The Experts below are selected from a list of 9987 Experts worldwide ranked by ideXlab platform
Johann W Kolar - One of the best experts on this subject based on the ideXlab platform.
-
Pump Characteristic based optimization of a direct water cooling system for a 10 kw 500 khz vienna rectifier
IEEE Transactions on Power Electronics, 2005Co-Authors: U Drofenik, G Laimer, Johann W KolarAbstract:An ultra high power density 10-kW/500-kHz three-phase pulse-width modulation rectifier (Vienna Rectifier) is under development at the Power Electronic Systems Laboratory, ETH Zurich. From preliminary measurements and numerical simulations the total efficiency is assumed to be 95% at full load, resulting in power losses of up to 150 W in each multichip power module that realizes a bridge leg of the rectifier. In order to maintain the required power density of the system high direct water cooling is employed where water is in direct contact with the module base plate. Based on the measured Characteristic of the water Pump (pressure drop dependent on the water flow rate) the geometry of different water channel structures below the module base plate is systematically optimized based on equations which are formulated using well-established fluid dynamics theory. The design optimization is constrained by the desire to keep the geometry of the water channels in a range which allows simple and low-cost manufacturing. The aim is to find a channel structure resulting in a minimum thermal resistance of the power module for a given Pump Characteristic. In this paper, a very simple slot channel is investigated. The dependency of the thermal resistance on the cooling system is calculated for various heights of the slot channel, and an optimized channel height is determined using the condition of simple manufacturability. The shortcomings of the simple slot structure are discussed, and a novel metallic inlay structure is introduced and optimized that results in a reduction of the thermal resistance of the direct water cooling scheme as compared to the slot channel system. All theoretical considerations are experimentally verified. The general optimization scheme introduced in this paper can easily be adapted to other cooling problems.
-
Pump Characteristic based optimization of a direct water cooling system for a 10 kw 500 khz vienna rectifier
Power Electronics Specialists Conference, 2004Co-Authors: U Drofenik, G Laimer, Johann W KolarAbstract:A high power density 10 kW/500 kHz three-phase PWM rectifier (Vienna Rectifier) is under development. Due to preliminary measurements and numerical simulations the total efficiency is assumed to be 95% at full load, resulting in power losses of up to 150 W in each multi-chip power module realizing a bridge leg of the rectifier. In order to keep the power density of the system high direct water cooling is employed where water is in direct contact with the module base plate. Based on the measured Characteristic of the water Pump (pressure drop dependent on water flow) the geometry of different water channel structures below the module base plate is systematically optimized based on analytical expressions which are formulated based on the well-established theory of fluid dynamics. The design optimization is constrained by the desire to keep the geometry of the water channels in a range that allows simple and low-cost manufacturing. The aim is to find a channel structure resulting in a minimum thermal resistance of the power module for a given Pump Characteristic. In this paper a very simple slot channel is investigated. The dependency of the thermal resistance on the cooling system is calculated in dependency on the height of the slot channel, and an optimized channel height is found under the side condition of simple manufacturability. Discussing the shortcomings of the simple slot structure, a novel metallic inlay structure is introduced and optimized resulting in a reduction of the thermal resistance of the direct water cooling scheme as compared to the slot channel system. All theoretical considerations are verified via experimental measurements. The general optimization scheme introduced in this paper can easily be adapted to other cooling problems.
U Drofenik - One of the best experts on this subject based on the ideXlab platform.
-
Pump Characteristic based optimization of a direct water cooling system for a 10 kw 500 khz vienna rectifier
IEEE Transactions on Power Electronics, 2005Co-Authors: U Drofenik, G Laimer, Johann W KolarAbstract:An ultra high power density 10-kW/500-kHz three-phase pulse-width modulation rectifier (Vienna Rectifier) is under development at the Power Electronic Systems Laboratory, ETH Zurich. From preliminary measurements and numerical simulations the total efficiency is assumed to be 95% at full load, resulting in power losses of up to 150 W in each multichip power module that realizes a bridge leg of the rectifier. In order to maintain the required power density of the system high direct water cooling is employed where water is in direct contact with the module base plate. Based on the measured Characteristic of the water Pump (pressure drop dependent on the water flow rate) the geometry of different water channel structures below the module base plate is systematically optimized based on equations which are formulated using well-established fluid dynamics theory. The design optimization is constrained by the desire to keep the geometry of the water channels in a range which allows simple and low-cost manufacturing. The aim is to find a channel structure resulting in a minimum thermal resistance of the power module for a given Pump Characteristic. In this paper, a very simple slot channel is investigated. The dependency of the thermal resistance on the cooling system is calculated for various heights of the slot channel, and an optimized channel height is determined using the condition of simple manufacturability. The shortcomings of the simple slot structure are discussed, and a novel metallic inlay structure is introduced and optimized that results in a reduction of the thermal resistance of the direct water cooling scheme as compared to the slot channel system. All theoretical considerations are experimentally verified. The general optimization scheme introduced in this paper can easily be adapted to other cooling problems.
-
Pump Characteristic based optimization of a direct water cooling system for a 10 kw 500 khz vienna rectifier
Power Electronics Specialists Conference, 2004Co-Authors: U Drofenik, G Laimer, Johann W KolarAbstract:A high power density 10 kW/500 kHz three-phase PWM rectifier (Vienna Rectifier) is under development. Due to preliminary measurements and numerical simulations the total efficiency is assumed to be 95% at full load, resulting in power losses of up to 150 W in each multi-chip power module realizing a bridge leg of the rectifier. In order to keep the power density of the system high direct water cooling is employed where water is in direct contact with the module base plate. Based on the measured Characteristic of the water Pump (pressure drop dependent on water flow) the geometry of different water channel structures below the module base plate is systematically optimized based on analytical expressions which are formulated based on the well-established theory of fluid dynamics. The design optimization is constrained by the desire to keep the geometry of the water channels in a range that allows simple and low-cost manufacturing. The aim is to find a channel structure resulting in a minimum thermal resistance of the power module for a given Pump Characteristic. In this paper a very simple slot channel is investigated. The dependency of the thermal resistance on the cooling system is calculated in dependency on the height of the slot channel, and an optimized channel height is found under the side condition of simple manufacturability. Discussing the shortcomings of the simple slot structure, a novel metallic inlay structure is introduced and optimized resulting in a reduction of the thermal resistance of the direct water cooling scheme as compared to the slot channel system. All theoretical considerations are verified via experimental measurements. The general optimization scheme introduced in this paper can easily be adapted to other cooling problems.
G Laimer - One of the best experts on this subject based on the ideXlab platform.
-
Pump Characteristic based optimization of a direct water cooling system for a 10 kw 500 khz vienna rectifier
IEEE Transactions on Power Electronics, 2005Co-Authors: U Drofenik, G Laimer, Johann W KolarAbstract:An ultra high power density 10-kW/500-kHz three-phase pulse-width modulation rectifier (Vienna Rectifier) is under development at the Power Electronic Systems Laboratory, ETH Zurich. From preliminary measurements and numerical simulations the total efficiency is assumed to be 95% at full load, resulting in power losses of up to 150 W in each multichip power module that realizes a bridge leg of the rectifier. In order to maintain the required power density of the system high direct water cooling is employed where water is in direct contact with the module base plate. Based on the measured Characteristic of the water Pump (pressure drop dependent on the water flow rate) the geometry of different water channel structures below the module base plate is systematically optimized based on equations which are formulated using well-established fluid dynamics theory. The design optimization is constrained by the desire to keep the geometry of the water channels in a range which allows simple and low-cost manufacturing. The aim is to find a channel structure resulting in a minimum thermal resistance of the power module for a given Pump Characteristic. In this paper, a very simple slot channel is investigated. The dependency of the thermal resistance on the cooling system is calculated for various heights of the slot channel, and an optimized channel height is determined using the condition of simple manufacturability. The shortcomings of the simple slot structure are discussed, and a novel metallic inlay structure is introduced and optimized that results in a reduction of the thermal resistance of the direct water cooling scheme as compared to the slot channel system. All theoretical considerations are experimentally verified. The general optimization scheme introduced in this paper can easily be adapted to other cooling problems.
-
Pump Characteristic based optimization of a direct water cooling system for a 10 kw 500 khz vienna rectifier
Power Electronics Specialists Conference, 2004Co-Authors: U Drofenik, G Laimer, Johann W KolarAbstract:A high power density 10 kW/500 kHz three-phase PWM rectifier (Vienna Rectifier) is under development. Due to preliminary measurements and numerical simulations the total efficiency is assumed to be 95% at full load, resulting in power losses of up to 150 W in each multi-chip power module realizing a bridge leg of the rectifier. In order to keep the power density of the system high direct water cooling is employed where water is in direct contact with the module base plate. Based on the measured Characteristic of the water Pump (pressure drop dependent on water flow) the geometry of different water channel structures below the module base plate is systematically optimized based on analytical expressions which are formulated based on the well-established theory of fluid dynamics. The design optimization is constrained by the desire to keep the geometry of the water channels in a range that allows simple and low-cost manufacturing. The aim is to find a channel structure resulting in a minimum thermal resistance of the power module for a given Pump Characteristic. In this paper a very simple slot channel is investigated. The dependency of the thermal resistance on the cooling system is calculated in dependency on the height of the slot channel, and an optimized channel height is found under the side condition of simple manufacturability. Discussing the shortcomings of the simple slot structure, a novel metallic inlay structure is introduced and optimized resulting in a reduction of the thermal resistance of the direct water cooling scheme as compared to the slot channel system. All theoretical considerations are verified via experimental measurements. The general optimization scheme introduced in this paper can easily be adapted to other cooling problems.
Alireza Riasi - One of the best experts on this subject based on the ideXlab platform.
-
the effects of viscoelastic fluid on the cavitation inception and development within a centrifugal Pump an experimental study
International Communications in Heat and Mass Transfer, 2019Co-Authors: Saber Azad, Hossein Lotfi, Alireza RiasiAbstract:Abstract Cavitation in a transparent centrifugal Pump has been experimentally investigated using viscoelastic fluid. Viscoelastic fluids are aqueous solutions of polyacrylamide with different concentrations of 100, 200, and 400 ppm at room temperature. The cavitation inception and the bubble population through the blade passages were extracted using two different methods: (a) visually observing the population of bubbles in the flow and (b) Pump Characteristic curves analysis. The results illustrated that the polymer concentration, cavitation number, and degradation can dramatically affect the bubble initiation and development. Bubble initiation was postponed in the case of polymer solutions and this effect was more significant in higher concentrations. Besides, at the same conditions, the population of the bubbles in the polymer solutions significantly decreased compared to the water, especially at higher concentrations. This effect was decreased with decreasing the cavitation number. Also, the fresh polymer solutions had lower critical cavitation numbers in comparison with the tap water. In addition to the fresh polymer solution, the effect of the degradation was investigated in the current study, too. Results showed that with degradation, bubble initiation occurred sooner and the population of the bubbles significantly increased compared to the fresh solutions.
-
the effect of wear ring clearance on flow field in the impeller sidewall gap and efficiency of a low specific speed centrifugal Pump
Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2018Co-Authors: Mohammadreza Daqiqshirazi, R Torabi, Alireza Riasi, Seyed NourbakhshAbstract:In this paper, the flow in the impeller sidewall gap of a low specific speed centrifugal Pump is analyzed to study the effect of wear ring clearance and the resultant through-flow on flow field in this cavity and investigate the overall efficiency of the Pump. Centrifugal Pumps are commonly subject to a reduction in the flow rate and volumetric efficiency due to abrasive liquids or working conditions, since the wear rings are progressively worn, the internal leakage flow is increased. In the new operating point, the overall efficiency of the Pump cannot be predicted simply by using the Pump Characteristic curves. The flow field is simulated with the use of computational fluid dynamics and the three-dimensional full Navier–Stokes equations are solved using CFX software. In order to verify the numerical simulations, static pressure field in volute casing and Pump performance curves are compared with the experimental measurements. The results show that, for the Pump with minimum wear ring clearance, the disk...
Youlin Yang - One of the best experts on this subject based on the ideXlab platform.
-
Estimation of centrifugal Pump operational state with dual neural network architecture based model
Neurocomputing, 2016Co-Authors: Qinghuan Shen, Xinjun Wang, Youlin YangAbstract:Abstract The sensorless estimation of the operational state of a centrifugal Pump system provides new opportunities for the monitoring and control of Pumping systems. In this paper, the disadvantages of traditional estimation methods based on Pump Characteristic equations are investigated and analyzed. A novel estimation method based on dual neural network architecture is advised and trained offline to determine the operation state of the Pump drive. Simulation studies are performed on ISG150-400 centrifugal Pump using the proposed estimation method. The test results are provided to validate the effectiveness.
