The Experts below are selected from a list of 132 Experts worldwide ranked by ideXlab platform

Lingen Chen - One of the best experts on this subject based on the ideXlab platform.

  • performance optimization of an open simple cycle gas turbine combined cooling heating and power plant driven by basic oxygen furnace gas in china s steelmaking plants
    Energy, 2020
    Co-Authors: Lingen Chen, Bo Yang, Huijun Feng, Shaojun Xia
    Abstract:

    Abstract Based on production data of some steelmaking plants in China and applying finite-time thermodynamics, this paper establishes a physical model of simple open gas turbine combined cooling, heating and power plant driven by basic oxygen furnace gas. Thermal process of each component is analyzed. Useful energy output rate and first law efficiency are considered as optimization objectives. Cases with or without constraints of fuel mass flow rate and overall size are investigated. In the case of without constraints, Compressor Inlet Pressure drop (i.e. air mass flow rate) and Pressure ratio are respectively optimized, and the maximum useful energy output rate is obtained. In the case of with constraints, it is found that the first law efficiency also exists maximum with respect to Compressor Inlet Pressure drop and Pressure ratio, the optimal flow area allocations among the components are obtained. The results show that maximum useful energy output rate and first law efficiency increase with heat source temperature, efficiencies of Compressors and turbine, component flow area and cooling temperature, while decrease with heating temperature. Effects of energy and exergy saving, CO2 emission reduction and cost saving are analyzed compared with conventional separate generation plants, and partial model is validated.

  • Thermodynamic optimization of a triple-shaft open intercooled, recuperated gas turbine cycle. Part 2: power and efficiency optimization
    International Journal of Low-Carbon Technologies, 2013
    Co-Authors: Wenhua Wang, Lingen Chen, Fengrui Sun
    Abstract:

    The power and the efficiency of a triple-shaft open intercooled, recuperated gas turbine cycle are analyzed and optimized based on the model established using thermodynamic optimization theory in Part 1 of this paper by adjusting the low-Pressure Compressor Inlet relative Pressure drop, the mass flow rate and the distribution of Pressure losses along the flow path. First, the power output is optimized by adjusting the intercooling Pressure ratio, the air mass flow rate or the distribution of Pressure losses along the flow path. Second, the thermodynamic first-law efficiency is optimized subject to a fixed fuel flow rate and a fixed overall size by seeking the optimal intercooling Pressure ratio, the Compressor Inlet Pressure drop and optimal flow area allocation ratio between the low-Pressure Compressor Inlet and the power turbine outlet. The numerical examples show that increase in effectiveness of intercooler increases power output and its corresponding efficiency and increase in effectiveness of recuperator decreases power output appreciably but increases its corresponding efficiency; there exist an optimal low-Pressure Compressor Inlet relative Pressure drop and an optimal intercooling Pressure ratio, which lead to a maximum power. For a fixed fuel mass rate and a fixed overall area of low-Pressure Compressor Inlet and power turbine outlet, maximum thermodynamic first-law efficiency is obtained by optimizing low-Pressure Compressor Inlet relative Pressure drop and intercooling Pressure ratio. The double-maximum thermodynamic first- law efficiency is obtained by searching optimal flow area allocation between low-Pressure Compressor Inlet and power turbine outlet.

  • Thermodynamic optimization of a triple-shaft open intercooled-recuperated gas turbine cycle. Part 1: description and modeling
    International Journal of Low-Carbon Technologies, 2013
    Co-Authors: Lingen Chen, Wenhua Wang, Fengrui Sun
    Abstract:

    Considering the flow processes of the working fluid with the Pressure drops, a thermodynamic model for a triple-shaft open intercooled-recuperated gas turbine cycle is established using thermodynamic optimization theory in Part 1 of this paper. The relative Pressure drops associated with the flow through various cross-sectional areas are derived as functions of the low-Pressure Compressor Inlet relative Pressure drop. The analytical formulae of the cycle's power and efficiency are derived. The performance of the model cycle is optimized by adjusting the Compressor Inlet Pressure, the mass flow rate and the distribution of Pressure losses along the flow path in Part 2 of this paper.

  • Power and efficiency optimization for combined Brayton and inverse Brayton cycles
    Applied Thermal Engineering, 2009
    Co-Authors: W Zhang, Lingen Chen, Fengrui Sun
    Abstract:

    A thermodynamic model for open combined Brayton and inverse Brayton cycles is established considering the Pressure drops of the working fluid along the flow processes and the size constraints of the real power plant using finite time thermodynamics in this paper. There are 11 flow resistances encountered by the gas stream for the combined Brayton and inverse Brayton cycles. Four of these, the friction through the blades and vanes of the Compressors and the turbines, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in flow cross-section at the Compressor Inlet of the top cycle, combustion Inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger Inlet, and Compressor Inlet of the bottom cycle. These resistances control the air flow rate and the net power output. The relative Pressure drops associated with the flow through various cross-sectional areas are derived as functions of the Compressor Inlet relative Pressure drop of the top cycle. The analytical formulae about the relations between power output, thermal conversion efficiency, and the Compressor Pressure ratio of the top cycle are derived with the 11 Pressure drop losses in the intake, compression, combustion, expansion, and flow process in the piping, the heat transfer loss to the ambient, the irreversible compression and expansion losses in the Compressors and the turbines, and the irreversible combustion loss in the combustion chamber. The performance of the model cycle is optimized by adjusting the Compressor Inlet Pressure of the bottom cycle, the air mass flow rate and the distribution of Pressure losses along the flow path. It is shown that the power output has a maximum with respect to the Compressor Inlet Pressure of the bottom cycle, the air mass flow rate or any of the overall Pressure drops, and the maximized power output has an additional maximum with respect to the Compressor Pressure ratio of the top cycle. When the optimization is performed with the constraints of a fixed fuel flow rate and the power plant size, the power output and efficiency can be maximized again by properly allocating the fixed overall flow area among the Compressor Inlet of the top cycle and the turbine outlet of the bottom cycle.

  • Power and efficiency optimization for combined Brayton and two parallel inverse Brayton cycles. Part 2: Performance optimization
    Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2008
    Co-Authors: W Zhang, Lingen Chen
    Abstract:

    The power and efficiency of the open combined Brayton and two parallel inverse Brayton cycles are analysed and optimized based on the model established using finite-time thermodynamics in Part 1 of the current paper by adjusting the Compressor Inlet Pressure of the two parallel inverse Brayton cycles, the mass flowrate and the distribution of Pressure losses along the flow path. It is shown that the power output has a maximum with respect to the Compressor Inlet Pressures of the two parallel inverse Brayton cycles, the air mass flowrate or any of the overall Pressure drops, and the maximized power output has an additional maximum with respect to the Compressor Pressure ratio of the top cycle. The power output and the thermal conversion efficiency have the maximum values when the mass flowrates of the first and the second inverse Brayton cycles are the same. When the optimization is performed with the constraints of a fixed fuel flowrate and the power plant size, the power output and thermal conversion eff...

Fengrui Sun - One of the best experts on this subject based on the ideXlab platform.

  • Thermodynamic optimization of a triple-shaft open intercooled, recuperated gas turbine cycle. Part 2: power and efficiency optimization
    International Journal of Low-Carbon Technologies, 2013
    Co-Authors: Wenhua Wang, Lingen Chen, Fengrui Sun
    Abstract:

    The power and the efficiency of a triple-shaft open intercooled, recuperated gas turbine cycle are analyzed and optimized based on the model established using thermodynamic optimization theory in Part 1 of this paper by adjusting the low-Pressure Compressor Inlet relative Pressure drop, the mass flow rate and the distribution of Pressure losses along the flow path. First, the power output is optimized by adjusting the intercooling Pressure ratio, the air mass flow rate or the distribution of Pressure losses along the flow path. Second, the thermodynamic first-law efficiency is optimized subject to a fixed fuel flow rate and a fixed overall size by seeking the optimal intercooling Pressure ratio, the Compressor Inlet Pressure drop and optimal flow area allocation ratio between the low-Pressure Compressor Inlet and the power turbine outlet. The numerical examples show that increase in effectiveness of intercooler increases power output and its corresponding efficiency and increase in effectiveness of recuperator decreases power output appreciably but increases its corresponding efficiency; there exist an optimal low-Pressure Compressor Inlet relative Pressure drop and an optimal intercooling Pressure ratio, which lead to a maximum power. For a fixed fuel mass rate and a fixed overall area of low-Pressure Compressor Inlet and power turbine outlet, maximum thermodynamic first-law efficiency is obtained by optimizing low-Pressure Compressor Inlet relative Pressure drop and intercooling Pressure ratio. The double-maximum thermodynamic first- law efficiency is obtained by searching optimal flow area allocation between low-Pressure Compressor Inlet and power turbine outlet.

  • Thermodynamic optimization of a triple-shaft open intercooled-recuperated gas turbine cycle. Part 1: description and modeling
    International Journal of Low-Carbon Technologies, 2013
    Co-Authors: Lingen Chen, Wenhua Wang, Fengrui Sun
    Abstract:

    Considering the flow processes of the working fluid with the Pressure drops, a thermodynamic model for a triple-shaft open intercooled-recuperated gas turbine cycle is established using thermodynamic optimization theory in Part 1 of this paper. The relative Pressure drops associated with the flow through various cross-sectional areas are derived as functions of the low-Pressure Compressor Inlet relative Pressure drop. The analytical formulae of the cycle's power and efficiency are derived. The performance of the model cycle is optimized by adjusting the Compressor Inlet Pressure, the mass flow rate and the distribution of Pressure losses along the flow path in Part 2 of this paper.

  • Power and efficiency optimization for combined Brayton and inverse Brayton cycles
    Applied Thermal Engineering, 2009
    Co-Authors: W Zhang, Lingen Chen, Fengrui Sun
    Abstract:

    A thermodynamic model for open combined Brayton and inverse Brayton cycles is established considering the Pressure drops of the working fluid along the flow processes and the size constraints of the real power plant using finite time thermodynamics in this paper. There are 11 flow resistances encountered by the gas stream for the combined Brayton and inverse Brayton cycles. Four of these, the friction through the blades and vanes of the Compressors and the turbines, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in flow cross-section at the Compressor Inlet of the top cycle, combustion Inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger Inlet, and Compressor Inlet of the bottom cycle. These resistances control the air flow rate and the net power output. The relative Pressure drops associated with the flow through various cross-sectional areas are derived as functions of the Compressor Inlet relative Pressure drop of the top cycle. The analytical formulae about the relations between power output, thermal conversion efficiency, and the Compressor Pressure ratio of the top cycle are derived with the 11 Pressure drop losses in the intake, compression, combustion, expansion, and flow process in the piping, the heat transfer loss to the ambient, the irreversible compression and expansion losses in the Compressors and the turbines, and the irreversible combustion loss in the combustion chamber. The performance of the model cycle is optimized by adjusting the Compressor Inlet Pressure of the bottom cycle, the air mass flow rate and the distribution of Pressure losses along the flow path. It is shown that the power output has a maximum with respect to the Compressor Inlet Pressure of the bottom cycle, the air mass flow rate or any of the overall Pressure drops, and the maximized power output has an additional maximum with respect to the Compressor Pressure ratio of the top cycle. When the optimization is performed with the constraints of a fixed fuel flow rate and the power plant size, the power output and efficiency can be maximized again by properly allocating the fixed overall flow area among the Compressor Inlet of the top cycle and the turbine outlet of the bottom cycle.

W Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Power and efficiency optimization for combined Brayton and inverse Brayton cycles
    Applied Thermal Engineering, 2009
    Co-Authors: W Zhang, Lingen Chen, Fengrui Sun
    Abstract:

    A thermodynamic model for open combined Brayton and inverse Brayton cycles is established considering the Pressure drops of the working fluid along the flow processes and the size constraints of the real power plant using finite time thermodynamics in this paper. There are 11 flow resistances encountered by the gas stream for the combined Brayton and inverse Brayton cycles. Four of these, the friction through the blades and vanes of the Compressors and the turbines, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in flow cross-section at the Compressor Inlet of the top cycle, combustion Inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger Inlet, and Compressor Inlet of the bottom cycle. These resistances control the air flow rate and the net power output. The relative Pressure drops associated with the flow through various cross-sectional areas are derived as functions of the Compressor Inlet relative Pressure drop of the top cycle. The analytical formulae about the relations between power output, thermal conversion efficiency, and the Compressor Pressure ratio of the top cycle are derived with the 11 Pressure drop losses in the intake, compression, combustion, expansion, and flow process in the piping, the heat transfer loss to the ambient, the irreversible compression and expansion losses in the Compressors and the turbines, and the irreversible combustion loss in the combustion chamber. The performance of the model cycle is optimized by adjusting the Compressor Inlet Pressure of the bottom cycle, the air mass flow rate and the distribution of Pressure losses along the flow path. It is shown that the power output has a maximum with respect to the Compressor Inlet Pressure of the bottom cycle, the air mass flow rate or any of the overall Pressure drops, and the maximized power output has an additional maximum with respect to the Compressor Pressure ratio of the top cycle. When the optimization is performed with the constraints of a fixed fuel flow rate and the power plant size, the power output and efficiency can be maximized again by properly allocating the fixed overall flow area among the Compressor Inlet of the top cycle and the turbine outlet of the bottom cycle.

  • Power and efficiency optimization for combined Brayton and two parallel inverse Brayton cycles. Part 2: Performance optimization
    Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2008
    Co-Authors: W Zhang, Lingen Chen
    Abstract:

    The power and efficiency of the open combined Brayton and two parallel inverse Brayton cycles are analysed and optimized based on the model established using finite-time thermodynamics in Part 1 of the current paper by adjusting the Compressor Inlet Pressure of the two parallel inverse Brayton cycles, the mass flowrate and the distribution of Pressure losses along the flow path. It is shown that the power output has a maximum with respect to the Compressor Inlet Pressures of the two parallel inverse Brayton cycles, the air mass flowrate or any of the overall Pressure drops, and the maximized power output has an additional maximum with respect to the Compressor Pressure ratio of the top cycle. The power output and the thermal conversion efficiency have the maximum values when the mass flowrates of the first and the second inverse Brayton cycles are the same. When the optimization is performed with the constraints of a fixed fuel flowrate and the power plant size, the power output and thermal conversion eff...

  • Power and efficiency optimization for combined Brayton and two parallel inverse Brayton cycles. Part 2: performance optimization
    2007
    Co-Authors: W Zhang, Lingen Chen, F Sun
    Abstract:

    Abstract: The power and efficiency of the open combined Brayton and two parallel inverse Brayton cycles are analysed and optimized based on the model established using finite-time thermodynamics in Part 1 of the current paper by adjusting the Compressor Inlet Pressure of the two parallel inverse Brayton cycles, the mass flowrate and the distribution of Pressure losses along the flow path. It is shown that the power output has a maximum with respect to the Compressor Inlet Pressures of the two parallel inverse Brayton cycles, the air mass flowrate or any of the overall Pressure drops, and the maximized power output has an additional maxi-mum with respect to the Compressor Pressure ratio of the top cycle. The power output and the thermal conversion efficiency have the maximum values when the mass flowrates of the first and the second inverse Brayton cycles are the same. When the optimization is performed with the constraints of a fixed fuel flowrate and the power plant size, the power output and ther-mal conversion efficiency can be maximized again by properly allocating the fixed overall flow area among the Compressor Inlet of the top cycle and the turbine outlets of the two parallel inverse Brayton cycles. The numerical examples show the effects of design parameters on the power output and heat conversion efficiency

Gang Xiao - One of the best experts on this subject based on the ideXlab platform.

  • Thermodynamic analysis of a combined supercritical CO2 and ejector expansion refrigeration cycle for engine waste heat recovery
    Energy Conversion and Management, 2020
    Co-Authors: Mingzhang Pan, Xingyan Bian, Yan Zhu, Youcai Liang, Gang Xiao
    Abstract:

    Abstract An engine waste heat driven combined power and refrigeration system, comprised of a regenerative supercritical CO2 Brayton cycle (RSCBC) and an ejector expansion refrigeration cycle (EERC), is proposed. In this system, the RSCBC is adopted as the topping cycle to generate power by recovering the high-temperature waste heat of engine. Meanwhile, the power is utilized by the Compressor in the EERC. Such a waste heat recovery system can not only decrease the specific fuel consumption, but also provide refrigeration for refrigerated trucks to realize food preservation. Energy and exergy analysis are conducted on the RSCBC/EERC. The performance of four zeotropic mixtures used in EERC and different mixture compositions are compared. Moreover, the effects of several significant operating parameters are discussed in detail, including turbine Inlet Pressure and temperature, Compressor Inlet Pressure and temperature, Pressure drop in the ejector, evaporating temperature, and condensing temperature. To investigate the influence of the installation of the RSCBC/EERC system, weight estimation analysis is conducted. The results show that the refrigerating capacity and COPcomb of the system with R32/CO2 (0.9/0.1) are up to 225.5 kW and 2.05, respectively. And the equivalent power loss due to the additional weight is estimated to be 5.21 kW. In general, the RSCBC/EERC has proven its application potential in recovering waste heat to provide refrigeration through thermodynamic analysis.

Gary E Rochau - One of the best experts on this subject based on the ideXlab platform.

  • Dry-Cooled Supercritical CO2 Power for Advanced Nuclear Reactors
    Journal of Engineering for Gas Turbines and Power, 2014
    Co-Authors: Thomas M. Conboy, Matthew D. Carlson, Gary E Rochau
    Abstract:

    Currently, waste heat rejection from electrical power systems accounts for the largest fraction of water withdrawals from the U.S. fresh water table. Siting of nuclear power plants is limited to areas with access to a large natural supply of fresh or sea water. Due to a rise in energy needs and increased concern over environmental impact, dry air cooling systems are poised to play a large role in the future energy economy. In practice, the implementation of dry air-cooled condensing systems at steam plants has proven to be capital-intensive and requires the power cycle to take a significant efficiency penalty. These shortcomings are fundamental to dry-air steam condensation, which must occur at a fixed temperature. Closed-cycle gas turbines are an alternative to the conventional steam Rankine plant that allows for much improved dry heat rejection compatibility. Recent research into advanced nuclear energy systems has identified the supercritical CO2 (s-CO2) Brayton cycle in particular as a viable candidate for many proposed reactor types. The s-CO2 Brayton cycle can maintain superior thermal efficiency over a wide range of ambient temperatures, making these power systems ideally suited for dry air cooling, even in warm climates. For a sodium fast reactor (SFR) operating at 550 °C, thermal efficiency is calculated to be 43% with a 50 °C Compressor Inlet temperature. This is achieved by raising CO2 Compressor Inlet Pressure in response to rising ambient temperatures. Preliminary design studies have shown that s-CO2 power cycle hardware will be compact and therefore well-matched to near-term and advanced integral small modular reactor (SMR) designs. These advantages also extend to the cooling plant, where it is estimated that dry cooling towers for an SFR-coupled s-CO2 power cycle will be similar in cost and scale to the evaporative cooling tower for a light-water reactor (LWR). The projected benefits of the s-CO2 power cycle coupled to dry air heat rejection may enable the long-awaited rise of next-generation nuclear energy systems, while redrawing the map for siting of small and large nuclear energy systems.

  • Dry-Cooled Supercritical CO2 Power for Advanced Nuclear Reactors
    Volume 3B: Oil and Gas Applications; Organic Rankine Cycle Power Systems; Supercritical CO2 Power Cycles; Wind Energy, 2014
    Co-Authors: Thomas M. Conboy, Matthew D. Carlson, Gary E Rochau
    Abstract:

    Currently, waste heat rejection from electrical power systems accounts for the largest fraction of water withdrawals from the US fresh water table. Siting of nuclear power plants is limited to areas with access to a large natural supply of fresh or sea water. Due to a rise in energy needs and increased concern over environmental impact, dry air cooling systems are poised to play a large role in the future energy economy. In practice, the implementation of dry air-cooled condensing systems at steam plants has proven to be capital-intensive and requires the power cycle to take a significant efficiency penalty. These shortcomings are fundamental to dry-air steam condensation, which must occur at a fixed temperature. Closed-cycle gas turbines are an alternative to the conventional steam Rankine plant that allow for much improved dry heat rejection compatibility. Recent research into advanced nuclear energy systems has identified the supercritical CO2 (s-CO2) Brayton cycle in particular as a viable candidate for many proposed reactor types. The s-CO2 Brayton cycle can maintain superior thermal efficiency over a wide range of ambient temperatures, making these power systems ideally suited for dry air cooling, even in warm climates. For an SFR operating at 550°C, thermal efficiency is calculated to be 43% with a 50°C Compressor Inlet temperature. This is achieved by raising CO2 Compressor Inlet Pressure in response to rising ambient temperatures. Preliminary design studies have shown that s-CO2 power cycle hardware will be compact and therefore well-matched to near-term and advanced integral SMR designs. These advantages also extend to the cooling plant, where it is estimated that dry cooling towers for an SFR-coupled s-CO2 power cycle will be similar in cost and scale to the evaporative cooling tower for an LWR. The projected benefits of the s-CO2 power cycle coupled to dry air heat rejection may enable the long-awaited rise of next-generation nuclear energy systems, while re-drawing the map for siting of small and large nuclear energy systems.Copyright © 2014 by ASME