Enhancement Of Heat Transfer Rate Research Articles

Wiped film evaporator with a roller wiper and an internally mounted condenser for the recovery of TBP and n-DD from degraded PUREX solvent

Wiped Film Evaporator (WFE) is a promising choice for processing viscous and thermally labile compounds due to its short residence time, enhanced heat transfer rates, and a high fraction of distillate yield in a single pass. This article evaluates the viability of a WFE with a roller wiper and an internally mounted condenser to recover tri-butyl phosphate (TBP) and n-dodecane (n-DD) from degraded PUREX solvent by vacuum distillation. Degraded solvents derived from different sources were purified using a combination of primary cleanup by sodium carbonate scrubbing and secondary cleanup by vacuum distillation using the WFE. Primary cleanup could efficiently remove the acidic degradation products of TBP. However, the scrubbed solvents were not of acceptable quality due to their poor physical properties. Secondary cleanup by vacuum distillation notably improved the physical properties of the solvent. A detailed quality assessment of the recovered solvents in terms of density, viscosity, interfacial tension (IFT), and phase separation time (PST) ratio showed that all the solvents recovered were of acceptable quality. The highest PST ratio and lowest IFT of the recovered solvents were 1.36 and 8.6 mN m−1, respectively. The maximum solvent recovery, TBP recovery, and n-DD recovery obtained were 93.8%, 83.8%, and 99.8%, respectively.

Analysis of the laminar flow and enhanced heat transfer rate through a triangular array of cylinders embedded in a fluid-saturated porous media with mixed convection

An investigation of the laminar flow and enhanced heat transfer rate through a triangular array of cylinders embedded in a fluid-saturated porous media is considered. Mixed convection covering forced convection cases has been studied using a finite-volume approach considering the local thermal equilibrium model. Darcy–Brinkman–Forchheimer momentum equations are used to characterize the porous media in question. The study is constrained to the low and intermediate Peclet number (Re = 5 to 40, Pr = 50) and high range of Darcy number (Da = 10−3 to 10−1) for different cylinder spacings (0.7 ≤ φ ≤ 0.99). It is anticipated that porous media would enhance heat transfer, but it derives a multiple order in pressure drop indubitably not desirable in many heat applications. Investigation reveals that both mean drag coefficient (CD ) and Nusselt number (Nu) are strong functions of Da and φ; however, the influence of the buoyancy parameter is mainly witnessed in higher permeability levels and high Peclet numbers. The study also details the effect of governing parameters on mean gap velocities and pressure coefficients. Surprisingly, recirculation wakes exist for the lowest cylinder spacing (φ = 0.7) in high fluid momentum. Low φ and high permeability are desirable in a forced convection regime, whereas both φ and Da should be high in the case of mixed convection. This article also quantifies the combined effect of the Darcy number and buoyancy parameter on the heat-transfer enhancement ratio. A maximum of 112% increase in Nu for φ = 0.7 and 452% for φ = 0.99 are reported at Da = 10−1, but at the cost of higher pressure drop in the latter case.

Ferrohydrodynamics Mixed Convection of a Ferrofluid in a Vertical Channel with Porous Blocks of Various Shapes

Numerical simulations of (water-Fe3O4) ferrohydrodynamics (FHD) mixed convection inside a vertical channel are performed. The magnetic field is produced by three sources positioned outside the channel’s right wall. The latter is provided with localized heat sources surmounted by variously shaped porous blocks: rectangular, trapezoidal, and triangular. The general model of Darcy-Brinkman-Forchheimer is employed to describe the fluid flow in the porous regions, and the resulting equations are numerically solved by the finite volume approach. The influence of significant parameters, including the magnetic number (Mn), the Richardson number (Ri), and the shape of blocks, is examined. The results essentially reveal that the enhanced heat transfer brought by the magnetic field and its intensity increase is suppressed by the augmentation of Ri until a critical value, rising with Mn, beyond which the global Nusselt number increases again. The mean friction coefficient increases with increased Mn and reduced Ri. Compared to the case with no magnetic field, the maximum enhancement in heat transfer rate is around 132% for the rectangular blocks, 146% for the trapezoidal blocks, and 160% for the triangular blocks, while the maximum increase in pressure drop is approximately 45% for all the shapes. The triangular shape seems the most efficient because it leads to high heat transfer rates and low mean friction coefficients; its performance factor is 2.32 for a dominant magnetic field and 2.62 for a dominant buoyancy force. The current research's conclusions will help optimize the operation of various thermal engineering systems, including electronic devices, where the improved heat removal rate will keep the electronic components at a safe operating temperature.

A short & updated review of nanofluids utilization in solar parabolic trough collector

The world is facing a crisis of energy because fossil fuels are depleting day by day. The growth of any country mainly depends upon 3Es namely energy, economy and environment. These are the three pillars of sustainability also. The ejaculation of greenhouse gases is also the ultimatum for the world. The major constituent of greenhouse gas is CO2 and it increased rapidly in the last decade which increases the earth's temperature very rapidly. The problem of the energy crisis as well as greenhouse gas emissions from oil and coal-based energy sources can be overcome by the utilization of renewable sources of energy such as solar, wind, hydro, tidal and many more. The sun is the primary source of energy on earth since it is readily available, cost-free, and has no negative effects on the environment. Without emitting greenhouse gases, solar energy can be transformed directly into thermal energy in the form of heat and then into electrical energy. The main obstacle in the utilization of solar energy is the enhancement of heat transfer rate which can be overcome by utilizing a high thermal conductivity fluid known as nanofluid. In the present study progress of nanofluid utilization in solar parabolic trough collectors are reviewed. The effects of various variables such as volume fraction, the flow rate of mass, thermal conductivity and rate of heat transfer are reviewed. The effects of nanofluid utilization for enhancement of efficiency, exergy and pressure drop in PTC are also reviewed.

Long-lasting ceria-based anti-frosting surfaces

Suppressing condensation frosting using superhydrophobic surfaces can have a substantial impact on improving efficiency and safety in many industrial applications. However, the low surface energy coatings on such surfaces can be easily damaged during various harsh operations, which has limited the application potential of passive anti-frosting approaches. Here, we propose robust ceria-based anti-frosting surfaces, where superhydrophobicity is induced by not surface coating but adsorbed hydrocarbon. We also demonstrate how the incorporation of a hydrocarbon source as a binder to the ceria-based coating allows for the quick recovery of superhydrophobicity. In comparison to untreated aluminum surfaces, the developed coatings decreased the frost propagation speed and the ice adhesion strength by 60% and 89%, respectively. The coatings could maintain a low contact angle hysteresis even after 200 cycles of frosting/de-frosting robustness tests and 15,000 cycles of acidity/salinity exposure tests. Using a scalable one-step dipping process, the created coating was incorporated to a fin-tube type heat exchanger, and provided 210% enhanced heat transfer rate and 60% decreased pressure drop. The coatings also provided substantially improved robustness compared to the silane-treated superhydrophobic coating. These findings suggest that the developed ceria-based coatings can be helpful in creating scalable and resilient anti-frosting surfaces for real-world applications.

EFFECTS OF NANOPARTICLE SIZE ON PROPERTIES OF NANOFLUID AND HEAT TRANSFER ENHANCEMENT IN SPIRAL EXCHANGER USING TURBULATORS

In energy systems that use nanofluids as heat transfer fluid, the physical properties of nanofluids are important parameters in the efficiency of various heat exchangers, including small-scale micro channels or large-scale heat exchangers. In the present work, a comprehensive study is conducted to evaluate the thermal performance of a spiral heat exchanger with ball-type turbulators using nanofluid Al<sub>2</sub>O<sub>3</sub>/water. To investigate the effect of particle dimensions on nanofluid properties, nanoparticles with sizes of 20 nm and 50 nm at a volume concentration of 2% were examined. Heat transfer rate in the heat exchanger, performance evaluation criteria, heat transfer coefficient value, pressure drop, friction factor, Reynolds-Nusselt numbers relationship and pump power for fluid circulation have been calculated. ANSYS Fluent software as a computational fluid dynamic method was utilized to analyze the spiral heat exchanger under different working conditions. It was observed that both thermal conductivity and viscosity values increased as the nanoparticle size decreased. Heat transfer coefficient analyses showed that nanofluids with 20 and 50 nm particles exhibited a maximum improvement of 30.59% and 21.53%, respectively, when compared to pure water at an inlet velocity of 0.1 m/s. Additionally, the heat exchanger with turbulator showed a maximum increase of 24.87% at an inlet velocity of 0.5 m/s compared to the heat exchanger without turbulator. Moreover, maximum heat transfer rate enhancement was found to be 14.07% when the exchanger was equipped with turbulators.

PV Panel Heat Transfer Rate Enhancement Using a Novel Heat Exchanger with High-Resolution Spikes and Dimples

PV cell electrical efficiency has an inverse relationship with its temperature. This study uses a novel and commercialized backsheet to reduce PV panel surface temperature. The novel backsheet consists of spikes and dimples to increase the air turbulence and convection heat transfer rate. Experimentally validated computational fluid dynamic (CFD) models are developed to investigate the influence of GripMetal backsheet on PV cell temperature and efficiency of PV panels and PVT collectors. Under 1000 W/m2 solar irradiation, it is shown that a PVT collector with a 2.25 mm spikes height has almost 10% more electrical efficiency than a PVT collector with a flat plate channel. A maximum 22.5℃ temperature drop was observed by using the GM-based PVT collector for slow-motion airflow. It is shown that the GM spikes are more efficient in low Reynolds numbers and can enhance air turbulence more effectively. The GM PVT collector has the best performance at low Reynolds numbers which is suitable for air-based PVT applications.

Heat transfer analysis in thermal energy storage—A comprehensive review‐based latent heat storage system

AbstractThermal energy storage (TES) system is the most eminent storage method that aids in the power generation. Latent heat storage (LHS) is on the rapid mark‐up that fosters the TES with the utilization of the phase transition of a material to store the heat. Typically the phase change materials (PCM) are used in the LHS system to store the energy. During the material's phase transition, thermal energy is stored and released. Nevertheless, the low thermal conductivity of the PCM in the LHS is susceptible to deteriorate the charging and discharging of the thermal energy. Hence there is a necessity to enhance the thermal performance of the LHS system, on which various studies have been done. Therefore this paper aims in providing a review on the enhancements of the LHS system with improved heat transfer rate and heat transfer enhancement techniques in the PCM for better efficiency. A comprehensive review on the LHS system component is provided to make an emphasis on the heat transfer enhancement rate and storage time. Various characterizations and categories of the PCM are provided to intensify the outcomes of the review as PCMs are most viable materials for storing thermal energy. In addition the recent researches on the integration of PCM with other materials are also discussed that help in the improvements of the thermal conductivity of the PCM. The selection parameters of the PCM materials are also discussed in brief to avoid the poor performance of the PCMs. The heat transfer analysis methods are analyzed to improve the efficiency and reduce the heat loss. Finally, advancements in the future trends for the enhancement of heat transfer is provided.

Buoyancy-induced convective flow and heat transfer over obstacles embedded inside a Cu–water nanofluid-saturated porous cavity

In this article, a comprehensive study of convective flow over the obstacles (i.e., heaters and freezer) inside the cavity filled with Cu–water nanofluid-saturated porous medium is made. The flow is induced due to heated vertical walls and a cooled top wall, as well as partial attachment of obstacles with the bottom wall. A non-Darcy model that includes Darcy and Brinkman terms has been adopted. The coupled governing equations are solved numerically by the finite element method using the penalty approach. The influence of different controlling parameters, Rayleigh number (Ra), nanoparticle volume fraction (), Darcy number (Da), Prandtl number (Pr), aspect ratio (Ar ), and porosity (ε) on the dynamics of flow and heat transfer rate have been addressed. The flow dynamics as well as heat transfer rate have been analyzed with help of streamfunction and temperature contours. Results show that the flow structure (i.e. streamlines) is controlled by nipple shape bicellular structure and the velocity profile includes the point of inflection. The variation of the Nusselt number as a function of the volume fraction of the nanoparticle is almost linear. In contrast to pure fluid, at 10% volume fraction of nanoparticle, the enhancement in heat transfer rate is found up to 30%.

Intensification of thermal efficiency of a cross-flow heat exchanger under turbulent flow conditions using CuFe2O4/water nanofluid

The use of nanofluids has opened new intellectual horizons in improving the performance of heat exchangers. Therefore, in this work an experimental study was conducted for investigating the effect of CuFe2O4/water nanofluid on the heat transfer rate enhancement in a cross-flow type heat exchanger under turbulent flow conditions. Heat transfer rate were examined at different volume percentages of CuFe2O4 nanoparticle (0≤ φ ≤ 0.9% vol.) with a nominal diameter of 28 nm at three inlet fluid temperatures of 72, 80 and 88 °C, water pump rotational speeds of 2000 rpm and 3000 rpm, and cross-flow fan speeds of 1500, 2000 and 2500 rpm. According to the results, the heat transfer rate in the case of using nanofluids with a volume percentage of 0.1% was significantly higher than that of distilled water in all test conditions. The highest relative increase in the universal heat transfer coefficient (U) equal to 92.3%, compared to the use of water (φ = 0) was obtained at 0.1% vol% of nanoparticles, the lowest temperature of fluid entering the heat exchanger (72 °C), medium pump speed (2000 rpm) and low fan speed (1500 rpm). The maximum Performance Evaluation Criterion (PEC) improvement of 44.46% also occurred at this working condition.

Role of curved walls on efficient thermal convection in porous beds confined within enclosures: heatline and entropy production maps

PurposeThis study aims to elucidate the role of curved walls in the presence of identical mass of porous bed with identical heating at a wall for two heating objectives: enhancement of heat transfer to fluid saturated porous beds and reduction of entropy production for thermal and flow irreversibilities.Design/methodology/approachTwo heating configurations have been proposed: Case 1: isothermal heating at bottom straight wall with cold side curved walls and Case 2: isothermal heating at left straight wall with cold horizontal curved walls. Galerkin finite element method is used to obtain the streamfunctions and heatfunctions associated with local entropy generation terms.FindingsThe flow and thermal maps show significant variation from Case 1 to Case 2 arrangements. Case 1 configuration may be the optimal strategy as it offers larger heat transfer rates at larger values of Darcy number, Dam. However, Case 2 may be the optimal strategy as it provides moderate heat transfer rates involving savings on entropy production at larger values of Dam. On the other hand, at lower values of Dam (Dam ≤ 10−3), Case 1 or 2 exhibits almost similar heat transfer rates, while Case 1 is preferred for savings of entropy production.Originality/valueThe concave wall is found to be effective to enhance heat transfer rates to promote convection, while convex wall exhibits reduction of entropy production rate. Comparison between Case 1 and Case 2 heating strategies enlightens efficient heating strategies involving concave or convex walls for various values of Dam.

Complex wave’s impact on the cilia-generated flow in a vertical tube with an endoscope

ABSTRACT This research object is focused to discuss the cilia-driven flow along complex wave progression via cilia tips. Suspension of nanocomposites is considered in this analysis to discuss the enhanced heat transfer rate properties of the base fluid blood. The endoscopic tube is inserted into the flow region covered by cilia tips to overcome the cilia disorders. Governed mathematical equations are solved by the Mathematica DSolve command after using lubrication approximation. To see the theoretical consequence of complex cilia movement along the tube, graphical results are plotted for different innovative parameters which are discussed in detail. Streamlines are strategized to see the blood circulation pattern in the presence of the complex cilia waves. From a theoretical point of view, it is noted that complex cilia waves accelerate the fluid circulations more significantly near the ciliated walls. Moreover, the cilia-driven fluid flow has a substantial role in multiple progressions such as clearance of respiratory mucus, right-left pattern in the embryonic node, gamete transport in the oviduct, and cerebrospinal fluid flow.

Element Differential Method for Non-Fourier Heat Conduction in the Convective-Radiative Fin with Mixed Boundary Conditions

Fin is an efficient and straightforward way to enhance heat transfer rate. When the heat source varies dramatically in a very short time, non-Fourier heat conduction should be considered. In the paper, taking advantage of numerical stability and no integral and easy-to-implement features of an element differential method, a numerical model is developed to evaluate the fin efficiency of the convective-radiative fin within non-Fourier heat conduction. In this fin, heat is generated by an internal heat source and dissipated by convection and radiation. Both periodic and adiabatic boundary conditions are considered. The accuracy and efficiency of the element differential method is validated by several numerical examples with analytical solutions. The results indicate that the element differential method has high precision and flexibility to solve non-Fourier heat conduction in convective-radiative fin. Besides, the effects of Vernotte number, dimensionless periodicity, thermal conductivity coefficient, and emissivity coefficient on dimensionless fin tip temperature, instantaneous fin efficiency, and average fin efficiency are comprehensively analyzed.

Porous-fin microchannel heat sinks for future micro-electronics cooling

Porous-fin microchannel heat sinks offering high solid-fluid interfacial areas have the potential to be an integral part of future microelectronic cooling systems. Replacing solid with porous fins reduces the pressure drop penalty of the straight plate-fin microchannel heat sinks. However, prior research has shown that in some cases porous fins adversely affect the thermal performance of the microchannel heat sinks. The reduced effective thermal conductivity of the porous fins compared to the solid ones has been considered the main reason for the reduced thermal performance of porous-fin microchannels. In this work, a detailed study is conducted to assess the feasibility of using porous fins to simultaneously improve the thermal and hydraulic performances of the straight plate-fin microchannel heat sinks. Results revealed that the porous-fin microchannels outperform the solid-fin microchannels at small channel heights. However, at high channel heights, the low effective thermal conductivity of porous fins results in a weak vertical thermal diffusion. Consequently, replacing solid with porous fins degrades the thermal performance of the microchannel at high channel heights. Additionally, the porous-fin microchannels exhibit better thermal performance than the solid-fin microchannels at fin to fluid width ratios above 0.25. The increased coolant mass flow penetrated the porous fin section is the main reason for the enhanced heat transfer rate of the porous-fin microchannels at higher width ratios. Moreover, the porous-fin microchannels offer a lower pressure drop penalty than the solid-fin microchannels under all examined operating conditions. This research confirms the potential of substituting solid with porous fins to simultaneously improve the thermal and hydraulic performances of the straight plate-fin microchannel heat sinks.

Three-dimensional numerical investigation of hybrid nanofluids in chain microchannel under electrohydrodynamic actuator

Energy efficiency enhancement methods have received considerable attention within the industry and scientific community, owing to the rising concern of global energy sustainability. The present article attempts to scrutinize the effects of electrohydrodynamics and nanofluids on the rate of heat transfer and fluid flow in the 3-D chain microchannels. Improved heat exchangers (e.g., chain microchannel) would have a key role in increasing of the performance of such systems since they provide efficient thermal management needed for more robust computational power. To date, analysis of electrohydrodynamics and nanofluids in the chain microchannel was not comprehensively discussed. Here, steady-state, laminar, and three-dimensional chain microchannel are numerically modeled based on a control volume method in Fluent. Results show that by increasing the volume fraction of nanoparticles, the viscosity of the nanofluid increases leading to an increase in pressure drops. Moreover, Nusselt at Re = 125, 250, 500 and 1000 for hybrid nanofluid () is 1.206, 1.541, 2.075 and 2.707, respectively which, in turn, depicts surging by 22.94%, 24.17%, 24.70% and 24.707% in comparison to water, respectively. In addition, at low Reynolds number (0.416 the lower Reynolds results in decreasing of percentage of pressure drop. Meanwhile, imposing electrohydrodynamic (V = 30 KV) at Re= 125, 250, 500 and 1000 leads to increasing by 23%, 22%, 20% and 18% of Nusselt number in comparison to absence of electric field, respectively. It means that the considered effect of the increasing the Nusselt number at lower Reynolds number is more effective. Moreover, heat transfer rises with augmentation of supplied voltage and Reynolds number. Highlights Using active (electrohydrodynamics and hybrid nanofluid) and passive (3-D chain microchannel) methods to enhance heat transfer rate. Adding two additional equations (including and V) in Fluent With Using UDS (User Defined Scalar). Writing UDM to achieve E () as well as UDF to solve source terms (E and Considering the charge convection term () in the electric current density ( owing to used fluids (water and nanofluids) in this article, whilst it is negligible for air. Investigation of effects of different types of nanofluid and their concentration as well as impacts of adding electrode and its voltages. Imposing electrohydrodynamic (V = 30 KV) at Re= 125, 250, 500 and 1000 leads to increasing by 23%, 22%, 20% and 18% of Nusselt number in comparison to absence of electric field, respectively.

Hybrid Nanofluid on Mixed Convection Flow Past a Stretching Sheet with Irregular Heat Source/Sink

This research studies the behaviour of hybrid nanofluid on mixed convection flow over a stretching sheet by considering the effect of non-uniform heat source/sink. The chosen base fluid is water with two different nanoparticles which are copper and aluminium oxide. The governing partial differential equations are reduced into ordinary differential equations using a similarity transformation technique. The resulting governing system then solved numerically using Keller-box method. The influence of space- and temperature-dependents of non-uniform heat source and sink parameters as well as the unsteadiness parameter is presented graphically. The current study shows that, the space- and temperature dependents of non-uniform heat source and sink significantly raises the fluid’s temperature. Comparative study also shows that hybrid nanofluid has higher temperature and heat transfer coefficient than single nanofluid and conventional fluid. It can also be concluded that, the enhancement of heat transfer rate can be achieved by reducing the parameter of space- and temperature dependents of non-uniform heat source and sink.

Influence of sawtooth twisted tape on thermal enhancement of heat exchanger tube

This article employs sawtooth twisted tapes to generate swirling flow and interrupted flowing disturbance in order to increase the level of heat transfer rate. The influences of the sawtooth twisted tape (S-TT) on enhanced heat transfer rate, friction factor and aerothermal performance index (API) behaviors are analyzed. The sawtooth twisted tapes (S-TTs) possessing constant pitch/twist ratio (y//W) of 3.0 and six sawtooth angles (α) of 20°, 30°, 40°, 50°, 60°, and 70° are assessed. Considering turbulent flow using air as the testing fluid, experiments were investigated at 6,000 <Re < 20,000 under boundary conditions of constant heat flux. According to the experimental findings, sawtooth twisted tape (S-TT) improves heat transfer rate and raises pressure loss with varying rates based on sawtooth angles (α). With the sawtooth twisted tape (S-TT) and 70° sawtooth angles, the optimum API of 1.33 is attained, while Nusselt number and friction factor are 32 and 0.135 at Re = 6,000. The recommended sawtooth twisted tape (S-TT) yields a highest Nusselt number of 78, which is 1.6 times greater than the typical twisted tape (TT) and 1.1 times greater than the plain tube. The combination of the TT and sawtooth patterns can be beneficial in terms of boosting heat transfer rate and API relating coupling of swirling flow and interrupted flowing disruption effects since the sawtooth twisted tape (S-TT) offers superior performance than the TT. Additionally, the heat exchanger tubes fitted with sawtooth twisted tape (S-TT) at sawtooth angles (α) of 20°, 30°, 40°, 50°, 60°, and 70° gain greater Nusselt number than the plain tube up to 158.3%, 162.2%, 166.1%, 171.7%, 179.7% and 186.2%, respectively.

Unsteady EMHD free convective second grade fluid flow past an exponentially accelerated vertical porous plate

This paper presents a detailed account of unsteady, incompressible, viscous, electrically conducting, unidirectional, free convective second grade fluid through an exponentially accelerated vertically infinite plate with both applied electric field and magnetic field being present. The equation of motion and energy manifested as nonlinear partial differential equation are represented as algebraic equations using implicit finite difference scheme and solved numerically by implementing the damped-Newton method. With the help of the momentum and energy equation, we defined the expressions for skin friction and Nusselt number. The cases n = 1(constant acceleration) and n = 0.5(variable acceleration) are also taken into consideration. The solution obtained is eventually simulated using MATLAB and the resulting graphs representing the influence of non-dimensional parameters on flow field and temperature field are discussed thoroughly. We have also validated the results obtained from the present methodology with the results obtained from already existing methodologies under some limited cases. It is interesting to note that when the plate is being cooled by free convection current, with increase in viscoelastic parameter the viscous forces are dominated by the elastic effects which results in accelerating the velocity flow profile. For comparatively smaller values of Ec the temperature distribution decreases with increasing Re as the suction propagation facilitates decrease in boundary layer thickness which consequently enhances heat transfer rate. The effect of Ec is to raise the temperature profile due to enhancement in viscous dissipation effects. Practically, the combined effects of the physical parameters are remarkably important in various engineering, medical and industrial applications.

Numerical study of nanofluid flow and heat transfer through a non-uniformly heated converging duct

Fundamental understanding on the enhancement of heat transfer rate and decreasing the maximum operating temperature is crucial for proper design of thermal systems. The present study discusses the influence of non-uniform heating on the forced convective flow of nanofluid through converging miniduct. Numerical simulations are performed using the Euler-Lagrangian two-phase flow model by finite volume method to find the effects of Reynolds number (Re), nanofluid volume fraction (φ), and amplitude (A) of sinusoidal heat flux on the heat transfer. The effect of various parameters on the magnitude of crest and trough of local Nusselt numbers is found to be a crucial factor in determining the total heat transfer. The results indicate a considerable increase in average Nusselt number (Nuav) with φ and Re. At Re = 100 the increments in Nuav are 3.4%, 6.7%, and 13.4% when φ is increased from 0 to 1, 3, and 5%, respectively, while it increases by 107%, 114%, and 116% for amplitudes of 0, 0.75, and 1, respectively, when Re is increased from 100 to 800. Increasing A reduces the heat transfer rate. The highest performance factor is found to be 0.945 at Re = 600, φ = 5% and A = 0.

Enhancement of heat transfer rate in shell & tube heat exchanger using CuO/Al2O3-water based nanofluids

It is well known that saving energy is one of the most important concerns of every industry and its utilization or the possible mode/devices for the transferring of it is an important parameter. For chemical industries, heat exchangers are backbone of them. Now a days Nano-fluids along with heat exchanger can be an option to enhance the heat transfer rate. So, Shell and Tube heat exchanger are frequently using by the several industries for heat removal/exchange purposes. These Nano-particles or Nano-fluids help to increase the heat transfer rate by providing large surface area. Using this quality of Nano-fluid along with Shell and Tube heat exchanger is main focus of present work. So, an attempt is made to perform the analysis for quantification of the effects of concentration of nanofluid on the various design parameter of Shell-Tube heat exchanger device i.e., heat transfer characteristic and fluid flow characteristic and also studied the effect of nanofluid concentration on thermal physical properties of Al2O3-water and CuO-water based nanofluid. Results are suggested better heat transfer capabilities of Nano-fluid over normal by doing comparable study for the nanofluid in terms of thermo-physical properties that is thermal conductivity, density and viscosity with base fluid in Shell-Tube heat exchanger. It can suggest easily that nanofluid gives excellent heat transfer coefficient than pure water (base fluid) so the result comes out in the form of reduced area for heat transfer with similar heat exchange capacity. Effect of Nano-particles concentration on the values of Reynolds number (Re) and Prandtl number (Pr) was also observed and it is found that Re and Pr is decreases with increasing value of particle concentration in the base fluid.