The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform
Brian Agnew - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic analysis of combined open-Cycle-twin-shaft gas turbine (Brayton Cycle) and exhaust gas operated absorption refrigeration unit
Applied Thermal Engineering, 1998Co-Authors: M. Mostafavi, A. Alaktiwi, Brian AgnewAbstract:The exhaust gases of a gas turbine carry a significant amount of thermal energy that is usually expelled to the atmosphere without taking any further part in the power generation processes. The low grade thermal energy can however be put to beneficial use. This paper explores the utilisation of the exhaust gases of an open-Cycle-twin-shaft gas turbine. An air standard Cycle is assumed for the gas turbine, first with the aid of thermodynamic laws the specific network and the efficiency of the Cycle as a function of temperature ratio and pressure ratio of the Cycle are calculated, and the realistic bounds placed on the Cycle by the thermodynamic analysis is shown. Then the temperature of the exhaust gases and the heat that can be put to benefit for precooling in terms of the temperature ratio and pressure ratio of the Cycle are determined. The specific network and efficiency of a precooled Cycle have been calculated and compared to conventional systems. It has been concluded that the precooling has a marked effect on the specific network and efficiency at low temperature ratios. Also without increasing the maximum Cycle temperature the precooled Cycle can work at a higher compressor pressure ratio and at a higher temperature ratio.
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Thermodynamic analysis of combined diesel engine and absorption refrigeration unit—supercharged engine
Applied Thermal Engineering, 1996Co-Authors: M. Mostafavi, Brian AgnewAbstract:Abstract This paper describes an attempt to calculate the amount of network, efficiency and also cooling capacity available in the exhaust gases of a supercharged diesel engine (ideal Cycle) that is interfaced with an absorption refrigeration unit. An air standard Cycle is assumed for the diesel engine. The variations of net work and efficiency of the diesel engine as a function of Cycle pressure ratio and temperature ratio are calculated.
Sindhu Preetham Burugupally - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of a Combustion-Based Mesoscale Thermal Actuator in Open and Closed Operating Cycles
Actuators, 2019Co-Authors: Sindhu Preetham BurugupallyAbstract:A combustion-based mesoscale thermal actuator is proposed and its performance is studied in both open and closed Cycle operations using a physics-based lumped-parameter model. The actuator design is unique as it implements a free-piston complaint architecture where the piston is free to move in a linear direction. Our objective is to study the actuator behavior in both the Cycles to help identify the benefits and highlight the differences between the two Cycles. The actuator is modeled as a spring-mass-damper system by taking an air standard Cycle approach. Three observations are reported: (1) for nominal heat inputs (140 J/Cycle), the actuator can produce large displacement strokes (16 cm) that is suitable for driving mesoscale robots; (2) the efficiency of the actuator depends on the heat input; and (3) for a specific heat input, both the open and closed Cycles operate differently—with different stroke lengths, peak pressures, and thermal efficiencies. Our study reveals that the performance metrics of the actuator make it an ideal candidate for high speed, large force, and large displacement stroke related applications.
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Evaluation of a Mesoscale Thermal Actuator in Open and Closed Operating Cycles
2019Co-Authors: Sindhu Preetham BurugupallyAbstract:Thermal-based actuators are known for generating large force and displacement strokes at mesoscale (millimeter) regime. In particular, two-phase thermal actuators are found to benefit from the scaling laws of physics at mesoscale to offer large force and displacement strokes; but they have low thermal efficiencies. As an alternative, a combustion-based thermal actuator is proposed and its performance is studied in both open and closed Cycle operations. Through a physics-based lumped-parameter model, we investigate the behavior and performance of the actuator using a spring-mass-damper analogy and taking an air standard Cycle approach. Three observations are reported: (1) the mesoscale actuator can generate peak forces of up to 400 N and displacement strokes of about 16 cm suitable for practical applications; (2) an increase in heat input to the actuator results in increasing the thermal efficiency of the actuator for both open and closed Cycles; and (3) for a specific heat input, both the open and closed Cycle operations respond differently - different stroke lengths, peak pressures, and thermal efficiencies.
M. Mostafavi - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic analysis of combined open-Cycle-twin-shaft gas turbine (Brayton Cycle) and exhaust gas operated absorption refrigeration unit
Applied Thermal Engineering, 1998Co-Authors: M. Mostafavi, A. Alaktiwi, Brian AgnewAbstract:The exhaust gases of a gas turbine carry a significant amount of thermal energy that is usually expelled to the atmosphere without taking any further part in the power generation processes. The low grade thermal energy can however be put to beneficial use. This paper explores the utilisation of the exhaust gases of an open-Cycle-twin-shaft gas turbine. An air standard Cycle is assumed for the gas turbine, first with the aid of thermodynamic laws the specific network and the efficiency of the Cycle as a function of temperature ratio and pressure ratio of the Cycle are calculated, and the realistic bounds placed on the Cycle by the thermodynamic analysis is shown. Then the temperature of the exhaust gases and the heat that can be put to benefit for precooling in terms of the temperature ratio and pressure ratio of the Cycle are determined. The specific network and efficiency of a precooled Cycle have been calculated and compared to conventional systems. It has been concluded that the precooling has a marked effect on the specific network and efficiency at low temperature ratios. Also without increasing the maximum Cycle temperature the precooled Cycle can work at a higher compressor pressure ratio and at a higher temperature ratio.
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Thermodynamic analysis of combined diesel engine and absorption refrigeration unit—supercharged engine
Applied Thermal Engineering, 1996Co-Authors: M. Mostafavi, Brian AgnewAbstract:Abstract This paper describes an attempt to calculate the amount of network, efficiency and also cooling capacity available in the exhaust gases of a supercharged diesel engine (ideal Cycle) that is interfaced with an absorption refrigeration unit. An air standard Cycle is assumed for the diesel engine. The variations of net work and efficiency of the diesel engine as a function of Cycle pressure ratio and temperature ratio are calculated.
C. Wu - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic analysis of mirror gas turbine Cycle
International Journal of Power and Energy Systems, 2020Co-Authors: C. Wu, J.-s. TsaiAbstract:An interesting configuration of the gas turbine is the mirror gas turbine Cycle. There have been several developments in the thermodynamic analysis of various combined or co-generation Cycle schemes, with more advanced heat recovery capabilities. One of such novel Cycles is the mirror Cycle, a conceptual combination of Brayton and inverted Brayton Cycles with heat sink by intercooling. In this analysis, an air standard Cycle is assumed for the gas turbine. Analysis about the specific net-power and the efficiency of the mirror gas turbine as a function of maximum temperature ratio, compressor pressure ratio, and turbine overall expansion ratio of the Cycle are performed. The obtained results provide significant guidance to the evaluation and improvement of the mirror gas turbine.
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The effect of combustion on a power-optimized endoreversible dual Cycle
International Journal of Power and Energy Systems, 1994Co-Authors: D. A. Blank, C. WuAbstract:The power potential of an endoreversible Dual Cycle with combustion is analyzed and optimized. The endoreversible Cycle is one in which the heating process by combustion and the heat-removing process to the surroundings are the only irreversible processes in the Cycle. A mathematical expression is derived and optimized for the power output of the Cycle. This paper provides another criteria besides thermal efficiency, mean effective pressure, and detonation for use in the evaluation of the performance and the suitability of spark ignition and diesel engines which have been modeled thermodynamically using the Dual air standard Cycle.
Shawki M. Eldighidy - One of the best experts on this subject based on the ideXlab platform.
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Optimum outlet temperature of solar collector for maximum work output for an Otto Air-Standard Cycle with ideal regeneration
Solar Energy, 1993Co-Authors: Shawki M. EldighidyAbstract:The optimum solar collector outlet temperature for maximizing the work output for an Otto Air-Standard Cycle with ideal regeneration is investigated. A mathematical model for the energy balance on the solar collector along with the useful work output and the thermal efficiency of the Otto Air-Standard Cycle with ideal regeneration is developed. The optimum solar collector outlet temperature for maximum work output is determined. The effect of radiative and convective heat losses from the solar collector, on the optimum outlet temperature is presented. The results reveal that the highest solar collector outlet temperature and, therefore, greatest Otto Cycle efficiency and work output can be attained with the lowest values of radiative and convective heat losses. Moreover, high Cycle work output (as a fraction of absorbed solar energy) and high efficiency of an Otto heat engine with ideal regeneration, driven by a solar collector system, can be attained with low compression ratio.
