High Heat Transfer Rates Research Articles

Eminence of ferrite particle shapes in stratified nanofluids concerning the melting phenomenon: Lie group and spectral analysis

The current study is being done to determine how the shape factors of NiZnFe2O4 (nickel zinc ferrite) nanosolid particles affect the free convective flow of engine oil (C8H18) based stratified nanofluid over a melting stretchable surface, which play a part in establishing flow patterns and thermal features. NiZn ferrite nanoparticles of needle, platelet, and brick shapes are used to assess the impact of shape factors in the presence of melting phenomena, heat generation/absorption, and viscous dissipation. Optimal solutions are obtained by the spectral local linearization method via Lie group analysis, with an emphasis on residual errors. According to the evaluation, this type of nanofluid is found to have a lower friction factor, entropy, and Bejan number when compared to conventional fluids. In the presence of viscous dissipation, brick-shaped particles are found to have a higher heat transport rate, whereas needle-shaped particles minimize entropy by 58.66%. Suspended ferrite nanoparticles with a melting effect reduce the entropy up to 62.4% and stratified nanofluid with a brick shape has a higher heat transfer rate as compared to ordinary nanofluid. It is also observed that heat absorption produces less heat transport compared to heat generation. This research is found to be useful in many sectors, such as tumor treatments, electromagnetic interfaces (EMI), microwave applications, bone plate surgeries, and aerodynamic extrusion processes.

Analysis of chemically reactive squeezing flow of silica and titania hybrid nanoparticles in water-based medium between two parallel plates with higher order slip

Considering the significance of hybrid nanofluid over convectional fluid in terms of high rate of heat transfer, nanoscience and nanotechnology has been enhanced by dispersing nanoparticles in the base fluid to obtain new material with series of properties and applications. In this study, the analysis of chemically reactive squeezing flow conveying silica and titanium dioxide nanoparticles in water-based medium across two parallel plates with higher order velocity slip is carried out employing three different chemical kinetics for exothermic/endothermic reactions. The system of partial differential equations resulting from the fluid model assumed the ordinary differential form in alliance with appropriate similarity variables. The modified ordinary differential equations is simulated numerically in MATLAB software package using fourth order Runge–Kutta integration scheme in line with shooting techniques. The tested validity for limited case conform to preceding reports in the literature. The outcomes from the scrutiny uncovered in tables and graphs revealed that the velocity and temperature distributions of the hybrid nanofluid decrease steadily as first order slip factor varies from 0.2 to 1.0 but increase with second order slip factor at all levels of chemical kinetics. Moreover, for exothermic reaction, the rate of heat transfer decreases at the lower plate by −221.923% with increasing value of activation energy parameter when m=−2,0,0.5 but converse is the case in endothermic reaction as the rate of heat transfer increases by 106.382%.

Analysis of effects of moving wall direction in a one sided semi-circular porous cavity on mixed magneto-bioconvection in the presence of hybrid nanofluid with oxytactic bacteria

A computational analysis on the effects of direction of wall movement in a one sided semi-circular porous cavity on mixed magneto-bioconvection of hybrid nanofluid in the presence of oxytactic bacteria has been performed. The working fluid is the hybrid nanofluid. The enclosure is cooled from semi-circle side and heated from moving lid under the effect of uniform magnetic field in the horizontal direction. The numerical solution of governing equations is obtained by using the higher order finite element method (FEM). The reliability of designed solver is tested through the experimental and numerical data available in the literature. Two cases of the boundary conditions are considered related to the tendency of right vertical lid of the cavity. Other parameters are Richardson number, Darcy number, Hartmann number, Peclet number and porosity. It is found that moving lid direction is the most effective parameter for the flow field, isotherms, oxygen and microorganism distributions. Moreover, higher heat transfer rate is obtained in Case-I for different values of Darcy number. Around 10% increment is occurred on mass transfer with different Pe number in case of downward moving lid due to increment of convection mode of heat transfer inside the cavity.

Flow-Induced vibration and heat transfer enhancement in tandem cylinders: Effects of cylinder shape, corner radii, and spacing ratio

In this work, flow-induced vibration (FIV) of two heated cylinders in the tandem arrangement is numerically investigated at a Reynolds number of 150. The effect of the spacing ratio (L/D) and the corner radius (r*) is investigated by changing L/D from 2 to 4 and r* from 0 to 1, where 0 corresponds to the square cross-section and 1 to the circular cross-section. The cylinders are oriented to maintain a constant angle of attack of 45° and are allowed to vibrate in the transverse direction only. The one degree of freedom (1-DOF) motion of the cylinders is studied with varying reduced velocities (Ur = 2–10). The mass ratio (m*) of the cylinder is taken as 10, while the damping is neglected to obtain the maximum vibrational amplitude. The findings suggest that the maximum vibrational amplitude (A/D) occurs for square-shaped cylinders, while the least occurs for circular shapes. It was found that the lock-in for a single cylinder occurred at Ur = 6, irrespective of the corner radius. For tandem cylinders with L/D = 2, the lock-in region occurred at Ur = 6–8 for circular cylinders and at Ur = 8–10 for square cylinders. However, lock-in occurred at Ur = 6–8 for both square and circular tandem cylinders at L/D = 4. The vorticity patterns observed in this study include 2S, C(2S), 2P, and P + S. The flow topology, the response behavior of the cylinders, and local (Nul) and average (Nuavg) Nusselt numbers were affected by various parameters, including the corner radius, spacing ratio, reduced velocity, and the average drag coefficient. For the single cylinder, changing the shape from square to circular resulted in a 40.4% and 4.71% decrease in the maximum A/D and Nuavg, respectively. Considering the twin square cylinders in tandem with L/D = 2, the upstream and downstream cylinders experienced 3.86% and 58.0% higher A/D as compared to the single cylinder. However, increasing L/D to 4 from 2 decreased the maximum A/D for upstream and downstream square cylinders by 5.41% and 3.07%, respectively. Compared to the square cylinders at L/D = 4, the circular cylinders resulted in a 28.6% and 35.1% decrease in maximum A/D for upstream and downstream cylinders, respectively, whereas at the same time experienced 33.1% and 32.0% higher Nuavg, respectively. In conclusion, the circular cylinders in tandem arrangement give higher rates of heat transfer while experiencing lower vibration as compared to square and filleted cylinders.

Investigating the thermal performance of nano-encapsulated phase change materials-water nanofluid in the presence of a heat source as applied in electronic devices

BackgroundGlobal warming and the human need for power resources in the last decades have highlighted the concerns related to energy saving for long-term applications. Thermal energy-saving systems are an important technique to overcome this issue. MethodsIn the present study, we aim to simulate the performance of a thermal energy-storing system with Nano-Encapsulated Phase Change Materials (NEPCMs) by Computational Fluid Dynamics (CFD). Free convection heat transfer through a square enclosure is numerically simulated, and a hot block is located at pisitions of the enclosure. The simulation is done with the FVM method and SIMPLE algorithm. The analyzed parameters are different Ra numbers (5 × 103 − 105), non-dimensional melting temperatures (0.1 ≤ θf ≤ 0.9), and NEPCM melting intensities (0.01 ≤ χ ≤ 0.03). Significant FindingsT The results revealed that the θf = 0.3 is corresponding to the optimum heat transfer rate, and it is independent of the Ra number. In the case with the highest heat transfer rate, adding NEPCMs to the based fluid caused the heat transfer to improve by 12.5%. Furthermore, in this θf number, uniform heat transfers through the cold walls of the enclosure. A low number of χ also revealed less Nusselt number. Increasing AR in high Ra number improves Nusselt number by 5%.

Ferrofluid droplet impingement cooling of modified surfaces under the influence of a magnetic field

This paper documents the spreading characteristics and heat transfer of a single ferrofluid droplet impinging onto dry solid surfaces with and without a magnetic field. Three surfaces were investigated: a pure silicon substrate, a silicon substrate with a thin titanium film, and a superhydrophobic coating. Fluid dynamics and cooling results of a ferrofluid droplet were compared to that of pure water and water-surfactant droplets for the same Weber number (We = 61) and initial surface temperature (T0 = 95∘C). Our results show that the magnetic field (magnetic Bond number Bom = 2186) increased the droplet spreading diameter up to 12% and suppressed droplet rebound, thus improving the cooling performance of a ferrofluid droplet. The highest heat transfer rates were measured for the pure silicon substrate under a magnetic field with an average value of 14 W. The lowest cooling performance was observed for the superhydrophobic surface without a magnetic field with a peak value of 0.82 W. However, using the magnetic field, the superhydrophobic surface achieved 263% higher heat transfer rate than the non-magnetic case because of the suppression of droplet rebound. Moreover, the surface did not foul from ferrofluid deposition, an advantage for spray cooling applications when using any nanofluid.

Thermal performance of nanofluids in a sinusoidal channel with embedded porous region

Inclusion of porous structures in micro-channels enhances heat transfer rates in energy harvesting devices, which signifies as the working fluid becomes a nanofluid. The present study compares the thermal performance of CuO-water, TiO2-water and graphene-water nanofluids in a sinusoidal channel with a porous insert. The flow and heat transfer characteristics are simulated and the effects of volumetric fraction of nanofluids, Reynolds number ( Re), porous insert width, and its permeability on the flow and temperature fields are examined. The findings reveal that CuO-water nanofluid results in higher heat transfer rates than those of other nanofluids considered. Graphene-water nanofluid gives rise to lower performance than that of CuO-water nanofluid in terms of convection heat transfer despite the fact that graphene has higher thermal conductivity than CuO. In this case, a decrease in Nusselt number of as much as 6.34% is observed for CuO-water nanofluid among all the cases considered for the Reynolds number of 100. Increasing the permeability of the porous insert slightly enhances (∼0.24%) the average Nusselt number. The porous insert with a small width in the channel improves the heat transfer rates (2.25% increase in Nusselt number), i.e. the average Nusselt number reduces as the porous insert width increases.

Heat transfer analysis of water-ethylene glycol (50:50) based nanofluid over a cone with the influences of magnetic field and uniform heat generation/absorption

Aim:The novelty of the problem is to examine the heat transfer analysis of H2O–C2H6O2 (50:50) mixture based Al2O3 and Fe3O4 over a heated and spinning down-pointing vertical cone with the effect of heat generation or absorption in the presence of magnetic field. Findings:Results are demonstrated in terms of graphs to examine the influence of various physical parameters that come across such as Magnetic parameter M, Spin parameter ϵ, Nanoparticle volume fraction ϕ, Heat generation or absorption parameter Δ, velocity slip parameter Γ1 and thermal slip parameter Γ2 on dimensionless velocity profile F′(y), G(y) and temperature profile H(y). The effect of M, ϵ, ϕ, Δ,Γ1,Γ2on skin friction and local Nusselt number are examined in tabulation form. Significant outcomes:It is pointed out that enhancement in Magnetic parameter and thermal slip parameter leads to declination of the velocity profile. Influence of Heat generation or absorption parameter magnifies the thermal characteristic of the flow. Moreover, the numerical statistics was triggered and catalogued to analogize the results of existing outcomes with those of previous literature for some special cases and established excellent agreement. Fe3O4 possess 0.78% and 0.92% of high surface drag force and heat transfer rate respectively than Al2O3 with respect to heat generation or absorption parameter. Approach:The system of partial differential equations is transformed into set of nonlinear ordinary differential equations. Solutions for the system of nonlinear Ordinary differential equation are obtained by Numerical method. The numerical scheme is developed based on fourth order Runge Kutta scheme along with shooting techniques. Practical implications:In this current growing scenario, engineers and scientists are making an endeavour to gratify the global needs. Nanofluids are considered as inevitable one for achieving industrial and global needs. The investigation of heat transfer over rotating cone with the effect of magnetic field is of considerable interest due to its presence in industrial and technological applications. Especially in the design of turbines and turbo equipment’s and in understanding the path of flight of rotating wheels.

A preliminary evaluation of a molten metal helical coil solar receiver for heating pressurised air

Heating pressurised air to high temperatures with concentrated solar thermal energy is technically challenging mainly due to the heat transfer properties of the pressurised air and the intermittent nature of the solar energy. To address this challenge, a novel molten metal helical coil (M2HC) solar receiver for heating pressurised air or other gases is presented. This system comprises a cavity and a helical coil, both of which are submerged in a molten bath, e.g. a molten metal, which serves as a heat transfer fluid (HTF) between the submerged cavity and the helical coil. The absorbed concentrated solar thermal heat in the cavity is transferred to the molten bath via convection. Pressurised air is heated within the submerged helical coil, without any contact with the molten bath. The molten bath is agitated via the bubbles of an injected inert gas enabling a high rate of heat transfer between the submerged cavity and the helical coil. The purpose of this paper is to introduce the concept of the M2HC solar receiver and provide a preliminary evaluation to identify its potential benefits and challenges. In doing so, a one-dimensional model of the proposed M2HC solar receiver is developed, predicting the system performance considering gallium (Ga) and argon (Ar) as the HTF and dispersed inert gas into the molten Ga bath, respectively. The heat transfer model of the cavity, gallium bath, Ar bubbles and the helical coil is implemented with the consideration of convective and radiative losses in the cavity. The mixture of Ga and Ar bubbles is considered as one phase and modelled with a one-dimensional drift-flux correlations. A 1-D model has been also considered for the heating of the pressurised air within the coil. The reliability of the model was assessed through comparison with the available relevant experimental data in literature. The model is then employed to perform a sensitivity analysis to the variations in the temperature of the outlet air, length of helical coil and the ratio of the mass flow rates of the injected Ar into the molten bath and the inlet air. The predicted absorption and exergy efficiencies of the proposed M2HC solar receiver are ∼64% and 73%, respectively, at an output temperature of 900 °C and 5% Ar to air mass flow ratio. It has been also found that the variation of Ar to air mass ratio from 0% to 25% decreases the fraction of the absorbed energy that goes to air from 100% to ∼90%. Nonetheless, it increases the convective heat transfer between the molten bath, submerged cavity and the helical coil.

Mathematical model of ciliary flow and entropy for carreau nanofluid with electroosmosis and radiations in porous medium: A numerical work

Functionalizing the nanoparticles like titanium oxide (TiO2), silica (SiO2), and aluminum oxide (AI2O3) with therapeutic agents like anticancer drugs, antibiotics, or gene therapy agents allow targeted delivery and controlled release. We investigate how thermal radiation in Carreau constitutive model base liquid (blood) affects the flow of a ternary-hybrid nanofluid made of the said particles. Connecting the conduit to battery terminals outside accounts for entropy and electroosmosis. After translating the observation model into a wave frame, lubrication theory's physical limits are used to better explain the wave phenomena. The study uses Mathematica NDSolve to simulate boundary value issues using shooting. The Carreau fluid has a 17–18% higher heat transfer rate than the Williamson fluid, according to the literature. Elastic electroosmotic pumping, cilia motion, and magnetic fields improve fluid transport. Ternary hybrid nanofluids improve transport mechanisms and thermal conductivity. Elastic electroosmotic pumping and cilia motion produce the least entropy and increase thermodynamic efficiency.

Effect of temperature-dependent internal heat generation over exponential and dovetail convective-radiative porous fin wetted in hybrid nanofluid

The main objective of this research is to conduct a comparative study of the thermal variations in a dovetail and exponential fin, considering fully wet conditions, ternary nanofluid, and internal heat generation in the form of both linear and non-linear functions. Additionally, the influence of a magnetic field as a driving force for heat transfer systems is taken into account. The mathematical modelling involves the use of dimensionless transformations to convert the energy equation into an ordinary differential equation, which is then analytically solved using the Differential transformation method (DTM). The study focuses on exploring the effects of significant thermal parameters such as radiation conduction, wet factor, heat generation, and ambient temperature on the temperature profile. Graphical analysis is employed to investigate the thermal performance. The main findings indicate that ternary nanoliquid exhibits a higher thermal response compared to nano and hybrid nanoliquid. Moreover, the nonlinear forms of internal heat generation and ternary nanofluids demonstrate a higher rate of heat transfer.

Compound Heat Transfer Enhancement in Dimpled and Sinusoidal Metal Solar Wall Ducts Fitted with Wired Inserts

An improved Metal Solar Wall (MSW) with integrated thermal energy storage is presented in this research. The proposed MSW makes use of two, combined, enhanced heat transfer methods. One of the methods is characterized by filling the tested ducts with a commercially available copper Wired Inserts (WI), while the other one uses dimpled or sinusoidal shaped duct walls instead of plane walls. Ducts having square or semi-circular cross sectional areas are tested in this work.A developed numerical model for simulating the transported thermal energy in MSW is solved by finite difference method. The model is described by system of three governing energy equations. An experimental test rig has been built and six new duct configurations have been fabricated and tested. Air is passed through the six ducts with Reynolds numbers from 1825 to 7300.Six, new, correlations for Nusselt number and friction factor are developed to assess the benefits that are gained from using the WI and the dimpled and sine-wave duct walls. It is found that higher heat transfer rates are achieved using the Dimpled, semi–circular duct with Wired Inserts (DCWI). Also, it is found that Nusselt number and the pressure drop in the DCWI are respectively(44.2% -100%) and (101.27% - 172.8%) greater than those of the flat duct with WI. The improvement in Nusselt number for flat duct with WI is found to be (1.4 – 2) times the values for flat duct with no WI. The results demonstrated that DCWI provides enhancements efficiency value that is higher than those obtained from other types of ducts. The developed MSW ducts have added to local knowledge a better understanding of the compound heat transfer enhancement.

Numerical modelling of the evaporative cooling effect on solid walls in steam sterilisers

Steam sterilisation is based on high heat transfer rates which occur during the condensation of steam on medical devices or the steriliser walls themselves. To ensure these high heat transfer rates, non-condensable gases (NCGs) such as air must be removed from the chamber. One method is to extract the NCGs by using vacuum pumps. Due to the reduction in pressure, the saturation temperature drops as well, causing water droplets to evaporate; thus, the walls and loads cool down. This mechanism was investigated using a three-phase CFD model. A highly time-efficient heat transfer model for the evaporation process was developed as a result of this investigation. Evaporative cooling effects on the steriliser walls could be achieved by using a mass source term which varied in terms of time and space. Our results indicate that the model can be used to predict the temperatures of the fluid as well as the solids in a numerically inexpensive manner. In addition, this model allows the user to predict whether surfaces can be completely dried, an aspect which is crucial for ensuring the quality of a sterilisation process. The model created allows researches to simulate the entire sterilisation cycle, addressing a previously existing knowledge gap. Furthermore, the presented methods are also suitable for use in other industrial applications where condensation and evaporation effects on solids need to be effectively and inexpensively determined.

A study of Cu/Ag nanoparticle shape-augmented heat transfer in Darcy–Brinkman–Forchheimer flow in a square cavity

ABSTRACT The present work is an analysis of heat transfer flow phenomena due to the natural convection process in a square enclosure filled with a porous medium containing Cu/Ag water-based nanofluid. Multiphysics faceted Darcy–Brinkman–Forchheimer model is used to govern the flow in a porous medium. Different shapes (sphere, blades, bricks, cylinders, and platelets) of the nanoparticles are considered to examine their influence on heat transfer. The model has been solved by the finite element method. The numerical results have been validated against results from the literature. Computed results have been presented graphically by streamlines, isotherms, local and cumulative Nusselt number plots for various physical parameters, Rayleigh number (Ra), inverse Darcy number (), Brinkman effect (Λ), the porosity of the porous medium and solid volume fraction of the nanoparticles. The study pioneers the investigation on the significance of the combined influence of effective viscosity and nanofluid viscosity through the Brinkman effect and reports its importance on nanoparticle shape-based heat transfer augmentation. Cost-effective Cu nanoparticles are shown to augment the heat transfer as achieved by the conventionally preferred Ag nanoparticles. While spherical nanoparticles outperform other shapes in heat transfer augmentation for Brinkman effect , the blade-shaped nanoparticles dominate when Brinkman effect . Higher heat transfer rates are noticed for lesser values of the Brinkman effect, high porosity, the maximum volume fraction of the nanoparticles, high Rayleigh number, and low permeability with spherical-shaped nanoparticles than blade-shaped nanoparticles.

A numerical study on thin film flow and heat transfer enhancement for copper nanoparticles dispersed in ethylene glycol

Abstract The current study examines thin film flow and heat transfer phenomena with some additional effects such as magnetohydrodynamic, viscous dissipation, and slip condition over unsteady radially stretching surfaces for various shapes of copper ( Cu ) \left({\rm{Cu}}) nanoparticles dispersed in ethylene glycol ( EG ) \left({\rm{EG}}) . The effective thermal conductivity of a nanofluid made of Cu nanometer-sized particles distributed in EG {\rm{EG}} is significantly higher than that of pure EG. Partial differential equations are transformed into ordinary differential equations using the proper transformations. An effective convergent technique (i.e., BVP4C) is used to compute the solutions of nonlinear systems. MATLAB software is used to perform the calculations. The effect of numerous emerging physical characteristics on temperature and velocity, such as unsteadiness parameter ( S ) \hspace{ 1em}\left(S) , slip parameter ( K ) \left(K) , Hartmann number ( M ) \left(M) , solid volume fraction ( ϕ ) (\phi ) , and Eckert number ( EC ) \left({\rm{EC}}) is investigated and illustrated graphically. The physical quantities, such as the skin friction coefficient and the Nusselt number, are calculated, described, and displayed in tabular form. It is observed that blade-shaped Cu nanoparticles had the lowest surface drag, highest heat transfer rate, and minimum film thickness compared to the brick and cylinder-shaped nanoparticles. According to our detailed investigation blade-shaped Cu {\rm{Cu}} nanoparticle is the most suited solution for manufacturing unsteady radially stretching modules.

Enhanced Exhaust after-Treatment Warmup in a Heavy-Duty Diesel Engine System via Miller Cycle and Delayed Exhaust Valve Opening

The exhaust after-treatment (EAT) threshold temperature is a significant concern for highway vehicles to meet the strict emission norms. Particularly at cold engine start and low loads, EAT needs to be improved above 250 °C to reduce the tailpipe emission rates. Conventional strategies such as electrical heating, exhaust throttling, or late fuel injection mostly need a high fuel penalty for fast EAT warmup. The objective of this work is to demonstrate using a numerical model that a combination of the Miller cycle and delayed exhaust valve opening (DEVO) can improve the tradeoff between EAT warmup and fuel consumption penalty. A relatively low-load working condition (1200 RPM speed and 2.5 bar BMEP) is maintained in the diesel engine model. The Miller cycle via retarded intake valve closure (RIVC) is noticeably effective in increasing exhaust temperature (as high as 55 °C). However, it also dramatically reduces the exhaust flow rate (over 30%) and, thus, is ineffective for rapid EAT warmup. DEVO has the potential to enhance EAT warmup via increased exhaust temperature and increased exhaust flow rate. However, it considerably decreases the brake thermal efficiency (BTE)—by up to 5%—due to high pumping loss in the system. The RIVC + DEVO combined technique can elevate the exhaust temperature above 250 °C with improved fuel consumption—up to 10%—compared to DEVO alone as it requires a relatively lower rise in pumping loss. The combined method is also superior to RIVC alone. Unlike RIVC alone, the RIVC + DEVO combined mode does not need the extreme use of RIVC to increase engine-out temperature above 250 °C and, thus, provides relatively higher heat transfer rates (up to 103%) to the EAT system through a higher exhaust flow rate. The RIVC + DEVO combined method can be technically more difficult to implement compared to other methods. However, it has the potential to maintain accelerated EAT warmup with improved BTE and, thus, can keep emission rates at low levels during cold start and low loads.

Entropy Generation-Based Analysis of Laminar Magneto-Convection in Different Cross-Section Channel Filled with Ferrofluid and Subjected to Partial and Full Magnetic Fields

Heat transfer and entropy generation of laminar flow of a ferrofluid in different cross-section channel subjected to partial and full magnetic field are investigated in this study. A constant heat flux condition was applied on the external surface. The conservation equations (mass, momentum, and energy) are solved numerically via the finite volume method with a second-order precision. The effects of fully or partially applying a magnetic field with different directions and intensities on thermodynamic features, heat transfer, and entropy generation have been investigated. Analyses were carried out in four different cross-section channels, namely triangular, rectangular, circular, and elliptical. Results indicate that the circular cross-section channel provides higher heat transfer rates and lower entropy generation than non-circular cross-section channels.

Unsteady hybrid nanofluid (Cu-UO2/blood) with chemical reaction and non-linear thermal radiation through convective boundaries: An application to bio-medicine

This study is focused on modeling and simulations of hybrid nanofluid flow. Uranium dioxide UO2 nanoparticles are hybrid with copper Cu, copper oxide CuO and aluminum oxide Al2O3 while considering blood as a base fluid. The blood flow is initially modeled considering magnetic effect, non-linear thermal radiation and chemical reactions along with convective boundaries. Then for finding solution of the obtained highly nonlinear coupled system we propose a methodology in which q-homotopy analysis method is hybrid with Galerkin and least square Optimizers. Residual errors are also computed in this study to confirm the validity of results. Analysis reveals that rate of heat transfer in arteries increases up to 13.52 Percent with an increase in volume fraction of Cu while keeping volume fraction of UO2 fixed to 1% in a base fluid (blood). This observation is in excellent agreement with experimental result. Furthermore, comparative graphical study of Cu,CuO and Al2O3 for increasing volume fraction is also performed keeping UO2 volume fraction fixed. Investigation indicates that Cu has the highest rate of heat transfer in blood when compared with CuO and Al2O3. It is also observed that thermal radiation increases the heat transfer rate in the current study. Furthermore, chemical reaction decreases rate of mass transfer in hybrid blood nanoflow. This study will help medical practitioners to minimize the adverse effects of UO2 by introducing hybrid nano particles in blood based fluids.

Characterisation of Heat Transfer within 3D Printed TPMS Heat Exchangers

Recent advances in additive manufacturing technology have enabled rapid and inexpensive prototyping of designs to explore shape effects across a range of engineering applications. In this work, we measure the heat transfer performance of a range of heat exchangers based on triply periodic minimal surfaces (TPMS). The results showed that the sheet gyroid TPMS design produced a high rate of heat transfer and moderate pressure drop. The sheet gyroid TPMS design was further investigated to determine its performance over porosities ranging from 40% to 85%, hydraulic diameters from 2 to 10 mm, and wall thicknesses from 0.4 to 2.6 mm. Our results show that all correctly parameterised TPMS of the same type have results positioned on the same Nusselt versus Reynolds number curves. A correlation was developed for the purpose of designing micro-channel heat exchangers over the operating range 100<ReH<2500. At equal pumping power, the Nusselt number was improved by 13% through the use of the gyroid TPMS, as compared to a straight tube heat exchanger.

Internal Flow Heat Transfer Rate for Parallel Heat Exchanger Pipes One Pass of Rice Husk to Air

The research was conducted to analyze the heat transfer rate of heat exchangers from black steel pipes with rice husk as an energy source. This can be used as a recommendation to replace solar energy in the post-harvest drying process, especially for small farmers in rural areas. Research by converting rice husk biomass into heat energy using a heat exchanger of black steel pipes arranged parallel to one air fluid flow. Heat exchanger pipes are placed inside the furnace with dimensions of 50 cm x 50 cm x 80 cm. Forced convection is applied through a fan placed in the drying chamber with a constant speed of 2 m/s. It was found that the ambient temperature increased by an average of 11.70% without adding rice husk mass during the test. The average ambient temperature (Ti) is 305.10 K and ranges from 300.60 to 307.40 K which can be increased to (To) 340.80 K with a range of 317.25 to 366.30 K. This temperature is the out the heat exchanger pipes that can be used for the drying process. The value of the heat transfer rate reached an average of 39.19 W with a range of 18.62-63.19 W. The pattern of distribution of heat transfer rates follows the trend of temperature distribution. It was found that when rice husk turns into charcoal it causes a high heat transfer rate. High heat transfer rates are needed in the drying process of a product so that the required time is shorter and optimal. In addition, rice husk biomass can be used as alternative energy because it is easy to obtain, especially in agricultural areas that grow rice.