10 results on '"Md. Zishan Akhter"'
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2. Aerodynamics of a three-dimensional bionic morphing flap
- Author
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Md. Zishan Akhter, Ahmed Riyadh Ali, and Farag Khalifa Omar
- Subjects
Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology - Published
- 2022
- Full Text
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3. Design and Analysis of a Morphing Trailing Edge System
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Ahmed Riyadh Ali, Md. Zishan Akhter, and Farag K. Omar
- Subjects
Surface (mathematics) ,Morphing ,Quadratic equation ,Computer science ,Surface wave ,Deflection (engineering) ,Trailing edge ,Mechanical engineering ,Aerodynamics ,Finite element method - Abstract
The morphing technologies represent a potential candidate for replacing conventional control surface devices. The design of an actively driven compliant trailing edge structure is demonstrated. The generated deflection layout is identified with a three-dimensional, seamless, and continuous wave-like quadratic layout upon activation. The numerical finite element modeling and results of the adaptive structure are presented.
- Published
- 2021
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4. Wind Turbine Power Augmentation Using Virtually Morphed Trailing Edge
- Author
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Farag K. Omar, Md. Zishan Akhter, and Ahmed Riyadh Ali
- Subjects
Wind power ,Boosting (machine learning) ,business.industry ,Computer science ,Rotor (electric) ,Turbine ,GeneralLiterature_MISCELLANEOUS ,Wind speed ,law.invention ,Power (physics) ,law ,Control system ,Trailing edge ,Aerospace engineering ,business - Abstract
The constant reliance on sustainable energy resources is driving the research community toward adopting advanced and effective wind turbine systems. A trailing-edge segment featuring seamless and continuous morphed layout is presented. The aim is to quantitatively assess the potentials of the morphed surface in boosting the power output of small-scale wind turbines. Integration of the morphed trailing edge to the rotor blade demonstrated significant contribution in promoting power extraction particularly under low wind speed.
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- 2021
- Full Text
- View/download PDF
5. Ballistic and thermomechanical characterisation of paraffin-based hybrid rocket fuels loaded with light metal hydrides
- Author
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Md. Zishan Akhter, M. A. Hassan, and School of Mechanical and Aerospace Engineering
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Propellant ,020301 aerospace & aeronautics ,Materials science ,Hydride ,Magnesium hydride ,Aerospace Engineering ,Rocket propellant ,02 engineering and technology ,Hybrid Rocket Fuel ,Lithium aluminium hydride ,Combustion ,01 natural sciences ,Light metal ,chemistry.chemical_compound ,0203 mechanical engineering ,chemistry ,Paraffin wax ,0103 physical sciences ,Mechanical engineering [Engineering] ,Composite material ,Rheology ,010303 astronomy & astrophysics - Abstract
Rocket fuels are subjected to intense in-flight inertial, pressure and thermal loads that has drastic effect on its performance. In order to achieve optimal results, we require functionally-graded solid propellant (FGSPs), specifically designed for each flight condition. A novel series of FGSPs were developed using Paraffin Wax (as fuel) and Hydroxyl-terminated polybutadiene (as binder); treated with Dioctyl adipate (C22H42O4), Toluene diisocyante (C9H6N2O2) and Glycerol (C3H8O3). These FGSPs were further doped with light metal hydride nano-powders including Lithium aluminium hydride (LiAlH4) and Magnesium hydride (MgH2). The FGSPs were investigated for thermo-physical and ballistic performance using several characterisation techniques. The Magnesium hydride-doped FGSPs exhibited lower viscosity that fostered entrainment-aided combustion. FGSPs doped with Lithium aluminium hydride featured solid-like behaviour that makes them more stable in solid phase and less susceptible to in-flight loads. Thermal characterisation revealed that Lithium aluminium hydride makes FGSPs comparatively more resistant towards pyrolysis thereby producing greater char-yield. Eventually, combustion characteristics were evaluated by performing static ballistic firings of the developed FGSPs. The doped FGSPs exhibited significant enhancement in regression compared to the base fuel and conventional HTPB fuel. The MgH2-doped FGSP exhibited maximum enhancements of up to 224% and 353% as compared with the base fuel and HTPB, respectively. Accepted version The corresponding author thankfully acknowledge the grant from Science and Engineering Research Board, Department of Science and Technology, Government of India vide file no. ECR/001003/2017.
- Published
- 2020
6. Energetic Additives for Hybrid Rocket Propulsion - Review
- Author
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M. A. Hassan and Md. Zishan Akhter
- Subjects
Propellant ,chemistry.chemical_compound ,Materials science ,chemistry ,Chemical engineering ,Hydrogen ,Aluminium ,Ammonia borane ,Magnesium hydride ,chemistry.chemical_element ,Rocket propellant ,Aluminium hydride ,Lithium aluminium hydride - Abstract
Hybrid propulsion offers safe, reliable and environment friendly alternative to conventional systems. There is a wide range of propellants and additives reported for hybrid propulsion. In this paper some energetic particles comprising metals, and light metal hydrides and their advantages in terms of regression behavior are discussed. Additive particles like aluminium, boron, boron carbide, tungsten, iron, carbon, magnesium, magnesium hydride, aluminium hydride, lithium aluminium hydride, ammonium perchlorate and ammonia borane are discussed. Regression rate enhancement of 20%-150% has been reported and found to be dependent on additive percentage. Metals have high density and heat of oxidation which helps in regression rate augmentation. Metal hydrides are good source of hydrogen varying from 7.6% for Magnesium hydride to 19.6% for Ammonia borane. These hydrides release nascent hydrogen during combustion and improve regression rate thereby boosting specific impulse and characteristic velocity of the rocket. Energetic particle laden hybrid rocket fuel has potential to make chemical propulsion safer, economical and sustainable.
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- 2020
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7. Temporal and Economic Benefits of Vertical Take-Off and Landing Vehicles in Urban Transport
- Author
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Md. Zishan Akhter, Mohsin Raza, and Syed Haris Iftikhar
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Transport engineering ,Mode of transport ,Computer science ,Service (economics) ,media_common.quotation_subject ,Hyperloop ,Mode (statistics) ,Mode choice ,Economic benefits ,Metropolitan area ,Vertical take off and landing ,media_common - Abstract
Vertical take-off and landing (VTOL) is a futuristic mode of transport that can potentially revolutionize the way we commute. However, despite the technical leads offered by VTOL, the feasibility of this state-of-the-art urban commute needs to be established from various aspects. This study assesses the temporal and economic benefits offered by VTOL technology over the conventional road taxi service. The mode ‘taxi’ is chosen as it is thought to compete, as a chief mode of urban transport, with the VTOL transport in future. The comparison is based on two decisive factors: the peak hour travel-time and fare by taxi and VTOL on 44 routes in five metropolitan cities: New York, Los Angeles, London, Munich and Shanghai. Analysis of Variance (ANOVA) is performed on the data set and conclusion is drawn on the statistical significance of the difference in the response variables (time and fare) by mode choice (VTOL versus Taxi). VTOL is found to offer significant advantages over the surface transport (taxi) in terms of time and fare. The findings of this study are expected to assist in determining the practicality of VTOL systems. Moreover, the methodology used here is reproducible and provides a framework for testing the practicality of other futuristic transport modes (such as hyperloop).
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- 2020
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8. Corrigendum to 'Performance enhancement of a small-scale wind turbine featuring morphed trailing edge' [Sustain. Energy Technol. Assess. 45 (2021) 101229]
- Author
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Md. Zishan Akhter, Farag K. Omar, Narasimalu Srikanth, and Ahmed Riyadh Ali
- Subjects
Scale (ratio) ,Renewable Energy, Sustainability and the Environment ,business.industry ,Energy Engineering and Power Technology ,Environmental science ,Trailing edge ,Aerospace engineering ,Performance enhancement ,business ,Turbine ,Energy (signal processing) - Published
- 2021
- Full Text
- View/download PDF
9. Performance enhancement of a small-scale wind turbine featuring morphed trailing edge
- Author
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Md. Zishan Akhter, Farag K. Omar, and Ahmed Riyadh Ali
- Subjects
Wind power ,Turbine blade ,Renewable Energy, Sustainability and the Environment ,business.industry ,Rotor (electric) ,020209 energy ,Energy Engineering and Power Technology ,02 engineering and technology ,Aerodynamics ,Computational fluid dynamics ,Turbine ,Wind speed ,law.invention ,020401 chemical engineering ,law ,0202 electrical engineering, electronic engineering, information engineering ,Trailing edge ,Environmental science ,0204 chemical engineering ,business ,Marine engineering - Abstract
The constant increase in reliance on sustainable energy resources is driving the research community towards adopting innovative and efficient wind turbine systems. A trailing-edge segment featuring seamless, wavelike, and continuous deflected layout is presented and integrated into a small-scale wind turbine blade. The study aims to quantitatively assess the potential of a moderately morphed (bumped) trailing edge in enhancing the power output of the wind turbines mainly at low wind velocity operating conditions. The National Renewable Energy Laboratory (NREL) Phase-II wind turbine is selected to be the benchmark model for the current quantitative analysis. Three-dimensional transient computational fluid dynamic (CFD) numerical analysis is established at three operating wind velocities using Ansys Fluent solver. The computed results of the baseline rotor blade are validated using data taken from the NREL/NASA-Ames experimental report. The implementation of a morphed (bumped) trailing edge shows a significant contribution in promoting energy harvesting with just a few degrees of smooth and gradual deformation. Compared to the baseline model, up to 53% in additional power gain is obtained from the rotor blade with integrated morphed (bumped) trailing edge segment. Thus, the compromised aerodynamic performance of stall-controlled small-scale wind turbines can be greatly improved with the utilization of morphing-capable trailing edge systems.
- Published
- 2021
- Full Text
- View/download PDF
10. Characterisation of paraffin-based hybrid rocket fuels loaded with nano-additives
- Author
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Md. Zishan Akhter, M. A. Hassan, and School of Mechanical and Aerospace Engineering
- Subjects
ballistic performance ,Materials science ,Biomedical Engineering ,Nanoparticle ,Bioengineering ,Rocket propellant ,02 engineering and technology ,Combustion ,Lithium aluminium hydride ,lcsh:Chemical technology ,01 natural sciences ,010305 fluids & plasmas ,space propulsion ,chemistry.chemical_compound ,0203 mechanical engineering ,Paraffin wax ,0103 physical sciences ,lcsh:TA401-492 ,General Materials Science ,lcsh:TP1-1185 ,Hybrid Fuel ,020301 aerospace & aeronautics ,Magnesium hydride ,Nascent hydrogen ,nano-additives ,Solid fuel ,Hybrid fuel ,Nano-additives ,chemistry ,Chemical engineering ,Mechanical engineering [Engineering] ,rheology ,lcsh:Materials of engineering and construction. Mechanics of materials ,solid fuel - Abstract
In this work, a new composition based on Paraffin wax and HTPB fuel, loaded with nanoparticles has been proposed for hybrid propulsion system. Lithium aluminium hydride (LiAlH4) and Magnesium hydride (MgH2) nanoparticles have been used as additives. A detailed rheological, thermal and ballistic characterisation has been carried out. The Magnesium hydride doped hybrid fuel exhibits lower viscosity as compared to the Lithium aluminium hydride doped one, leading to comparatively enhanced entrainment-aided combustion. LiAlH4 doped hybrid fuels also exhibit solid-like behaviour and thus greater stability in the solid phase in contrast to the MgH2 doped fuel. LiAlH4 doped fuel is thermally more stable and produces relatively greater residual-mass. The loading of nanoparticles significantly improves the fuel regression performance during ballistic firing. This can be attributed to the release of nascent hydrogen and metal nanoparticles during dehydrogenation of metal hydrides. Regression rate enhancement in the range of 350%–475% is observed in comparison to the conventional HTPB hybrid fuels. A power law governing regression rate has been proposed for the tested hybrid fuels. Accepted version
- Published
- 2018
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