Diego Alejandro Penagos Vásquez | ITM - Instituto Tecnológico Metropolitano (original) (raw)

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Papers by Diego Alejandro Penagos Vásquez

A pump as turbine (PAT) is a turbomachine that converts hydraulic energy into electricity. One of... more A pump as turbine (PAT) is a turbomachine that converts hydraulic energy into electricity. One of the study topics in PAT is the efficiency due to centrifugal pumps are not designed to operate in reverse mode. Geometric variations of the impeller have been studied in the literature. However, it was not possible to evidence the influence of the inclination of the blade leading and trailing edge. Therefore, the objective of this work is to analyze numerically and fluid dynamically the inclination angle of the blade leading and trailing edge of a centrifugal pump, in pump and turbine mode. First, the characteristic curve was validated. Then, the inclination of the leading and the trailing edge was modified, in a range of 25° to 90°, obtaining head, efficiency, and power graph. As a result, in pump mode was evidenced that an angle close to 90° on the blade trailing edge provides a higher efficiency of 50.26% and decreases until 40.77% when the angle approaches 30°, reducing the head to around 20%, while power remained constant. In turbine mode, an inverse effect was obtained, where the maximum efficiency was 60.9% and the generated power increased up to 4.76 kW in the blade leading edge. Therefore, the angular variation of the leading and the trailing edge is adequate in turbine mode, while in pump mode there is a loss of capacity.

A centrifugal pump as a turbine (PAT) is the inverse operation of a conventional pump, which take... more A centrifugal pump as a turbine (PAT) is the inverse operation of a conventional pump, which takes advantage of the hydraulic energy of water to convert it into rotational mechanical energy and subsequently into electrical energy, through a generator. The CFD analysis allows predicting the fluid dynamic behavior and calculating the operating characteristic curve of the PAT, thus reducing costs in experimental setups. In the literature, the operation of the turbomachine in pump and turbine mode is evidenced. However, there is no methodology applied in commercial axial flow pumps that exposes a structured step-by-step to carry out the numerical and fluid dynamic analysis. In this study, a novel structured methodology is developed describing the numerical and CFD analysis of a commercial axial flow centrifugal pump, which allows validating the characteristic curve in pump mode and then obtaining the site conditions in turbine mode, for its application in small hydroelectric power plants. As a result, in pump mode, an error of less than 8% is obtained between the manufacturer's curve and the numerical curve. In turbine mode, the best performance is around 73%. The aim is to propose a replicable algorithm in future works that allows the proper analysis in commercial axial flow pumps.

This article presents a mathematical model to calculate the cost and production of electrical ene... more This article presents a mathematical model to calculate the cost and production of electrical energy of a system that combines energy storage through renewable sources such as wind and solar energy, applying a theoretical framework of mathematical aspects to evaluate a pumped storage system with Pelton turbines, using a novel methodology, easy to replicate. The results show that a greater increase in the diameter in the pipe of the pumping equipment reduces the electrical power supplied to the pump. On the other hand, the hydraulic losses in the pipe leading to the Pelton turbine are negligible for long lengths, so setting the maximum length instead of a variable-length with the hydraulic height does not affect the result. Finally, the information and explanation of each of the graphs that correlate to the variables of interest are shown. This seeks to offer a contribution to support technological development in areas that do not have electricity, taking advantage of natural resources.

In this work, we seek to predict the characteristic curve of a commercial centrifugal radial flow... more In this work, we seek to predict the characteristic curve of a commercial centrifugal radial flow pump operating as a turbine, applying a novel methodology based on the state of the art. Initially, the characteristic curve in pump mode is validated through numerical simulations. The results obtained are approximate to the points awarded by the manufacturer, with an error of less than 7% at the best efficiency point. Subsequently, the characteristic curve is generated in turbine mode, obtaining an error of less than 10% respect to mathematical model. Then, velocity and pressure contours are evaluated to validate the fluid dynamic behavior. Finally, the site operating conditions for electricity generation are obtained. With this, it is proposing a methodology for the selection of these turbomachines, applying an economic technology for zones that do not have access to the electrical energy, since it was not found a method that is being applied for its correct election in the hydroelectric generation at low scale.

A pump as turbine (PAT) is a turbomachine that converts hydraulic energy into electricity. One of... more A pump as turbine (PAT) is a turbomachine that converts hydraulic energy into electricity. One of the study topics in PAT is the efficiency due to centrifugal pumps are not designed to operate in reverse mode. Geometric variations of the impeller have been studied in the literature. However, it was not possible to evidence the influence of the inclination of the blade leading and trailing edge. Therefore, the objective of this work is to analyze numerically and fluid dynamically the inclination angle of the blade leading and trailing edge of a centrifugal pump, in pump and turbine mode. First, the characteristic curve was validated. Then, the inclination of the leading and the trailing edge was modified, in a range of 25° to 90°, obtaining head, efficiency, and power graph. As a result, in pump mode was evidenced that an angle close to 90° on the blade trailing edge provides a higher efficiency of 50.26% and decreases until 40.77% when the angle approaches 30°, reducing the head to around 20%, while power remained constant. In turbine mode, an inverse effect was obtained, where the maximum efficiency was 60.9% and the generated power increased up to 4.76 kW in the blade leading edge. Therefore, the angular variation of the leading and the trailing edge is adequate in turbine mode, while in pump mode there is a loss of capacity.

A centrifugal pump as a turbine (PAT) is the inverse operation of a conventional pump, which take... more A centrifugal pump as a turbine (PAT) is the inverse operation of a conventional pump, which takes advantage of the hydraulic energy of water to convert it into rotational mechanical energy and subsequently into electrical energy, through a generator. The CFD analysis allows predicting the fluid dynamic behavior and calculating the operating characteristic curve of the PAT, thus reducing costs in experimental setups. In the literature, the operation of the turbomachine in pump and turbine mode is evidenced. However, there is no methodology applied in commercial axial flow pumps that exposes a structured step-by-step to carry out the numerical and fluid dynamic analysis. In this study, a novel structured methodology is developed describing the numerical and CFD analysis of a commercial axial flow centrifugal pump, which allows validating the characteristic curve in pump mode and then obtaining the site conditions in turbine mode, for its application in small hydroelectric power plants. As a result, in pump mode, an error of less than 8% is obtained between the manufacturer's curve and the numerical curve. In turbine mode, the best performance is around 73%. The aim is to propose a replicable algorithm in future works that allows the proper analysis in commercial axial flow pumps.

This article presents a mathematical model to calculate the cost and production of electrical ene... more This article presents a mathematical model to calculate the cost and production of electrical energy of a system that combines energy storage through renewable sources such as wind and solar energy, applying a theoretical framework of mathematical aspects to evaluate a pumped storage system with Pelton turbines, using a novel methodology, easy to replicate. The results show that a greater increase in the diameter in the pipe of the pumping equipment reduces the electrical power supplied to the pump. On the other hand, the hydraulic losses in the pipe leading to the Pelton turbine are negligible for long lengths, so setting the maximum length instead of a variable-length with the hydraulic height does not affect the result. Finally, the information and explanation of each of the graphs that correlate to the variables of interest are shown. This seeks to offer a contribution to support technological development in areas that do not have electricity, taking advantage of natural resources.

In this work, we seek to predict the characteristic curve of a commercial centrifugal radial flow... more In this work, we seek to predict the characteristic curve of a commercial centrifugal radial flow pump operating as a turbine, applying a novel methodology based on the state of the art. Initially, the characteristic curve in pump mode is validated through numerical simulations. The results obtained are approximate to the points awarded by the manufacturer, with an error of less than 7% at the best efficiency point. Subsequently, the characteristic curve is generated in turbine mode, obtaining an error of less than 10% respect to mathematical model. Then, velocity and pressure contours are evaluated to validate the fluid dynamic behavior. Finally, the site operating conditions for electricity generation are obtained. With this, it is proposing a methodology for the selection of these turbomachines, applying an economic technology for zones that do not have access to the electrical energy, since it was not found a method that is being applied for its correct election in the hydroelectric generation at low scale.