Mohammad Arqam | Universiti Teknologi Malaysia - UTM (original) (raw)
Papers by Mohammad Arqam
Deleted Journal, Mar 1, 2024
Applied Thermal Engineering, Sep 1, 2021
Abstract The design of compact, high performance electric swashplate refrigeration compressors de... more Abstract The design of compact, high performance electric swashplate refrigeration compressors demands a clear understanding of different physical phenomena and their interactions taking place inside the compressor. The dynamic characteristics of the compressor are associated with the start-up transients of the swash-plate mechanism and the time variation of suction and discharge pressures. An experimentally validated, easy to implement transient swashplate compressor model has been developed that can capture the essential physics, including inertia of the pistons and swashplate to evaluate the electric motor torque loading during compressor start-up. The effects of moment of inertia, bearing torque, viscous resistance to piston motion, and suction and discharge pressures on the torque and compressor mechanical input power are investigated. For model validation, the start-up behavior is tracked experimentally using a high-speed data logger to monitor the changing phase currents of the brushless DC motor, capturing both the instantaneous power and rotational speed. Rotational mass moment of inertia is found to have only a small effect on the compressor torque and power output and can be made negligible by changing settings in the start-up algorithm for the electric motor controller. Suction and discharge pressures during start-up are found to have the largest influence on the required starting torque. More than 95% of torque is found to be because of the line pressures. Predictions are in good agreement with measurements and show that depending on the starting refrigerant pressures in the supply lines, the starting torque can be lower than the operating torque for the compressor. The original contribution of this work is in deriving a transient swash-plate compressor model that includes the inertia of the swash-plate mechanism and in clarifying the relative importance of inertia, line pressures, viscous losses and bearing resistance on the required start-up torque for this type of compressor.
This PhD is sponsored by industry and is part of a project to develop and manufacture smart elect... more This PhD is sponsored by industry and is part of a project to develop and manufacture smart electric compressor for mobile refrigeration and air conditioning applications on commercial and heavy vehicles including industrial machinery. Compact electric compressors are of great value for the future due to the growth of the electric vehicle market. Recent advancements in the field of mobile air conditioning and refrigeration have witnessed extensive use of the swashplate compressor due to its compact structure, continuous operation, small size, light weight and better thermal comfort inside the vehicle. The design of the swashplate compressor is complex so that it requires considerable contributions from different fields of engineering viz. engineering mechanics, heat transfer and fluid dynamics. The estimate of compressor performance through modelling and experiments at the early stages of design and development serves as a useful tool for the designer. The input power, torque, in-cy...
2020 Winter Conference of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2020
Computational Modelling in Industry 4.0, 2022
Developing Charging Infrastructure and Technologies for Electric Vehicles, 2022
The interest in developing clean and environmentally-friendly energy devices to be used on vehicl... more The interest in developing clean and environmentally-friendly energy devices to be used on vehicles is intensifying because of emissions from conventional internal combustion engines considered as one of the significant contributors to the rapidly changing climate. Fuel cell energy devices, especially the proton exchange membrane (PEM) type, are the solid contender to replace the conventional vehicle propulsion technology in the transport sector. The PEM fuel cell technology needs a lot of efforts to overcome some existing problems such as durability, hydrogen storage, and cost for its successful worldwide commercialisation. This chapter deals with the durability, cost, and performance challenges related to the utilization of PEM fuel cell technology in electrified transportation. Recent advancements concerning the current challenges have been discussed. Moreover, issues of hydrogen storage and infrastructure are outlined.
Materials Today: Proceedings, 2017
DNS has been carried out for Rayleigh-Bénard convection for two-dimensional flow in a shear enclo... more DNS has been carried out for Rayleigh-Bénard convection for two-dimensional flow in a shear enclosure at fixed Reynolds number of 10,000 and Richardson numbers 0, 25, 50, 75, 87.5, while Prandtl number was fixed as 7.0. The key effect observed was that (apart from the basic vortical flow in an enclosure due to the shearing effects) there was simultaneous induction of buoyancy driven flow in an enclosure due to the convection of heat in the flow. For the cases with low and moderate Richardson number the resulting flow was found to be unperturbed, steady and laminar with an original vortical flow unaltered while for cases with high Richardson numbers the resulting flow was found to be unstable and chaotic in nature that attains a quasi-steady state after a certain period of time with strong bifurcations.
Fuel cell hybrid vehicles (FCVs) including batteries and fuel cell are being studied. In hybridis... more Fuel cell hybrid vehicles (FCVs) including batteries and fuel cell are being studied. In hybridisation of fuel cell the consideration of fuel economy, efficiency, emissions and characteristics of power output are necessary. Hybridization allows the size of the fuel cell is to be reduced by using a battery and an Ultracapacitor, and it is beneficial when the power demand is high, like with higher loads or acceleration, and it permits the fuel cell system to be operated more efficiently. In association with the above, the cost of vehicle can be reduced by reducing the cost of expensive fuel cell. When the power demand is low, the fuel cell will provides the required power. Battery and Ultracapacitor will assist in fast start up of the fuel cell and allows capture of the regenerative energy. This study deals with the comparison between two powertrain strategies for the All-Terrain Vehicles (ATVs): a Fuel Cell- Battery powertrain strategy and a Fuel Cell-Battery-Ultracapacitor powertrai...
Article history: Received 16 October 2016 Received in revised form 25 November 2016 Accepted 30 N... more Article history: Received 16 October 2016 Received in revised form 25 November 2016 Accepted 30 November 2016 Available online 8 December 2016 The spray combustion simulation includes the modelling of many physical processes that interact with each other such as droplet breakup, evaporation, mixing, and reaction which pose a challenge to the modelling effort. The present study evaluates the accuracy of an unsteady spray combustion solver based on a benchmark methanol spray combustion database. Extensive validation has been done to evaluate the accuracy of the models and improvements to the state-of-the-art of spray combustion model are proposed. A monocomponent fuel, methanol is chosen due to its well established physical and chemical properties. A comprehensive boundary condition for spray is modelled in OpenFOAM to capture the size and velocity of different droplet groups in the radial direction near the burner. A qualitative validation of the global spray-combustion characteristi...
Applied Thermal Engineering, 2021
Abstract The design of compact, high performance electric swashplate refrigeration compressors de... more Abstract The design of compact, high performance electric swashplate refrigeration compressors demands a clear understanding of different physical phenomena and their interactions taking place inside the compressor. The dynamic characteristics of the compressor are associated with the start-up transients of the swash-plate mechanism and the time variation of suction and discharge pressures. An experimentally validated, easy to implement transient swashplate compressor model has been developed that can capture the essential physics, including inertia of the pistons and swashplate to evaluate the electric motor torque loading during compressor start-up. The effects of moment of inertia, bearing torque, viscous resistance to piston motion, and suction and discharge pressures on the torque and compressor mechanical input power are investigated. For model validation, the start-up behavior is tracked experimentally using a high-speed data logger to monitor the changing phase currents of the brushless DC motor, capturing both the instantaneous power and rotational speed. Rotational mass moment of inertia is found to have only a small effect on the compressor torque and power output and can be made negligible by changing settings in the start-up algorithm for the electric motor controller. Suction and discharge pressures during start-up are found to have the largest influence on the required starting torque. More than 95% of torque is found to be because of the line pressures. Predictions are in good agreement with measurements and show that depending on the starting refrigerant pressures in the supply lines, the starting torque can be lower than the operating torque for the compressor. The original contribution of this work is in deriving a transient swash-plate compressor model that includes the inertia of the swash-plate mechanism and in clarifying the relative importance of inertia, line pressures, viscous losses and bearing resistance on the required start-up torque for this type of compressor.
Renewable and Sustainable Energy Reviews, 2021
Abstract This systematic study aims to provide an extensive review of the experimental and numeri... more Abstract This systematic study aims to provide an extensive review of the experimental and numerical studies conducted on natural convection heat transfer and fluid flow in a vertical annulus. Natural convection in vertical annular geometry has wide applications, such as in the design of the nuclear reactor, electronic equipment cooling, insulation of aircraft cabin, and control of heating and ventilation in building design, etc. Parameters with significant impact on the design and performance are discussed in detail. This includes viz. the effect of operating and geometrical parameters, the effect of cylinder rotation, the effect of magnetic field, effects of using porous media, effects of discrete heating, conjugate analysis, boiling flow, use of Nano-fluids and some miscellaneous. Furthermore, the study highlights weak points and important research gaps such as the lack of experimental studies, 3D studies, etc. Following this, some directions for future research to address these research gaps are provided.
... Mohd Nor, Mohammad Arqam (2009) SISTEM PERPUSTAKAAN MENGGUNAKAN WAP DAN SMS. ... Wireless App... more ... Mohd Nor, Mohammad Arqam (2009) SISTEM PERPUSTAKAAN MENGGUNAKAN WAP DAN SMS. ... Wireless Application Protocol technology is the facto worldwide standard for providing Internet communication and advice service on digital mobile phone, PDA and other ...
International Journal of Refrigeration, 2020
A real-gas, restricted-flow valve model is compared with an ideal-gas, ideal-valve model for a 10... more A real-gas, restricted-flow valve model is compared with an ideal-gas, ideal-valve model for a 10-cylinder swashplate refrigeration compressor. Real gas properties of R134a are evaluated using the NIST standard reference database. A minor-loss discharge-coefficient approach is used to model the refrigerant flow rate through reed valves while the ideal-valve model requires no pressure difference to open the valve. In contrast with the ideal model, the discharge temperature, refrigerant mass flow rate and volumetric efficiency as a function of rotational speed are predicted well by including real-gas properties and flow restriction on the inlet valve. The ideal-gas model significantly overpredicts the discharge temperature and shows no dependence on rpm. Heat transfer to and from the cylinder wall during compression and expansion is found to have only a small effect on predictions of compressor performance. The valve model for the suction side has the largest influence on compressor performance predictions as a function of rpm.
Deleted Journal, Mar 1, 2024
Applied Thermal Engineering, Sep 1, 2021
Abstract The design of compact, high performance electric swashplate refrigeration compressors de... more Abstract The design of compact, high performance electric swashplate refrigeration compressors demands a clear understanding of different physical phenomena and their interactions taking place inside the compressor. The dynamic characteristics of the compressor are associated with the start-up transients of the swash-plate mechanism and the time variation of suction and discharge pressures. An experimentally validated, easy to implement transient swashplate compressor model has been developed that can capture the essential physics, including inertia of the pistons and swashplate to evaluate the electric motor torque loading during compressor start-up. The effects of moment of inertia, bearing torque, viscous resistance to piston motion, and suction and discharge pressures on the torque and compressor mechanical input power are investigated. For model validation, the start-up behavior is tracked experimentally using a high-speed data logger to monitor the changing phase currents of the brushless DC motor, capturing both the instantaneous power and rotational speed. Rotational mass moment of inertia is found to have only a small effect on the compressor torque and power output and can be made negligible by changing settings in the start-up algorithm for the electric motor controller. Suction and discharge pressures during start-up are found to have the largest influence on the required starting torque. More than 95% of torque is found to be because of the line pressures. Predictions are in good agreement with measurements and show that depending on the starting refrigerant pressures in the supply lines, the starting torque can be lower than the operating torque for the compressor. The original contribution of this work is in deriving a transient swash-plate compressor model that includes the inertia of the swash-plate mechanism and in clarifying the relative importance of inertia, line pressures, viscous losses and bearing resistance on the required start-up torque for this type of compressor.
This PhD is sponsored by industry and is part of a project to develop and manufacture smart elect... more This PhD is sponsored by industry and is part of a project to develop and manufacture smart electric compressor for mobile refrigeration and air conditioning applications on commercial and heavy vehicles including industrial machinery. Compact electric compressors are of great value for the future due to the growth of the electric vehicle market. Recent advancements in the field of mobile air conditioning and refrigeration have witnessed extensive use of the swashplate compressor due to its compact structure, continuous operation, small size, light weight and better thermal comfort inside the vehicle. The design of the swashplate compressor is complex so that it requires considerable contributions from different fields of engineering viz. engineering mechanics, heat transfer and fluid dynamics. The estimate of compressor performance through modelling and experiments at the early stages of design and development serves as a useful tool for the designer. The input power, torque, in-cy...
2020 Winter Conference of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2020
Computational Modelling in Industry 4.0, 2022
Developing Charging Infrastructure and Technologies for Electric Vehicles, 2022
The interest in developing clean and environmentally-friendly energy devices to be used on vehicl... more The interest in developing clean and environmentally-friendly energy devices to be used on vehicles is intensifying because of emissions from conventional internal combustion engines considered as one of the significant contributors to the rapidly changing climate. Fuel cell energy devices, especially the proton exchange membrane (PEM) type, are the solid contender to replace the conventional vehicle propulsion technology in the transport sector. The PEM fuel cell technology needs a lot of efforts to overcome some existing problems such as durability, hydrogen storage, and cost for its successful worldwide commercialisation. This chapter deals with the durability, cost, and performance challenges related to the utilization of PEM fuel cell technology in electrified transportation. Recent advancements concerning the current challenges have been discussed. Moreover, issues of hydrogen storage and infrastructure are outlined.
Materials Today: Proceedings, 2017
DNS has been carried out for Rayleigh-Bénard convection for two-dimensional flow in a shear enclo... more DNS has been carried out for Rayleigh-Bénard convection for two-dimensional flow in a shear enclosure at fixed Reynolds number of 10,000 and Richardson numbers 0, 25, 50, 75, 87.5, while Prandtl number was fixed as 7.0. The key effect observed was that (apart from the basic vortical flow in an enclosure due to the shearing effects) there was simultaneous induction of buoyancy driven flow in an enclosure due to the convection of heat in the flow. For the cases with low and moderate Richardson number the resulting flow was found to be unperturbed, steady and laminar with an original vortical flow unaltered while for cases with high Richardson numbers the resulting flow was found to be unstable and chaotic in nature that attains a quasi-steady state after a certain period of time with strong bifurcations.
Fuel cell hybrid vehicles (FCVs) including batteries and fuel cell are being studied. In hybridis... more Fuel cell hybrid vehicles (FCVs) including batteries and fuel cell are being studied. In hybridisation of fuel cell the consideration of fuel economy, efficiency, emissions and characteristics of power output are necessary. Hybridization allows the size of the fuel cell is to be reduced by using a battery and an Ultracapacitor, and it is beneficial when the power demand is high, like with higher loads or acceleration, and it permits the fuel cell system to be operated more efficiently. In association with the above, the cost of vehicle can be reduced by reducing the cost of expensive fuel cell. When the power demand is low, the fuel cell will provides the required power. Battery and Ultracapacitor will assist in fast start up of the fuel cell and allows capture of the regenerative energy. This study deals with the comparison between two powertrain strategies for the All-Terrain Vehicles (ATVs): a Fuel Cell- Battery powertrain strategy and a Fuel Cell-Battery-Ultracapacitor powertrai...
Article history: Received 16 October 2016 Received in revised form 25 November 2016 Accepted 30 N... more Article history: Received 16 October 2016 Received in revised form 25 November 2016 Accepted 30 November 2016 Available online 8 December 2016 The spray combustion simulation includes the modelling of many physical processes that interact with each other such as droplet breakup, evaporation, mixing, and reaction which pose a challenge to the modelling effort. The present study evaluates the accuracy of an unsteady spray combustion solver based on a benchmark methanol spray combustion database. Extensive validation has been done to evaluate the accuracy of the models and improvements to the state-of-the-art of spray combustion model are proposed. A monocomponent fuel, methanol is chosen due to its well established physical and chemical properties. A comprehensive boundary condition for spray is modelled in OpenFOAM to capture the size and velocity of different droplet groups in the radial direction near the burner. A qualitative validation of the global spray-combustion characteristi...
Applied Thermal Engineering, 2021
Abstract The design of compact, high performance electric swashplate refrigeration compressors de... more Abstract The design of compact, high performance electric swashplate refrigeration compressors demands a clear understanding of different physical phenomena and their interactions taking place inside the compressor. The dynamic characteristics of the compressor are associated with the start-up transients of the swash-plate mechanism and the time variation of suction and discharge pressures. An experimentally validated, easy to implement transient swashplate compressor model has been developed that can capture the essential physics, including inertia of the pistons and swashplate to evaluate the electric motor torque loading during compressor start-up. The effects of moment of inertia, bearing torque, viscous resistance to piston motion, and suction and discharge pressures on the torque and compressor mechanical input power are investigated. For model validation, the start-up behavior is tracked experimentally using a high-speed data logger to monitor the changing phase currents of the brushless DC motor, capturing both the instantaneous power and rotational speed. Rotational mass moment of inertia is found to have only a small effect on the compressor torque and power output and can be made negligible by changing settings in the start-up algorithm for the electric motor controller. Suction and discharge pressures during start-up are found to have the largest influence on the required starting torque. More than 95% of torque is found to be because of the line pressures. Predictions are in good agreement with measurements and show that depending on the starting refrigerant pressures in the supply lines, the starting torque can be lower than the operating torque for the compressor. The original contribution of this work is in deriving a transient swash-plate compressor model that includes the inertia of the swash-plate mechanism and in clarifying the relative importance of inertia, line pressures, viscous losses and bearing resistance on the required start-up torque for this type of compressor.
Renewable and Sustainable Energy Reviews, 2021
Abstract This systematic study aims to provide an extensive review of the experimental and numeri... more Abstract This systematic study aims to provide an extensive review of the experimental and numerical studies conducted on natural convection heat transfer and fluid flow in a vertical annulus. Natural convection in vertical annular geometry has wide applications, such as in the design of the nuclear reactor, electronic equipment cooling, insulation of aircraft cabin, and control of heating and ventilation in building design, etc. Parameters with significant impact on the design and performance are discussed in detail. This includes viz. the effect of operating and geometrical parameters, the effect of cylinder rotation, the effect of magnetic field, effects of using porous media, effects of discrete heating, conjugate analysis, boiling flow, use of Nano-fluids and some miscellaneous. Furthermore, the study highlights weak points and important research gaps such as the lack of experimental studies, 3D studies, etc. Following this, some directions for future research to address these research gaps are provided.
... Mohd Nor, Mohammad Arqam (2009) SISTEM PERPUSTAKAAN MENGGUNAKAN WAP DAN SMS. ... Wireless App... more ... Mohd Nor, Mohammad Arqam (2009) SISTEM PERPUSTAKAAN MENGGUNAKAN WAP DAN SMS. ... Wireless Application Protocol technology is the facto worldwide standard for providing Internet communication and advice service on digital mobile phone, PDA and other ...
International Journal of Refrigeration, 2020
A real-gas, restricted-flow valve model is compared with an ideal-gas, ideal-valve model for a 10... more A real-gas, restricted-flow valve model is compared with an ideal-gas, ideal-valve model for a 10-cylinder swashplate refrigeration compressor. Real gas properties of R134a are evaluated using the NIST standard reference database. A minor-loss discharge-coefficient approach is used to model the refrigerant flow rate through reed valves while the ideal-valve model requires no pressure difference to open the valve. In contrast with the ideal model, the discharge temperature, refrigerant mass flow rate and volumetric efficiency as a function of rotational speed are predicted well by including real-gas properties and flow restriction on the inlet valve. The ideal-gas model significantly overpredicts the discharge temperature and shows no dependence on rpm. Heat transfer to and from the cylinder wall during compression and expansion is found to have only a small effect on predictions of compressor performance. The valve model for the suction side has the largest influence on compressor performance predictions as a function of rpm.