Meishen Li - Academia.edu (original) (raw)

Papers by Meishen Li

Research paper thumbnail of Modeling the Initial Droplet Size Distribution in Sprays Based on the Maximization of Entropy Generation

Atomization and Sprays, 2005

The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and v... more The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and velocity distribution in sprays, is, strictly speaking, only applicable for isolated systems in thermodynamic equilibrium; whereas the spray formation processes are ...

Research paper thumbnail of An Improved Model for the Droplet Size Distribution in Sprays Developed From the Prin- ciple of Entropy Generation maximization

The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and v... more The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and velocity distribution in sprays, is, strictly speaking, only applicable for isolated systems in thermodynamic equilibrium; whereas the spray formation processes are irreversible and non-isolated with interaction between the atomizing liquid and its surrounding gas medium. In this study, a new model for the droplet size distribution has been developed based on the thermodynamically consistent concept – the maximization of entropy generation during the liquid atomization process. The model prediction compares favorably with the experimentally measured size distribution for droplets, near the liquid bulk breakup region, produced by an air-blast annular nozzle, a planar nozzle and a practical gas turbine nozzle. Therefore, the present model can be used to predict the initial droplet size distribution in sprays. Corresponding author Introduction Since the later 1980s, Maximum Entropy Principle...

Research paper thumbnail of A Second-Order Newton-Raphson Method for Improved Numerical Stability in the Determination of Droplet Size Distributions in Sprays

Atomization and Sprays, 2006

Research paper thumbnail of Modeling the Initial Droplet Size Distribution in Sprays Based on the Maximization of Entropy Generation

Atomization and Sprays, 2005

The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and v... more The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and velocity distribution in sprays, is, strictly speaking, only applicable for isolated systems in thermodynamic equilibrium; whereas the spray formation processes are ...

Research paper thumbnail of A Comparison of Coarse-resolution Numerical Simulation with Experimental Measurements of Wind Turbine Aerodynamic Performance

Procedia Engineering, 2014

Coarse-resolution computational fluid dynamics simulations using the unsteady Delayed-Detached-Ed... more Coarse-resolution computational fluid dynamics simulations using the unsteady Delayed-Detached-Eddy simulation (DDES) and the steady Reynolds-Averaged Navier-Stokes (RANS) methodologies were conducted to predict the aerodynamic performance of the Fortis Montana 5.8-kW horizontal-axis wind turbine (HAWT). The turbulence models used for the closure of the DDES and RANS methodologies were the one-equation Spalart-Allmaras model and the two-equation shear stress transport k model, respectively. To assess and validate the predictive performance of these two simulation strategies conducted with coarse-resolution computational grids, experimental measurements of the Fortis Montana 5.8-kW HAWT were conducted at the 9 m 9 m National Research Council Canada wind tunnel. Results of a detailed comparison between the wind tunnel experimental measurements and the model predictions are presented. It was found that predictions of the power curve using the DDES methodology yielded good conformance with the associated experimental measurements. Furthermore, it was found that the RANS method fails to capture the correct power output at moderate and high tip speed ratios. It is concluded that accuracy in a wind turbine power curve prediction using the relatively coarse mesh in this study is probably satisfactory for most real-world industrial and engineering applications.

Research paper thumbnail of Droplet Size Distribution in Sprays Based on Maximization of Entropy Generation

Abstract: The maximum entropy principle (MEP), which has been popular in the modeling of droplet ... more Abstract: The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and velocity distribution in sprays, is, strictly speaking, only applicable for isolated systems in thermodynamic equilibrium; whereas the spray formation processes are irreversible and non-isolated with interaction between the atomizing liquid and its surrounding gas medium. In this study, a new model for the droplet size distribution has been developed based on the thermodynamically consistent concept – the maximization of entropy generation during the liquid atomization process. The model prediction compares favorably with the experimentally measured size distribution for droplets, near the liquid bulk breakup region, produced by an air-blast annular nozzle and a practical gas turbine nozzle. Therefore, the present model can be used to predict the initial droplet size distribution in sprays.

Research paper thumbnail of Investigation of wind characteristics and assessment of wind energy potential for Waterloo region, Canada

Energy conversion and management, 2005

Wind energy becomes more and more attractive as one of the clean renewable energy resources. Know... more Wind energy becomes more and more attractive as one of the clean renewable energy resources. Knowledge of the wind characteristics is of great importance in the exploitation of wind energy resources for a site. It is essential in designing or selecting a wind energy conversion system for any application. This study examines the wind characteristics for the Waterloo region in Canada based on a data source measured at an elevation 10 m above the ground level over a 5-year period (1999-2003) with the emphasis on the suitability for wind energy technology applications. Characteristics such as annual, seasonal, monthly and diurnal wind speed variations and wind direction variations are examined. Wind speed data reveal that the windy months in Waterloo are from November to April, defined as the Cold Season in this study, with February being the windiest month. It is helpful that the high heating demand in the Cold Season coincides with the windy season. Analysis shows that the day time is the windy time, with 2 p.m. in the afternoon being the windiest moment. Moreover, a model derived from the maximum entropy principle (MEP) is applied to determine the diurnal, monthly, seasonal and yearly wind speed frequency distributions, and the corresponding Lagrangian parameters are determined. Based on these wind speed distributions, this study quantifies the available wind energy potential to provide practical information for the application of wind energy in this area. The yearly average wind power density is 105 W/m 2. The day and night time wind power density in the Cold Season is 180 and 111 W/m 2 , respectively.

Research paper thumbnail of MEP-type distribution function: a better alternative to Weibull function for wind speed distributions

Renewable energy, 2005

The probabilistic distribution of wind speed is one of the important wind characteristics for the... more The probabilistic distribution of wind speed is one of the important wind characteristics for the assessment of wind energy potential and for the performance of wind energy conversion systems, as well as for the structural and environmental design and analysis. In this study, an exponential family of distribution functions has been developed for the description of the probabilistic distribution of wind speed, and comparison with the wind speed data taken from different sources and measured at different geographical locations in the world has been made. This family of distributions is developed by introducing a pre-exponential term to the theoretical distribution derived from the maximum entropy principle (MEP). The statistical analysis parameter based on the wind power density is used as the suitability judgement for the distribution functions. It is shown that the MEPtype distributions not only agree better with a variety of the measured wind speed data than the conventionally used empirical Weibull distribution, but also can represent the wind power density much more accurately. Therefore, the MEP-type distributions are more suitable for the assessment of the wind energy potential and the performance of wind energy conversion systems.

Research paper thumbnail of MEP-type distribution function: a better alternative to Weibull function for wind speed distributions

Renewable energy, 2005

The probabilistic distribution of wind speed is one of the important wind characteristics for the... more The probabilistic distribution of wind speed is one of the important wind characteristics for the assessment of wind energy potential and for the performance of wind energy conversion systems, as well as for the structural and environmental design and analysis. In this study, an exponential family of distribution functions has been developed for the description of the probabilistic distribution of wind speed, and comparison with the wind speed data taken from different sources and measured at different geographical locations in the world has been made. This family of distributions is developed by introducing a pre-exponential term to the theoretical distribution derived from the maximum entropy principle (MEP). The statistical analysis parameter based on the wind power density is used as the suitability judgement for the distribution functions. It is shown that the MEPtype distributions not only agree better with a variety of the measured wind speed data than the conventionally used empirical Weibull distribution, but also can represent the wind power density much more accurately. Therefore, the MEP-type distributions are more suitable for the assessment of the wind energy potential and the performance of wind energy conversion systems.

Research paper thumbnail of On the probabilistic distribution of wind speeds: theoretical development and comparison with data

International Journal of Exergy, 2004

Research paper thumbnail of Modeling the Initial Droplet Size Distribution in Sprays Based on the Maximization of Entropy Generation

Atomization and Sprays, 2005

The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and v... more The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and velocity distribution in sprays, is, strictly speaking, only applicable for isolated systems in thermodynamic equilibrium; whereas the spray formation processes are ...

Research paper thumbnail of An Improved Model for the Droplet Size Distribution in Sprays Developed From the Prin- ciple of Entropy Generation maximization

The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and v... more The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and velocity distribution in sprays, is, strictly speaking, only applicable for isolated systems in thermodynamic equilibrium; whereas the spray formation processes are irreversible and non-isolated with interaction between the atomizing liquid and its surrounding gas medium. In this study, a new model for the droplet size distribution has been developed based on the thermodynamically consistent concept – the maximization of entropy generation during the liquid atomization process. The model prediction compares favorably with the experimentally measured size distribution for droplets, near the liquid bulk breakup region, produced by an air-blast annular nozzle, a planar nozzle and a practical gas turbine nozzle. Therefore, the present model can be used to predict the initial droplet size distribution in sprays. Corresponding author Introduction Since the later 1980s, Maximum Entropy Principle...

Research paper thumbnail of A Second-Order Newton-Raphson Method for Improved Numerical Stability in the Determination of Droplet Size Distributions in Sprays

Atomization and Sprays, 2006

Research paper thumbnail of Modeling the Initial Droplet Size Distribution in Sprays Based on the Maximization of Entropy Generation

Atomization and Sprays, 2005

The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and v... more The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and velocity distribution in sprays, is, strictly speaking, only applicable for isolated systems in thermodynamic equilibrium; whereas the spray formation processes are ...

Research paper thumbnail of A Comparison of Coarse-resolution Numerical Simulation with Experimental Measurements of Wind Turbine Aerodynamic Performance

Procedia Engineering, 2014

Coarse-resolution computational fluid dynamics simulations using the unsteady Delayed-Detached-Ed... more Coarse-resolution computational fluid dynamics simulations using the unsteady Delayed-Detached-Eddy simulation (DDES) and the steady Reynolds-Averaged Navier-Stokes (RANS) methodologies were conducted to predict the aerodynamic performance of the Fortis Montana 5.8-kW horizontal-axis wind turbine (HAWT). The turbulence models used for the closure of the DDES and RANS methodologies were the one-equation Spalart-Allmaras model and the two-equation shear stress transport k model, respectively. To assess and validate the predictive performance of these two simulation strategies conducted with coarse-resolution computational grids, experimental measurements of the Fortis Montana 5.8-kW HAWT were conducted at the 9 m 9 m National Research Council Canada wind tunnel. Results of a detailed comparison between the wind tunnel experimental measurements and the model predictions are presented. It was found that predictions of the power curve using the DDES methodology yielded good conformance with the associated experimental measurements. Furthermore, it was found that the RANS method fails to capture the correct power output at moderate and high tip speed ratios. It is concluded that accuracy in a wind turbine power curve prediction using the relatively coarse mesh in this study is probably satisfactory for most real-world industrial and engineering applications.

Research paper thumbnail of Droplet Size Distribution in Sprays Based on Maximization of Entropy Generation

Abstract: The maximum entropy principle (MEP), which has been popular in the modeling of droplet ... more Abstract: The maximum entropy principle (MEP), which has been popular in the modeling of droplet size and velocity distribution in sprays, is, strictly speaking, only applicable for isolated systems in thermodynamic equilibrium; whereas the spray formation processes are irreversible and non-isolated with interaction between the atomizing liquid and its surrounding gas medium. In this study, a new model for the droplet size distribution has been developed based on the thermodynamically consistent concept – the maximization of entropy generation during the liquid atomization process. The model prediction compares favorably with the experimentally measured size distribution for droplets, near the liquid bulk breakup region, produced by an air-blast annular nozzle and a practical gas turbine nozzle. Therefore, the present model can be used to predict the initial droplet size distribution in sprays.

Research paper thumbnail of Investigation of wind characteristics and assessment of wind energy potential for Waterloo region, Canada

Energy conversion and management, 2005

Wind energy becomes more and more attractive as one of the clean renewable energy resources. Know... more Wind energy becomes more and more attractive as one of the clean renewable energy resources. Knowledge of the wind characteristics is of great importance in the exploitation of wind energy resources for a site. It is essential in designing or selecting a wind energy conversion system for any application. This study examines the wind characteristics for the Waterloo region in Canada based on a data source measured at an elevation 10 m above the ground level over a 5-year period (1999-2003) with the emphasis on the suitability for wind energy technology applications. Characteristics such as annual, seasonal, monthly and diurnal wind speed variations and wind direction variations are examined. Wind speed data reveal that the windy months in Waterloo are from November to April, defined as the Cold Season in this study, with February being the windiest month. It is helpful that the high heating demand in the Cold Season coincides with the windy season. Analysis shows that the day time is the windy time, with 2 p.m. in the afternoon being the windiest moment. Moreover, a model derived from the maximum entropy principle (MEP) is applied to determine the diurnal, monthly, seasonal and yearly wind speed frequency distributions, and the corresponding Lagrangian parameters are determined. Based on these wind speed distributions, this study quantifies the available wind energy potential to provide practical information for the application of wind energy in this area. The yearly average wind power density is 105 W/m 2. The day and night time wind power density in the Cold Season is 180 and 111 W/m 2 , respectively.

Research paper thumbnail of MEP-type distribution function: a better alternative to Weibull function for wind speed distributions

Renewable energy, 2005

The probabilistic distribution of wind speed is one of the important wind characteristics for the... more The probabilistic distribution of wind speed is one of the important wind characteristics for the assessment of wind energy potential and for the performance of wind energy conversion systems, as well as for the structural and environmental design and analysis. In this study, an exponential family of distribution functions has been developed for the description of the probabilistic distribution of wind speed, and comparison with the wind speed data taken from different sources and measured at different geographical locations in the world has been made. This family of distributions is developed by introducing a pre-exponential term to the theoretical distribution derived from the maximum entropy principle (MEP). The statistical analysis parameter based on the wind power density is used as the suitability judgement for the distribution functions. It is shown that the MEPtype distributions not only agree better with a variety of the measured wind speed data than the conventionally used empirical Weibull distribution, but also can represent the wind power density much more accurately. Therefore, the MEP-type distributions are more suitable for the assessment of the wind energy potential and the performance of wind energy conversion systems.

Research paper thumbnail of MEP-type distribution function: a better alternative to Weibull function for wind speed distributions

Renewable energy, 2005

The probabilistic distribution of wind speed is one of the important wind characteristics for the... more The probabilistic distribution of wind speed is one of the important wind characteristics for the assessment of wind energy potential and for the performance of wind energy conversion systems, as well as for the structural and environmental design and analysis. In this study, an exponential family of distribution functions has been developed for the description of the probabilistic distribution of wind speed, and comparison with the wind speed data taken from different sources and measured at different geographical locations in the world has been made. This family of distributions is developed by introducing a pre-exponential term to the theoretical distribution derived from the maximum entropy principle (MEP). The statistical analysis parameter based on the wind power density is used as the suitability judgement for the distribution functions. It is shown that the MEPtype distributions not only agree better with a variety of the measured wind speed data than the conventionally used empirical Weibull distribution, but also can represent the wind power density much more accurately. Therefore, the MEP-type distributions are more suitable for the assessment of the wind energy potential and the performance of wind energy conversion systems.

Research paper thumbnail of On the probabilistic distribution of wind speeds: theoretical development and comparison with data

International Journal of Exergy, 2004