farooq najar | University of Kashmir, Srinagar, J&K, India (original) (raw)
Papers by farooq najar
IOP Conference Series: Materials Science and Engineering, 2017
International Journal of Precision Technology, 2015
The present paper describes the thermal effect on a sector shaped pad extensively used in thrust ... more The present paper describes the thermal effect on a sector shaped pad extensively used in thrust bearings, which supports the heavy duty axial loads. Large hydrogenerator thrust bearings are susceptible to too much thermo-elastic deformation when oil film thickness is subjected to high pressure and temperature, which can even lead to the bearing failure. So as a remedy, this study is an effort towards reducing the oil film temperature by incorporating a suitable cooling treatment. The cooling circuit, in this study, essentially follows a path of hot spots observed by solving Reynolds equation, energy equation and generalised Fourier heat conduction equation. The numerical scheme followed during investigation is finite difference method (FDM). The water circuit developed is just beneath the Babbitt lining of the pads. It has been observed that the overall temperature has reduced significantly when compared with a traditional cooling systems.
ASME 2014 Gas Turbine India Conference, 2014
The present paper analyzes the thermal effect on a sector shaped pad extensively used in thrust b... more The present paper analyzes the thermal effect on a sector shaped pad extensively used in thrust bearings which supports the heavy axial loads. Large hydro-generator thrust bearings are susceptible to too much thermo-elastic deformation when oil film thickness is subjected to high pressure and temperature which can even lead to the bearing failure. So as a remedy, this study is an effort towards reducing the oil film temperature by incorporating a suitable cooling treatment. The cooling circuit, in this study, essentially follows a path of hot spots observed by solving Reynolds equation, energy equation and generalized Fourier heat conduction equation. The numerical scheme followed during investigation is finite difference method (FDM). The water circuit developed is just beneath the Babbitt lining of the pads. It has been observed that overall temperature has reduced significantly as compared to traditional cooling systems.
International Scholarly Research Notices, 2014
Reynolds equation is solved using finite difference method (FDM) on the surface of the tilting pa... more Reynolds equation is solved using finite difference method (FDM) on the surface of the tilting pad to find the pressure distribution in the lubricant oil film. Different pressure profiles with grid independence are described. The present work evaluates pressure at various locations after performing a thorough grid refinement. In recent similar works, this aspect has not been addressed. However, present study shows that it can have significant effect on the pressure profile. Results of a sector shaped pad are presented and it is shown that the maximum average value of pressure is 12% (approximately) greater than the previous results. Grid independence occurs after 24 × 24 grids. A parameter “ψ” has been proposed to provide convenient indicator of obtaining grid independent results. ψ=|(Prefinedgrid-PRefrence-grid)/Prefinedgrid|, ψ≤ε, where “ε” can be fixed to a convenient value and a constant minimum film thickness value of 75 μm is used in present study. This important parameter is ...
Abstract: This paper reviews the design optimization of wind turbine blades through investigating... more Abstract: This paper reviews the design optimization of wind turbine blades through investigating the design methods and analyzing the performance of the blades. The current research work in this area include wind turbine blade geometric design and optimization, aerodynamics analysis, wind turbine blade structural design and dynamics analysis. Blade geometric design addresses the design parameters, including airfoils and their aerodynamic coefficients, attack angles, design tip speed ratio, design and/or rated wind speed, rotor diameter, blade aerodynamic shape with chord length and twist distributions, so that the blade achieves an optimum power performance. The geometry of the blade is an aerodynamic shape with nonlinear chord and twist distribution, which can be obtained based on the BEM theory with respect to given aerofoil with known aerodynamic coefficients. In terms of blade aerodynamics analysis, there are four types of aerodynamic models which can be used to predict the aer...
Jurnal Tribologi, 2016
This paper deals with the study of the influence on performance characteristics of a thrust beari... more This paper deals with the study of the influence on performance characteristics of a thrust bearing with the introduction of cooling circuit and flow velocity of coolant within the designed thrust bearings is described. New method of cooling circuit configuration is taken into consideration and water has been chosen as a coolant here in the present work. Flow velocity of coolant, ranging from 0.5m/s to 2.0m/s is proposed. The Finite difference based numerical model has been developed in order to notice the effect on the heat transfer on a large hydrodynamic lubrication thrust bearing in-terms of its performance characteristics. In the present work, the solution of Reynolds equation, an energy equation with viscosity variation and Fourier heat conduction equations, applied with appropriate boundary conditions. From the present investigation, it is observed significant amount of heat content is removed from the bearing with the increase of flow velocity of coolant in an embedded cooli...
World Academy of Science, Engineering and Technology, International Journal of Aerospace and Mechanical Engineering, 2017
Abstract—The present study investigates the effect of inclusions on the shape and size of crack t... more Abstract—The present study investigates the effect of inclusions on the shape and size of crack tip plastic zones in engineering materials subjected to static loads by employing the element free Galerkin method (EFGM). The modeling of the discontinuities produced by cracks and inclusions becomes independent of the grid chosen for analysis. The standard displacement approximation is modified by adding additional enrichment functions, which introduce the effects of different discontinuities into the formulation. The level set method has been used to represent different discontinuities present in the domain. The effect of inclusions on the extent of crack tip plastic zones is investigated by solving some numerical problems by the EFGM.
This paper reviews the design optimization of wind turbine blades through investigating the desig... more This paper reviews the design optimization of wind turbine blades through investigating the design methods and analyzing the performance of the blades. The current research work in this area include wind turbine blade geometric design and optimization, aerodynamics analysis, wind turbine blade structural design and dynamics analysis. Blade geometric design addresses the design parameters, including airfoils and their aerodynamic coefficients, attack angles, design tip speed ratio, design and/or rated wind speed, rotor diameter, blade aerodynamic shape with chord length and twist distributions, so that the blade achieves an optimum power performance. The geometry of the blade is an aerodynamic shape with nonlinear chord and twist distribution, which can be obtained based on the BEM theory with respect to gi ven aerofoil with known aerodynamic coefficients. In terms of blade aerodynamics analysis, there are four types of aerodynamic models which can be used to predict the aerodynamic ...
Jurnal Tribologi, 2016
This paper deals with the study of the influence on performance characteristics of a thrust beari... more This paper deals with the study of the influence on performance characteristics of a thrust bearing with the introduction of cooling circuit and flow velocity of coolant within the designed thrust bearings is described. New method of cooling circuit configuration is taken into consideration and water has been chosen as a coolant here in the present work. Flow velocity of coolant, ranging from 0.5m/s to 2.0m/s is proposed. The Finite difference based numerical model has been developed in order to notice the effect on the heat transfer on a large hydrodynamic lubrication thrust bearing in-terms of its performance characteristics. In the present work, the solution of Reynolds equation, an energy equation with viscosity variation and Fourier heat conduction equations, applied with appropriate boundary conditions. From the present investigation, it is observed significant amount of heat content is removed from the bearing with the increase of flow velocity of coolant in an embedded cooli...
Reynolds equation is solved using finite difference method (FDM) on the surface of the tilting pa... more Reynolds equation is solved using finite difference method (FDM) on the surface of the tilting pad to find the pressure distribution
in the lubricant oil film. Different pressure profiles with grid independence are described. The present work evaluates pressure at
various locations after performing a thorough grid refinement. In recent similarworks, this aspect has not been addressed.However,
present study shows that it can have significant effect on the pressure profile. Results of a sector shaped pad are presented and it is
shown that the maximum average value of pressure is 12% (approximately) greater than the previous results. Grid independence
occurs after 24 × 24 grids. A parameter “𝜓” has been proposed to provide convenient indicator of obtaining grid independent
results. 𝜓 = |(𝑃refinedgrid − 𝑃Refrence-grid)/𝑃refinedgrid|, 𝜓 ≤ 𝜀, where “𝜀” can be fixed to a convenient value and a constant minimum
film thickness value of 75 𝜇m is used in present study. This important parameter is highlighted in the present work; the location of
the peak pressure zone in terms of (𝑟, 𝜃) coordinates is getting shifted by changing the grid size which will help the designer and
experimentalist to conveniently determine the position of pressure measurement probe.
The present paper analyzes the thermal effect on a sector shaped pad extensively used in thrust b... more The present paper analyzes the thermal effect on a sector
shaped pad extensively used in thrust bearings which supports
the heavy axial loads. Large hydro-generator thrust bearings are
susceptible to too much thermo-elastic deformation when oil
film thickness is subjected to high pressure and temperature
which can even lead to the bearing failure. So as a remedy, this
study is an effort towards reducing the oil film temperature by
incorporating a suitable cooling treatment. The cooling circuit,
in this study, essentially follows a path of hot spots observed by
solving Reynolds equation, energy equation and generalized
Fourier heat conduction equation. The numerical scheme
followed during investigation is finite difference method
(FDM). The water circuit developed is just beneath the Babbitt
lining of the pads. It has been observed that overall temperature
has reduced significantly as compared to traditional cooling
systems.
IOP Conference Series: Materials Science and Engineering, 2017
International Journal of Precision Technology, 2015
The present paper describes the thermal effect on a sector shaped pad extensively used in thrust ... more The present paper describes the thermal effect on a sector shaped pad extensively used in thrust bearings, which supports the heavy duty axial loads. Large hydrogenerator thrust bearings are susceptible to too much thermo-elastic deformation when oil film thickness is subjected to high pressure and temperature, which can even lead to the bearing failure. So as a remedy, this study is an effort towards reducing the oil film temperature by incorporating a suitable cooling treatment. The cooling circuit, in this study, essentially follows a path of hot spots observed by solving Reynolds equation, energy equation and generalised Fourier heat conduction equation. The numerical scheme followed during investigation is finite difference method (FDM). The water circuit developed is just beneath the Babbitt lining of the pads. It has been observed that the overall temperature has reduced significantly when compared with a traditional cooling systems.
ASME 2014 Gas Turbine India Conference, 2014
The present paper analyzes the thermal effect on a sector shaped pad extensively used in thrust b... more The present paper analyzes the thermal effect on a sector shaped pad extensively used in thrust bearings which supports the heavy axial loads. Large hydro-generator thrust bearings are susceptible to too much thermo-elastic deformation when oil film thickness is subjected to high pressure and temperature which can even lead to the bearing failure. So as a remedy, this study is an effort towards reducing the oil film temperature by incorporating a suitable cooling treatment. The cooling circuit, in this study, essentially follows a path of hot spots observed by solving Reynolds equation, energy equation and generalized Fourier heat conduction equation. The numerical scheme followed during investigation is finite difference method (FDM). The water circuit developed is just beneath the Babbitt lining of the pads. It has been observed that overall temperature has reduced significantly as compared to traditional cooling systems.
International Scholarly Research Notices, 2014
Reynolds equation is solved using finite difference method (FDM) on the surface of the tilting pa... more Reynolds equation is solved using finite difference method (FDM) on the surface of the tilting pad to find the pressure distribution in the lubricant oil film. Different pressure profiles with grid independence are described. The present work evaluates pressure at various locations after performing a thorough grid refinement. In recent similar works, this aspect has not been addressed. However, present study shows that it can have significant effect on the pressure profile. Results of a sector shaped pad are presented and it is shown that the maximum average value of pressure is 12% (approximately) greater than the previous results. Grid independence occurs after 24 × 24 grids. A parameter “ψ” has been proposed to provide convenient indicator of obtaining grid independent results. ψ=|(Prefinedgrid-PRefrence-grid)/Prefinedgrid|, ψ≤ε, where “ε” can be fixed to a convenient value and a constant minimum film thickness value of 75 μm is used in present study. This important parameter is ...
Abstract: This paper reviews the design optimization of wind turbine blades through investigating... more Abstract: This paper reviews the design optimization of wind turbine blades through investigating the design methods and analyzing the performance of the blades. The current research work in this area include wind turbine blade geometric design and optimization, aerodynamics analysis, wind turbine blade structural design and dynamics analysis. Blade geometric design addresses the design parameters, including airfoils and their aerodynamic coefficients, attack angles, design tip speed ratio, design and/or rated wind speed, rotor diameter, blade aerodynamic shape with chord length and twist distributions, so that the blade achieves an optimum power performance. The geometry of the blade is an aerodynamic shape with nonlinear chord and twist distribution, which can be obtained based on the BEM theory with respect to given aerofoil with known aerodynamic coefficients. In terms of blade aerodynamics analysis, there are four types of aerodynamic models which can be used to predict the aer...
Jurnal Tribologi, 2016
This paper deals with the study of the influence on performance characteristics of a thrust beari... more This paper deals with the study of the influence on performance characteristics of a thrust bearing with the introduction of cooling circuit and flow velocity of coolant within the designed thrust bearings is described. New method of cooling circuit configuration is taken into consideration and water has been chosen as a coolant here in the present work. Flow velocity of coolant, ranging from 0.5m/s to 2.0m/s is proposed. The Finite difference based numerical model has been developed in order to notice the effect on the heat transfer on a large hydrodynamic lubrication thrust bearing in-terms of its performance characteristics. In the present work, the solution of Reynolds equation, an energy equation with viscosity variation and Fourier heat conduction equations, applied with appropriate boundary conditions. From the present investigation, it is observed significant amount of heat content is removed from the bearing with the increase of flow velocity of coolant in an embedded cooli...
World Academy of Science, Engineering and Technology, International Journal of Aerospace and Mechanical Engineering, 2017
Abstract—The present study investigates the effect of inclusions on the shape and size of crack t... more Abstract—The present study investigates the effect of inclusions on the shape and size of crack tip plastic zones in engineering materials subjected to static loads by employing the element free Galerkin method (EFGM). The modeling of the discontinuities produced by cracks and inclusions becomes independent of the grid chosen for analysis. The standard displacement approximation is modified by adding additional enrichment functions, which introduce the effects of different discontinuities into the formulation. The level set method has been used to represent different discontinuities present in the domain. The effect of inclusions on the extent of crack tip plastic zones is investigated by solving some numerical problems by the EFGM.
This paper reviews the design optimization of wind turbine blades through investigating the desig... more This paper reviews the design optimization of wind turbine blades through investigating the design methods and analyzing the performance of the blades. The current research work in this area include wind turbine blade geometric design and optimization, aerodynamics analysis, wind turbine blade structural design and dynamics analysis. Blade geometric design addresses the design parameters, including airfoils and their aerodynamic coefficients, attack angles, design tip speed ratio, design and/or rated wind speed, rotor diameter, blade aerodynamic shape with chord length and twist distributions, so that the blade achieves an optimum power performance. The geometry of the blade is an aerodynamic shape with nonlinear chord and twist distribution, which can be obtained based on the BEM theory with respect to gi ven aerofoil with known aerodynamic coefficients. In terms of blade aerodynamics analysis, there are four types of aerodynamic models which can be used to predict the aerodynamic ...
Jurnal Tribologi, 2016
This paper deals with the study of the influence on performance characteristics of a thrust beari... more This paper deals with the study of the influence on performance characteristics of a thrust bearing with the introduction of cooling circuit and flow velocity of coolant within the designed thrust bearings is described. New method of cooling circuit configuration is taken into consideration and water has been chosen as a coolant here in the present work. Flow velocity of coolant, ranging from 0.5m/s to 2.0m/s is proposed. The Finite difference based numerical model has been developed in order to notice the effect on the heat transfer on a large hydrodynamic lubrication thrust bearing in-terms of its performance characteristics. In the present work, the solution of Reynolds equation, an energy equation with viscosity variation and Fourier heat conduction equations, applied with appropriate boundary conditions. From the present investigation, it is observed significant amount of heat content is removed from the bearing with the increase of flow velocity of coolant in an embedded cooli...
Reynolds equation is solved using finite difference method (FDM) on the surface of the tilting pa... more Reynolds equation is solved using finite difference method (FDM) on the surface of the tilting pad to find the pressure distribution
in the lubricant oil film. Different pressure profiles with grid independence are described. The present work evaluates pressure at
various locations after performing a thorough grid refinement. In recent similarworks, this aspect has not been addressed.However,
present study shows that it can have significant effect on the pressure profile. Results of a sector shaped pad are presented and it is
shown that the maximum average value of pressure is 12% (approximately) greater than the previous results. Grid independence
occurs after 24 × 24 grids. A parameter “𝜓” has been proposed to provide convenient indicator of obtaining grid independent
results. 𝜓 = |(𝑃refinedgrid − 𝑃Refrence-grid)/𝑃refinedgrid|, 𝜓 ≤ 𝜀, where “𝜀” can be fixed to a convenient value and a constant minimum
film thickness value of 75 𝜇m is used in present study. This important parameter is highlighted in the present work; the location of
the peak pressure zone in terms of (𝑟, 𝜃) coordinates is getting shifted by changing the grid size which will help the designer and
experimentalist to conveniently determine the position of pressure measurement probe.
The present paper analyzes the thermal effect on a sector shaped pad extensively used in thrust b... more The present paper analyzes the thermal effect on a sector
shaped pad extensively used in thrust bearings which supports
the heavy axial loads. Large hydro-generator thrust bearings are
susceptible to too much thermo-elastic deformation when oil
film thickness is subjected to high pressure and temperature
which can even lead to the bearing failure. So as a remedy, this
study is an effort towards reducing the oil film temperature by
incorporating a suitable cooling treatment. The cooling circuit,
in this study, essentially follows a path of hot spots observed by
solving Reynolds equation, energy equation and generalized
Fourier heat conduction equation. The numerical scheme
followed during investigation is finite difference method
(FDM). The water circuit developed is just beneath the Babbitt
lining of the pads. It has been observed that overall temperature
has reduced significantly as compared to traditional cooling
systems.