The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform
R H Lenssen - One of the best experts on this subject based on the ideXlab platform.
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series hybrid electric aircraft comparing the well to Propeller Efficiency with a conventional Propeller aircraft
2016Co-Authors: R H LenssenAbstract:THE aviation industry is responsible for 12% of the total transportation impact of CO2 while awareness, for decreasing the total carbon footprint, is rising. Both the aerospace and the automotive industry are facing an increasing pressure from society to make the transportation sector more sustainable. Within the automotive industry slowly an increase in electric vehicles can be noticed (<1%). Also in the aerospace industry a rise in electrification can be seen, with small aircraft as the E-Star and E-Fan (two seaters) as commercial examples. Electrification of the transportation sector could further result in a decrease in noise and an increase in lifespan of parts as vibrations are decreased. This master’s thesis is written in conjunction with the chair Flight Performance and Propulsion at the faculty of Aerospace Engineering at the Delft University of Technology. The main purpose is to gain more insight in modelling an (hybrid) electric aircraft and the potential improvements with respect to well-to-Propeller Efficiency (usefull energy over total energy ratio). This is achieved by first creating a baseline conventional Propeller aircraftmodel (ATR72) and then a hybrid electric version of the same aircraft. The variations between the sub-models and validation data are calculated in order to have a feeling for the accuracy of each individual model. Furthermore, both the theoretical and current practical state of technologies are used in the overall model. Finally, a sensitivity analysis is performed to find the driving parameters in the outcome of the model. The analysis of the series hybrid electric aircraft showed first of all that the expected advantages of the concept are ’small to non-existent’. The electric energy used to charge the batteries should first of all come from a renewable source of energy to make the concept feasible. Secondly, the theoretical limits of technology should be approached in order for the well-to-Propeller Efficiency to exceed that of the conventional ATR72 aircraft (with a maximum of 2%). It is seen that the model converges to an all electric version of the ATR72 if the battery energy density is increased to 2,802 [Wh/kg], this would correspond to the theoretical limit of Lithium Sulphur battery-technology. Furthermore, for an increase in voltage the battery Efficiency decreases while all other components will improve in Efficiency. The optimum is found in increasing the voltage up to the practical limit of 25 [kV]. Electric propulsion creates new design possibilities as distributed propulsion and variable shaft-speed. Within this thesis it is however shown that the ’benefits’ of distributed propulsion do not outweigh the downsides (increase inweight and decrease in Efficiency of all components). Furthermore electric motors allow for temporary torque overloading, by decreasing the rotational speed and increasing the torque, the overall result is an increase in Efficiency, which could for example be usefull during the climb or take-off phase. Concluding, the concept of series hybrid electric aircraft is at this moment in time rendered infeasible. The potential within a 35 year time-frame is doubtfull as especially battery technology should improvewith at least 400 [%]. In order to accelerate the transition to hybrid electric or all electric aircraft, the main areas of research should be: battery technology and the integration of alternating current and superconducting materials in rotating machine parts.
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Series Hybrid Electric Aircraft: Comparing the Well-to-Propeller Efficiency With a Conventional Propeller Aircraft
2016Co-Authors: R H LenssenAbstract:THE aviation industry is responsible for 12% of the total transportation impact of CO2 while awareness, for decreasing the total carbon footprint, is rising. Both the aerospace and the automotive industry are facing an increasing pressure from society to make the transportation sector more sustainable. Within the automotive industry slowly an increase in electric vehicles can be noticed (
T. Szelangiewicz - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of influence of streamline rudder on screw Propeller Efficiency
Polish Maritime Research, 2010Co-Authors: Tomasz Abramowski, Jakub Handke, T. SzelangiewiczAbstract:During designing the ship its designer tends to obtain as high as possible Efficiency of ship propulsion system. To this end on certain ships additional elements such as: nozzles, half-nozzles or suitably profiled fins attached to underwater part of ship’s hull before screw Propeller, are applied (sometimes they are intended for the mitigating of vibration resulting from operation of screw Propeller). Another device which affects operation of screw Propeller is streamline rudder capable of improving its Efficiency (most of the transport ships is fitted with single screw Propeller and streamline rudder placed behind it). In this paper the influence of streamline rudder on screw Propeller Efficiency has been examined with the use of numerical methods of fluid dynamics (CFD).The obtained results indicate a very favourable influence of the rudder on screw Propeller Efficiency. Research in this area is continued and its results concerning impact of particular geometrical parameters of rudder on screw Propeller Efficiency, will be presented in the future.
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numerical analysis of effect of asymmetric stern of ship on its screw Propeller Efficiency
Polish Maritime Research, 2010Co-Authors: Tomasz Abramowski, Katarzyna żelazny, T. SzelangiewiczAbstract:During designing the ship its designer tends to achieve as-high-as possible Efficiency of ship’s propulsion system. The greatest impact on the Efficiency is introduced by ship’s screw Propeller whose Efficiency depends not only on its geometry but also distribution of wake current velocity. To change wake current distribution and improve Propeller Efficiency an asymmetric form is usually applied to stern part of ship hull. This paper presents results of numerical analysis of wake current velocity distribution, performed by using a CFD method for a B 573 ship of symmetric stern and the same ship of an asymmetric stern. Next, the mean values of screw Propeller Efficiency in non-homogenous water velocity field were calculated for both the hull versions of B 573 ship.
Subhendu Maity - One of the best experts on this subject based on the ideXlab platform.
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Numerical investigation to observe combined effect of Propeller boss cap fin (PBCF) and Propeller duct to improve Propeller Efficiency
Journal of Marine Science and Technology, 2020Co-Authors: Pritam Majumder, Dileep Kumar Avanapu, Subhendu MaityAbstract:Propeller is the main device in marine vehicle to generate propulsive energy. During practical manoeuvring condition, it losses a major part of energy due to the formation of hub as well as tip vortex. This fact becomes a great concern for researcher and motivates to find some alternate energy saving device (ESD). In this paper numerical investigations, based on Reynolds Average Navier Stokes (RANS) equation, are carried out to observe the combined effect of PBCF and Propeller duct as ESDs to improve Propeller Efficiency. Here, aerofoil shape PBCF with NACA4412 profile has been combined with 19A and 19Am duct to observe their ability to improve Propeller Efficiency in moving reference frame approach. Along that to make a comparative study, numerical investigations are also performed with Propeller and 19A duct without PBCF. Results show that in comparison to the combined effect of PBCF and ducted Propeller, only duct (19A) without PBCF plays a prominent role to enhance Propeller Efficiency by approximately 9.21%. To obtain more details of flow phenomenon, fluctuation of velocity, pressure, vortex strength, etc., at various locations are also investigated. Besides that, the effect of angle of attack of the duct on a PBCF introduced ducted Propeller is also investigated numerically.
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RETRACTED ARTICLE: Numerical investigation to observe combined effect of Propeller boss cap fin (PBCF) and Propeller duct to improve Propeller Efficiency
Journal of Marine Science and Technology, 2020Co-Authors: Pritam Majumder, Dileep Kumar Avanapu, Subhendu MaityAbstract:Propeller is the main device in marine vehicle to generate propulsive energy. During practical manoeuvring condition, it losses a major part of energy due to the formation of hub as well as tip vortex. This fact becomes a great concern for researcher and motivates to find some alternate energy saving device (ESD). In this paper numerical investigations, based on Reynolds Average Navier Stokes (RANS) equation, are carried out to observe the combined effect of PBCF and Propeller duct as ESDs to improve Propeller Efficiency. Here, aerofoil shape PBCF with NACA4412 profile has been combined with 19A and 19Am duct to observe their ability to improve Propeller Efficiency in moving reference frame approach. Along that to make a comparative study, numerical investigations are also performed with Propeller and 19A duct without PBCF. Results show that in comparison to the combined effect of PBCF and ducted Propeller, only duct (19A) without PBCF plays a prominent role to enhance Propeller Efficiency by approximately 9.21%. To obtain more details of flow phenomenon, fluctuation of velocity, pressure, vortex strength, etc., at various locations are also investigated. Besides that, the effect of angle of attack of the duct on a PBCF introduced ducted Propeller is also investigated numerically.
Hassan Ghassemi - One of the best experts on this subject based on the ideXlab platform.
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Propeller Efficiency Enhancement by the Blade's Tip Reformation
American Journal of Mechanical Engineering, 2017Co-Authors: Meysam Maghareh, Hassan GhassemiAbstract:Many devices are designed to augment thrust and Efficiency. Propeller’s blade plays a fundamental role in order to enhance Efficiency. In this paper, DTMB4382 is selected as reference Propeller in which blade reformation has been applied on the tip toward suction and pressure side and hydrodynamic performance have been discussed by using numerical investigation. Numerical results of the hydrodynamic characteristics of the Propeller at the different blade tip angles are presented and discussed.
Tomasz Abramowski - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of influence of streamline rudder on screw Propeller Efficiency
Polish Maritime Research, 2010Co-Authors: Tomasz Abramowski, Jakub Handke, T. SzelangiewiczAbstract:During designing the ship its designer tends to obtain as high as possible Efficiency of ship propulsion system. To this end on certain ships additional elements such as: nozzles, half-nozzles or suitably profiled fins attached to underwater part of ship’s hull before screw Propeller, are applied (sometimes they are intended for the mitigating of vibration resulting from operation of screw Propeller). Another device which affects operation of screw Propeller is streamline rudder capable of improving its Efficiency (most of the transport ships is fitted with single screw Propeller and streamline rudder placed behind it). In this paper the influence of streamline rudder on screw Propeller Efficiency has been examined with the use of numerical methods of fluid dynamics (CFD).The obtained results indicate a very favourable influence of the rudder on screw Propeller Efficiency. Research in this area is continued and its results concerning impact of particular geometrical parameters of rudder on screw Propeller Efficiency, will be presented in the future.
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numerical analysis of effect of asymmetric stern of ship on its screw Propeller Efficiency
Polish Maritime Research, 2010Co-Authors: Tomasz Abramowski, Katarzyna żelazny, T. SzelangiewiczAbstract:During designing the ship its designer tends to achieve as-high-as possible Efficiency of ship’s propulsion system. The greatest impact on the Efficiency is introduced by ship’s screw Propeller whose Efficiency depends not only on its geometry but also distribution of wake current velocity. To change wake current distribution and improve Propeller Efficiency an asymmetric form is usually applied to stern part of ship hull. This paper presents results of numerical analysis of wake current velocity distribution, performed by using a CFD method for a B 573 ship of symmetric stern and the same ship of an asymmetric stern. Next, the mean values of screw Propeller Efficiency in non-homogenous water velocity field were calculated for both the hull versions of B 573 ship.
