The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Jesus M Fernandezoro - One of the best experts on this subject based on the ideXlab platform.
-
energy storage in underground coal mines in nw spain assessment of an underground lower water reservoir and preliminary energy balance
Renewable Energy, 2019Co-Authors: Javier Menéndez, Jorge Loredo, Monica Galdo, Jesus M FernandezoroAbstract:During the last decades, the Asturian Central Coal Basin (ACCB) has been a highly exploited coal mining area by means of underground mining and its network of tunnels extend among more than 30 mines. Parts of this infrastructure will soon become available for alternative uses since most of the coal mining facilities in Spain will fade out in 2018. Increasing penetration of renewable energy sources into the electrical grid, with intermittent and fluctuating supply, leads to excessive frequency variations, so the development of energy storage technologies are required, such as Pumped Storage Hydroelectricity (PSH). Reduced environmental impacts, deep, non-flooded shafts and abundance of water from underground run-off, make coal mines in ACCB suitable for the development of Underground Pumped-Storage Hydropower projects (UPSH). The network of tunnels of a mine facility has an unusual geometry for a water storage system. Although there are numerous studies for the construction of UPSH plants, until now there have been no known projects of this type under operation. Filling and emptying processes during the operation of the Turbine-Pump are complex due to the presence of two fluids interacting inside the tunnels, water and air. This paper explores the viability of a network of tunnels as an underground water reservoir. Two-phase three-dimensional CFD models have been developed in order to know the flow behavior in the tunnels. The pressure and velocity results that have been obtained in the simulations confirm that the use of underground mines as a lower reservoir of a UPSH is technically possible.
G. Símunovic - One of the best experts on this subject based on the ideXlab platform.
-
Wear factors of vertical Turbine Pump shaft sleeves | Čimbenici trošenja zaštitnih čahura vratila vertikalne crpke
Tehnicki Vjesnik, 2000Co-Authors: K. Símunovic, G. SímunovicAbstract:By the analysis of the partial tribological systems being of a vertical Turbine Pump shaft sleeve being one of the elements, wear mechanism - abrasion wear of shaft sleeves, caused by sand particles in Pumping river water, has been defined. Therefore the presence of sand in river water is a direct wear factor of shaft sleeves. Indirect factor is the river water leakage into the cooling area of stuffing box and slide bearings. It may happen because of pressure difference between river water and clean cooling water and as well because of leaking on packing. Knowledge of these direct and indirect factors lead to the solution of this problem that causes considerable losses.
-
Wear factors of vertical Turbine Pump shaft sleeves
Tehnicki Vjesnik, 2000Co-Authors: K. Símunovic, G. SímunovicAbstract:By the analysis of the partial tribological systems being of a vertical Turbine Pump shaft sleeve being one of the elements, wear mechanism - abrasion wear of shaft sleeves, caused by sand particles in Pumping river water, has been defined. Therefore the presence of sand in river water is a direct wear factor of shaft sleeves. Indirect factor is the river water leakage into the cooling area of stuffing box and slide bearings. It may happen because of pressure difference between river water and clean cooling water and as well because of leaking on packing. Knowledge of these direct and indirect factors lead to the solution of this problem that causes considerable losses.
Javier Menéndez - One of the best experts on this subject based on the ideXlab platform.
-
energy storage in underground coal mines in nw spain assessment of an underground lower water reservoir and preliminary energy balance
Renewable Energy, 2019Co-Authors: Javier Menéndez, Jorge Loredo, Monica Galdo, Jesus M FernandezoroAbstract:During the last decades, the Asturian Central Coal Basin (ACCB) has been a highly exploited coal mining area by means of underground mining and its network of tunnels extend among more than 30 mines. Parts of this infrastructure will soon become available for alternative uses since most of the coal mining facilities in Spain will fade out in 2018. Increasing penetration of renewable energy sources into the electrical grid, with intermittent and fluctuating supply, leads to excessive frequency variations, so the development of energy storage technologies are required, such as Pumped Storage Hydroelectricity (PSH). Reduced environmental impacts, deep, non-flooded shafts and abundance of water from underground run-off, make coal mines in ACCB suitable for the development of Underground Pumped-Storage Hydropower projects (UPSH). The network of tunnels of a mine facility has an unusual geometry for a water storage system. Although there are numerous studies for the construction of UPSH plants, until now there have been no known projects of this type under operation. Filling and emptying processes during the operation of the Turbine-Pump are complex due to the presence of two fluids interacting inside the tunnels, water and air. This paper explores the viability of a network of tunnels as an underground water reservoir. Two-phase three-dimensional CFD models have been developed in order to know the flow behavior in the tunnels. The pressure and velocity results that have been obtained in the simulations confirm that the use of underground mines as a lower reservoir of a UPSH is technically possible.
R. D. Flack - One of the best experts on this subject based on the ideXlab platform.
-
Laser Velocimeter Measurements in the Turbine of an Automotive Torque Converter: Part II—Unsteady Measurements
Journal of Turbomachinery, 1997Co-Authors: K. Brun, R. D. FlackAbstract:The unsteady velocity field found in the Turbine of an automotive torque converter was measured using laser velocimetry. Velocities in the inlet, quarter, mild, and exit planes of the Turbine were investigated at two significantly different Turbine/Pump rotational speed ratios: 0.065 and 0.800. A data organization method was developed to visualize the three-dimensional, periodic unsteady velocity field in the rotating frame. For this method, the acquired data are assumed to be periodic at synchronous and blade interaction frequencies. Two shaft encoders were employed to obtain the instantaneous angular position of the torque converter Pump and Turbine at the instant of laser velocimeter data acquisition. By proper “registration” of the velocity data, visualizing the transient interaction effects between the Turbine, Pump, and stator was possible. Results showed strong cyclic velocity fluctuations in the Turbine inlet plane as a function of the relative Turbine-Pump position. These fluctuations are due to the passing of upstream Pump blades by the slower rotating Turbine blades. Typical fluctuations in the through flow velocity were 3.6 m/s. Quarter and midplane velocity fluctuations were seen to be lower; typical values were 1.5 m/s and 0.8 m/s, respectively. The flow field in the Turbine exit plane was seen to be relatively steady with negligible fluctuations of less than 0.03 m/s. From the velocity data, the fluctuations of Turbine performance parameters such as flow inlet angles, root-mean-square unsteadiness, and output torque per blade passage were calculated. Incidence angles were seen to vary by 3 and 6 deg for the 0.800 and 0.065 speed ratios, respectively, while the exit angles remained steady. The Turbine output torque per blade passage fluctuated by 0.05 Nm for the 0.800 speed ratio and 0.13 Nm for the 0.065 speed ratio.
-
Laser Velocimeter Measurements in the Turbine of an Automotive Torque Converter: Part I—Average Measurements
Journal of Turbomachinery, 1997Co-Authors: K. Brun, R. D. FlackAbstract:The three-dimensional average velocity field in an automotive torque converter Turbine was examined. Two significantly different operating conditions of the torque converter were tested: the 0.065 and 0.800 Turbine/Pump speed ratio. Velocities were measured using a one-directional, frequency-shifted laser velocimeter. The instantaneous angular positions of the torque converter Turbine and Pump were recorded using digital shaft encoders. Shaft encoder information and velocities were correlated to generate average velocity blade-to-blade profiles and velocity vector plots. Measurements were taken in the inlet, quarter, mid, and exit planes of the Turbine. From the experimental velocity measurements, mass flows, Turbine output torque, average vorticities, viscous dissipation, inlet incidence flow angles, and exit flow angles were calculated. Average mass flows were 23.4 kg/s and 14.7 kg/s for the 0.065 and 0.800 speed ratios, respectively. Velocity vector plots for both Turbine/Pump speed ratios showed the flow field in the Turbine quarter and midplanes to be highly nonuniform with separation regions and reversed flows at the core-suction corner. For the conditions tested, the Turbine inlet flow was seen to have a high relative incidence angle, while the relative Turbine exit flow angle was close to the blade angle.
-
Laser Velocimeter Measurements in the Pump of an Automotive Torque Converter: Part I—Average Measurements
Journal of Turbomachinery-transactions of The Asme, 1996Co-Authors: J. K. Gruver, R. D. Flack, K. BrunAbstract:The three-dimensional average velocity field in an automotive torque converter Turbine was examined. Two significantly different operating conditions of the torque converter were tested: the 0.065 and 0.800 Turbine/Pump speed ratio. Velocities were measured using a one-directional, frequency-shifted laser velocimeter. The instantaneous angular positions of the torque converter Turbine and Pump were recorded using digital shaft encoders. Shaft encoder information and velocities were correlated to generate average velocity blade-to-blade profiles and velocity vector plots. Measurements were taken in the inlet, quarter, mid, and exit planes of the Turbine. From the experimental velocity measurements, mass flows, Turbine output torque, average vorticities, viscous dissipation, inlet incidence flow angles, and exit flow angles were calculated. Average mass flows were 23.4 kg/s and 14.7 kg/s for the 0.065 and 0.800 speed ratios, respectively. Velocity vector plots for both Turbine/Pump speed ratios showed the flow field in the Turbine quarter and midplanes to be highly nonuniform with separation regions and reversed flows at the core-suction corner. For the conditions tested, the Turbine inlet flow was seen to have a high relative incidence angle, while the relative Turbine exit flow angle was close to the blade angle.
-
Laser Velocimeter Measurements in the Turbine of an Automotive Torque Converter: Part II — Unsteady Measurements
Volume 1: Turbomachinery, 1995Co-Authors: Klaus Bran, R. D. FlackAbstract:The unsteady velocity field found in the Turbine of an automotive torque converter was measured using laser velocimetry. Velocities in the inlet, quarter, mid, and exit planes of the Turbine were investigated at two significantly different operating conditions: Turbine/Pump rotational speed ratios of 0.065, and 0.800. A data organization method was developed to visualize the three-dimensional, periodic unsteady velocity field in the rotating frame. For this method, the acquired data is assumed to be periodic at synchronous and blade interaction frequencies. Two shaft encoders were employed to obtain the instantaneous angular position of the torque converter Pump and Turbine at the instant of laser velocimeter data acquisition. By proper “registration” of the velocity data, visualizing the transient interaction effects between the Turbine, Pump, and stator was possible. Results showed strong cyclic velocity fluctuations in the Turbine inlet plane as a function of the relative Turbine-Pump position. These fluctuations are due to the passing of upstream Pump blades by the slower rotating Turbine blades. Typical fluctuations in the through flow velocity were 3.6 m/s. Quarter and mid plane velocity fluctuations were seen to be lower; typical values were 1.5 m/s and 0.8 m/s, respectively. The flow field in the Turbine exit plane was seen to be relatively steady with negligible fluctuations of less than 0.03 m/s. From the velocity data, the fluctuations of Turbine performance parameters such as flow inlet angles, root-mean-square unsteadiness, and output torque per blade passage were calculated. Incidence angles were seen to vary by 3° and 6° for the 0.800 and 0.065 speed ratios, respectively, while the exit angles remained steady. The Turbine output torque per blade passage fluctuated by 0.05 Nm for the 0.800 speed ratio and 0.13 Nm for the 0.065 speed ratio.© 1995 ASME
-
Laser Velocimeter Measurements in the Turbine of an Automotive Torque Converter: Part I — Average Measurements
Volume 1: Turbomachinery, 1995Co-Authors: Klaus Bran, R. D. FlackAbstract:The three-dimensional average velocity field in an automotive torque converter Turbine was examined. Two significantly different operating conditions of the torque converter were tested: the 0.065 and 0.800 Turbine/Pump speed ratio. Velocities were measured using a one-directional, frequency shifted laser velocimeter. The instantaneous angular positions of the torque converter Turbine and Pump were recorded using digital shaft encoders. Shaft encoder information and velocities were correlated to generate average velocity blade-to-blade profiles and velocity vector plots. Measurements were taken in the inlet, quarter, mid, and exit planes of the Turbine. From the experimental velocity measurements, mass flows, Turbine output torque, average vorticities, viscous dissipation, inlet incidence flow angles, and exit flow angles were calculated. Average mass flows were 23.4 kg/s and 14.7 kg/s for the 0.065 and 0.800 speed ratios, respectively. Velocity vector plots for both Turbine/Pump speed ratios showed the flow field in the Turbine quarter and mid planes to be highly non-uniform with separation regions and reversed flows at the core-suction corner. For the conditions tested, the Turbine inlet flow was seen to have a high relative incidence angle, while the relative Turbine exit flow angle was close to the blade angle.
K. Símunovic - One of the best experts on this subject based on the ideXlab platform.
-
Wear factors of vertical Turbine Pump shaft sleeves | Čimbenici trošenja zaštitnih čahura vratila vertikalne crpke
Tehnicki Vjesnik, 2000Co-Authors: K. Símunovic, G. SímunovicAbstract:By the analysis of the partial tribological systems being of a vertical Turbine Pump shaft sleeve being one of the elements, wear mechanism - abrasion wear of shaft sleeves, caused by sand particles in Pumping river water, has been defined. Therefore the presence of sand in river water is a direct wear factor of shaft sleeves. Indirect factor is the river water leakage into the cooling area of stuffing box and slide bearings. It may happen because of pressure difference between river water and clean cooling water and as well because of leaking on packing. Knowledge of these direct and indirect factors lead to the solution of this problem that causes considerable losses.
-
Wear factors of vertical Turbine Pump shaft sleeves
Tehnicki Vjesnik, 2000Co-Authors: K. Símunovic, G. SímunovicAbstract:By the analysis of the partial tribological systems being of a vertical Turbine Pump shaft sleeve being one of the elements, wear mechanism - abrasion wear of shaft sleeves, caused by sand particles in Pumping river water, has been defined. Therefore the presence of sand in river water is a direct wear factor of shaft sleeves. Indirect factor is the river water leakage into the cooling area of stuffing box and slide bearings. It may happen because of pressure difference between river water and clean cooling water and as well because of leaking on packing. Knowledge of these direct and indirect factors lead to the solution of this problem that causes considerable losses.
