Optimum Nanofluid Concentration Research Articles

Optimization of Nanofluid Concentration for Energy Intensification in Corrugated Plate Type Heat Exchanger

The overall heat transfer coefficient of the heat exchanger will improve with an increase in the flow rate and concentration of nanofluid. But beyond an optimum nanoparticle concentration, the overall effectiveness seems to decrease due to an increase in pressure drop that consequently leads to an increase in pumping power. The novelty of the present work is to find the optimum concentration of CuO-Water nanofluid that exhibits the optimum heat transfer rate and global minimum pumping power, using both experimental and numerical study. The cold nanofluid and hot water entered the counter currently at 303.15 and 333.15 K respectively in the corrugated plate heat exchanger. It was observed from the experimental and numerical results that the values of overall heat transfer coefficient and pressure drop were increased monotonically (454–710 W/(m2-K) and 6–133 Pa respectively), with the increment in the concentration and flow rates of the nanofluid. Because of this trend, it was challenging to figure out the optimum nanofluid concentration using these parameters. Later, a procedure was presented to obtain an optimum concentration of nanofluid, to reduce the hot stream temperature by 288.15 K. The hydraulic power exhibited a global minimum at an optimum concentration of 0.5 vol% of nanofluid.

Evaluation of the thermal efficiency of nanofluid flows in flat plate solar collector

In this research, flat plate solar collectors (FPSC) were studied due to their simplicity, low maintenance, and cost-effectiveness. The study focused on comparing FPSC thermal performance using CuO/H2O nanofluids. Experiments were conducted over three months during the Iraqi weather conditions (January, February, and March) with carefully selected nanoparticle concentrations. Data was collected from 9 A.M. to 3 P.M., using various mass flow rates (ranging from 0.003 to 0.076 kg/s). Results showed a direct correlation between temperature and nanoparticle concentrations, with the highest outlet temperature (50°C) observed at 3 P.M. for 1% CuO-water nanofluid. Notably, at 1 P.M. in March, the 1% CuO-water nanofluid exhibited a 32% increase in collector thermal efficiency, surpassing pure water by 11.3%. This would improve the performance of FPSC by achieving higher efficiency increments. These improvements were attributed to the unique physical properties of nanoparticles, their increased surface area, and higher thermal conductivity. The study determined that the optimum nanofluid concentration for superior collector efficiency was 1%.

Utilizing Nanofluid to Enhance Thermosyphon Heat Pipe Thermal Efficiency

This is a study on the enhancement of the thermal performance of a thermosyphon heat pipe (THP) using the nanoparticle in a mixture of water and Triton X-100 (TX-100) surfactant. The effects of nanoparticle concentration, surfactant concentration, input power, inclination angle, and filling ratio on the thermal efficiency of THP is evaluated experimentally. Experiments were designed by the Taguchi method using Minitab software. According to the results, utilizing a nanofluid/surfactant mixture decreases the evaporator’s temperature, which decreases the thermal resistance and increases the thermal efficiency of THP. The maximum enhancement of thermal efficiency was observed to be 17.7%, and the maximum decrease in thermal resistance was 42.5% using the optimum concentration of nanofluid and TX-100 compared to water. The maximum thermal efficiency predicted by the Taguchi method was 0.8877, which was in good agreement with the experimental value of 0.917.

Optimum Utilisation of CuO Nanofluid in Flat Plate Solar Collector

The optimum utilisation of CuO-nanofluid in flat plate solar collector has been investigated under Malaysian climatic condition. To determine the optimum nanoparticle concentration required in the base fluid, a simulation was carried out using MATLAB program. From the simulation, it was found that, 0.5 vol.% of CuO nanoparticles in the base fluid yielded maximum collector efficiency. The test was conducted over six months following the ASHRAE standard with nanofluid in the flat plate collector to ascertain its efficiency. The maximum average solar radiation incident on the collector, collector outlet and ambient temperatures were observed about 1000 W/m2, 50 ºC and 38 ºC respectively. From the efficiency curve, the absorbed and removed energy parameters were found to be 0.501 and 24.23 respectively. At a mass flow rate of one litre per minute, the maximum average instantaneous efficiency was 51%. The result of experimental efficiency was compared with the result of simulation and the efficiency values were within 4% of each other. CuO nanofluid base collector increases the efficiency compared to water as the collector fluid. The experimental results revealed that the efficiency of FPSC with CuO nanofluid was 4.78% higher than water base collector at the same mass flow rate of 1 L/min. The uncertainty analysis of result has shown that instantaneous efficiency uncertainty was about 3.3%. The simulation result has indeed minimised number of experiments required to determine the optimum concentration of nanofluid for maximum efficiency.

Orthogonal study and analysis of variance on a thermal management system for high-power LED package

Determination of influences of various factors is important for improvement and optimization of a thermal management system for microelectronics. In this study, a series of orthogonal experiments and analysis of variance were performed on an LED cooling system which integrates thermoelectric cooler with microchannel heat sink using nanofluid as coolant. The significance of four factors, including nanofluid concentration, ambient temperature, nanofluid temperature, and power of the thermoelectric cooler, were evaluated. Substrate temperature was measured and temperature distribution of the LED was estimated. Results indicate that nanofluid demonstrated better cooling capacity compared with water. Results of difference analysis and analysis of variance indicate that all the four factors showed significant effects on the LED temperature, while the dominant factor was nanofluid concentration. The optimum nanofluid concentration was obtained. The variation of the nanofluid effect on the cooling performance with ambient temperature and nanofluid temperature were observed. The influence of dispersion stability of the nanofluid on the cooling performance was discussed.

Performance of environmental friendly water-based calcium carbonate nanofluid as enhanced recovery agent for sandstone oil reservoirs

Recent studies have demonstrated great potential of nanofluids as enhanced oil recovery (EOR) agent. Many mechanisms behind increasing oil recovery inducing alteration of surface wettability toward more water wet have been proposed when displacing oil by nanofluids. In this study, the effect of calcium carbonate nanofluid on wettability alteration of sandstone rock samples was studied. Nanoparticle was synthesized by chemical precipitation method and characterized by X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FE-SEM) and dynamic light scattering (DLS). The average particle size of nanoparticles was 55.4 nm. The rock samples were aged in oil to ensure desired oil-wet conditions. The effects of nanofluid concentration and temperature on wettability change were investigated and optimum concentration of calcium carbonate nanofluid was determined. Adsorption of nanoparticles on rock surface was characterized by FE-SEM. The wettability alteration was evaluated by measuring/calculating contact angle (static, advancing and receding), surface energy, liquid area fraction, and wettability index. 2-D oil-wet glass micromodel was used to compare the performance of optimum nanofluid concentration obtained from wettability tests against normal water flooding. Results showed alteration of wettability from oil-wet to water-wet for all nanofluid concentrations. More wettability alteration was observed at higher temperature (80 °C) than ambient conditions (25 °C). Optimum nanofluid concentration (0.025 wt%) was obtained that changed contact angle from 116.41° (non-treated surface) to 46.99° at 25 °C and 28.7° at 80 °C. Flooding oil-wet 2-D glass micromodel with optimum nanofluid concentration resulted in 20% additional ultimate recovery factor compares to normal water flooding.

Adsorption of natural CaCO3 nanoparticles on the reservoir rock surfaces in the enhanced oil recovery process: equilibrium, thermodynamics, and kinetics study

The major challenges in using nanoparticles in oil and gas industry projects are high investment costs and environmental problems. Bio-nanoparticles provide a solution to environmental and economic challenges in the nano-assisted EOR processes. In this work, the potential of natural calcium carbonate nanoparticles containing chitin for wettability alteration in enhanced oil recovery was studied. The adsorption behavior of bio-nanoparticles onto calcite-dolomite rock surface was distinguished through kinetics, equilibrium, and thermodynamics assessments. Besides, oil recovery is measured through forced imbibition experiments. The Taguchi experimental design was conducted to optimize the parameters influencing oil recovery factor in forced imbibition experiments, including nanofluid concentration, temperature, and oil type. Results of the adsorption experiment showed that adsorption kinetics of bio-Ca nanoparticles onto calcite-dolomite surface follows the pseudo-second-order model and monolayer, Langmuir adsorption of bio-nanoparticles. The endothermic heat of physical adsorption (physisorption) was found 3.32 kJ/mol. Based on the experimental design, the optimum parameters that can rise to additional oil displacement are a nanofluid concentration of 0.05 wt.%, normal heptane as liquid phase, minimum salinity (Milli-Q-water), and ambient temperature. The oil recovery factor increased by 17.52% at an optimum nanofluid concentration of 0.05 wt.% in comparison to a base fluid without nanoparticle. The results indicate that synthesized bio-Ca nanoparticles have proper EOR potential in both light oil and heavy oil reservoirs at certain conditions.

Heat pipes: progress in thermal performance enhancement for microelectronics

The aim of this study is to oversee the impact of various techniques on thermal performance of heat pipes and to comprehensively cover the progress made so far in improving thermal performance. Thermal performance of heat pipes has been considerably improved by applying very novel techniques proposed by different investigators. Some major techniques have been reviewed and discussed: use of nanofluids, manufacturing different types of grooves and fins, use of different types of wicks, by inner surface treatment, use of self-rewetting fluids, use of embedded heat pipes that is passive cooling mechanism, using various inclination angles in heat pipes, etc. The presented study concludes that there are diverse methods for thermal performance enhancement of heat pipes each having its own impact level and constraints such as optimized parameters, manufacturing constraints, economic feasibility and commercial barriers. Some techniques show reversion in results when exceeded a certain level, e.g., crossing optimum concentration of nanofluid would reduce thermal performance of heat pipes. This review yields enough knowledge to optimize alteration parameters to get maximum augmentation in results and provides strong insight to decide about, which specific technique should be used for a case.

Flow of nanofluid and hybrid fluid in porous channels: Experimental and numerical approach

Abstract Heat enhancement and heat storage are becoming important engineering topics related to renewable energy. Different fluid classes have been proposed, and various types of phase change materials have been used for energy storage. Nanofluids, which consist of nano metallic particles in liquids such as water, have been receiving a lot of attention recently. Some exaggerations regarding the conductivity of these fluids lead researchers to conduct further investigations on the physical properties of this new class of fluid. In this paper, an attempt was made to conduct a detailed experiment aiming to investigate the quality of heat enhancement one should expect from this fluid class. The experiment, consisting of the forced convection of a nanofluid composed of Al2O3 in water, demonstrated that heat enhancement is obtainable in the 6% range, regardless of the concentration of nanoparticles in the water. Computational fluid dynamics were in good agreement with the experimental data. The studies revealed that there is an optimum nanofluid concentration which achieves the highest heat transfer enhancement. As the concentration of nanoparticles increases beyond the optimum concentration, there is no longer a significant enhancement in heat transfer. Besides, the pressure drop increases along with increases in the nanoparticle concentration. A new hybrid fluid composed of aluminum oxide and copper oxide in water revealed further enhancement but a further increase in the pressure drop. It is therefore concluded that the hybrid fluid is an alternate choice if one needs to extract heat at the expense of the pressure drop.

Tribological performance of SiO2-based nanofluids in minimum quantity lubrication grinding of Si3N4 ceramic

Recently, there has been increased need for alternative lubrication techniques in grinding of advanced engineering ceramics. Literatures have indicated that the minimum quantity lubrication (MQL) method is a viable option for lubrication during grinding operations. The MQL technique was found to be non-hazardous, sustainable, eco-friendly, inexpensive and possess superior tribology than the conventional flood cooling technique. This work entails an experimental investigation on grinding of silicon nitride (Si3N4) ceramic using MQL with vegetable-oil-based silicon dioxide (SiO2) nanofluid. The grinding experiments were conducted using different process based on Taguchi L16 experimental design. The acquired results of tangential, normal grinding forces, and surface quality were analysed using Taguchi SN ratio analysis. Subsequently, an ANFIS prediction model was developed to analyse the effects of the process parameters on the forces and surface quality. The developed ANFIS prediction model was found to be highly accurate in predicting the performances of the grinding operations. The results obtained show that, by increasing the nanofluid concentration, the grinding forces decreases significantly, with resultant improvement in the surface quality. The 2 w/w percentage was found to be the optimum nanofluid concentration whereas the air pressure of 0.8 MPa gave better performance. Lastly, an optimum parameter setting for grinding the engineering ceramic was obtained.

Combined effect of nanofluid concentration and filling ratio on heat transfer performance of pulsating heat pipe

n experimental work was investigated to study combined effect of nanofluid concentration and liquid filling ratio on heat transfer performance of pulsating heat pipe (PHP).The PHP was made of copper tube with external diameter of 4mm and inner diameter of 2mm and bended into a closed loop serpentine made of 6 U-turns. In the experiment, Al2O3/water nanofluid concentration changed from 0wt% to 0.7wt%, Al2O3/water nanofluid filling ratio ranged from 30% to 70%, and Al2O3 / water nanofluid or de-ionized water was the working fluid. Experimental results showed that there was a 0.3wt% optimum nanofluid concentration and a 50% optimum filling ratio, besides, the heat transfer efficiency of PHP with Al2O3/water could reach its maximum value (about 10.28%) only under the combined action of two parts when compared with the de-ionized water.

Determination of Optimum Concentration of Nanofluid for Process Intensification of Heat Transfer Using Corrugated Plate Type Heat Exchanger

Abstract In this study cooling of hot water is taken up using a compact heat exchanger such as corrugated plate type heat exchanger and with utility fluid as a nanofluid prepared from mixing Al2O3 in water. In general a monotonic increase of 30 % to 70 % in overall heat transfer coefficient is observed for increase in nanofluid concentration as well as its flow rate. An optimum concentration of nanofluid is hence not possible to be found as heat transfer coefficient exhibited a monotonic trend. But there is a penalty for using nanofluid of higher concentrations in heat exchangers in the form of additional hydraulic power required to supply the nanofluid due its higher viscosity. Hence, as a novel approach, a target temperature drop of 15 °C for hot fluid (with constant flow rate) is assumed and the minimum critical flow rate of cold nanofluid of various concentrations required for achieving this is determined using simulation. For such a critical flow rate at various nanofluid concentrations, the determined hydraulic power (product of pressure drop and flow rate) exhibited a global minimum around 0.75 % volume concentration of Al2O3 in water. Thus this article presents the process intensification procedure for the heat exchangers using nanofluids as heat transfer enhancement option.

Optimum concentration of nanofluids for heat transfer enhancement under cavity flow natural convection with TiO2 – Water

The purpose of the research is to identify the optimum concentration of nanofluid during natural convection process using a square cavity with opposite walls heated and cooled, and all other walls are insulated. In the experimental investigation, the mixture of titanium dioxide and water is used as a nanofluid. The nanofluid consist of nanoparticles with the average size of 50 nm. The temperature of the heated and cooled walls, as well as the volume fraction of the nanofluid, are varied to investigate their effects on the heat transfer. The volume fraction of the nanofluids was varied from 0.05 Vol% to 0.8 Vol%, and the Ra in this study was from 4.9 × 108 to 1.47 × 109. From this study, it is understood that the addition of titanium dioxide nanoparticles enhances the heat transfer and also found that there is an optimum concentration for maximum heat transfer. The maximum heat transfer enhancement of 8.2% is found at a volume concentration of 0.05%.

Thermo-physical properties of Cu-Zn-Al LDH nanofluid and its application in spray cooling

The current experimental investigation deals with the thermo-physical attributes of Cu-Zn-Al LDH nanofluid its use in high temperature steel cooling. Here, authors used three metals (Copper, Aluminium, and Zinc) having high thermal conductivity to synthesize a brand new nanofluid for heat transfer application. Authors have achieved moderate increment (13.9%) in thermal conductivity value compared to water. A section of this work also aims to maximize the cooling rate which aids in improving mechanical properties of quenched steel plate. The maximum cooling rate of 158.4 °C/s was attained at 160 ppm of nanofluid concentration which is 18.5% higher than that attained by water. In addition to enhanced thermal conductivity, nanoparticle deposition on the cooling surface also contributes to the heat transfer enhancement by providing additional nucleation site. It is also to be considered that above an optimum nanofluid concentration both thermal conductivity and cooling rate values decline. Such trend is owed to several factors namely poor suspension stability, high agglomeration tendency and formation of nanoparticle layer on steel surface which prevents contact between coolant and surface.

Experimental study on the influence of the aspect ratio of square cavity on natural convection heat transfer with Al2O3/Water nanofluids

Cavity design is an important aspect in thermal systems, and proper cavity design saves plenty of energy as losses are minimised through better design. In this work, the influence that the Aspect Ratio (AR) of a rectangular cavity filled with nanofluids has on the natural convection process is studied experimentally. Three different cavities with the AR of 1, 2 and 4 are fabricated, and the heat transfer performance is studied using two different fluids namely de-ionised water and Al2O3/Water nanofluids. It is found that the AR of the cavity has a significant effect on the heat transfer coefficient and Nusselt number. More importantly, the optimum nanofluid concentration for maximum heat transfer varies with the AR of the cavity. It also found that the Rayleigh number has a strong effect on the Nusselt number as well as nanofluid buoyancy.

Experimental investigation of SiO2 nanoparticles on enhanced oil recovery of carbonate reservoirs

Wettability alteration is an important method to increase oil recovery from oil-wet carbonate reservoirs. Chemical agents are used as wettability modifiers in carbonate systems; however, the role of Nanoparticles in this field is still in its infancy and consequently has attracted the attention of many researchers in the last decade. In this work, the impact of SiO2 Nanoparticles on the wettability of a carbonate reservoir rock was experimentally studied. The impact of these Nanoparticles on the wettability of carbonate systems is still in its infancy. For this purpose, the effect of Nanofluid’s concentration on wettability and interfacial tension were investigated to determine the optimum concentration of Nanofluid for injection into core samples. The result suggests that a concentration of 4 g/L of Nanofluid could significantly alter the wettability of the rock from a strongly oil-wet to a strongly water-wet condition. Moreover, we studied the Nanofluids’ potential in enhanced oil recovery of oil-wet core plugs. The results show that a considerable amount of oil can be recovered right after start of water injection to the aged core plug with Nano fluid.