Dustin Ray - Academia.edu (original) (raw)
Papers by Dustin Ray
In this study, the performance of a microchannel heat sink (MCHS) filled with various nanofluids ... more In this study, the performance of a microchannel heat sink (MCHS) filled with various nanofluids and the corresponding base fluid without nanoparticles are examined 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/m 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 (50Re300), 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...
Processes
The fluid dynamic and thermal performance of three nanofluids containing aluminum oxide, copper o... more The fluid dynamic and thermal performance of three nanofluids containing aluminum oxide, copper oxide, and silicon dioxide nanoparticles dispersed in 60:40 ethylene glycol and water base fluid as a coolant in a microchannel heatsink are compared here by two methods. The first is a simple analytical analysis, which is acceptable for very low nanoparticle volumetric concentration (1–2%). The second method is a rigorous three-dimensional finite volume conjugate heat transfer and fluid dynamic model based upon a constant heat flux boundary condition, which is applicable for cooling electronic chips. The fluids’ thermophysical properties employed in the modeling are based on empirically derived, temperature dependent correlations from the literature. The analytical and computational results for pressure drop and Nusselt number were in good agreement with the nanofluids showing a maximum difference of 4.1% and 2.9%, respectively. Computations cover the practical range of Reynolds number f...
Journal of Fluids Engineering
A three-dimensional laminar flow model was used for 37 Reynolds numbers (0.1, 0.2...1, 2...10, 20... more A three-dimensional laminar flow model was used for 37 Reynolds numbers (0.1, 0.2...1, 2...10, 20...100, 200...1000) through six rectangular microchannels (aspect ratios: 1, 0.75, 0.5, 0.25, 0.2, 0.125) to develop correlations for hydrodynamic entrance length. The majority of the Reynolds numbers are in the low regime (Re< 100) to fulfill the need to determine the hydrodynamic entrance length for microchannels. Examination of the fully developed flow condition was considered using the velocity or fRe criteria. Numerical results from the present simulations were validated by comparing the fRe results. Two new correlations were developed from a vast amount of numerical data (222 simulations). The velocity criterion correlations predict entrance length with a mean error of 4.67% and maximum error of 10.28%. The fRe criterion generated better correlations and were developed as a function of aspect ratio to predict entrance length with a mean error less than 2% and maximum error of 5....
International Journal of Heat and Mass Transfer, 2016
Journal of Thermal Science and Engineering Applications, 2016
Density measurements were performed on several nanofluids containing nanoscale particles of alumi... more Density measurements were performed on several nanofluids containing nanoscale particles of aluminum oxide (Al2O3), zinc oxide (ZnO), copper oxide (CuO), titanium oxide (TiO2), and silicon dioxide (SiO2). These particles were individually dispersed in a base fluid of 60:40 propylene glycol and water (PG/W) by volume. Additionally, carbon nanotubes (CNTs) dispersed in de-ionized water (DI) was also tested. Initially, a benchmark test was performed on the density of the base fluid in the temperature range of 0–90 °C. The measured data agreed within a maximum error of 1.6% with the values presented in the handbook of American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). After this validation run, the density measurements of various nanofluids with nanoparticle volumetric concentrations from 0 to 6% and nanoparticle sizes ranging from 10 to 76 nm were performed. The temperature range of the measurements was from 0 to 90 °C. These results were compared with...
International Journal of Heat and Mass Transfer, 2015
ABSTRACT A three‒dimensional turbulent flow and heat transfer of two different nanofluids, contai... more ABSTRACT A three‒dimensional turbulent flow and heat transfer of two different nanofluids, containing aluminum oxide (Al2O3) and copper oxide (CuO) nanoparticles, dispersed in ethylene glycol and water mixture (EG/W) in the flat tubes of an automotive radiator have been numerically studied to evaluate their performance. Computations have been carried out for nanoparticles volumetric concentrations up to 6% and over a Reynolds number range typically encountered in automobile radiators. Appropriate correlations for density, viscosity, specific heat and thermal conductivity of nanofluids as a function of particle volume concentration and temperature, developed from experiments have been used in this study. Numerical results have been first validated for the flow of single phase liquids, such as water and EG/W by comparing the computed values of Nusselt number and friction factor with those given by accurate correlations available in the literature. Inside the flat tube continuous reductions in the local heat transfer coefficient and wall shear stress are observed around the periphery of the flat tube, starting from the mid-point of the flat-wall and proceeding to the center of the curved wall. For the same Reynolds number, computations with nanofluids show an increase of friction factor and heat transfer coefficient with an increase in the particle volume concentration. The study reveals that under the basis of equal pumping power, Al2O3 and CuO nanofluids up to 3% and 2% particle volumetric concentrations respectively provide higher heat transfer coefficients than that of the base fluid. From the present study, several new correlations to determine the Nusselt number and friction factor for the nanofluids flowing in the flat tubes of a radiator have been proposed for the entrance as well as the fully developed regions.
Journal of Thermal Science and Engineering Applications, 2014
In this study, the performance of a microchannel heat sink (MCHS) filled with various nanofluids ... more In this study, the performance of a microchannel heat sink (MCHS) filled with various nanofluids and the corresponding base fluid without nanoparticles are examined 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/m 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 (50Re300), 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...
Processes
The fluid dynamic and thermal performance of three nanofluids containing aluminum oxide, copper o... more The fluid dynamic and thermal performance of three nanofluids containing aluminum oxide, copper oxide, and silicon dioxide nanoparticles dispersed in 60:40 ethylene glycol and water base fluid as a coolant in a microchannel heatsink are compared here by two methods. The first is a simple analytical analysis, which is acceptable for very low nanoparticle volumetric concentration (1–2%). The second method is a rigorous three-dimensional finite volume conjugate heat transfer and fluid dynamic model based upon a constant heat flux boundary condition, which is applicable for cooling electronic chips. The fluids’ thermophysical properties employed in the modeling are based on empirically derived, temperature dependent correlations from the literature. The analytical and computational results for pressure drop and Nusselt number were in good agreement with the nanofluids showing a maximum difference of 4.1% and 2.9%, respectively. Computations cover the practical range of Reynolds number f...
Journal of Fluids Engineering
A three-dimensional laminar flow model was used for 37 Reynolds numbers (0.1, 0.2...1, 2...10, 20... more A three-dimensional laminar flow model was used for 37 Reynolds numbers (0.1, 0.2...1, 2...10, 20...100, 200...1000) through six rectangular microchannels (aspect ratios: 1, 0.75, 0.5, 0.25, 0.2, 0.125) to develop correlations for hydrodynamic entrance length. The majority of the Reynolds numbers are in the low regime (Re< 100) to fulfill the need to determine the hydrodynamic entrance length for microchannels. Examination of the fully developed flow condition was considered using the velocity or fRe criteria. Numerical results from the present simulations were validated by comparing the fRe results. Two new correlations were developed from a vast amount of numerical data (222 simulations). The velocity criterion correlations predict entrance length with a mean error of 4.67% and maximum error of 10.28%. The fRe criterion generated better correlations and were developed as a function of aspect ratio to predict entrance length with a mean error less than 2% and maximum error of 5....
International Journal of Heat and Mass Transfer, 2016
Journal of Thermal Science and Engineering Applications, 2016
Density measurements were performed on several nanofluids containing nanoscale particles of alumi... more Density measurements were performed on several nanofluids containing nanoscale particles of aluminum oxide (Al2O3), zinc oxide (ZnO), copper oxide (CuO), titanium oxide (TiO2), and silicon dioxide (SiO2). These particles were individually dispersed in a base fluid of 60:40 propylene glycol and water (PG/W) by volume. Additionally, carbon nanotubes (CNTs) dispersed in de-ionized water (DI) was also tested. Initially, a benchmark test was performed on the density of the base fluid in the temperature range of 0–90 °C. The measured data agreed within a maximum error of 1.6% with the values presented in the handbook of American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). After this validation run, the density measurements of various nanofluids with nanoparticle volumetric concentrations from 0 to 6% and nanoparticle sizes ranging from 10 to 76 nm were performed. The temperature range of the measurements was from 0 to 90 °C. These results were compared with...
International Journal of Heat and Mass Transfer, 2015
ABSTRACT A three‒dimensional turbulent flow and heat transfer of two different nanofluids, contai... more ABSTRACT A three‒dimensional turbulent flow and heat transfer of two different nanofluids, containing aluminum oxide (Al2O3) and copper oxide (CuO) nanoparticles, dispersed in ethylene glycol and water mixture (EG/W) in the flat tubes of an automotive radiator have been numerically studied to evaluate their performance. Computations have been carried out for nanoparticles volumetric concentrations up to 6% and over a Reynolds number range typically encountered in automobile radiators. Appropriate correlations for density, viscosity, specific heat and thermal conductivity of nanofluids as a function of particle volume concentration and temperature, developed from experiments have been used in this study. Numerical results have been first validated for the flow of single phase liquids, such as water and EG/W by comparing the computed values of Nusselt number and friction factor with those given by accurate correlations available in the literature. Inside the flat tube continuous reductions in the local heat transfer coefficient and wall shear stress are observed around the periphery of the flat tube, starting from the mid-point of the flat-wall and proceeding to the center of the curved wall. For the same Reynolds number, computations with nanofluids show an increase of friction factor and heat transfer coefficient with an increase in the particle volume concentration. The study reveals that under the basis of equal pumping power, Al2O3 and CuO nanofluids up to 3% and 2% particle volumetric concentrations respectively provide higher heat transfer coefficients than that of the base fluid. From the present study, several new correlations to determine the Nusselt number and friction factor for the nanofluids flowing in the flat tubes of a radiator have been proposed for the entrance as well as the fully developed regions.
Journal of Thermal Science and Engineering Applications, 2014