Download or read book Evaluation of Alumina Nanofluids and Surfactant Drag Reducing Solutions to Improve Heat Transfer for Aircraft Cooling Systems written by Javier Artemio Narvaez Bazan and published by . This book was released on 2018 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is a critical need for improved coolants for military aircraft applications. Research in this area has focused on either synthesizing novel coolants with improved thermal properties or developing additives for current coolants that can improve heat transfer capability in recirculating systems. This dissertation focuses on the latter alternative investigating the effect of nanoparticles or drag-reducing surfactant additives on effective heat transfer coefficients. Nanoparticles are reported to not only enhance thermal conductivity of coolants, but also increase the heat transfer coefficient. Some setbacks related to the use of nanofluids have been identified, such as increased pressure loss, erosion, and fluid instability. Surfactant drag-reducing additives greatly reduce skin friction, thereby reducing resistance to flow in tubes. Lower flow resistance means that the volumetric flow rate can be greatly increased at constant pumping power. Under these circumstances, the heat transfer coefficient can be enhanced. However, researchers have found that the heat transfer coefficient in tube heat exchangers is reduced by the addition of drag-reducing additives. Moreover, the percentage of heat transfer reduction in tube heat exchangers is greater than the corresponding drag reduction. The reason for the loss of heat transfer is that surfactant drag reducers lower flow resistance by damping turbulent eddies, which are known to drive heat transfer. Several researchers have tried to overcome heat transfer reduction in heat exchangers by different means described in this dissertation. However, despite their efforts, the improvements they achieved were not enough to eliminate the heat transfer reduction. Instead of focusing on turbulence, this dissertation explored the impact of increased heat transfer area per volume within microchannel devices, as the flow regime is typically laminar. The objective of this dissertation is to evaluate two approaches for heat transfer enhancement by additives--nanoparticles and surfactants--in aircraft cooling systems. For proof-of-concept experiments carried out in this work, the base fluid selected was DI water. A computational fluid dynamics study on the pressure, velocity, and temperature profiles was performed to analyze the flow and temperature patterns inside a cold plate, the microcooling device used in this research. A small study on the flow inside an elbow was also performed to analyze secondary flows. Alumina/DI water nanofluids were evaluated at system level. It was observed that, at the same volumetric flow, there was no significant improvement in convective heat transfer coefficients. Problems such as increase of pressure loss, particle settling, and especially vaporization were observed. Next, an aqueous surfactant solution was also tested within the heat exchanger system. A small reduction in both pressure loss and heat transfer coefficient at the system level was found. The relatively high pressure loss was due to the large ratio of form friction to total friction. Other problems associated with the use of surfactants as a heat transfer enhancer were surfactant poisoning and chemical degradation. Finally, alternatives to improve heat transfer coefficient by nanoparticles and surfactant additives are proposed, based on the analysis identified by this study.

Download or read book System Level Thermal Hydraulic Performance of Water based and PAO based Alumina Nanofluids written by Aaron Richard Veydt and published by . This book was released on 2011 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current and future military aircraft have a critical need for improved avionics heat removal. A drop-in replacement is sought for the existing heat transfer fluid, poly-alpha-olefin (PAO). Nanofluids have been considered for this application due reports of increases in thermal conductivity higher than predicted by conventional theory. In this study, a coolant loop apparatus was designed and built to evaluate the laminar and turbulent heat transfer performance of water-based and PAO-based alumina nanofluids in a flowing system. Alumina/water solutions showed an increase in pressure drop with particle loading which caused the heat transfer coefficient (HTC) at equal pumping power to be lower than at equal flowrates. In turbulent heat transfer, the alumina/water nanofluids show a 1-5% increase in HTC at equal flowrates. At equal pumping power, the nanofluid HTC is lower than water. In laminar flow at equal flowrates the HTC is decreased, which is not predicted. The alumina/PAO nanofluid showed similar pressure drop performance to the pure PAO base fluid. In turbulent flow at equal flowrates and equal pumping power, the HTC increase is only 1-3%. In laminar flow, a similar increase of 1-3% was observed. This increase is too small to warrant further testing of these fluids. In addition, particle settling was observed after only a few hours, which leads to questions about the long term stability of these nanofluids in a continuously flowing system. Overall, the fluids tested showed only marginal enhancement to the heat transfer coefficient. There were no significant (i.e. order of magnitude) increases observed between the results and conventional theory as have been reported elsewhere. The results of this work show that coolant loop apparatus is a valuable system-level screening tool for the U.S. Air Force to evaluate new single-phase coolants for avionics cooling.

Download or read book Assessment of the Wear Effects of Alumina nanofluids on Heat exchanger Materials written by FNU. Aktaruzzaman and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Author's abstract: Nanofluids are nano-size-powder suspensions in liquids that are mainly studied for their abnormal thermal transport properties, and hence as enhanced alternatives to ordinary cooling fluids. The tribological effects of nanofluids are, however, largely unknown, in particular their likely wear and/or erosion effects, because of their interaction with cooling-system (heat-exchanger) materials. The thesis presents research to establish methodologies for testing and evaluating surface-change by nanofluid impact. The work is presented on development of novel test rigs and testing methodologies, and on the use of typical surface analysis tools for assessment of wear and erosion that may be produced by nanofluids; prediction of such effects in cooling systems is discussed. Two new tests rigs were designed and developed: a multiple nozzle test rig and a parallel flow test rig. A main purpose of this research work was to assess the use of these new test rigs to evaluate nanofluid wear, and the ad-hoc newly proposed testing methodologies are discussed. Experimental results are presented on typical nanofluids (as 2%-volume of alumina nanopowders in 50/50 water/ethylene glycol solution, and in distilled water) which are jet-impinged (on aluminum and copper specimens) with 3.5 m/s to 15.5 m/s jet-speeds and in a 1 m/s parallel-flow (along the test specimen surface) during long test periods. The obtained surface modifications were assessed by roughness measurements, by weighing of removed-material, and by optical-microscopy. The results are presented on the observed substantially different surface modifications when same tests are conducted in aluminum and copper, and by both the base fluids and its alumina-nanofluids. The likely mechanisms of early erosion and abrasion, and the possibility of extrapolating the test-rig results and methodologies to typical cooling systems are discussed.

Download or read book Heat Transfer Enhancement in Turbulent Drag Reducing Surfactant Solutions written by Andrew J. Maxson and published by . This book was released on 2017 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the second study, the behavior of a mixed cationic / zwitterionic drag reducing surfactant system was explored. Precipitation of the solution into surfactant-rich and water-rich phases was observed under certain conditions, and this behavior was found to be extremely sensitive to composition, temperature, and shear. A heat transfer enhancement scheme exploiting the phase behavior was successfully demonstrated in which heat transfer reduction was eliminated while drag reduction performance was maintained.

Download or read book Enhanced Heat Transfer Mechanism of Nanofluid MQL Cooling Grinding written by Li, Changhe and published by IGI Global. This book was released on 2019-10-25 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: In today’s modern world, the manufacturing industry is embracing an energy-efficient initiative and adopting green techniques. One aspect that has failed to adopt this scheme is flood grinding. Current flood grinding methods increase the treatment cost of grinding fluid and waste large quantities. In order to remain sustainable and efficient, in-depth research is necessary to study green grinding technologies that can ensure machining precision and surface quality of workpiece and reduce grinding fluid-induced environmental pollution. Enhanced Heat Transfer Mechanism of Nanofluid MQL Cooling Grinding provides emerging research exploring the theoretical and practical aspects of nanofluid lubrication and its application within grinding flow and green manufacturing. Featuring coverage on a broad range of topics such as airflow distribution, morphology analysis, and lubrication performance, this book is ideally designed for mechanical professionals, engineers, manufacturers, researchers, scientists, academicians, and students seeking current research on clean and low-carbon precision machining methods.

Download or read book Nanofluids for Heat Exchangers written by Hafiz Muhammad Ali and published by Springer Nature. This book was released on 2022-08-31 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the importance of heat transfer in heat exchangers, and fluids properties play a vital role to increase heat transfer rate translating the size of the equipment and cuts in the capital and running cost in the long term. Nanofluids applications in heat exchangers will help to improve the thermophysical properties of the fluid and therefore heat transfer. And, this book explains the enhancing mechanisms of heat transfer by employing nanofluids in heat exchangers. A critical discussion will enable to estimate the pros and cons of such fluids in different types of heat exchangers. Prevailing working conditions for short- and long-term implementation of various types of nanofluids will be discussed and introduced to the readers. This book helps the researchers, scientist and academicians working in the domain to be able to get a comprehensive knowledge at one place regarding the preparation, properties, measurements, data reduction, characteristics and applications of nanofluids in heat exchangers.

Download or read book Mathematical Modelling of Heat Transfer Performance of Heat Exchanger using Nanofluids written by Prashant Maheshwary and published by CRC Press. This book was released on 2023-09-19 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents a detailed discussion of nanomaterials, nanofluids and application of nanofluids as a coolant to reduce heat transfer. It presents a detailed approach to the formulation of mathematical modelling applicable to any type of case study with a validation approach and sensitivity and optimization. Covers the aspects of formulation of mathematical modelling with optimization and sensitivity analysis Presents a case study based on heat transfer improvement and performs operations using nanofluids Examines the analysis of experimental data by the formulation of a mathematical model and correlation between input data and output data Illustrates heat transfer improvement of heat exchangers using nanofluids through the mathematical modelling approach Discusses applications of nanofluids in cooling systems This book discusses the aspect of formulation of mathematical modelling with optimization and sensitivity analysis. It further presents a case study based on the heat transfer improvement and performing operations using nanofluids. The text covers sensitivity analysis and analysis from the indices of the model. It also discusses important concepts such as nanomaterials, applications of nanomaterials, and nanofluids. It will serve as an ideal reference text for senior undergraduate, and graduate students in fields including mechanical engineering, chemical engineering, aerospace engineering, industrial engineering, and manufacturing engineering.

Download or read book Thermal Characteristics and Convection in Nanofluids written by Aditya Kumar and published by Springer Nature. This book was released on 2021-01-04 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers synthesis, characterization, stability, heat transfer and applications of nanofluids. It includes different types of nanofluids, their preparation methods as well as its effects on the stability and thermophysical properties of nanofluids. It provides a discussion on the mechanism behind the change in the thermal properties of nanofluids and heat transfer behaviour. It presents the latest information and discussion on the preparation and advanced characterization of nanofluids. It also consists of stability analysis of nanofluids and discussion on why it is essential for the industrial application. The book provides a discussion on thermal boundary layer properties in convection. Future directions for heat transfer applications to make the production and application of nanofluids at industrial level are also discussed.

Download or read book Heat Transfer Due to Laminar Natural Convection of Nanofluids written by De-Yi Shang and published by Springer. This book was released on 2018-07-30 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a theoretical study of heat transfer due to laminar natural convection of nanofluids, using Al2O3-water nanofluid as an example. An innovative method of similarity transformation of velocity fields on laminar boundary layers is applied for the development of a mathematical governing model of natural convection with actual nanofluids, and a novel model of the nanofluid's variable thermophysical properties is derived by a mathematical analysis based on the developed model of variable physical properties of fluids combined with the model of the nanofluid's thermal conductivity and viscosity. Based on these, the physical property factors of nanofluids are produced, which leads to a simultaneous solution for deep investigations of hydrodynamics and heat transfer of nanofluid's natural convection. The book also proposes novel predictive formulae for the evaluation of heat transfer of Al2O3-water nanofluid’s natural convection. The formulae have reliable theoretical and practical value because they are developed by rigorous theoretical analysis of heat transfer combined with full consideration of the effects of the temperature-dependent physical properties of nanofluids and the nanoparticle shape factor and concentration, as well as variations of fluid boundary temperatures. The conversion factors proposed help to turn the heat transfer coefficient and rate of fluid natural convection into those of nanofluid natural convection. Furthermore, several calculation examples are provided to demonstrate the heat transfer application of the proposed predictive formulae.

Download or read book Heat Transfer Enhancement with Nanofluids written by Vincenzo Bianco and published by CRC Press. This book was released on 2015-04-01 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanofluids are gaining the attention of scientists and researchers around the world. This new category of heat transfer medium improves the thermal conductivity of fluid by suspending small solid particles within it and offers the possibility of increased heat transfer in a variety of applications. Bringing together expert contributions from

Download or read book Alumina Nanofluid for Spray Cooling Heat Transfer Enhancement written by Aditya Bansal and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Nanofluids have been demonstrated to be promising for heat transfer enhancement in forced convection and boiling applications. The addition of carbon, copper, and other high-thermal-conductivity material nanoparticles to water, oil, ethylene glycol, and other fluids has been determined to increase the thermal conductivities of these fluids. The increased effective thermal conductivities of these fluids enhance their abilities to dissipate heat in such applications. The use of nanofluids for spray cooling is an extension of the application of nanofluids for enhancement of heat dissipation. In this investigation, experiments were performed to determine the level of heat transfer enhancement with the addition of alumina nanoparticles to the fluid. Using mass percentages of up to 0.5% alumina nanoparticles suspended in water, heat fluxes and surface temperatures were measured and compared. Compressed nitrogen was used to provide constant spray nozzle pressures to produce full-cone sprays in an open loop spray cooling system. The range of heat fluxes measured were for single-phase and phase-change spray cooling regimes.

Download or read book Modelling of Convective Heat and Mass Transfer in Nanofluids with and without Boiling and Condensation written by Andriy A. Avramenko and published by Springer Nature. This book was released on 2022-02-12 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents step-by-step description of the use of Lie group analysis to find symmetry forms and similarity solutions for single- and two-phase laminar and turbulent flows of nanofluids. It outlines novel and unique analytical solutions validated via comparisons with experimental data. The main part of the book is devoted to analytical modeling of film condensation of still and moving vapor with nanoparticles, stable film boiling of nanofluids, instantaneous unsteady boiling and condensation of nano- and ordinary fluids and clarification and quantification of instability conditions in the vapor layer, as well as centrifugal and Dean instability in nanofluids. It was demonstrated that such complex phenomena can be successfully simulated using the proposed approaches validated via reliable experiments. The book is intended for scientists, engineers, graduate and undergraduate students specializing in the area of engineering thermodynamics, heat and mass transfer and energy systems.

Download or read book Evaluation of Thermophysical Properties Friction Factor and Heat Transfer of Alumina Nanofluid Flow in Tubes written by Sanjib Tiwari and published by . This book was released on 2013 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational and Experimental Evaluation of Nanofluids in Heating and Cooling Forced Convection Applications written by Roy T. Strandberg and published by . This book was released on 2021 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of the research was to examine the heat transfer and fluid dynamic performance of various nanofluids in heating and cooling applications using empirical and computational methods. Two experiments were performed to characterize and compare the performance of a Al2O3/60% ethylene glycol (60% EG) nanofluid to that of its base fluid. In the first experiment, the nanofluid was comprised of Al2O3 nanoparticles with 1% volumetric concentration in a 60% ethylene glycol/40% water (60% EG by mass) solution to that of 60%EG in a liquid to air heat exchanger. The test bed used in the experiment was built to simulate a small air handling system typical of that used in heating, ventilating and air conditioning (HVAC) applications. Previously established empirical correlations for thermophysical properties of fluids were used to determine the values of various parameters (e.g. Nusselt number, Reynolds number, and Prandtl number). The testing shows that the 1% Al2O3 nanofluid generates a marginally higher heat rate than the 60% EG under certain conditions. At Re=3,000, the nanofluid produced a heat rate that was 2% higher than that of the 60% EG. The empirically determined Nusselt number associated with the convection inside the coil tubing follows the behavior predicted by the Dittus-Boelter correlation quite well (R2=0.97), while the empirically determined Nusselt number for the 60% EG follows the Petukhov correlation similarly well (R2=0.97). Pressure loss and hydraulic power for the nanofluid were higher than for the base fluid over the range of conditions tested. The exergy destroyed in the heat exchange and fluid flow processes were between 8 and 13% higher for the nanofluid over the tested range of Reynolds numbers. The objective of the second study was to experimentally characterize and compare the performance of a nanofluid comprised of Al2O3 nanoparticles with 1, 2 and 3% volumetric concentrations in a 60% EG solution to that of 60% EG in a liquid to air heat exchanger. In this experiment, the heating system was operated in a higher temperature regime than in the first experiment. As in the first experiment, the test bed used in the experiment simulated a small air handling system typical of that used in HVAC applications. Entering conditions for the air and liquid were selected to emulate typical operating conditions of commercial air handling systems in sub arctic regions (such as Alaska). In the experiment the nanofluids generally did not perform as well as expected based on previous analytical work. The performance of the 1% nanofluid was generally equal to that of the base fluid considering identical entering conditions. However, the 2% and 3% nanofluids performance was considerably worse than that of the base fluid. The higher concentration nanofluids exhibited heat rates up to 14.6% lower than that of the 60%EG, and up to 44.3% lower heat transfer coefficient. The 1% Al2O3/60% EG exhibited 100% higher pressure drop across the coil than the base fluid considering equal heat output. In the computational portion of the research, the performance of a microchannel heat sink (MCHS), similar to those used to cool microprocessors filled with various nanofluids and the corresponding base fluid without nanoparticles are examined. The MCHS is modeled using a three- dimensional conjugate heat transfer and fluid dynamic finite-volume model over a range of conditions. The model incorporates a fixed heat flux of 1,000,000 W/m2 at the base of the solid domain. The thermophysical properties of the fluids are based on empirically obtained correlations, and vary with temperature. Nanofluids considered include 60% Ethylene Glycol/40% Water solutions with CuO, SiO2, and Al2O3 nanoparticles dispersed in volumetric concentrations ranging from 1 to 3%. The flow conditions analyzed are in the laminar range (50£Re£300), and consider multiple inlet temperatures. The analyses predict that when compared on an equal Reynolds number basis, the 60%EG/3% CuO nanofluid exhibits the highest heat transfer coefficient, and the largest reduction in average base temperature. At an inlet Reynolds number of 300, and an inlet temperature of 308K the nanofluid is predicted to have an average heat transfer coefficient that is 30% higher than that of the base fluid, while the average temperature on the base of the heat exchanger is 1K lower than that of the base fluid. In contrast, the inlet pressure required for these entering conditions is 192% higher than that for the base fluid, while the required hydraulic power to drive the flow is 366% higher than that of the base fluid. The enhanced heat transfer performance potential of nanofluids comes at the expense of generally higher pumping power consumption.

Download or read book Assessment of the Wear Effects of Alimuna Nanofluids on Heat Exchanger Materials written by FNU Aktaruzzaman and published by . This book was released on 2015 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Author's abstract: Nanofluids are nano-size-powder suspensions in liquids that are mainly studied for their abnormal thermal transport properties, and hence as enhanced alternatives to ordinary cooling fluids. The tribological effects of nanofluids are, however, largely unknown, in particular their likely wear and/or erosion effects, because of their interaction with cooling-system (heat-exchanger) materials. The thesis presents research to establish methodologies for testing and evaluating surface-change by nanofluid impact. The work is presented on development of novel test rigs and testing methodologies, and on the use of typical surface analysis tools for assessment of wear and erosion that may be produced by nanofluids; prediction of such effects in cooling systems is discussed. Two new tests rigs were designed and developed: a multiple nozzle test rig and a parallel flow test rig. A main purpose of this research work was to assess the use of these new test rigs to evaluate nanofluid wear, and the ad-hoc newly proposed testing methodologies are discussed. Experimental results are presented on typical nanofluids (as 2%-volume of alumina nanopowders in 50/50 water/ethylene glycol solution, and in distilled water) which are jet-impinged (on aluminum and copper specimens) with 3.5 m/s to 15.5 m/s jet-speeds and in a 1 m/s parallel-flow (along the test specimen surface) during long test periods. The obtained surface modifications were assessed by roughness measurements, by weighing of removed-material, and by optical-microscopy. The results are presented on the observed substantially different surface modifications when same tests are conducted in aluminum and copper, and by both the base fluids and its alumina-nanofluids. The likely mechanisms of early erosion and abrasion, and the possibility of extrapolating the test-rig results and methodologies to typical cooling systems are discussed.

Download or read book Heat Transfer Enhancement Using Nanofluids in the Automotive Cooling System written by Adnan Mohammed Hussein and published by . This book was released on 2014 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The automotive cooling system is a significant part of the car that removes the engine generated heat outside across the radiator. The increasing demand of nanofluids for industrial applications has led many researchers to focus on the subject in the last decade. The limited thermophysical properties and heat transfer fo liquids across the car radiator have resulted in much research to find better coolant fluids. Space constraints are another key issue in the evofofotua applications to remove heat from high heat flux generating surfaces of automobile engines. In order to improve thermophysical properties of the coolant fluid to enhance heat transfer in the automotive cooling system, nanofluids have been utilized as a coolant. This study aims to enhance heat transfer with a slight pressure drop in the automotive cooling system by using multi types of nanoparticles dispersed in various types of basefluids. The appropriate type of nanofluids and the influence of different nanofluids on the heat transfer performance for the car cooling system have been identified. The radiator performance efficiency to reduce the radiator size and weight has been studied. The friction factor and heat transfer enhancement using different types of nanofluids are studied. The TiO2 and SiO2 nanopowders suspended in four different base fluids (pure water, EG, 10%EG+90%W and 20%EG+80%W) are prepared experimentally. The thermophysical properties of both nanofluids and base fluids have been measured and validated with the standard and the experimental data available. The experimental test rig setup included a car radiator, collecting tank, pump, rotameter, valves and plastic tubes. The evaluation of the friction factor and heat transfer coefficient by taking readings of the temperature and pressure drop under laminar flow condition were conducted. The volume flowrate was found to be in the range of (1-5LPM) for pure water and (3-12LPM) for other base fluids; while, the inlet temperature and nanofluid volume fraction were in the range of (60-80oC) and (1- 4%) respectively. The CFD analysis for the nanofluids flow inside the flat tube of a car radiator under laminar flow was carried out. A simulation study was conducted by using the finite volume oaotfm to solve the continuity, momentum, and energy equations. The geometry meshing of problem with a description of the boundary conditions was performed by using commercial software to determine the friction factor and heat transfer coefficient. The experimental results showed the friction factor decreased with the increase of the volume flowrate and increased with the increase of nanofluid volume fraction but slightly decreased with the increase of the inlet temperature. The simulation results showed good agreement with the experimental data with deviation not exceeding 4%. The experimental results showed the heat transfer coefficient increased with the increase of the volume flowrate, the nanofluid volume fraction and the inlet temperature. The simulation results showed good agreement with the experimental data with deviation not exceeding 6%. In addition, the SiO2 nanofluid showed higher values of the friction factor and heat transfer coefficient than TiO2 nanofluid. The base fluid (20%EG+80%W) gave higher values of the heat transfer coefficient and proper values of friction factor compared to other base fluids. The 4% of SiO2 nanoparticles suspended in (20%EG+80%W) base fluid was significant augmentation of heat transfer in the automobile radiator. The regression equations among input (Reynolds number, Prandtl number, and nanofluid volume fraction) and response (friction factor and Nusselt number) were found to be correlated. The experimental results were compared with the experimental data available and there were good agreements with a maximum deviation of approximately 5%.

Download or read book Heat Transfer Enhancement of Spray Cooling with Nanofluids written by Christian David Martinez and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Spray cooling is a technique for achieving large heat fluxes at low surface temperatures by impinging a liquid in droplet form on a heated surface. Heat is removed by droplets spreading across the surface, thus removing heat by evaporation and by an increase in the convective heat transfer coefficient. The addition of nano-sized particles, like aluminum or copper, to water to create a nanofluid could further enhance the spray cooling process. Nanofluids have been shown to have better thermophysical properties when compared to water, like enhanced thermal conductivity. Although droplet size, velocity, impact angle and the roughness of the heated surface are all factors that determine the amount of heat that can be removed, the dominant driving mechanism for heat dissipation by spray cooling is difficult to determine. In the current study, experiments were conducted to compare the enhancement to heat transfer caused by using alumina nanofluids during spray cooling instead of de-ionized water for the same nozzle pressure and distance from the heated surface. The fluids were sprayed on a heated copper surface at a constant distance of 21 mm. Three mass concentrations, 0.1%, 0.5%, and 1.0%, of alumina nanofluids were compared against water at three pressures, 40psi, 45psi, and 50psi. To ensure the suspension of the aluminum oxide nanoparticles during the experiment, the pH level of the nanofluid was altered. The nanofluids showed an enhancement during the single-phase heat transfer and an increase in the critical heat flux (CHF). The spray cooling heat transfer curve shifted to the right for all concentrations investigated, indicating a delay in two-phase heat transfer. The surface roughness of the copper surface was measured before and after spray cooling as a possible cause for the delay.