three-dimensional steady-state computational fluid dynamics simulations with varying semicircular channel diameter (from 1 to 5 mm), zigzag angle (from 15° to 45°) and Reynolds number (from 40,000 to 100,000). The simulation results were validated by comparison with experimental results and existing correlations.

Findings

The results revealed that the thermal-hydraulic performance was mostly affected by the zigzag angle, followed by the ratio of the zigzag channel length to the hydraulic diameter. Overall, smaller zigzag angles favored heat transfer intensification while keeping reasonably low pressure drops.

Originality/value

This study is, to date, the only one providing thermal-hydraulic correlations for PCHEs with zigzag channels under high Reynolds numbers. Besides, the broad range of parameters considered makes the proposed correlations valuable PCHE design tools.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 32 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 7 August 2020

Ali Akbar Abbasian Arani and Reza Moradi

Using turbulators, obstacles, ribs, corrugations, baffles and different tube geometry, and also various arrangements of these components have a noticeable effect on the shell and…

Abstract

Purpose

Using turbulators, obstacles, ribs, corrugations, baffles and different tube geometry, and also various arrangements of these components have a noticeable effect on the shell and tube heat exchangers (STHEs) thermal-hydraulic performance. This study aims to investigate non-Newtonian fluid flow characteristics and heat transfer features of water and carboxyl methyl cellulose (H2O 99.5%:0.5% CMC)-based Al2O3 nanofluid inside the STHE equipped with corrugated tubes and baffles using two-phase mixture model.

Design/methodology/approach

Five different corrugated tubes and two baffle shapes are studied numerically using finite volume method based on SIMPLEC algorithm using ANSYS-Fluent software.

Findings

Based on the obtained results, it is shown that for low-mass flow rates, the disk baffle (DB) has more heat transfer coefficient than that of segmental baffle (SB) configuration, while for mass flow rate more than 1 kg/s, using the SB leads to more heat transfer coefficient than that of DB configuration. Using the DB leads to higher thermal-hydraulic performance evaluation criteria (THPEC) than that of SB configuration in heat exchanger. The THPEC values are between 1.32 and 1.45.

Originality/value

Using inner, outer or inner/outer corrugations (outer circular rib and inner circular rib [OCR+ICR]) tubes for all mass flow rates can increase the THPEC significantly. Based on the present study, STHE with DB and OCR+ICR tubes configuration filled with water/CMC/Al2O3 with f = 1.5% and dnp = 100 nm is the optimum configuration. The value of THPEC in referred case was 1.73, while for outer corrugations and inner smooth, this value is between 1.34 and 1.57, and for outer smooth and inner corrugations, this value is between 1.33 and 1.52.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 11 October 2018

Soroush Sadripour

In this study, the effects of using corrugated absorber plate (instead of flat plate) and also using aerosol/carbon-black nanofluid (instead of air) on heat transfer and turbulent…

Abstract

Purpose

In this study, the effects of using corrugated absorber plate (instead of flat plate) and also using aerosol/carbon-black nanofluid (instead of air) on heat transfer and turbulent flow characteristics in solar collectors were numerically investigated.

Design/methodology/approach

The 3D continuity, momentum and energy equation were solved by finite volume and SIMPLE algorithm. As a result, the corrugated absorber plate was inspected in the case of triangle, rectangle and sinuous with the wave length of 1 mm and wave amplitude of 3 mm in turbulent flow regime and Reynolds number between 2,500 and 4,000. Choosing the proper geometry was carried out based on the best performance evaluation criteria (PEC) and increasing the air temperature from collector inlet to outlet.

Findings

The results revealed that for all times of the year the highest PEC was obtained for corrugated Sinusoidal model; however, the highest temperature increase from inlet to outlet was obtained for rectangular corrugated model. In addition, the results indicated that in sinusoidal model, the nanoparticles volume fractions increase leads to heat performance coefficient increase and the best heat performance conditions were attained in volume fraction of 0.1 per cent and Reynolds number of 4,000 for both six months period. In model with rectangular corrugated plate, usage of nanofluid in all range of Reynolds numbers leads to reduction of outlet temperature.

Originality/value

The effect of some nanoparticles on heat transfer using thermal– hydraulic performances in heat exchangers has been assessed, but the effects of atmospheric aerosol-based nanofluid using carbon-black nanoparticles (CBNPs) on the heat transfer in corrugated heat sink solar collectors by 3D numerical modeling has not been yet investigated. In present study, usage of CBNPs with different volume fractions in range of 0 to 0.1 per cent in turbulent regime of fluid flow is analyzed. Furthermore, in this paper, besides the effects of using CBNPs, a solar absorber located in Shiraz, as one of the best solar irradiation receiver cities in Iran is evaluated.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 April 2023

Chinedu Chinakwe, Adekunle Adelaja, Michael Akinseloyin and Olabode Thomas Olakoyejo

Inclination angle has been reported to have an enhancing effect on the thermal-hydraulic characteristics and entropy of some thermal systems. Therefore, this paper aims to…

Abstract

Purpose

Inclination angle has been reported to have an enhancing effect on the thermal-hydraulic characteristics and entropy of some thermal systems. Therefore, this paper aims to numerically investigate the effects of inclination angle, volume concentration and Reynolds number on the thermal and hydraulic characteristics and entropy generation rates of water-based Al2O3 nanofluids through a smooth circular aluminum pipe in a turbulent flow.

Design/methodology/approach

A constant heat flux of 2,000 Watts is applied to the circular surface of the tube. Reynolds number is varied between 4,000 and 20,000 for different volume concentrations of alumina nanoparticles of 0.5%, 1.0% and 2.0% for tube inclination angles of ±90o, ±60o, ±45o, ±30o and 0o, respectively. The simulation is performed in an ANSYS Fluent environment using the realizable kinetic energy–epsilon turbulent model.

Findings

Results show that +45o tube orientation possesses the largest thermal deviations of 0.006% for 0.5% and 1.0% vol. concentrations for Reynolds numbers 4,000 and 12,000. −45o gives a maximum pressure deviation of −0.06% for the same condition. The heat transfer coefficient and pressure drop give maximum deviations of −0.35% and −0.39%, respectively, for 2.0% vol. concentration for Reynolds number of 20,000 and angle ±90o. A 95%–99.8% and 95%–98% increase in the heat transfer and total entropy generation rates, respectively, is observed for 2.0% volume concentration as tube orientation changes from the horizontal position upward or downward.

Originality/value

Research investigating the effect of inclination angle on thermal-hydraulic performance and entropy generation rates in-tube turbulent flow of nanofluid is very scarce in the literature.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 24 September 2021

Ali Akbar Abbasian Arani and Ali Memarzadeh

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…

Abstract

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.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 32 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 23 May 2023

Ahmad Reza Roozbehi, Mohammad Zabetian Targhi, Mohammad Mahdi Heyhat and Ala Khatibi

This numerical study aims to investigate the modification of the hexagonal pin fin geometry to enhance both the thermal and hydraulic performance of the copper micropin fin heat…

Abstract

Purpose

This numerical study aims to investigate the modification of the hexagonal pin fin geometry to enhance both the thermal and hydraulic performance of the copper micropin fin heat sink with single-phase water coolant in a laminar regime. The heat sink performance evaluation criteria have been investigated for the parametric effects of vertex angle θ (10–120) and relative length (RL) (0.25–9) of hexagonal pin fins.

Design/methodology/approach

To carry out research and reduce the computational cost, only one heat sink unit is simulated and analyzed using periodic boundary conditions on the side walls and includes a hexagonal pin fin and half channel on both sides to reflect the structural characteristics completely. The governing equations are also solved using finite volume method.

Findings

The results reveal that θ = 60 and RL = 1 yield the optimum thermal performance and heat sink performance is significantly influenced by the vertex angle and RL. The modified hexagon geometry improves fluid flow behavior by reducing the volume of the recirculation region behind the pin fin, preventing its effects on the downstream pin fins and restricting the thermal boundary layer development on its straight side. At Re = 1,000, the modified geometry enhances the average Nusselt number by 24.46% and the thermal performance factor by 23.89%, demonstrating the potential of modified hexagonal pin fins to enhance micropin fin heat sink performance.

Originality/value

Prior studies suggest using the pin fins with a regular hexagonal cross-section to obtain better thermal performance. However, this comes with a higher pressure drop penalty. The modification of the hexagonal pin fin geometry has been investigated in this numerical study to enhance both the thermal and hydraulic performance of the micropin fin heat sink. Because little attention has been paid to the modification of the regular hexagonal pin fins, as a geometry inspired by natural honeycomb structures, its design optimization is relatively scarce, and a gap was felt in this field.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 22 November 2022

Mani Sekaran Santhanakrishnan, Timothy Tilford and Christopher Bailey

This study aims to provide an insight into the relationship between design parameters and thermal performance of plate fin heat sinks (PFHSs) incorporating longitudinal vortex…

Abstract

Purpose

This study aims to provide an insight into the relationship between design parameters and thermal performance of plate fin heat sinks (PFHSs) incorporating longitudinal vortex generators (VGs) inside a PFHS channel.

Design/methodology/approach

A computational fluid dynamics model of a delta winglet pair VG mounted inside a PFHS geometry is detailed, and the model is validated by comparison with experimental data. The validated model is used to perform a virtual design of experiments study of the heat sink with bottom plate and vertical plate mounted VGs. Data from this study is used to regress a response surface enabling the influence of each of the assessed design variables on thermal performance and flow resistance to be determined.

Findings

The results of this study show that the thermal hydraulic performances of a PFHS with bottom plate mounted VG and vertical plate fin mounted VG are, respectively, 1.12 and 1.17 times higher than the baseline PFHS. Further, the performance variation of the heat sink with VG, relative to delta winglet’s arrangement (common flow up and common flow down), trailing edge gap length and Reynolds number were also evaluated and reported.

Originality/value

For the first time, performance characteristics of delta winglet VGs mounted inside the PFHS are evaluated against different design variables and a polynomial regression model is developed. The developed regression model and computed results can be used to design high performance PFHSs mounted with delta winglet VGs.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 27 May 2014

Morteza Khoshvaght Aliabadi, Faramarz Hormozi and Elham Hosseini Rad

The main purpose of this paper is the generation of the heat transfer and pressure drop correlations by considering three working fluids, namely air, water, and ethylene glycol…

Abstract

Purpose

The main purpose of this paper is the generation of the heat transfer and pressure drop correlations by considering three working fluids, namely air, water, and ethylene glycol, for the wavy plate-fin heat exchangers (PFHEs).

Design/methodology/approach

In order to present the general correlations, various models with different geometrical parameters should be tested. Because of the problems, such as difficult, long time, and costly fabrication of the wavy fins in experimental tests, computational fluid dynamics (CFD) calculations can be a useful method for the generation of the heat transfer and pressure drop correlations with eliminating the experimental problems. Hence, the effective design parameters of the wavy plate-fin, including fin pitch, fin height, wave length, fin thickness, wave amplitude, and fin length, and also their levels were recognized from the literature. The Taguchi method was applied to formulate the CFD simulation work.

Findings

The simulation results were compared and validated with an available experimental data. The mean deviations of the Colburn factor, j, and Fanning friction factor, f, values between the simulation results and the experimental data were 3.74 and 9.07 percent, respectively. The presented air correlations and experimental data were in a good agreement, so that approximately 95 percent of the experimental data were correlated within ±12 percent. The j factor values varied for the different working fluids, while the f factor values did not sensibly change.

Practical implications

The presented correlations can be used to estimate the thermal-hydraulic characteristics and to design of the compact PFHE with the wavy channels.

Originality/value

This manuscript presents the new correlations for the compact PFHEs with the way channels by considering all the geometrical parameters and the working fluids with the different Prandtl numbers, 0.7, 7, and 150.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

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