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Most existing methods for energy transformation and use are inadvertently contaminating our watersupplies, releasing greenhouse gasses into the atmosphere, emitting compounds that diminish the earth'sprotective blanket of ozone, and depleting the earth's crust of natural resources. As a result, scientists andengineers are increasingly pursuing sustainable technologies so that costs associated with global warmingcan be minimized and adverse impact on living organisms can be prevented. A promising sustainablemethod is to harness energy from the wind via wind turbines. However, the noise generated by wind turbinesproves to be one of the most significant hindrances to the extensive use of wind turbines. In this study,noise generation produced by flow over objects is investigated to characterize the noise generated due toflow-structure interaction and aeroacoustics. As a benchmark, flow over a cylinder has been chosen for thisstudy, with the aim of correlating three main characteristics in noise generation. Hence, the generated soundpressure level, exergy destroyed and the normal flow velocity (∪ ∞) are employed to characterize the systemin order to relate the exergy destruction to the noise generated in the flow. The correlation has the potentialto be used in wind turbine designs to minimize noise pollution due to aerodynamic noise.
Ofelia A. Jianu; Marc A. Rosen. Preliminary Assessment of Noise Pollution Prevention in Wind Turbines Based on an Exergy Approach. European Journal of Sustainable Development Research 2017, 1, 1 -9.
AMA StyleOfelia A. Jianu, Marc A. Rosen. Preliminary Assessment of Noise Pollution Prevention in Wind Turbines Based on an Exergy Approach. European Journal of Sustainable Development Research. 2017; 1 (2):1-9.
Chicago/Turabian StyleOfelia A. Jianu; Marc A. Rosen. 2017. "Preliminary Assessment of Noise Pollution Prevention in Wind Turbines Based on an Exergy Approach." European Journal of Sustainable Development Research 1, no. 2: 1-9.
Most existing methods for energy transformation and use are inadvertently contaminating our watersupplies, releasing greenhouse gasses into the atmosphere, emitting compounds that diminish the earth'sprotective blanket of ozone, and depleting the earth's crust of natural resources. As a result, scientists andengineers are increasingly pursuing sustainable technologies so that costs associated with global warmingcan be minimized and adverse impact on living organisms can be prevented. A promising sustainablemethod is to harness energy from the wind via wind turbines. However, the noise generated by wind turbinesproves to be one of the most significant hindrances to the extensive use of wind turbines. In this study,noise generation produced by flow over objects is investigated to characterize the noise generated due toflow-structure interaction and aeroacoustics. As a benchmark, flow over a cylinder has been chosen for thisstudy, with the aim of correlating three main characteristics in noise generation. Hence, the generated soundpressure level, exergy destroyed and the normal flow velocity (∪ ∞) are employed to characterize the systemin order to relate the exergy destruction to the noise generated in the flow. The correlation has the potentialto be used in wind turbine designs to minimize noise pollution due to aerodynamic noise.
Ofelia A. Jianu; Marc A. Rosen. Preliminary Assessment of Noise Pollution Prevention in Wind Turbines Based on an Exergy Approach. European Journal of Sustainable Development Research 2017, 1, 1 -9.
AMA StyleOfelia A. Jianu, Marc A. Rosen. Preliminary Assessment of Noise Pollution Prevention in Wind Turbines Based on an Exergy Approach. European Journal of Sustainable Development Research. 2017; 1 (2):1-9.
Chicago/Turabian StyleOfelia A. Jianu; Marc A. Rosen. 2017. "Preliminary Assessment of Noise Pollution Prevention in Wind Turbines Based on an Exergy Approach." European Journal of Sustainable Development Research 1, no. 2: 1-9.
Crystallization is an effective method to recover solids from solution, due to its relatively low energy utilization, low material requirements and lower cost compared to other alternatives. Hence, crystallization is of particular interest in the thermochemical copper-chlorine cycle for hydrogen production as an energy-saving means to extract solid CuCl2 from its aqueous solution. It has been determined from experiments that there is a range of concentrations that will demonstrate crystallization. If the initial concentration exceeds the upper bound of this range, the solution will be saturated and instantly become paste-like without forming crystals. Conversely, if the initial concentrations fall below the lower bound of a specified range, the solution will remain liquid upon cooling. As a result, it has been observed that crystallization does not occur for HCl concentrations below 3 M and above 9 M. Also, it has been found that anhydrous CuCl2 does not crystallize under any of the conditions tested. To analyze the composition of the recovered solids, X-ray diffraction (XRD) was employed. The samples were also analyzed using thermogravimetric analysis (TGA) in order to determine their thermochemical properties such as melting and decomposition temperatures. The stationary point on the TGA curve was found to be around 462 °C which is below the normal melting temperature of CuCl2. Also, the vaporization of the samples was found to be approximately 600 °C.
O.A. Jianu; M. Lescisin; Z. Wang; M.A. Rosen; G.F. Naterer. X-ray diffraction of crystallization of copper (II) chloride for improved energy utilization in hydrogen production. International Journal of Hydrogen Energy 2016, 41, 7848 -7853.
AMA StyleO.A. Jianu, M. Lescisin, Z. Wang, M.A. Rosen, G.F. Naterer. X-ray diffraction of crystallization of copper (II) chloride for improved energy utilization in hydrogen production. International Journal of Hydrogen Energy. 2016; 41 (19):7848-7853.
Chicago/Turabian StyleO.A. Jianu; M. Lescisin; Z. Wang; M.A. Rosen; G.F. Naterer. 2016. "X-ray diffraction of crystallization of copper (II) chloride for improved energy utilization in hydrogen production." International Journal of Hydrogen Energy 41, no. 19: 7848-7853.
Results of reaction kinetics studies of chemical processes related to materials integration of the thermochemical copper-chlorine cycle for hydrogen production are reported. The reaction rate of solid cuprous chloride (CuCl) in liquid hydrochloric acid is investigated experimentally for various acid concentrations. A rate constant—a function of constituent concentrations—describes how quickly the reactants are converted into products in satisfying the activation energy to enable the reaction to move forward. In this paper, the change in area of a solid CuCl particle is examined, rather than concentration in previous studies. New predictive models are developed to describe the characteristics of the chemical reaction in terms of its transition states and reaction mechanisms.
O. A. Jianu; Z. Wang; M. A. Rosen; G. F. Naterer. Experimental investigation of particle dissolution rates in aqueous solutions for hydrogen production. Heat and Mass Transfer 2015, 52, 2067 -2073.
AMA StyleO. A. Jianu, Z. Wang, M. A. Rosen, G. F. Naterer. Experimental investigation of particle dissolution rates in aqueous solutions for hydrogen production. Heat and Mass Transfer. 2015; 52 (10):2067-2073.
Chicago/Turabian StyleO. A. Jianu; Z. Wang; M. A. Rosen; G. F. Naterer. 2015. "Experimental investigation of particle dissolution rates in aqueous solutions for hydrogen production." Heat and Mass Transfer 52, no. 10: 2067-2073.
When hydrogen or oxygen is produced from water splitting by electrolysis, thermochemical cycles or solar-based photocatalytic methods, bubble flow and vapor transfer into the gas phase occur during phase transition. This undesirable vapor transfer requires the use of more energy input to compensate for the evaporation heat requirement as well as for subsequent gas purification in the downstream unit. In this paper, both experimental and modeling studies are performed to examine the dynamics of bubble flows and kinetics of water vapor transfer, particularly related to processes of hydrogen production. Experimental data are obtained using an advanced laser-based shadow imaging system and on-line vapor monitoring system. The bubble dynamics and water vapor transfer kinetics are modeled with non-dimensional parameters involving the bubble diameter, velocity and trajectories so that the water vapor transfer rate can be quantified under different operating conditions for various hydrogen production methods. Also, a predictive model is developed to simulate the physical processes of bubble transport in a vertical liquid column, as it occurs in water splitting processes such as oxygen generation in the thermochemical copper–chlorine cycle, as well as hydrogen generation in electrolytic and photocatalytic processes.
O.A. Jianu; M.A. Rosen; G.F. Naterer; Z. Wang. Two-phase bubble flow and convective mass transfer in water splitting processes. International Journal of Hydrogen Energy 2015, 40, 4047 -4055.
AMA StyleO.A. Jianu, M.A. Rosen, G.F. Naterer, Z. Wang. Two-phase bubble flow and convective mass transfer in water splitting processes. International Journal of Hydrogen Energy. 2015; 40 (11):4047-4055.
Chicago/Turabian StyleO.A. Jianu; M.A. Rosen; G.F. Naterer; Z. Wang. 2015. "Two-phase bubble flow and convective mass transfer in water splitting processes." International Journal of Hydrogen Energy 40, no. 11: 4047-4055.
The hydrogen economy is one potential avenue to a clean energy system, and a promising option for hydrogen production is thermochemical water decomposition. This process involves multiple steps, some consisting of multiphase reaction systems. Here, the thermodynamics and kinetics of vapour diffusion and entrainment for ascending bubbles in a vertical column are examined through experimental studies for various gas production rates. The vapour entrainment is interpreted in terms of the phase transition rate, and its dependence on such operating parameters as gas bubble size, liquid depth, temperature, pressure and concentration is examined. These effects are investigated experimentally, and a phase transition correlation is developed to analyze these parameters. Also, a predictive model is developed to simulate the physical processes of bubble transport in a vertical liquid column, as it occurs in water splitting processes such as oxygen generation in the copper-chlorine thermochemical cycle, as well as hydrogen generation in electrolytic and photocatalytic processes.
O. A. Jianu; Marc A Rosen; Greg Naterer; Zhengtao Wang. Mass Transfer and Bubble Flow Dynamics in Aqueous Solutions for Hydrogen Production Cycles. Progress in Sustainable Energy Technologies Vol II 2014, 387 -404.
AMA StyleO. A. Jianu, Marc A Rosen, Greg Naterer, Zhengtao Wang. Mass Transfer and Bubble Flow Dynamics in Aqueous Solutions for Hydrogen Production Cycles. Progress in Sustainable Energy Technologies Vol II. 2014; ():387-404.
Chicago/Turabian StyleO. A. Jianu; Marc A Rosen; Greg Naterer; Zhengtao Wang. 2014. "Mass Transfer and Bubble Flow Dynamics in Aqueous Solutions for Hydrogen Production Cycles." Progress in Sustainable Energy Technologies Vol II , no. : 387-404.
This paper presents experimental studies of particle dynamics, dissolution and transport processes for hydrogen production and thermochemical water decomposition. The processes involve multiple steps, some consisting of multiphase reaction systems. It examines the importance of design optimization of gas–solid–liquid phase systems and process integration of a thermochemical copper–chlorine cycle for hydrogen production. The dissolution of copper (I) chloride particle in hydrochloric acid is examined. This dissolution step is investigated in order to provide a predictive modeling method for more complex multiphase reacting systems.
O.A. Jianu; Z. Wang; M.A. Rosen; Greg Naterer. Shadow imaging of particle dynamics and dissolution rates in aqueous solutions for hydrogen production. Experimental Thermal and Fluid Science 2013, 51, 297 -301.
AMA StyleO.A. Jianu, Z. Wang, M.A. Rosen, Greg Naterer. Shadow imaging of particle dynamics and dissolution rates in aqueous solutions for hydrogen production. Experimental Thermal and Fluid Science. 2013; 51 ():297-301.
Chicago/Turabian StyleO.A. Jianu; Z. Wang; M.A. Rosen; Greg Naterer. 2013. "Shadow imaging of particle dynamics and dissolution rates in aqueous solutions for hydrogen production." Experimental Thermal and Fluid Science 51, no. : 297-301.
Unsustainable human activities and practices are polluting water supplies and emitting to the atmosphere greenhouse gases as well as compounds that erode the earth\'s protective ozone layer. The potential impact on human health and economic costs associated with global warming have motivated scientists and engineers to seek sustainable technologies. One such technology is the wind turbine, which harnesses energy from the wind. However, a significant hindrance preventing the widespread use of wind turbines is the noise they produce. This study examines flow over an object and the consequent noise generation produced by this flow-structure interaction. Flow over a cylinder has been chosen as the benchmark. The aim of this study is to correlate three main characteristic parameters of the system, namely, the generated sound pressure level, the exergy destroyed, and the normal flow velocity). The main motivation for this work is to relate the exergy destruction to the noise generated in the flow to improve understanding and to provide a correlation can be utilized to reduce or minimize the noise of wind turbines.
Ofelia Jianu; Marc Rosen; Greg Naterer. An Exergy Based Approach to Noise Prevention in Wind Turbines: Concept and Preliminary Assessment. Proceedings of The 2nd World Sustainability Forum 2012, 1 .
AMA StyleOfelia Jianu, Marc Rosen, Greg Naterer. An Exergy Based Approach to Noise Prevention in Wind Turbines: Concept and Preliminary Assessment. Proceedings of The 2nd World Sustainability Forum. 2012; ():1.
Chicago/Turabian StyleOfelia Jianu; Marc Rosen; Greg Naterer. 2012. "An Exergy Based Approach to Noise Prevention in Wind Turbines: Concept and Preliminary Assessment." Proceedings of The 2nd World Sustainability Forum , no. : 1.
The global push towards sustainability has led to increased interest in alternative power sources other than coal and fossil fuels. One of these sustainable sources is to harness energy from the wind through wind turbines. However, a significant hindrance preventing the widespread use of wind turbines is the noise they produce. This study reviews recent advances in the area of noise pollution from wind turbines. To date, there have been many different noise control studies. While there are many different sources of noise, the main one is aerodynamic noise. The largest contributor to aerodynamic noise comes from the trailing edge of wind turbine blades. The aim of this paper is to critically analyse and compare the different methods currently being implemented and investigated to reduce noise production from wind turbines, with a focus on the noise generated from the trailing edge.
Ofelia Jianu; Marc A. Rosen; Greg Naterer. Noise Pollution Prevention in Wind Turbines: Status and Recent Advances. Sustainability 2012, 4, 1104 -1117.
AMA StyleOfelia Jianu, Marc A. Rosen, Greg Naterer. Noise Pollution Prevention in Wind Turbines: Status and Recent Advances. Sustainability. 2012; 4 (6):1104-1117.
Chicago/Turabian StyleOfelia Jianu; Marc A. Rosen; Greg Naterer. 2012. "Noise Pollution Prevention in Wind Turbines: Status and Recent Advances." Sustainability 4, no. 6: 1104-1117.
The global trend towards sustainability has led to increased interest in alternative power sources to coal and other fossil fuels. One of these sustainable sources is wind energy, which we can harness through wind turbines. However, a significant hindrance preventing the widespread use of wind turbines is the noise they produce. This study reviews recent advances in the area of noise pollution from wind turbines. To date, there have been many different noise control studies. In order to successfully reduce or prevent the noise generated, the sources of noise must be identified. Two major sources of noise are present during operation: mechanical noise and aerodynamic noise. Mechanical noise generally originates from the many different components within the wind turbine, such as the generator, the hydraulic systems and the gearbox. Different mechanical noise prevention strategies such as vibration suppression, vibration isolation and fault detection techniques are presented in this paper. Aerodynamic noise prevention strategies are also discussed. Aerodynamic noise is the dominant source of noise from wind turbines, with a sound power level of 99.2 dB A. Breaking this noise source down, the largest contributor to aerodynamic noise comes from the trailing edge of wind turbine blades. Strategies for reducing aerodynamic noise include adaptive solutions and wind turbine blade modification methods. There are a number of adaptive noise reduction solutions including varying the speed of rotation of the blades and increasing the pitch angle. Although such strategies have been successfully implemented for noise reduction purposes, they can cause significant power loss. Therefore, alternative methods of adaptive solutions are sought. Blade modification methods such as adding serrations have proven to be beneficial in reducing noise without any power loss. The aim of this paper is to critically analyse and compare the different methods currently being implemented and investigated to reduce noise production from wind turbines, with a focus on the noise generated from the trailing edge.
Ofelia Jianu; Greg Naterer; Marc Rosen. Noise Polution Prevention in Wind Turbines: Status and Recent Advances. Proceedings of The 1st World Sustainability Forum 2011, 1 .
AMA StyleOfelia Jianu, Greg Naterer, Marc Rosen. Noise Polution Prevention in Wind Turbines: Status and Recent Advances. Proceedings of The 1st World Sustainability Forum. 2011; ():1.
Chicago/Turabian StyleOfelia Jianu; Greg Naterer; Marc Rosen. 2011. "Noise Polution Prevention in Wind Turbines: Status and Recent Advances." Proceedings of The 1st World Sustainability Forum , no. : 1.