Porous Fin Research Articles

Optimization of porous finned heat exchanger configuration using the comprehensive performance methodology

This paper uses numerical simulations to investigate heat transfer in a heat exchanger with porous longitudinal fins and a counter-flow double tube. To improve the heat exchanger's overall heat transfer, porous media with uniform porosity is selected in longitudinal fins. To this end, the Darcy and Forchheimer models and the k-ɛ model are used to consider porous media effects and predict the turbulent flow structure. Furthermore, the energy equation was solved using the Local Thermal Non-Equilibrium method. According to the results, it has been noticed that there is a substantial increase in heat transfer upon decreasing the porosity. However, further decreases in porosity cause a growth in the porous material's resistance against fluid flow, which pushes it outside and prevents further increases. Finally, the heat exchanger's total performance variation shows that the optimum values of the permeability and porosity are equal to 10e-6 and 0.85, respectively. The results show the highest efficiency is achieved by a heat exchanger configuration associated with 40 porous fins, where the porous volume is considered as a constant portion of the total volume.

Heat transfer analysis of an inclined longitudinal porous fin of trapezoidal, rectangular and dovetail profiles using cascade neural networks

Heat transfer analysis of an inclined longitudinal porous fin of trapezoidal, rectangular and dovetail profiles using cascade neural networks

Significance of Convection and Internal Heat Generation on the Thermal Distribution of a Porous Dovetail Fin with Radiative Heat Transfer by Spectral Collocation Method.

A variety of methodologies have been used to explore heat transport enhancement, and the fin approach to inspect heat transfer characteristics is one such effective method. In a broad range of industrial applications, including heat exchangers and microchannel heat sinks, fins are often employed to improve heat transfer. Encouraged by this feature, the present research is concerned with the temperature distribution caused by convective and radiative mechanisms in an internal heat-generating porous longitudinal dovetail fin (DF). The Darcy formulation is considered for analyzing the velocity of the fluid passing through the fin, and the Rosseland approximation determines the radiation heat flux. The heat transfer problem of an inverted trapezoidal (dovetail) fin is governed by a second-order ordinary differential equation (ODE), and to simplify it to a dimensionless form, nondimensional terms are utilized. The generated ODE is numerically solved using the spectral collocation method (SCM) via a local linearization approach. The effect of different physical attributes on the dimensionless thermal field and heat flux is graphically illustrated. As a result, the temperature in the dovetail fin transmits in a decreasing manner for growing values of the porosity parameter. For elevated values of heat generation and the radiation-conduction parameter, the thermal profile of the fin displays increasing behavior, whereas an increment in the convection-conduction parameter downsizes the thermal dispersal. It is found that the SCM technique is very effective and more conveniently handles the nonlinear heat transfer equation. Furthermore, the temperature field results from the SCM-based solution are in very close accordance with the outcomes published in the literature.

Investigation of energy storage in parabolic rotary trough solar collectors using various porous fins with magnetic nanoparticles

The present study investigates the performance of various porous fin materials (copper, aluminum, bronze, and steel) with different porosities in a parabolic rotary trough solar collector driven by magnetic nanofluid. The nanofluid circulates in the rotary pipe and flows into the attached inner porous fin by a centrifugal force. This design enhances the heat transfer while reducing the pressure drop in the parabolic trough solar collector compared to previous configurations. Based on the results, the copper foam has the best performance among the studied materials, and the role of porous material is more salient in the rotational state than in the stationary one. Moreover, the increment of porosity causes more energy storage in the solar collector, while an optimal value is obtained for the rotational speed. The findings show that the heat transfer rate and pressure drop increase 3.7 times and 2.6 times in the optimal state of using copper porous fin with 97 % porosity in the rotary pipe with 0.6 rad/s angular velocity, respectively. Also, the energetic and exergetic performance increases from 71.6 % to 87.2 % and from 24.2 % to 40.5 %, respectively, and more than half of the lost energy is restored in the manipulated system.

Enthalpy-based immersed boundary-lattice Boltzmann model for solid-liquid phase change in porous media under local thermal non-equilibrium condition

Heat transfer enhancement structures are adopted to improve the performance of latent heat thermal energy storage (LHTES) systems, such as metallic porous matrix, multi-tube, and fin. The metallic porous matrix and complex geometries of the structures bring difficulties to the numerical studies of the solid-liquid phase transition in the enhanced LHTES system. In this work, an enthalpy-based immersed boundary (IB)-lattice Boltzmann (LB) model is proposed for solid-liquid phase change problems in porous media under the local thermal non-equilibrium (LTNE) condition. In this model, to reduce the numerical diffusion across the solid-liquid interface, a two-relaxation-time (TRT)-LB model is developed to obtain the temperature field of phase change material (PCM). Two single-relaxation-time (SRT)-LB equations (LBEs) are employed for the velocity field of the liquid PCM and the temperature field of the porous matrix, respectively. The partially saturated method is used for the non-slip boundary condition on the moving solid-liquid interface. Different discrete source term schemes are employed for source terms induced by surface heat transfer and IB. Based on the source term treatment, the multi-direct-forcing IB-LB method is employed for the implementation of velocity, enthalpy and temperature boundary conditions on the complex boundary. The proposed model is verified by four cases: one-dimensional conduction melting under the LTNE condition, natural convection in a metallic porous matrix-filled cavity, conduction melting in an annulus filled with metallic porous matrix, and constrained melting in an isothermal circular cylinder without porous media. As an example of application, a metallic porous matrix-enhanced LHTES system with different multi-tube arrangements at different Rayleigh numbers (Ra) and porosities is investigated.

Analytical fin efficiency model for open-cell porous metal fins based on Kelvin cell assumption

Open-cell porous metals are widely used to enhance convective heat transfer of thermal management devices. In this paper, the open-cell porous metal structure was represented by a polyhedron model known as the Kelvin cell, and an analytical model for the efficiency of the porous metal fin attached to an isothermal surface was derived. The forced convective heat transfer coupled with heat conduction through the ligaments of porous metal was analyzed to derive the fin efficiency model. The effects of pore diameter, ligament diameter, and porous metal fin height on the fin efficiency and heat transfer rate of porous metal fins were also investigated. The new analytical fin efficiency model based on the Kelvin cell was compared with the fin efficiency evaluated using computational fluid dynamics analysis results; good agreement was found. The proposed analytical fin efficiency model avoids the numerical calculations required for heat transfer analysis of porous metals used as extended surfaces in many engineering applications such as heat sinks and heat exchangers, and can produce simple but effective results.

Assessment of thermal distribution through an inclined radiative-convective porous fin of concave profile using generalized residual power series method (GRPSM)

The thermal distribution in a convective-radiative concave porous fin appended to an inclined surface has been examined in this research. The equation governing the temperature and heat variation in fin with internal heat generation is transformed using non-dimensional variables, and the resulting partial differential equation (PDE) is tackled using an analytical scheme, generalized residual power series method (GRPSM). Moreover, a graphical discussion is provided to examine the consequence of diverse non-dimensional variables including the parameters of convection-conduction, ambient temperature, radiation, heat generation, and porosity effect on the thermal field of the fin. Also, a graph is plotted to analyze the variations in unsteady temperature gradient using the finite difference method (FDM) and generalized residual power series method (GRPSM). The major result of this investigation unveils that as the convection-conduction parameter scale upsurges, the distribution of temperature in the fin diminishes. For the heat-generating parameter, the thermal distribution inside the fin increases.

Economic cost and thermal efficiency analysis of porous-minichannel heat exchanger for thermoelectric generator

Lightweight, low cost and high thermal performance are some main features of porous media. In this research, porous-minichannel heat exchanger is proposed and comprehensively studied from thermal and economic viewpoints as an innovative and efficient heat rejection mechanism for thermoelectric generators applicable in low-grade waste heat recovery. Numerical simulations are carried out to study the effect of various porous substrate configurations including the vertical/horizontal sandwich, rectangular sandwich, vertical/horizontal sandwich block, and rectangular sandwich block distributions on thermal and economic characteristics of TEG. Besides, the influence of different geometric and operational parameters including Re number, the width of solid fins (Wr), the thickness of porous inserts (tp), and number of the channels (Nch) on the performance of the TEG system are investigated. Generally, the results show that the proposed porous minichannel enhances the thermal performance of thermoelectric generator compared to the conventional minichannel heat exchangers without porous fins. The increment of porous fin thickness improves the output voltage and power but has minimal impact on the conversion efficiency. Around 17.3% and 1.2% improvement of output power compared to the base smooth minichannel is shown for the models “M3” and “M5” respectively.

Thermal and hydraulic performance of solid-porous compound wavy micro-channel heat sinks

In this numerical study, seven distinct three-dimensional unique models of micro-channel heat sinks have been investigated. A solid-porous compound wavy channel with optimum thickness of porous fins has been newly adapted to improve the thermal and hydraulic performance of the forthcoming micro-electronic devices. The finite volume method is used to solve the hydraulic and thermal performance of micro-channel heat sinks, and Darcy–Forchheimer flow models are applied for fluid flow through porous fins. Water is employed as a working fluid. Solid wall and porous fins are made of copper material; during analysis, Reynolds numbers vary from 50 to 300, and the effective thermal conductivity has been considered for porous fins as well as solid-porous compound fins. The effect of solid fins, porous fins, and compound fins are comprehensively determined. The result shows that as the thickness of porous fins increases in compound wavy channel, the heat transfer performance significantly increases up to 63.6% and pressure drop penalty decreases up to 55.32% as compared to the regular straight channel (solid fins) heat sinks. This is due to reduction of viscous shear stress at the place of fluid-porous interface and slip effect of fluids in the porous zone. Hence, the ability of the solid-porous compound wavy micro-channel heat sinks can effectively enhance the cooling performance of high-power electronic devices.

LSM and DTM-Pade approximation for the combined impacts of convective and radiative heat transfer on an inclined porous longitudinal fin

The novel exploration designates temperature variation through an inclined porous longitudinal fine with convective radiative phenomenon. The Rosseland approximation is considered for the radiation heat exchange. Using non-dimensional terms, the existing system of stated problem is reduced to ordinary form. To resolve the nonlinear ordinary system of heat transfer, the analytical approaches, differential transform method (DTM) with Pade approximant has been workout. Furthermore, simulations are developed to examine the outcomes of convincing flow parameters like radiative-conduction parameter, porosity parameter, and conduction-convection variable on the thermal distribution for different modes of heat transfer like nucleate boiling and radiative heat transfer. The results show that an increase in the conduction-convection variable, porosity variable, and radiation number causes a reduction in the thermal field. On the other hand, augmentation change is appeared due to heat generation constant. The thermal behavior of the fin declines with escalating angle.

Thermodynamic evaluation and particle migration of hybrid nanofluids flowing through a complex microchannel with porous fins

A compound method is established by adding Al2O3-TiO2/Water (W) nanofluids and porous media in a microchannel to reduce pressure drop and enhance heat transfer in the limited heat dissipated area. Effects of porosity and hybrid nanofluids are numerically investigated in the laminar region. Pressure drop, Nusselt number, velocity and temperature fields are used as indicators to evaluate the characteristics of flow and heat transfer. Furthermore, the analytical methods including thermodynamic evaluation and nanoparticle migration were performed to reveal the essential mechanism of heat transfer enhancement. Compared with non-porous microchannels, the maximum reduction of porous microchannels is 9.73% (ε = 0.5), 8.3% (ε = 0.6) and 6.8% (ε = 0.7) for pressure drop, while the maximum agument is 23.53% (ε = 0.5), 20.59% (ε = 0.6) and 16.67% (ε = 0.7) for Nusselt number. The permeability of fluid reduces pressure drop and enhances heat transfer in the porous region. The maximum heat transfer irreversibility reduces up to 64%, and exergy efficiency reaches 88% by adding nanofluids and porous media. Nanoparticle migration originating from thermophoresis affects the concentration distribution near the wall, and cold-hot fluids fully mix in the porous region, thereby increasing heat transfer. The effect of thermophoretic diffusion of dilute nanofluids in micro-scale convective heat transfer is higher than that in the macro-scale one.

Improvement of Heat Transfer by Using Porous Media, Nanofluid, and Fins: A Review

The world's interest in energy and as a result of the urgent importance of that, researchers focused on the development of heat transfer to have a significant impact on the consumption of that energy. Where we note the great interest by researchers in developing heat transfer and using the best possible methods to improve heat transfer. In this literary review, a large group of research has been carried out to find out the importance of heat transfer and the methods used by researchers to develop heat transfer. Porous materials, nanomaterials and fins were used in the development of heat transfer. Where we note the importance of adding these materials (porous materials, nanomaterials and fins) to the original materials contribute significantly and clearly to improving heat transfer and this has a significant impact on energy consumption or trying to dissipate it, as we note the clear difference when using the original materials without adding these materials as the heat transfer is less and it consumes more time. Researchers can focus on the importance of improving heat transfer for its importance in many applications that have a direct impact on human life.

Optimization of heat transfer rate in a moving porous fin under radiation and natural convection by response surface methodology: Sensitivity analysis

The remarkable advancement has been made in area of investigation and extensive demands for permeable fin in recent past. Permeable fins have numerous prospective employments including industrial applications specifically in engineering implementations such as in heat exchangers and super heaters. Additionally, the permeable fin performs a key role in aeronautic engineering. In this study the sensitivity analysis of natural convection and radiation transmission of heat in permeable fin is established. The main objective of the study is to optimize the rate of transmission of heat in a moving permeable fin in natural convection and radiation environment by utilizing Response Surface Methodology (RSM). Also, sensitivity of heat transfer rate is evaluated using RSM. The Darcy model is applied to imitate the impacts of permeable medium and convective heat. Midpoint (midrich) method is utilized to solve the energy equation numerically. The outcomes represents that the temperature of the fin enhance to the neighboring temperature as the value of permeable parameter rises. It is investigated that the heat along the length of fin decline for finite fin as the value of the dimensionless ratio of the surrounding temperature T∞to the difference of the base temperature Tb and surrounding temperature and radiation parameter rises. Also, rate of transmission of heat at the fin tip bring down as the value of Peclet number increased. The outcomes of sensitivity analysis represents that expansion in porosity parameter increases the heat transmission rate and its highest value is observed in level of (-1). Also, heat transfer rate has a non-negative sensitivity towards permeable parameter. However, the decline in dimensionless ratio of the surrounding temperature T∞ to the difference of the base temperature Tb and surrounding temperature and radiation parameter increases the heat transmission rate and its highest value is observed in level of (-1) and (+1). Furthermore, heat transmission rate has a non-positive sensitivity towards dimensionless ratio of surrounding temperature T∞ to the difference of base temperature Tb and surrounding temperature and radiation parameter.

Comments on ‘Nonlinear thermal analysis of a convective-radiative longitudinal porous fin of functionally graded material for efficient cooling of consumer electronics'

The purpose of these comments is to alert the International Journal of Ambient Energy. Discussion is presented on the investigation by Oguntala et al. [2019. “Nonlinear Thermal Analysis of a Convective-Radiative Longitudinal Porous fin of Functionally Graded Material for Efficient Cooling of Consumer Electronics.” International Journal of Ambient Energy], where the authors presented nonlinear thermal analysis and the radiative-convective longitudinal porous fin optimisation utilising functionally graded material. First of all, Oguntala et al. (2019. “Nonlinear Thermal Analysis of a Convective-Radiative Longitudinal Porous fin of Functionally Graded Material for Efficient Cooling of Consumer Electronics.” International Journal of Ambient Energy] defined in Nomenclature H as dimensionless heat transfer coefficient at the fin base with the units of W m−2 K−1. It is known that the dimensionless parameter must have no units. Also, the units of the permeability (K) are corrected. Using the correct units of the permeability (K) leads to the Darcy number (Da) is dimensionless. In addition, the radiation heat transfer number (Nr) and the convective heat transfer number (Nc) are dimensionless in the above paper.

Improvement of flow and heat transfer performance of manifold microchannel with porous fins

• Manifold microchannel with porous fins and the optimized arrangement are analyzed. • Pressure drops of manifold microchannel with porous fins reduced by up to 19%. • Reduction of thermal resistance up to 19.8% is achieved by the optimized arrangement. • Porous fins with 75% proportion on the outlet manifold side present the best PEC. Thermal management is restricting the further development of electronic devices. The rapid development of communication and chip manufacturing technologies results in an unprecedented increase on heat dissipation of electronics, which also makes the thermal management system consume a substantial amount of energy. Therefore, the manifold microchannel (MMC) is particularly important as an efficient thermal management scheme to enhance heat transfer and reduce the energy consumption. For this objective, the flow and heat transfer characteristics of MMCs with porous fins are investigated by numerical method in this study. The results show that the introduction of porous fins can reduce the pressure drop by up to 19%. In addition, the porous fins arranged on the outlet manifold side can significantly optimize the non-uniform flow distribution among the microchannels and strengthen the heat transfer of MMC. Furthermore, for MMC with the porous fins on the outlet manifold side with a proportion of 75%, the thermal resistance can be reduced by 19.8% and the PEC will increase by 46.2%, which performs the best among all the investigated cases.

Analysis of Thermal Performance, Efficiency, and Effectiveness of a Straight Porous Fin with Variable Thermal Conductivity

Analysis of Thermal Performance, Efficiency, and Effectiveness of a Straight Porous Fin with Variable Thermal Conductivity

Multiple Impinging Jet Cooling of a Wavy Surface by Using Double Porous Fins under Non-Uniform Magnetic Field

Coupled effects of double porous fins and inhomogeneous magnetic field on the cooling performance of multiple nanojet impingement for a corrugated surface were numerically analyzed. Different values of magnetic field parameters (strength, inclination, and amplitude of spatially varying part) and double porous fin parameters (inclination and permeability) were used, while finite element method is used as the solution method. When parametric computational fluid dynamics (CFD) simulations were performed, there were 162.5% and 34% Nusselt number (Nu) enhancement with magnetic field for flat and wavy surfaces, respectively. The variations of average Nu became 36% and 24% when varying the inclination and amplitude of inhomogeneous magnetic for a flat surface, while the amounts were 43.7% and 32% for a corrugated one. The vortex distribution in between the jets and cooling performance was affected by the variation of double porous fin permeability and inclination. An optimization method was used for the highest cooling performance, while the optimum set of parameters was obtained at (Ha, Amp, Da, Ω) = (0.224, 0.5835, 7.59×10−4, 0.1617). By using the double porous fins and inhomogeneous magnetic field, excellent control of the cooling performance of multiple impinging jet was obtained.

Entropy generation in moving exponential porous fins with natural convection, radiation and internal heat generation

Entropy generation in moving exponential porous fins with natural convection, radiation and internal heat generation

Entropy generation from convective\u2013radiative moving exponential porous fins with variable thermal conductivity and internal heat generations

The performance and thermal properties of convective–radiative rectangular and moving exponential porous fins with variable thermal conductivity together with internal heat generation are investigated. The second law of thermodynamics is used to investigate entropy generation in the proposed fins. The model is numerically solved using shooting technique. It is observed that the entropy generation depends on porosity parameter, temperature ratio, temperature distribution, thermal conductivity and fins structure. It is noted that entropy generation for a decay exponential fin is higher than that of a rectangular fin which is greater than that of a growing exponential fin. Moreover, entropy generation decreases as thermal conductivity increases. The results also reveal that entropy generation is maximum at the fin’s base and the average entropy production depends on porosity parameters and temperature ratio. It is further reveal that the temperature ratio has a smaller amount of influence on entropy as compared to porosity parameter. It is concluded that when the temperature ratio is increases from 1.1 to 1.9, the entropy generation number is also increase by 30% approximately. However, increasing porosity from 1 to 80 gives 14-fold increase in average entropy generation.

Metal foam and fin implementation into a triple concentric tube heat exchanger over melting evolution

It is believed that it is going to be a sizeable mismatch between supply and demand when it comes to renewable resources. Lately, researchers are on course to compensate for the unpredictabilityof such resources by the employment of phase change materials (PCMs). Having multiple advantages, PCMs generally suffer from inadequate thermal conductivity which causes prolonged transition procedures. To tackle this issue, this study is fixated on two parameterswhich are linked to fins addition and porous media incorporation in a melting process within a triple concentric tube heat exchanger (TCTHX). The results provided by multiple cases underlined the significance of natural convection in the bare system, although finned and copper-metal-foam cases outshine buoyancy forces by roughly 45% and 97%, respectively. Material is a major determent when it comes to the selection of porous media as Al2O3 registered the weakest performance among SiC, Ni and Cu, however, it managed to speed up the process by 75% which still is much higher than the finned system, implying that porous media is of higher priority over fins. The best scenario transpiredwhile fins and copper metal foam were integrated as 26% and 97% soars in efficacy have been obtained compared to individual incorporation of porous media and fins, respectively.