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Air-Standard Cycle

The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform

Brian Agnew – 1st expert on this subject based on the ideXlab platform

  • Thermodynamic analysis of combined open-Cycle-twin-shaft gas turbine (Brayton Cycle) and exhaust gas operated absorption refrigeration unit
    Applied Thermal Engineering, 1998
    Co-Authors: M. Mostafavi, A. Alaktiwi, Brian Agnew

    Abstract:

    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.

  • Thermodynamic analysis of combined diesel engine and absorption refrigeration unit—supercharged engine
    Applied Thermal Engineering, 1996
    Co-Authors: M. Mostafavi, Brian Agnew

    Abstract:

    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 – 2nd expert on this subject based on the ideXlab platform

  • Evaluation of a Combustion-Based Mesoscale Thermal Actuator in Open and Closed Operating Cycles
    Actuators, 2019
    Co-Authors: Sindhu Preetham Burugupally

    Abstract:

    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.

  • Evaluation of a Mesoscale Thermal Actuator in Open and Closed Operating Cycles
    , 2019
    Co-Authors: Sindhu Preetham Burugupally

    Abstract:

    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 – 3rd expert on this subject based on the ideXlab platform

  • Thermodynamic analysis of combined open-Cycle-twin-shaft gas turbine (Brayton Cycle) and exhaust gas operated absorption refrigeration unit
    Applied Thermal Engineering, 1998
    Co-Authors: M. Mostafavi, A. Alaktiwi, Brian Agnew

    Abstract:

    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.

  • Thermodynamic analysis of combined diesel engine and absorption refrigeration unit—supercharged engine
    Applied Thermal Engineering, 1996
    Co-Authors: M. Mostafavi, Brian Agnew

    Abstract:

    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.