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Heat Transfer Reinforcement Techniques in Heat Exchangers

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A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Applied Thermal Engineering".

Deadline for manuscript submissions: closed (5 January 2023) | Viewed by 22261

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Dr. Hijaz Ahmad

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Section of Mathematics, International Telematic University Uninettuno, Corso Vittorio Emanuele II, 39, 00186 Roma, Italy
Interests: numerical analysis; PDEs; fractional calculus
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Dear Colleagues,

Improving the thermal and dynamic performance of heat exchanger and solar collector channels is the goal of many numerical, analytical, and experimental studies in the field of renewable energies. Several methods have been followed for successful energy efficiency, such as restructuring the internal structure of the channel by adding extended surfaces or improving the thermal physical properties of the flow by creating new fluids, such as nanofluids. These energetic enhancement strategies are essential and have been the target of many recent studies. Several recent review studies have summarized various research related to promoting heat transfer and its applications with channels using baffle and fin-type obstacles. Various research studies have examined different types of turbulators, deflectors, and vortex generators for different flow conditions. On the other hand, nanofluids have witnessed significant development during the recent period by improving its structure, in addition to its multiple applications in various industrial fields. Many review analyses have dealt with the latest events of these fluids in terms of composition, as well as in terms of their use. In addition, the application of nanofluids has not only promoted heat transfer in the channels but was also used for other configurations, such as cavities and enclosures.

This Special Issue aims to seek and promote knowledge on the technology and science of heat-exchanger energy and its applications. Original research papers and reviews on the various topics of heat transfer systems and components are welcome. Papers of experimental aspect, numerical simulation and modeling are welcome. Topics of interest for the Special Issue include, but are not limited to, the following: models and applications of heat exchangers; heat transfer enhancement techniques (vortex generators, nanofluids, porous media, etc.); heat and mass transfer; fluid–solid interactions; modeling, simulation, optimization, experimentation, and characterization of heat exchangers.

Dr. Hijaz Ahmad
Guest Editor

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Keywords

heat exchangers
heat transfer reinforcement
vortex generators
nanofluids
porous media
heat and mass transfer
fluid–solid interactions
modeling
simulation
experimentation
optimization

Published Papers (11 papers)

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Research

11 pages, 2107 KiB

Open AccessArticle

Cleaning Schedule Optimization of Heat Exchanger Network Using Moving Window Decision-Making Algorithm

by Simegnsh Bekele Dekebo, Gi-Taek Oh and Min-Woo Lee

Appl. Sci. 2023, 13(1), 604; https://doi.org/10.3390/app13010604 - 1 Jan 2023

Cited by 2 | Viewed by 1387

Abstract

A moving window decision-making algorithm is proposed for the cleaning schedule optimization of heat exchanger network system subject to fouling in refinery crude preheat train. This algorithm is designed by incorporating the moving window scheme into a conventional multi-period optimal control problem (OCP) framework and has a distinct feature that it can efficiently handle a complex problem where a long-time horizon is considered. When compared with the conventional multi-period OCP method using fixed time horizon, our algorithm always shows an excellent performance regarding the computational time, still finding a compatible optimal solution. In our moving window decision-making algorithm, it is important to determine the optimal moving window size for the given time horizon as it significantly influences the optimization performance. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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16 pages, 4377 KiB

Open AccessArticle

Experimental Evaluation of a Solar Low-Concentration Photovoltaic/Thermal System Combined with a Phase-Change Material Cooling Technique

by Mahmoud B. Elsheniti, Saad Zaheer, Obida Zeitoun, Hassan Alshehri, Abdulrahman AlRabiah and Zeyad Almutairi

Appl. Sci. 2023, 13(1), 25; https://doi.org/10.3390/app13010025 - 20 Dec 2022

Cited by 4 | Viewed by 1497

Abstract

The high operating temperatures of photovoltaic (PV) panels negatively affect both electrical efficiency and material degradation rate. Combining both a water-cooling-based photovoltaic/thermal (PV/T) system and a phase-change material (PCM) with/without low concentration (LC) represents a promising solution for boosting the overall energy conversion efficiency of the PV system. This approach needs to be evaluated in harsh weather where the PCM should have a high melting temperature. Therefore, this study experimentally investigates the performance of three PV cooling systems, namely PV-PCM, PV/T-PCM, and LCPV/T-PCM, compared to a reference PV without cooling, under the weather conditions of Riyadh. The results show that the PV/T-PCM attained the highest daily average electrical and overall efficiencies of 14.24% (5% increase) and 42.7%, respectively, compared to 13.56% electrical efficiency of the reference panel. The electrical efficiency of the PV-PCM was 13.64% due to inefficient natural cooling in the afternoon. The LCPV/T-PCM recorded the best performance during the two hours around noon, with an average increase in electrical power and efficiency of 11.06% and a maximum overall efficiency of 70%. Finally, the LCPV/T-PCM system can be only effectively used to support the higher demand for electricity and thermal energy around noon; otherwise, a new design configuration with low concentration is needed to establish a higher electrical efficiency in most hours of sunlight. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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20 pages, 3103 KiB

Open AccessArticle

A New Fourth-Order Predictor–Corrector Numerical Scheme for Heat Transfer by Darcy–Forchheimer Flow of Micropolar Fluid with Homogeneous–Heterogeneous Reactions

by Yasir Nawaz, Muhammad Shoaib Arif and Wasfi Shatanawi

Appl. Sci. 2022, 12(12), 6072; https://doi.org/10.3390/app12126072 - 15 Jun 2022

Cited by 7 | Viewed by 1258

Abstract

This paper proposes a numerical scheme for solving linear and nonlinear differential equations obtained from the mathematical modeling of a flow phenomenon. The scheme is constructed on two grid points. It is a two-stage, or predictor–corrector type, scheme whose first stage (the predictor stage) comprises a forward Euler scheme. The stability region of the proposed scheme is larger than that of the first-order forward Euler scheme. A problem is constructed, comprised of a mathematical model for the Darcy–Forchheimer flow of micropolar fluid over a stretching sheet, and is modified using partial differential equations (PDEs) by incorporating the effects of homogeneous–heterogeneous reactions. A set of PDEs is further reduced into ordinary differential equations (ODEs) by several transformations and is solved using the proposed numerical scheme. By comparing the results obtained using the proposed scheme with those obtained using the existing forward Euler scheme, it can be observed that the proposed scheme achieved a smaller absolute error. The obtained results show that the angular velocity profile displayed dual behavior according to increases in the values of the microrotation and coupling constant parameters. As part of our research, we conducted a comparison with other existing schemes. The findings of this study can serve as a helpful guide for future investigations into fluid flow in closed-off industrial settings. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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20 pages, 7185 KiB

Open AccessArticle

A Compact Numerical Scheme for the Heat Transfer of Mixed Convection Flow in Quantum Calculus

by Yasir Nawaz, Muhammad Shoaib Arif and Kamaleldin Abodayeh

Appl. Sci. 2022, 12(10), 4959; https://doi.org/10.3390/app12104959 - 13 May 2022

Cited by 9 | Viewed by 1384

Abstract

This contribution aims to propose a compact numerical scheme to solve partial differential equations (PDEs) with q-spatial derivative terms. The numerical scheme is based on the q-Taylor series approach, and an operator is proposed, which is useful to discretize second-order spatial q-derivative terms. The compact numerical scheme is constructed using the proposed operator, which gives fourth-order accuracy for second-order q-derivative terms. For time discretization, Crank–Nicolson, and Runge–Kutta methods are applied. The stability for the scalar case and convergence conditions for the system of equations are provided. The mathematical model for the heat transfer of boundary layer flow under the effects of non-linear mixed convection is given in form of PDEs. The governing equations are transformed into dimensionless PDEs using suitable transformations. The velocity and temperature profiles with variations of mixed convection parameters and the Prandtl number are drawn graphically. From considered numerical experiments, it is pointed out that the proposed scheme in space and Crank–Nicolson in time is more effective than that in which discretization for the time derivative term is performed by applying the Runge–Kutta scheme. A comparison with existing schemes is carried out as part of the research. For future fluid-flow investigations in an enclosed industrial environment, the results presented in this study may serve as a useful guide. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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16 pages, 5265 KiB

Open AccessArticle

Numerical Analysis of Newtonian Heating Convective Flow by Way of Two Different Surfaces

by Khalil Ur Rehman, Wasfi Shatanawi, Shazia Ashraf and Nabeela Kousar

Appl. Sci. 2022, 12(5), 2383; https://doi.org/10.3390/app12052383 - 24 Feb 2022

Cited by 11 | Viewed by 2536

Abstract

In this paper, we offer a numerical study on heated non-Newtonian fluid with a Newtonian heating effect towards thermally stable stretching surfaces. A comparative analysis for two stretched surfaces, namely, plate and cylinder, is offered. The Casson fluid model is considered to be a non-Newtonian fluid model. By applying the suitable set of transformations, the non-linear coupled PDEs are transformed into non-linear ODEs. It is difficult to obtain the exact solution of such non-linear differential equations; therefore, we used the shooting method along with Runge–Kutta scheme. The influence of pertinent flow variables on velocity and temperature is presented through graphs. Notably from the results, heat generation parameters, Newtonian heating, and magnetic parameters enhanced the temperature profile, whereas Casson fluid and magnetic field parameters reduced the fluid velocity. It is also observed that increases in fluid temperature were more influenced at the cylindrical surface as compared with the flat plate. Moreover, we obtained remarkable results for the heat transfer rate by imposing Newtonian heating conditions at the surface; tables are used to present variations in the skin friction coefficient and Nusselt number at the thermally stable surfaces. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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19 pages, 3525 KiB

Open AccessArticle

A Group Theoretic Analysis of Mutual Interactions of Heat and Mass Transfer in a Thermally Slip Semi-Infinite Domain

by Khalil Ur Rehman, Wasfi Shatanawi, Kamaleldin Abodayeh and Taqi A. M. Shatnawi

Appl. Sci. 2022, 12(4), 2000; https://doi.org/10.3390/app12042000 - 14 Feb 2022

Cited by 13 | Viewed by 1590

Abstract

Group theoretic analysis is performed to get a new Lie group of transformations for non-linear differential systems constructed against mass and heat transfer in the thermally magnetized non-Newtonian fluid flow towards a heated stretched porous surface. The energy equation is used with additional effects, namely heat sink and heat source. The chemical reaction is also considered by the use of the concentration equation. The symmetry analysis helps us in numerical computations of surface quantities for (i) permeable and non-permeable surfaces, (ii) thermal slip and non-thermal slip flows, (iii) magnetized and non-magnetized flows, (iv) chemically reactive and non-reactive flows. For all these cases, the concerned emerging partial differential system is transformed into a reduced ordinary differential system and later solved numerically by using the shooting method along with the Runge-Kutta scheme. The observations are debated graphically, and numerical values are reported in tabular forms. It is noticed that the heat transfer rate increases for both the thermal slip and non-slip cases. The skin friction coefficient declines towards the Weissenberg number in the magnetized field. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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15 pages, 10140 KiB

Open AccessArticle

Numerical Simulation of Williamson Nanofluid Flow over an Inclined Surface: Keller Box Analysis

by Khuram Rafique and Hammad Alotaibi

Appl. Sci. 2021, 11(23), 11523; https://doi.org/10.3390/app112311523 - 5 Dec 2021

Cited by 17 | Viewed by 1545

Abstract

The study of nanofluids has become a key research area in mathematics, physics, engineering, and materials science. Nowadays, nanofluids are widely used in many industrial applications to improve thermophysical properties such as thermal conductivity, thermal diffusivity, convective heat transfer, and viscosity. This article discusses the effects of heat generation/absorption and chemical reaction on magnetohydrodynamics (MHD) flow of Williamson nanofluid over an inclined stretching surface. The impact of Williamson factor on velocity field is investigated numerically using Keller box analysis (KBA). Suitable similarity transformations are used to recover ordinary differential equations (ODEs) from the boundary flow equations. These ordinary differential equations are addressed numerically. The numerical computations revealed that energy and species exchange decrease with rising values of magnetic field. Moreover, it is found that increasing the chemical reaction parameter increases the Nusselt number and decreases skin friction. Further, the effect of Lewis parameter diminishes energy transport rate. In the same vein, it is also observed that increasing the inclination can enhance skin friction, while the opposite occurred for the energy and species transport rate. As given numerical computations demonstrate, our results are in reasonable agreement with the reported earlier studies. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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19 pages, 6377 KiB

Open AccessArticle

Analysis of Heat and Mass Transfer Features of Hybrid Casson Nanofluid Flow with the Magnetic Dipole Past a Stretched Cylinder

by Shafiq Ahmad, Muhammad Naveed Khan, Aysha Rehman, Bassem F. Felemban, Maram S. Alqurashi, Fahad M. Alharbi, Fakhirah Alotaibi and Ahmed M. Galal

Appl. Sci. 2021, 11(23), 11203; https://doi.org/10.3390/app112311203 - 25 Nov 2021

Cited by 19 | Viewed by 2061

Abstract

The main purpose of this research is to scrutinize the heat and mass transfer in the Casson hybrid nanofluid flow over an extending cylinder in the presence of a magnetic dipole and double stratification. The nanofluid contained chemically reactive hybrid nanoparticles (Ag, MgO) in the conventional fluids (water). The effects of viscous dissipation, radiation, and concentration stratification were taken into consideration. In the presence of gyrotactic microorganisms and the Non-Ficks Model, the flow was induced. Incorporating microorganisms into a hybrid nanofluid flow is thought to help stabilize the dispersed nanoparticles. For viscosity and thermal conductivity, experimental relations with related dependence on nanoparticle concentration were used. To acquire the nonlinear model from the boundary layer set of equations, suitable similarity transformations were employed. The built-in function bvp4c of Matlab software was utilized to solve the transformed equation numerically. The graphical results were obtained for temperature, velocity, concentration, and microorganism distribution for various parameters. The numerical amounts of drag friction, heat transport rate, and motile density number for different parameters are presented through tables. It is seen that the fluid velocity is augmented by the increase of the curvature parameter, while a decrease occurs in the fluid velocity with an increase in the magnetic and slips parameters. The comparison of the present study with previously available studies is discussed, which shows a good agreement with published results. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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21 pages, 881 KiB

Open AccessArticle

Numerical Investigation of Heat Transfer on Unsteady Hiemenz Cu-Water and Ag-Water Nanofluid Flow over a Porous Wedge Due to Solar Radiation

by Usman Inayat, Shaukat Iqbal, Tareq Manzoor and Muhammad Fahad Zia

Appl. Sci. 2021, 11(22), 10855; https://doi.org/10.3390/app112210855 - 17 Nov 2021

Cited by 2 | Viewed by 1449

Abstract

Nanoparticles are generally used to scatter and absorb solar radiations in nanofluid-based direct solar receivers to efficiently transport and store the heat. However, solar energy absorption in nanofluid can be enhanced by using differential materials and tuning nanofluid parameter. In this regard, theoretical investigations of unsteady homogeneous Hiemenz flow of an incompressible nanofluid having copper and silver nanoparticles over a porous wedge is carried out by using optimal homotopy asymptotic method (OHAM). Hence, a semi-analytical solver is applied to the transformed system to study the significance of magnetic field along with Prandtl number. In this work, impacts of conductive radiations, heat sink/source, unsteadiness, and flow parameters have been investigated for velocity and temperature profiles of copper and silver nanoparticles-based nanofluid. The effects of magnetic strength, volume fraction of nanoparticles, thermal conductivity, and flow parameters have also been studied on the considered nanofluids. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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20 pages, 7674 KiB

Open AccessArticle

Improvement of Multi-Hole Airflow Impingement on Flow and Heat Transfer Characteristics Inside a Turbine Vane Cavity

by Lixi Zhang, Gaopan Cao, Kai Feng, Yi Jia and Zhengyang Zhang

Appl. Sci. 2021, 11(21), 9924; https://doi.org/10.3390/app11219924 - 23 Oct 2021

Cited by 3 | Viewed by 1859

Abstract

The cooling effect of turbine vane is of great importance for ensuring thermal protection and economic operation of gas turbines. This study aims to reveal the influence mechanism and performance of impingement cooling and heat transfer within a turbine guide vane cavity. Then, a turbine guide vane cavity with a complex pin fins structure is numerically investigated at a multi-hole impingement by comparison with experiment verification. The results show that the larger the Reynolds number is, the larger the average Nusselt number is on the upper and lower surfaces of the cavity. The average Nusselt number increased on the upper and lower surfaces as the impingement hole diameter increased. Comparing 1 impingement hole with 16 ones, the average Nusselt number of the lower surface of the latter is 553.9% larger than that of the former. Furthermore, the average Nusselt number of the lower surface for pin fin height of 3 mm is only improved by 11.2% for pin fin height of 24 mm. The heat transfer effect near the impingement holes is better than that far away from the impingement holes. In particular, it is recommended to have 14 impingement holes with a hole diameter of 7.2 mm, as well as circular pin fins with a height of 3 mm and spacing of 25.8 mm. In addition, the entropy generation distribution in impingement cooling is analyzed. This study can provide a reference to enhance the turbine vane cooling performance by optimization design. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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18 pages, 21016 KiB

Open AccessArticle

Numerical Investigation of Thermal-Flow Characteristics in Heat Exchanger with Various Tube Shapes

by Fares Djeffal, Lyes Bordja, Redha Rebhi, Mustafa Inc, Hijaz Ahmad, Farouk Tahrour, Houari Ameur, Younes Menni, Giulio Lorenzini, Sayed K. Elagan and Taghreed M. Jawa

Appl. Sci. 2021, 11(20), 9477; https://doi.org/10.3390/app11209477 - 12 Oct 2021

Cited by 14 | Viewed by 3080

Abstract

In this study, eight configurations of oval and flat tubes in annular finned-tube thermal devices are examined and compared with the conventional circular tube. The objective is to assess the effect of tube flatness and axis ratio of the oval tube on thermal-flow characteristics of a three-row staggered bank for Re (2600 ≤ Re ≤ 10,200). It has been observed that the thermal exchange rate and Colburn factor increase according to the axis ratio and the flatness, where O1 and F1 provide the highest values. O1 produces the lowest friction factor values of all the oval tubes at all Re, and F4 gives 13.2–18.5% less friction than the other tube forms. In terms of performance evaluation criterion, all of the tested tubes outperformed the conventional circular tube (O5), with O1 and F1 obtaining the highest values. The global performance criterion of O1 has been found to be 9.6–45.9% higher as compared to the other oval tube geometries at lower values of Re, and the global performance criterion increases with the increase in flatness. The F1 tube shape outperforms all the examined tube designs; thus, this tube geometry suggests that it be used in energy systems. Full article

(This article belongs to the Special Issue Heat Transfer Reinforcement Techniques in Heat Exchangers)

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