Current Issue : January - March Volume : 2020 Issue Number : 1 Articles : 5 Articles
The present paper proposes a methodology to design and manufacture optimized turbomachinery components by leveraging the\npotential of Topology Optimization (TO) andAdditiveManufacturing (AM).The method envisages the use of TOto define the best\nconfiguration of the rotoric components in terms of both static and dynamic behavior with a resultant reduction of overall weight.\nEventually, the topology-optimized component ismanufactured by using appropriatematerials that can guarantee validmechanical\nperformances.The proposed strategy has been applied to a 2D impeller used for centrifugal compressors to prove the effectiveness\nof a TO+AM-based approach. Although this approach has never been extensively used before to centrifugal compressors and\nexpanders, its application on rotor and stator componentsmight unlock several benefits: tuning the natural frequencies, a reduction\nin the stress level, and a lighter weight of the rotating part. These objectives can be reached alone or in combination, performing\na single analysis or a multiple analyses optimization. Finally, the introduction of AM technologies as standard manufacturing\nresources could bring sensible benefits with respect to the time to production and availability of components. Such aspects are\nessential in the Oil and Gas context, when dealing with new projects but also for service operations....
This paper performs a systematic numerical study to investigate the effect of rotation friction ratio on the power extraction\nperformance of a passive rotation H-type vertical axis wind turbine (H-VAWT). In contrast to the previous literature, the present\nwork does not impose rotation velocity on the turbine, and the rotation friction ratio which reflects the effect of external load\ncharacteristics on the turbine is introduced to the governing equation of the turbine. During each iteration, the rotation velocity of\nthe turbine is computed after having determined the aerodynamic torque exerted on the blade of the turbine. This ismore consistent\nwith the actual working environment of the H-VAWT.A novel numerical coupling model was developed to simulate the interaction\nbetween the fluid and the passive rotation of the H-VAWT; then, the power extraction performance of the turbine with different\nrotation friction ratio was systematically analyzed. The results demonstrate that the power extraction performance of H-VAWTwill\nbe enhanced when the H-VAWT has appropriate rotation friction ratio. It is also found that the flow separation induced by large\nangle of attack is alleviated essentially if the H-VAWT has appropriate rotation friction ratio, which makes theH-VAWThave better\nenergy extraction performance....
To cope with the demand and supply of electrical load of an interconnected\npower system of a country, we need to forecast its demand in advance. In this\npaper, we use a fuzzy system to forecast electrical load on short-term basis.\nHere, we consider temperature, humidity, seasons of a year and time segments\nof a day as the parameters, which govern the demand of electrical load.\nFor each of the parameter, we use several membership functions (MFs) and\nthen apply the Mamdani rule on MFs and the output is determined by using\nthe centroid method. Finally, the surface plot reveals the real scenario of the\nload demand. The difference between actual load and the output of the fuzzy\nsystem is found as +1.65% to -13.76%. The concept of the paper can be applied\nin interconnected power system of Bangladesh to reduce power loss,\nespecially when generation is higher than the demand....
The rapid spreading of the Photovoltaic (PV) Systems as Distributed Generation\n(DG) in medium and low voltage networks created many effects and\nchanges on the existing power system networks. In this work, two methods\nhave been used and applied to determine the optimal allocation and sizing of\nthe PV to be installed as DGs (ranging from 250 kW up to 3 MW). The first\none is to determine the location according to the maximal power losses reduction\nover the feeder. The second one is by using the Harmony Search Algorithm\nwhich is claimed to be a powerful technique for optimal allocation of\nPV systems. The results of the two techniques were compared and found to\nbe nearly closed. Furthermore, investigation on the effects on the feeder in\nterms of voltage levels, power factor readings, and short circuit current levels\nhas been done. All calculations and simulations are conducted by using the\nMATLAB Simulation Program. Some field calculations and observations have\nbeen expended in order to substantiate the research findings and validation....
This paper analyzes the performance of a synchronous reluctance motor (SynRM)\nequipped with a limited amount of a permanent magnet (PM). This is conventionally implemented\nby inserting PMs in rotor flux barriers, and this is often called the PM-assisted SynRM (PMa-\nSynRM). However, common PMa-SynRMs could be vulnerable to irreversible demagnetization.\nTherefore, motor performance and PM demagnetization should be simultaneously considered, and\nthis would require the PM to be properly arranged. In this paper, various rotor configurations are\ncarefully studied and compared in order to maximize the motor performance, avoid irreversible\ndemagnetization and achieve higher PM utilization. Moreover, the field weakening capability is\ninvestigated and improved by regulating armature excitation. A particular rotor type with flux\nintensification was found to possess higher PM utilization, lower demagnetization possibility with\nfairly high performance. Thus, suitable rotor configurations are recommended for certain\napplications....
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