Nanofluid Jet Impingement Research Articles

Experimental and machine learning study on the influence of nanoparticle size and pulsating flow on heat transfer performance in nanofluid-jet impingement cooling

Maximizing heat transfer efficiency is crucial for enhancing performance and durability in diverse engineering applications, including fuel cells, EV batteries, and solar PV/T systems, thereby advancing sustainable energy innovation. This study investigates thermal dissipation from a simulated heat sink aligned with a PV cell’s back plate via jet impingement cooling. Specifically, it examines the impacts of pulsatile cooling and nanoparticle size in hybrid nanofluids, comprising combinations of Al2O3 and MWCNT in water, with varied nanofluid volume fraction (0.05 vol% ≤ ɸ ≤ 0.3 vol%) and flow Reynolds number (15000 < Re < 40000). Key findings reveal significant influences of nanoparticle size, nanofluid concentration, and pulsating flow on heat transfer performance. Notably, sample D demonstrated the highest heat transfer enhancement, achieving approximately 52.94 % and 79.06 % improvement in continuous and pulsating jet cooling compared to de-ionized water under continuous jet cooling. Machine learning classifiers were employed to identify critical thermal performance parameters, with Reynolds number identified as the most significant factor influencing heat transfer. Random Forest and Gradient Boosting classifiers showed notable accuracy in predicting Nu, emphasizing the role of machine learning techniques in optimizing thermal management strategies for improved heat dissipation from solar PV cell backplates.

Study on the flow and heat transfer characteristics of a hybrid nanofluid jet impingement microchannel heat sink with airfoil fins

AbstractDue to the continuously increasing power density of electronic devices, the improvement of the temperature uniformity and the reduction of the irreversible energy losses became crucial in these studies on enhanced cooling capacity of the heat sinks. In this paper, a jet impingement microchannel heat sink with airfoil fins (AF‐JIMHS) is proposed. The AF‐JIMHS with reversed fins arrangement has very high comprehensive heat transfer performance. The increase of the internal tangent circle radius and chord length of fin can improve the temperature uniformity of the AF‐JIMHS bottom surface and reduce the irreversible energy losses, at the expense of reducing its comprehensive heat transfer performance. Although the increase of the tangent arc length of fin reduces the temperature uniformity and increases the irreversible energy losses of the AF‐JIMHS, it improves the comprehensive heat transfer performance in a specific parameter range. The increase of fin height improves temperature uniformity of the AF‐JIMHS, while reducing its irreversible energy losses and improving its comprehensive heat transfer performance. Compared with the AF‐JIMHS with uniform height fins, the one with decreasing height fins has higher comprehensive heat transfer performance and lower irreversible energy losses. Moreover, the AF‐JIMHS with increasing height fins has better temperature uniformity.

Convective heat transfer by nanofluid jet impingement cooling on automobile radiator with nozzle plate spacing

Nanofluids are a type of emerging heat transfer fluid with great promise for thermal engineering due to its high heat transfer coefficients. Improving heat transmission remains an ongoing task in engineering fields as diverse as semiconductor technology and high-performance vehicles. This paper investigates and compares the jet impact heat transfer coefficient, thermal conductivity, and viscosity of nanofluids with those of a base fluid in an automobile radiator with nozzle plate spacing. Aluminium oxide (Al2O3) and deionised water were selected as the working fluids, and they were used in varying quantities ranging from 0 to 1 volume percent. The nanofluids were prepared using a two-step method with the aid of an ultrasonic homogeniser. The results reveal that the heat transfer coefficient increased by 11.68% at a nanofluid concentration of 1% when nanoparticles were suspended in the base fluid. Furthermore, a 45-49% improvement in the heat transfer coefficient was recorded using a nanoparticle volume concentration of 1% compared to the base fluid.

Energy management of a concentrated photovoltaic−thermal unit utilizing nanofluid jet impingement in existence of thermoelectric module

To generate a concentrated photovoltaic–thermal (CPVT) unit system, linear Fresnel concentrators have been attached to a PV unit and a thermoelectric generator (TEG) has been combined in this work to boost productivity. In the presence of concentrators, the temperature of the silicon layer increases. While electrical output is enhanced for the CPVT unit, the non-uniform isotherms can decrease the lifetime of the panel, so confined jets of alumina–water nanofluid have been applied for cooling. To validate the numerical code, previous papers were examined and good accommodations were reported. Various values of the inlet temperature (T in) and velocity (V in) of jets have been analysed. The impacts of installing concentrators on overall performance and CO2 mitigation have been investigated. An increase in V in leads to an incremental increase in thermal performance of about 4.2% and thermal uniformity is enhanced by about 13.91%. The thermal power of the system is enhanced by about 2.19 times as a result of adding concentrators. Also, the PV power is enhanced by 86.22% in the presence of the reflectors. With the increase in T in, the thermal and electrical performance decrease by about 19.95% and 5.24%, respectively. Installing concentrators enhances the overall performance by about 6.55%. After 10 years, the amount of CO2 mitigation for the CPVT-TEG system reaches 148.28 ton.

Pulsating nanofluid-jet impingement cooling and its hydrodynamic effects on heat transfer

Unlocking optimum heat transfer is essential for enhancing solar thermal collector efficiency and advancing sustainable energy solutions. This experimental study investigates a simulated solar thermal collector's heat transfer behavior using jet impingement cooling, emphasizing hydrodynamic effects in pulsating nanofluid-jet impingement. Al2O3-MWCNT/water hybrid nanofluid is utilized, varying pulsating frequency (0.2 Hz ≤ F ≤ 20 Hz), amplitude (4 Vp ≤ A ≤ 20 Vp), waveform (sine, squared, triangular), wave offset (0 ≤ Ⴋ ≤ 4), and nanofluid volume fraction (0.05 vol% ≤ φ ≤ 0.3 vol%) to optimize heat transfer. Results show a significant influence on heat transfer performance for all parameters except waveform. A peak heat transfer enhancement of 24 % is observed for 0.3 vol% Al2O3-MWCNT/water compared to de-ionized water under continuous jet impingement. Additionally, a 20 % enhancement is achieved with a sine waveform at φ = 0.3 vol%, F = 0.2, A = 8, and Ⴋ = 2. Pulsating jet impingement generally yields higher cooling rates, as the cooling curves indicate. These findings provide crucial insights for optimizing heat transfer in solar thermal collectors through pulsating hybrid nanofluid jet impingement cooling.

PARAMETRIC STUDY AND DEVELOPMENT OF A CORRELATION FOR NUSSELT NUMBER IN NANOFLUID JET IMPINGEMENT

Numerical simulations for nanofluid ( water with Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; nanoparticles) jet impinging perpendicularly on a flat circular heated p late have been performed. A heated p late is subjected to constant heat flux boundary condition. A two-phase modified mixture mo del was used for the prediction of heat transfer coefficient, and comparisons are made with standard mixture model. Present results for average Nusselt number are validated with experimental data available in the literature. Though a standard mixture model predicted heat transfer with accepted accuracy, it was found that accuracy of modified mixture model is better (around 5&amp;#37; improvement) compared to standard mixture model. Thereafter, parametric study was performed considering nozzle exit Reynolds number (Re), spacing ratio (&lt;i&gt;H/D&lt;/i&gt;), nanoparticle volume fraction (&amp;phi;), and nanoparticle diameter (dp) on heat transfer prediction. The results reveal that particle diameter in the range 10-100 nm has no effect on the Nusselt number, Furthermore, heat transfer increased with increasing Reynolds number and volume fraction. However, spacing ratio shows first increasing and then, decreasing trend (similar to a log-normal distribution curve) in the prediction of heat transfer. Finally, a new correlation was developed for Nusselt number using nonlinear regression analysis. In the correlation, a two-phase multiplier was used, which is the ratio between two-phase Nusselt number (Nu&lt;sub&gt;nf&lt;/sub&gt; ) and single-phase Nusselt number (Nu&lt;sub&gt;sp&lt;/sub&gt;). The simplified correlation is found to predict data with maximum error of 8.9&amp;#37;, average error of 2.74&amp;#37; and &lt;i&gt;R&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt; &amp;#61; 0.955.

Flow structure analysis of nanofluid impingement on modified target surface under different design parameters

The flow structures of jet impingement dominate heat and mass transfer process, even the whole thermal performance. In this study, we have inspected the flow structures and mechanism of nanofluid jet impingement onto a dimpled target surface with different design parameters. Investigations are performed for the relative depth of dimple ([Formula: see text]), the jet-to-plate spacing ([Formula: see text]), nanoparticle volume concentration ([Formula: see text]), and Reynolds number (Re) ranging to explore the mechanism of flow structure variations. Results indicate that these parameters have a significant effect on the flow structure of nanofluid jet impingement near the dimpled target surface. The flow begins to separate after passing the edge of the dimple along with the curvature of a dimple. [Formula: see text] will affect the form and location of flow separation and reattachment, and [Formula: see text] will affect the intensity of separation flow. The length of the flow separation bubble varies in different [Formula: see text] cases. When [Formula: see text] increases, the impinging energy and the velocity near the dimple edge decreases. The different Re has little effect on the length of the flow separation bubble and the tendency of the pressure coefficient (Cp). These results can provide further mechanism inspiration for the design of the flow structure of nanofluid jet impingement.

Concentrated solar photovoltaic cell equipped with thermoelectric layer in presence of nanofluid flow within porous heat sink: Impact of dust accumulation

Solar cell performance has been enhanced by means of a cooling system involving nanofluid jet impingement. A thermoelectric module has been located beneath the Tedlar layer resulting in greater electrical output. MWCNT nanoparticles were added to water as a testing fluid. The nanoparticles were concentrated up to a maximum value of 0.036, to achieve a homogenous mixture. To scrutinize the influence of dust accumulation on the performance of the unit, the transmissivity of glass was calculated based on dust density. Different concentration ratios (CR) were examined to assess their influence on the system's performance using Fresnel lenses in the setup. To further enhance the performance, the unit was tested both without (1) and with (2) pin fins. With the increase of CR from 2 to 14, the PV efficiency reduces by around 26.15% and 25.31% for cases 1 and 2, respectively. The value of TE efficiency for case 2 with CR=14 is 4.16 times greater than that with CR=2. The thermal efficiency of case 1 enhances by 4.8% with the growth of CR. For case 1, the improvement in PV, TE and thermal efficiencies is about 1.42%, 8.48% and 0.91%, respectively, with applying porous zones. Also, the temperature uniformity contributes a further 8.05% improvement. Thermal, TE and PV efficiency decrease respectively by about 7.69%, 12.11% and 26.47%, with an increase in dust density from 0 to 7.2 for case 2.

Mathematical formulation of Al2O3-Cu/water hybrid nanofluid performance in jet impingement cooling

Liquid coolant is an important substance often used to lower the temperature of an object. To increase the heat transfer performance of a coolant, metal nanoparticles are introduced into a base fluid such as water, which is then called a nanofluid. A further development is the hybrid nanofluid, in which researchers try to mix two types of metal nanoparticles with high thermal conductivity to further increase the heat transfer performance. In this work, the heat transfer performance of a hybrid nanofluid in delivering heat from a target surface is investigated using a cylindrical single-jet impingement method. A three-dimensional numerical analysis is performed using Ansys FLUENT to investigate the effects of different types of coolants on the heat transfer performance. The coolants used in the simulation were pure water, Al2O3-Cu/water hybrid nanofluid, Al2O3/water nanofluid, and Cu/water nanofluid with 0.5% volume concentration. The effects of Reynolds number on the heat transfer performance of hybrid nanofluid were presented and discussed in detail. The results showed that hybrid nanofluid has the highest heat transfer performance compared to pure water and single particle nanofluids. At the end of the study, mathematical formulation was developed to describe the correlation between Reynolds number and volume concentration on the average heat transfer coefficient. This will enable the assumption of hybrid nanofluid jet impingement cooling heat transfer performance for future development.

A Review on Experimental and Numerical Investigations of Jet Impingement Cooling Performance with Nanofluids.

Nanofluids offer great potential heat transfer enhancement and provide better thermophysical properties than conventional heat transfer fluids. Application of nanofluids in jet impingement cooling is used for many industrial and scientific purposes as it manages to effectively remove high localized heat. Owing to its tremendous improvement of the heat transfer field, the use of nanofluids in jet impingement cooling has caught the attention of many researchers. This paper reviews previous research and recent advancements of nanofluid jet impingement via both experimental and numerical studies. In experimental approaches, Al2O3-water nanofluids are the most used working fluids by researchers, and most experiments were conducted with conventional impinging jets. As for the numerical approach, the single-phase model was the preferred model over the two-phase model in obtaining numerical solutions, due to the lower computational time required. A deep insight is provided into nanofluid preparation and methods for stabilization. Parameters affecting the performance of the jet impinging system are also investigated with comparison to numerous publications. The main parameters for jet impinging include the jet-to-plate distance (H/D), the shape of the impinged plate (curved, flat or concave), nozzle configurations and the twisted tape ratio. Studies on conventional impinging jets (CIJs), as well as swirling impinging jets (SIJs), are presented in this paper.

A computational study on nanofluid impingement jets in thermal management of photovoltaic panel

Thermal management is essential to improve the overall performance of photovoltaic (PV) cells. This study presents a comprehensive numerical study on a PV panel to achieve economic efficiency cooling system. A nanofluid jet impingement cooling (JIC) system with different configurations is developed and integrated into the PV panel to control the surface temperature. A three-phase mixture model shows a satisfactory agreement between the simulation and measurement values. Then, the simulations are conducted to understand the importance of different influencing parameters, including inlet temperature (20–40 °C), number of nozzles (8−24), mass flow rate (0.045–0.12 kg/s), jet-to-surface distance (5.1–55 mm), and nozzle diameter (1 and 2 mm). Numerical results demonstrate that uncooled PV temperature reaches 68.5 °C, while using the JIC system reduces that by 36.4 °C. Lower inlet temperatures and larger mass flow rates result in higher PV efficiency. The number of nozzles affects the surface temperature and its uniformity. Small jet-to-surface distances enhance the turbulence kinetic energy and the heat transfer rate. For the nozzle diameters of 1 and 2 mm, the maximum power increment increases to 20.36% and 20.19%, respectively. However, the nozzle diameter of 1 mm increases the pumping power with a coefficient of energy of 1.18.

Nanofluid jet impingement heating of a cooled surface with a constant heat flux in the presence of porous layer

PurposeThe purpose of this study is to numerically investigate the confined single-walled carbon nanotube-water nanofluid jet impingement heating of a cooled surface with a uniform heat flux in the presence of a porous layer. The analysis of the convective heat transfer mechanism is introduced considering the buoyancy force effect under local thermal non-equilibrium conditions.Design/methodology/approachThe governing equations for the nanofluid and solid phase are discretized by the finite volume method and the SIMPLE algorithm is used to solve these equations.FindingsIt is observed that there is an increase in a local variation of temperature along the upper wall with increasing Reynolds, Darcy and Grashof numbers. For given parameters, the optimum values of thermal conductivity ratio and porous layer thickness leading to better heating on the upper wall are found as Kr = 1.0 and S = 0.5, respectively. The maximum and minimum values of temperature on the upper wall are obtained in the case of higher nanoparticle volume fraction at Re = 100, however, the temperature values get higher along the upper wall with increasing nanoparticle volume fraction at Re = 300.Originality/valueThe effects of various parameters, such as Reynolds number, Darcy number and Grashof number, on thermal behavior and nanofluid flow are examined to determine the desirable heating conditions for the upper wall. This paper provides a solution to problems such as icing on the surface with a suitable thermal design and optimum geometric configuration.

Combined effects of double porous layers and nanofluids on the performance of confined single and multi-jet impingement heat transfer

In this study, nanofluid jet impingement cooling performance with single and multiple jets are analyzed under the impacts of using double porous layers with finite element method (FEM). The numerical study is performed by using different values of pertinent parameters as: Re number (), permeability of the porous zones ( and ), second porous layer height (), distance between the porous layers (), solid volume fraction (), and particle diameter (). Discrepancies between the single and multiple jet configurations become higher for Re numbers while at Re = 300, the average heat transfer (HT) is 31% for multiple jet case. The presence of the double porous layers significantly affects the convective HT performance and the highest impact is observed by varying the permeability of the porous layers. When the lowest and highest permeability of the lower layer are compared, there is 119% variation in the average Nu for multi-jet (MJ) case and this value is 84.5% for single jet (SJ) case. When varying the permeability of the upper porous layer, the highest HT rate is achieved at Darcy number of while 32% higher Nu is obtained for MJ case as compared to SJ case. There is slight impact of the distance between the porous layers on the fluid flow and HT while varying the height of the upper layer results in 8.9% variation in the average Nu number. Inclusion of the nanoparticle (NP) further improves the average Nu by about 11% for single and multiple jet cases at the highest solid volume fraction while the impact of NP size is slight.

Parametric study of nanofluid jet impingement cooling of protruding heaters with porous medium

Parametric study of nanofluid jet impingement cooling of protruding heaters with porous medium

Effect of shape of nanoparticle on heat transfer and entropy generation of nanofluid-jet impingement cooling

ABSTRACT Al2O3/water nanofluid has been numerically examined for the first time with different nanoparticle shapes including, cylindrical, blade, brick, platelet and spherical, on the flat and triangular-corrugated impinging surfaces. The volume fractions of 1.0%, 2.0% and 3.0% nanoparticles have been used. The Reynolds number is between 100–500 depending on the slot diameter. The finite volume method is utilized to determine the governing equations. The study is analyzed to determine how the flow features, heat transfer features and entropy production were affected by the diversity of nanoparticle shape, nanoparticle volume fraction, and shape of impinging surface. Darcy friction factor and Nusselt number are studied in detail for different conditions. The temperature contours are presented in the case of different nanoparticle volume fractions, nanoparticle shapes and both impinging surfaces. The results of the study suggest that the nanoparticle shape of the platelet shows the highest heat transfer development due to the thinner thermal boundary layer. Heat transfer augments with increasing volume fraction of nanoparticles. In addition, the study is consistent with the results of the literature on heat transfer and flow properties.

Heat transfer characteristics of impinging jet on a hot surface with constant heat flux using Cu2O–water nanofluid: An experimental study

Abstract The experimental investigations are carried out on a circular nanofluid jet impingement for cooling an aluminum disk with constant heat flux. The study is performed to understand the effects of different factors such as Reynolds number and nanoparticle concentration on the fluid flow and characteristics of heat transfer. The target surface has a circular shape and is kept at constant heat flux with the value of 1414.71 W/m2. The copper oxide-nanoparticle concentrations are changed from 0.03 to 0.07 wt%. The experimental results show that the Cu2O nanofluid increases the heat transfer efficiency of the impinging jet cooling system. Compared to the case of using the base fluid, the nanofluid increases the convective heat transfer by 45% at 0.07 wt% concentration at Reynolds number of 7330. The center of the target surface, i.e. the stagnation zone, has the highest turbulence intensity because of impinging of the fluid flow on the surface center, while the endpoint of the target surface has the minimum turbulence intensity. Indeed, the turbulence intensity decreases along the radial direction, which augments the effect of employing the nanofluid because the heat transfer due to the turbulence diminishes and merit of using the nanofluid enhances.

Parametric study of nanofluid jet impingement cooling of protruding heaters with porous medium

Parametric study of nanofluid jet impingement cooling of protruding heaters with porous medium

ANN, numerical and experimental analysis on the jet impingement nanofluids flow and heat transfer characteristics in the micro-channel heat sink

In the present study, the application of computational fluid dynamic and artificial neural network to analyze the nanofluids jet impingement heat transfer and pressure drop in the micro-channel heat sink have been presented. For the ANN model, the Levenberg-Marquardt Backwardpropagation (LMB) training algorithm is applied to adjust errors for obtaining the optimal ANN model. For the numerical analysis, the Eulerian two-phase approach model has been used to analyze the problem. The results obtained from the ANN and CFD are verified with the measured data. Based on the optimal ANN model, the majority of the data falls within ±1.5% of the Nusselt number and pressure drop, respectively. While the maximum error for all cases between the measured data and the predicted results is 1.25%. The obtained optimal artificial neural network model and CFD have been applied to analyze the heat transfer and pressure drop the micro-channel heat sink with various configurations.

Numerical investigation of heat transfer by an impinging jet using alumina–water nanofluid

This article reports numerical investigations of turbulent flow field and heat transfer performance of water-alumina nanofluid jet impingement. The jet impinges over a flat, circular heated surface from a circular pipe of diameter . The influence of jet Reynolds number (1,200 ≤ ≤ 40,000), jet-outlet-to-target wall distance (2 ≤ ≤ 12.8), and particle volumetric concentration (0 ≤ φ ≤ 10%) on the fluid flow and heat transfer are examined. The results of fluid flow and heat transfer are compared with the published experimental data. It is found that the heat transfer increases with increasing values of the particle volumetric concentration while the flow field and turbulent kinetic energy distribution remain unchanged with the inclusion of nanoparticles. About 28% enhancement in stagnation Nusselt number is observed at low values of nanoparticle volumetric concentration (φ = 0.1%) and in the Reynolds number range of 29,000–40,000. For jet-outlet-to-target wall spacing values used in the current study, the local Nusselt number distributions vary according to Nu ∝ . Numerical simulations are performed using Reynolds-averaged Navier–Stokes method with the shear stress transport k-ω model in commercial CFD code ANSYS-CFX.

Continuous nanofluids jet impingement heat transfer and flow in a micro-channel heat sink

Experimental investigation on the TiO2 nanofluids jet impingement heat transfer and flow characteristics in the micro-channel heat sink are carried out. In the present study, three heat transfer enhancement techniques; micro-channel heat sink, jet impingement, and nanofluids are considered in which included the effect of relevant parameters of the nanofluids concentration, nozzle diameter, nozzle-to-heat sink distances, mass flow rate of nanofluids on the heat transfer performance of a micro-channel heat sink are considered. The obtained results showed that the suspending of nanoparticles in the base fluid remarkably increases the convective heat transfer by 18.56% at 0.015% nanofluids concentration. In addition, the obtained heat transfer coefficient tends to increase with increasing the nozzle diameter and decreasing nozzle level height. While the pressure drop across the test section increases as the nozzle diameter decreases and nozzle level height increases. However, the suspending of nanoparticles bring almost no extra addition of pressure drop as comparing with the base fluid. However, the obtained results point out that the proper selection of the relevant parameters to enhancement of heat transfer is important.