Nanofluid Mixture Research Articles

Numerical investigation of conjugate heat transfer in a microchannel with a hydrophobic surface utilizing nanofluids under a magnetic field

Conjugate heat transfer in a microchannel with a slip boundary condition imposed on the channel's walls by a uniform magnetic field is studied. The working fluid consists of a Water/Ag mixture nanofluid. A preconditioned lattice Boltzmann method (LBM), formed by combining the incompressible LBM with the regular LBM, is applied to the velocity field and temperature field, respectively. The microchannel's upper wall is thermally isolated when a constant heat flux is imposed on the basin of the microchannel. The simulations are carried out under a variety of different conditions, e.g., various Reynold numbers, Re = 50 and 150, nanoparticle concentrations (φ = 0, 3%), slip coefficients (0 ≤ B ≤ 0.03), and Hartmann numbers (0 ≤ Ha ≤ 30). Surface hydrophobicity results in a reduction of surface friction of up to 46% at B = 0.03 and Ha = 30. The surface friction reductions at Ha = 0, 10, and 20 are 15%, 27%, and 38%, respectively. These results indicate that as the surface slip increases, the drag resisting the fluid dynamics decreases. Moreover, adding the nanoparticles to the base flow can improve the heat transfer by 50%. Besides, using the magnetic field increase the shear stress and, consequently, the drag force dramatically (up 340%). On the other hand, the magnetic field enhances the heat transfer by improving the fluid velocity near the wall, while its effect on the Nu number improvement is not more than 20%. As a result, the magnetic power should be controlled to achieve the best heat transfer performance with the lowest pumping energy consumption.

Thermal performance of self-rewetting gold nanofluids: Application to two-phase heat transfer devices

This paper presents an experimental analysis of the phenomenon of phase change inside a porous medium using different types of working fluids. It represents the impact of these fluids on improving the characteristics of heat and mass transfer in a Capillary Heat Pipe (CHP). In this study, gold nanoparticles (5 nm in diameter with 1% Cv), a self-rewetting binary solution (butanol with 3% Cv), and a mixture of self-rewetting butanol and gold nanofluid are considered to be the operating fluids within the CHP. The experiments are carried out after designing and developing the capillary heat pipe section. It consists of a water tank with a pump, an evaporator attached to a copper porous medium on which thermocouples and power supplies are placed. The experimental results showed the positive influence of gold nanoparticles on the thermal system's performance by reducing the thermal resistance by 13% compared to pure water as the base working fluid. In addition, a self-rewetting butanol solution showed improvement in the performance of the capillary evaporator by decreasing its casing temperature. While a mixture of self-rewetting butanol solution (3 % Cv) and gold nanofluid (1% Cv) exhibited the best performance of heat and mass transfer performance by reducing the thermal resistance of the system by approximately 22 %. To explain the mechanism for improving heat transfer, the phase change phenomenon was visualized by an infrared camera for the three working fluids. It is shown that as the applied power increases, the shape of the vapor pocket developed in the wick also increases, for pure water, until it reaches a stable form. Whereas, with respect to nanofluid and self-rewetting fluid, the shape of the vapor pockets was smaller than that of pure water allowing more efficient mass and heat transfer. The thermophysical properties of these fluids such as thermal conductivity, stability, surface tension, Marangoni, wettability, and capillary forces were presented to ensure and validate the decrease in the vapor pocket as well as the enhancement of the CHP thermal system.

Experimental Investigation on the Optical and Stability of Aqueous Ethylene Glycol/Mxene as a Promising Nanofluid for Solar Energy Harvesting

In this research work, emerged nanomaterial (MXene) and Ethylene Glycol (EG) as base fluid is used to formulate a homogenous mixture of nanofluid with promising optical properties. Amphiphilic structure of ethylene glycol allows the dispersion of water and MXene nanoflakes appropriately. The studied nanofluids are prepared with a mixture of 70 % of EG and 30% of deionized water. The prepared aqueous EG is mixed with Ti3C2 nanoflakes with three different loading concentrations of 0.02, 0.05, and 0.1 wt.%. The Fourier Transform Infrared spectrum (FTIR) of the aqueous EG/MXene nanofluids is measured using a Perkin Elmer Spectrum Two-Universal ATR. Particle analyzer is used to measure the stability of the prepared nanofluids. The experimentally achieved data represents the highest stability with mean zeta potential value of -92.6 mV for aqueous EG/MXene with a loading concentration of 0.02 wt.%. Optical absorbance measurements are performed using Ultraviolet-visible (UV-Vis) spectroscopy. Perkin Elmer Lambda 750 is used to acquire spectra. The result of the observation indicates that the solution of nanofluid with a loading concentration of 0.1 wt. % of Ti3C2 exhibits the highest peak magnitude of light absorbance among the rest of the three samples. This is because of the more mass concentration value of that nanofluid solution, which is proportional to light absorption. Due to the hydrophilic nature of the utilized nanomaterial and base fluid, there is an excellent probability for them to form a potential homogenous mixture of nanofluid, which might accomplish high optical performance in terms of applying at the solar system.

Experimental Determination of Water, Water/Ethylene Glycol and TiO2-SiO2 Nanofluids mixture with Water/Ethylene Glycol to Three Square Multilayer Absorber Collector on Solar Water Heating System: A Comparative Investigation

This paper investigates three square multilayer absorber solar collector in Solar Water Heating System (SWHS) experimentally. The main aim was to study the output temperature of the solar absorber collector based on distilled water (DW), water/ethylene glycol (W/EG) and TiO2-SiO2 nanofluids. An experimental apparatus for testing absorber solar collector was designed and built at Universiti Malaysia Kelantan (Jeli Campus). By using the two-step method, TiO2-SiO2 nanofluids with ratio 30:70 and volume concentration at 1.0%. For W/EG the ratio is 60:40. The effect working fluid was studied experimentally on the output temperature of three square multilayer absorber solar collector in SWHS with Angle of Sunlight (AoS) at 45°, volume flow rate at 3 litres per minute (LPM) and varies Intensity of Light (IoL) at 300, 500 and 700 W/m2. The output temperature is determined through the experimental results by using this apparatus. The result reveals that the output temperature of the solar absorber collector is TiO2- SiO2 nanofluids with 1.0% of volume concentration as a best working fluid at each intensity of light.

Nodal/Saddle Stagnation Point Slip Flow of an Aqueous Convectional Magnesium Oxide–Gold Hybrid Nanofluid with Viscous Dissipation

In this analysis, convective heat transfer characteristics of a hybrid nanofluid mixture containing magnesium oxide (MgO) and gold (Au) nanoparticles are numerically studied. The impact of slip effects on nodal/saddle stagnation point boundary layer flow with viscous dissipation effect is mathematically modeled. The behavior of nanofluids is studied by employing Tiwari–Das nanofluid model. Pure water is the base fluid in this analysis. The governing partial differential equations with many independent variables are reduced to ordinary differential equations with one independent variable and then numerically solved by the Runge–Kutta–Fehlberg method with the desired accuracy. The outputs showed that MgO–Au/water hybrid nanofluid sharply raises the base fluid's thermal behavior. Results reveal that in the nodal and saddle point areas, the impact of higher slip effects significantly increases the local heat transfer rate.

Nanofluids for flat plate solar collectors: Fundamentals and applications

Among different sources of renewable energy, solar energy is widely used almost exclusively because of its ease of availability and its lowest environmental effects. The most commonly used solar collectors are the flat plate solar collectors (FPSCs). However, they are less powerful (low capacity to convert solar energy to thermal energy). It is possible to classify the use of nanofluid on FPSCs as an efficient way to boost the solar collectors’ performance. In this paper, studies on metal oxides , non-metal oxides, solid metals, semiconductor nanomaterials , carbon nanostructured, and nanocomposite nanofluids used as heat transfer fluids (HTFs) within FPSCs are examined sequentially. Various parameters affecting the FPSC’s thermal efficiency , such as nanoparticle type, nanoparticle concentration, nanoparticle size/shape, solar radiance, and mass flow rate , are extensively analyzed. Studies have also compared various types of single nanofluids or mixture nanofluids with FPSCs under the same operating conditions. It is found that the use of carbon-based nanofluids compared to metal oxides of nanofluids under the same conditions has resulted in a major improvement in the energetic and exergetic performance of the FPSC. Furthermore, the reviewed research revealed that there is a tremendous opportunity to achieve the commercial application of carbon-based nanofluid FPSC. The obstacles and opportunities for further study are also highlighted.

Investigation of the novelty of latent functionally thermal fluids as alternative to nanofluids in natural convective flows

This paper presents a detailed comparison between the latent functionally thermal fluids (LFTFs) and nanofluids in terms of heat transfer enhancement. The problem used to carry the comparison is natural convection in a differentially heated cavity where LFTFs and nanofluids are considered the working fluids. The nanofluid mixture consists of Al2O3 nanoparticles and water, whereas the LFTF mixture consists of a suspension of nanoencapsulated phase change material (NEPCMs) in water. The thermophysical properties of the LFTFs are derived from available experimental data in literature. The NEPCMs consist of n-nonadecane as PCM and poly(styrene-co-methacrylic acid) as shell material for the encapsulation. Finite volume method is used to solve the governing equations of the LFTFs and the nanofluid. The computations covered a wide range of Rayleigh number, 104 ≤ Ra ≤ 107, and nanoparticle volume fraction ranging between 0 and 1.69%. It was found that the LFTFs give substantial heat transfer enhancement compared to nanofluids, where the maximum heat transfer enhancement of 13% was observed over nanofluids. Though the thermal conductivity of LFTFs was 15 times smaller than that of the base fluid, a significant enhancement in thermal conductivity was observed. This enhancement was attributed to the high latent heat of fusion of the LFTFs which increased the energy transport within the cavity and accordingly the thermal conductivity of the LFTFs.

Toward mechanistic understanding of wettability alteration in calcite and dolomite rocks: The effects of resin, asphaltene, anionic surfactant, and hydrophilic nano particles

Wettability as related to an oil reservoir represents a fluid ‘s propensity to adsorb or stick to a solid surface in the presence of another immiscible liquid. Therefore, wettability is a key aspect in assessing the degree of recovery of oil from the reservoir. This paper aims at the investigation of the effect of resin, asphaltene, anionic surfactant, and hydrophilic nanoparticles on the wettability alteration of calcite and dolomite rocks. In order to provide a better insight into wettability alteration, several laboratory tests were carried out including energy dispersive X-ray (EDX) analysis, Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM). The contact angles measured on the calcite and dolomite rock surfaces for resin (1000 ppm in toluene) after three weeks were 88° and 93°, respectively. The results of contact angle analyses as a screen for two rocks (calcite and dolomite) wettability showed that resin altered the wettability of rock samples to oil-wet. Also, asphaltene as a heavy and polar component has more influence than resin on the wettability alteration towards oil-wet state. The polarization interaction mechanism is the principle method for altering the wettability of samples by asphaltene and resin. EDX analysis illustrated that the amount of carbon and oxygen after aging rocks in oil, asphaltene, and resin increased, and the heteroatoms N and S were appeared on the calcite and dolomite surfaces. Afterwards, the combination of silica (SiO2) nanofluid and anionic surfactant (sodium dodecyl sulfate (SDS)) for modification of wettability of oil-wet carbonate surface was investigated. The most significant changes were observed after 24 h of contacts of rocks with a mixture of nanofluid and anionic surfactant. The contact angle decreased from about 88° to 16° for calcite and from 93° to 15° in the case of dolomite. The main mechanisms responsible for wettability modification by SiO2-SDS surfactant are: first) hydrogen bonding between the hydroxyl groups of silica nanoparticles and the tail of the anionic surfactant, second) the adsorption of SiO2-nanoparticles to the carbonate rock substrate due to a high degree of negative charges.

Numerical analysis of oblique stagnation point flow of nanofluid over a curved stretching/shrinking surface

This work analyses the heat transfer characteristics and the flow properties for two-dimensional oblique stagnation point flow of viscous, incompressible nanofluid over a curved stretching/shrinking surface. The nanofluid mixture is prepared by suspending the nanoparticles into the base fluid water. The governing equations are transformed into a non-linear coupled differential equation and are solved through bvp4c function in MATLAB. The assessment of the present result confirms that the addition of nanoparticles in base fluid strengthens the drag force and lowers the heat transfer rate at the surface. For stable solution, the skin friction coefficient is maximum on the flat surface as compared to the curved surface though the rate of heat transfer is same both over a flat surface and curved surface, however, for the unstable solution it is higher over the flat surface compared to the curved surface. Moreover, the increment of shrinking strengthens the drag force and lowers the heat transfer rate at the surface.

Optimizing density, dynamic viscosity, thermal conductivity and specific heat of a hybrid nanofluid obtained experimentally via ANFIS-based model and modern optimization

In this study, rGO/Co3O4 nanocomposite was synthesized, characterized, and then the thermophysical properties were obtained experimentally, after which the experimental data at varying values of temperature and particle loadings was used for optimization purposes. The study was concerned with different values of the controlling parameters. The in-situ/chemical reduction technique was used to synthesize the rGO/Co3O4 nanocomposite and then characterized with x-ray diffraction, transmission electron microscope, and magnetometry. The system was studied at temperature values ranging at 20, 30, 40, 50, and 60 °C and with particle loadings of 0.05%, 0.1%, and 0.2% wt%. The authors in this article have introduced a novel population-based algorithm that is known as Marine Predators Algorithm to obtain the optimal values of the controlling parameters (i.e., temperature and nanofluid mixture percentage) that minimize two controlled variables (i.e., density and viscosity) as well as maximize the other two controlled variables (thermal conductivity and specific heat). The rGO/Co3O4 nanocomposite nanofluid thermal conductivity and viscosity were investigated experimentally, and a maximum increment of 19.14% and 70.83% with 0.2% particle loadings at 60 °C was obtained. At 0.05%, 0.1%, and 0.2% particle loading wt%, the density increased by 0.115%, 0.23%, and 0.451% at a temperature of 20 °C; simultaneously, density increased by 0.117%%, 0.235%, and 0.469% at 60 °C, respectively as compared to water. At 0.2 wt%, the maximum decreased specific heat was 0.192% and 0.194% at 20 °C and 60 °C. When compared with water, no effect was observed with an increase in temperature/: a similar trend as that of the water was followed. The optimal values were found to be at a temperature of 60 °C and for 0.05% particle loading of the prepared nanofluid. However, among the conducted experiments, the optimizer pointed out that the optimal experiment was the one conducted at a temperature of 60 °C and a nanofluid percentage at 0.05. In conclusion, the proposed methodology of modelling with an artificial intelligence tool such as an adaptive network-based fuzzy inference system technique and then determining the optimal parameters with the marine predators algorithm accomplished the goal of the study with major success.

Effect of hybrid nanofluids mixture ratio on the performance of a photovoltaic thermal collector

Solar photovoltaic-thermal (PV/T) collectors, are hybrid collectors used to convert solar radiation into usable thermal and electrical energy. Recently, the field of research on PV/T is has focused on improving the efficiency of the PV/T collector by replacing the conventional heat transfer fluids (HTFs) with nanofluids. This article investigates the effect of hybrid nanofluids mixture ratio on the useful energy and overall efficiency of a PV/T collector operating with Al2O3-ZnO water nanofluid as the HTF. Experiments to measure the thermophysical properties of the hybrid nanofluids were conducted for various temperatures, volume concentrations, and mixture ratios, furthermore, accurate correlation models were proposed. Metrological data and energy output readings collected from the PV solar farm at Cyprus International University were used to validate our model. The study observed that at the optimum mixture ratio (0.47 of Al2O3 in the hybrid), the electrical, thermal, and exergy efficiencies of the PV/T collector are 13.8%, 55.9%, and 15.13% respectively. Also, the cell temperature drops by 21% when the mass flow rate is 0.1 kg/s as compared to when it is 0.01 kg/s. Finally, the study concludes that by using the Al2O3-ZnO hybrid nanofluid an overall peak thermal efficiency of 91% can be attained, and this represents a 34% enhancement in the collector's performance when compared to water.

Using the Characteristic Of hybrid Mixture from Nanomaterials to Improve and Modified the Parameter of the Heat Transfer

hybrid hybrid nanofluid is the fluid which have nanomateriales, this nanomaterials led to enhancement the heat transfer in the cooling equipement therefore the interest of the characteristic of the Nanomaterials to improve the properties of heat transfer of the fluid by using mixture of nanomaterials to obtain the best performance for the cooling. The nanomaterials which used in this work are zirconium (50-100 nm) oxide and titanium oxide (50-100 nm) with equal percent from each material. The percent which add to the fluid (water) is (0.2, 0.4, 0.6, 0.8, 1, and 1.2% wt. percent from the zirconium (50-100 nm) oxide and titanium oxide (50-100 nm). The result show that the factor of the friction of the fluid (water) decrease with increasing the Reynolds number, the factor of the friction of the hybrid hybrid nano fluid is decreasing with enhance the Reynolds number and the friction factor increase with increasing the percentage of the nanomaterials mixture. The overall heat transfer coefficient and Peclet number of the mixture of the hybrid hybrid nanofluid increases with increasing the weight fraction of the nano materials (zirconium oxide and titanium oxide). Nusselt number increases with increasing Reynolds and Peclet number and the content of the nanomaterials, however increase the weight content cause enhance in the viscosity of the hybrid hybrid nano fluid mixture led to enhance in the factor of the friction.

Hydro-thermal performance of normal-channel facile heat sink using TiO2-H2O mixture (Rutile–Anatase) nanofluids for microprocessor cooling

Thermal management of microelectronics is a challenging task in modern high heat generating devices. In this work, thermal performance of normal-channel facile heat sink has been investigated using water and TiO2-H2O (mixture of Rutile and Anatase) nanofluids with volumetric concentration of 0.005% and 0.01%. The maximum reduction in base temperature was noted for TiO2-H2O (∅ = 0.01%) and TiO2-H2O (∅ = 0.005%) as 8.2% and 5.5%, respectively, when compared with water. The thermal performance of normal-channel facile heat sink was then compared with the mini-channel integral fin heat sink. The base temperature of normal-channel facile heat sink was found very close to mini-channel integral fin heat sink with a maximum difference of 1.8%. The total cost to fabricate mini-channel heat sink was almost 5.3 times greater than normal-channel heat sink. So, the normal-channel heat sink has economical advantage over the mini-channel heat sink in terms of lower fabrication cost with similar thermal performance. However, the pressure drop was found greater for normal-channel as compared to mini-channel heat sink. The experimental results of normal-channel facile heat sink were also validated numerically, and a good agreement was found.

Effect of radiation on engine oil-TC4/NiCr mixture nanofluid flow over a revolving cone in mutable permeable medium

Abstract In this study, we premeditated the free convective flow of time-independent hybrid nanofluid flow above a rotating upright cone in the mutable permeable medium. The heat transmission is deliberated in the attendance of nonlinear radiative heat flux. We considered the TC4 (Ti-6Al-4 V) and Nichrome (80%Ni and 20%Cr) nanoparticles and suspended them into unused Engine Oil (EO). Simultaneous solutions are presented for unused engine oil and hybrid nanofluid cases. Runge-Kutta and Newton’s methods resolve the transferred governing system. The influence of numerous emerging limits on velocity and temperature is examined graphically. Also, wall resistance and Nusselt number are discussed numerically. It is originated that the thermal field of EO-TC4/NiCr hybrid nanofluid is highly influenced by the inverse Darcy number, thermal radiation, and cone angle parameters. The heat transmission rate of EO-TC4/NiCr hybrid nanoliquid is comparatively lower than the base liquid (engine oil).

Thermal cooling system with Ag/Fe3O4 nanofluids mixture as coolant for electronic devices cooling

The thermal dissipation resistance has encountered a problem in the thermal analysis of the electronic components. Due to the limitation of the coolant heat removal capacity, the nanofluid and flow feature of the coolant flowing through the thermal cooling system have proposed. The mixture of Ag and Fe3O4 nanoparticles and flow direction guide vane of coolant for cooling electronic devices have been investigated. The effects of coolant flow rate, coolant type, and heat sink configuration on the thermal dissipation efficiency are considered. Ag and Fe3O4 nanoparticles suspending in the base fluid test and compared with the de-ionized water. The obtained results found that the proposed water blocks have a significant effect on the flow feature of coolant flowing through the thermal cooling system, which results in 11.94% increase in thermal dissipation efficiency. Besides, the thermal dissipation efficiency from Ag/Fe3O4 nanofluid mixture as the coolant is higher than Ag nanofluids and higher than that de-ionized water as the coolant, respectively.

Evaporation of Water/Alumina Nanofluid Film by Mixed Convection Inside Heated Vertical Channel

In industrial devices like heat recovery systems, heat pumps, as well as symmetric and complex engineering systems, a nano fluid mixture is used. Regarding the nature of the energy sources (thermal or thermal and electrical), many physical systems could represent possible applications in manufactural activities. The presence of nanoparticles inside a solvent is of great interest in order to optimize the efficacy of the nano-technology systems. The present work deals with heat and mass transfer through a vertical channel where an alumina/water film mixture flows on one of its plates. For simulation, we use a numerical method under mixed convection during water/alumina nano fluid evaporation. We heat the flown plate uniformly while the other is dry and exchange heat with a constant coefficient. The gas mixture enters channel with a constant profile. Results show that an augmentation of the volume rate of the nanoparticle disadvantages evaporation if the heating is absent. Otherwise, if the heating exists, an increasing volume rate of the nanoparticle advantages evaporation. We found also that the film velocity behavior when the volume rate of the nanoparticle varies, independent of the heating.

Optimization of the finned double-pipe heat exchanger using nanofluids as working fluids

The heat exchanger pipe diameter has a significant effect on the flow characteristics as well as on the initial investment, operation and overall cost. Increasing fin dimensions increases the annulus hydraulic diameters. Even though the total volume of the heat exchanger remains unchanged between the finned and bare designs, the heat duty increases with increased heat transfer area for the finned design. The fins should be designed, and the dimensions should be calculated with special attention for different flow rates and heat exchanger dimensions. In this study, number, geometry and dimensions of the fins are determined using the algorithms available in the literature. The operational condition optimization is carried out accompanied with the cost analysis. In addition, the effects of the types of working fluids and fouled and clean cases are investigated for the total heat transfer enhancement in parallel with performance, lifetime and cost issues. A detailed analysis is presented for finned and unfinned double-pipe heat exchanger models for pure engine oil and its nanofluid mixtures with Ti, TiO2, Cu, CuO, Al and Al2O3 nanoparticles, multi-wall carbon nanotubes and graphene nanosheet having a constant particle concentration in the liquid phase. The nanofluid is flowing in annulus side, whereas the seawater is flowing in the tube side. It is observed that both the pressure drop and the pumping power increase with the increasing fin number and decrease with the cleanliness factor, whereas the total tube number decreases with increasing fin number. It is found that different types of nanofluids affect the cost and optimum annulus side velocity significantly. The results are summarized in several figures that consider the increasing Reynolds number with the cleanliness factor, the heat transfer coefficient and the pressure drop, the friction factor with changing mass flow rate and the cost values with corresponding annulus side velocities. Finally, the overall characteristics of the trend lines are provided in the figures.

Performance analysis of paraffin wax as PCM by using hybrid zinc-cobalt-iron oxide nano-fluid on latent heat energy storage system

This paper presents that the efficiency of thermal energy storage system is increased by reducing the charging time of Phase Change Material (PCM) by using the mixture of hybrid nanofluid (Zinc Cobalt Iron Oxide) and water as Heat Transfer Fluid (HTF). By using nanofluids it is found that the charging time for paraffin wax is reduced to about 25% and discharging time is also reduced to about 20%. Discharge using nanofluid is not so beneficiary because it reduces the time of discharging which is generally not required therefore it is advised to use nanofluid for charging purpose and simple water for discharging purpose to obtain maximum efficiency of the system.

Entropy generation analysis of mixture nanofluid (H2O/c2H6O2)–Fe3O4 flow between two stretching rotating disks under the effect of MHD and nonlinear thermal radiation

ABSTRACT The flow of water and a mixture of water–ethylene glycol as a base fluid and Fe3O4, as a nanoparticle between two stretching rotating disks, are investigated. The entropy generation has been modelled by the second thermodynamic low. The thermal irreversibility, fluid friction irreversibility and joule dissipation irreversibility are considered in this model. The Lorentz force and Joule heating effect due to a magnetic field and nonlinear thermal radiation have been considered in governing equations. The fifth-order Runge–Kutta method is applied to solve the nonlinear governing equations. The results are compared with those of the previously published papers and show excellent agreement. The effects of Radiation parameter, magnetic field, Brinkman number and volume fraction of nanoparticles on total entropy generation and Bejan number are investigated. Also the effects of the variable parameter on the velocity and temperature profile, skin friction coefficient and Nusselt number are examined. The results are compared with those of the mixture base fluid (water–ethylene glycol) and pure water.

Effect of Nanofluid and Surfactant on Thermosyphon Heat Pipe Performance

An experimental analysis is done to investigate the thermal performance of a thermosyphon heat pipe (THP) using three working fluids, namely, distilled water, nanofluid, and a mixture of nanofluid and surfactant. The working nanofluid is titanium dioxide and THP is made of copper tube with the outer diameter of 15 mm and length of 1000 mm. The effects of the input power and inclination angle on the THP performance are investigated. The experimental results indicated that with increasing the concentration of nanofluid, thermal efficiency increases and thermal resistance of the thermosyphon decreases. According to the results, mixing the nanofluid with the surfactant will decrease the evaporator wall temperature and the thermal resistance, while it increases the thermal efficiency of THP. Comparison between two nanofluids and a conventional fluid in a THP shows that the best pipe inclination angles are 60° for water and 90° for nanofluids. Adding the proper amount of surfactant increases THP’s thermal efficiency by 20%. The best thermal performance of THP achieved at the input power of 200 W for all the working fluids. The average deviation of 1% was observed between the experimental results of this study and those available in the open literature.