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03094 Emerging power technologies and oxide scale spallation
10
Engines (power generation
and propulsion,
electrical vehicles)
Development of cumulative and availability rate 97103091 balances in a multi-cylinder turbocharged indirect injection diesel engine
97103096 Exergetic evaluation of methods for improving power generation efficiency of a gas turbine cogeneration system
EnrrXy Cor1vers. M~r?ll. lY97. 38, Rakopoulos, C. D. and Giakoumis, E.G. (4). 347-369. A single-zone thermodynamic model was used to analyse a multi-cylinder turbocharged Diesel engine from a second law analysis point of view. For this purpose, a comprehensive digital computer program is developed that incorporates sub-routines to simulate, among other things, combustion. heat transfer, indirect fuel injection. mass flow through valves, turbocharger and aftercooler behaviour. and real multi-cylinder engine action. This is tested favourably against relevant data from an experimental investigation conducted at the authors’ laboratory. A second law analysis was performed in all parts of the engine. The analysis provides the proper evaluation of every component’s irreversibilities. The model is applied to a six-cylinder, turbocharged and aftercooled, indirect injection, four-stroke, medium-high speed diesel engine, installed at the authors’ laboratory. The results demonstrate that the second law analysis offers a more spherical and comprehensive insight into the processes occurring in a diesel engine than its traditional first law counterpart.
Pak. P.S. and Suzuki, Y. Int. J. Energy Res., 1097, 21. (X), 737-747. The paper describes a cogeneration system generating both heat and power for district heating and cooling is required to be more efficient to improve its economy. Three typical methods for improving the power generation efficiency of a gas turbine cogeneration system are evaluated hy examining exergy flow at various points of the system. These are: (a) to raise turbine inlet temperature, (b) to incorporate a regenerative cycle. and (c) to introduce a dual-fluid cycle. Exergy flows at various point\ ot each cogeneration system have heen evaluated. It has hecn shown through quantitative analyses of exergy flows (I) what kind of exergy loss of the system can be reduced by introducing each efficiency-improving method. (2) that the method of incorporating a regenerative cycle is highly useful in improving exergy efficiency of the cogeneration system.
97103092 bio-fuel oil
Development
of gas turbine
combustor
fed with
Proc.-Biomass Conf Am.: Energy, EI1l?ron., Ape. lad., Ardy, P.L.et ul. 2nd 1995, 429-438. ENELiCRT carried out some experimental investigations on the feasibility of biofuels utilization in the electricity production systems. The paper considers the experimental activity for the development and the design optimization of a gas turbine combustor suitable to he fed with biofuel oil. It is based on the pressurized combustion performance obtained in a small gas turbine combustor fed with biofuel oil and ethanol-biofuel oil mixtures. Combustion tests were performed using the combustion chamber of a 40 kW gas turbine. A small pressurized rig has been constructed including a nozzle for pressurization and a heat recovering combustion air preheating system, together with a proper injection system consisting of two dual fuel atomizers. A parametric investigation on the combustion performance has been performed in order to evaluate the effect of fuel properties, operating conditions and injection system geometry, especially as regards CO and NO, emissions and smoke index.
97103093
Effect of temoerature
on the droolet size in a diesel
spray
Rev. Gen. Therm., 1997, 36. (I), 51-58. (In French) Amara, S. ef al. By experimental conditions close to those of a diesel engine, the fuel spray from a one-hole injector was characterized. Droplet sizes and velocity histories were measured using a phase-Doppler analyzer in a transparent constant-volume combustion chamber. The combined effects of temperature, coalescence, and aerodynamic drag lead to an increase of the Sauter mean diameter with increasing penetration of the spray. At room temperature, droplet coalescence predominates and at higher temperatures, this growth is mainly due to the smallest drops evaporating.
97103094 spallation
Emerging
power
technologies
and
oxide
scale
97103097 performance
A generalised
model of a real heat engine
and its
Chen L. ef nl. J. Imr. Energy, December IYYh, (4X1). 214-222. The loss of heat resistance between the engine and its surrounding heat reservoirs is the sole irreversibility considered in an cndo-revrraihle Carnot heat engine model. Several internal irreversihilities of the heat engine are taken into account to present a new steady-state-now irrever\ihle Carnot heat engine model. A constant parameter and a constant coefficient, together with the loss of heat resistance is used to achieve this. The model was analysed to investigate the effect of the various irrcversibllitics on the performance of the model. Numerical examples arc given to shon the model’s effectiveness.
97103098 Improved energy storage
load-frequency
control
with
capacitive
Tripathy, S. C. Ener&y Cmwrs. M~II, IY97, 38, (6). 551-562. Fast acting energy storage devices can effectively damp electromechanical oscillations in a power system. This is because additional energy storage capacity is provided as a supplement to the kinetic energy storage in the moving mass of the generator rotor. The energy storage devices share the sudden changes in power requirement in the load A new scheme using a small rating capacitive energy storage unit is proposed in this paper to improve the dynamic performance of a power system having load-frequcncl control. A comprehensive digital computer model of a two-arca interconnected power system. which includes the governor dead-band nonlinearity, steam reheat turbine, boiler dynamics and the generator rate constraint. is developed for the analysis.
97103099 system
The
momentum
turbine:
a gravitational
energy
Sen, A. K. Energy Convers. Mgmt. 1997. 38, (7). 665-677. A complete review of the author’s work during the past decade on a new scheme for generating electricity using gravitational energy is reported. The system is called a ‘momentum turhine’, and it uses a set of massi\,e underground spinning wheels. Each wheel is fitted with a mechanism to receive and transmit gravitational torque pulses from a passing vehicle to keep the wheels in motion. In combination with an appropriate gear system. each wheel then acts as the prime mover of an alternator which produces the electricity. It is shown that as much as 9.4 Megawatts of mechanical power can be easily generated with a reasonable design of the momentum turbine.
Starr, F. Mater. High Temp., 1995 (Pub. 1996). 13, (4), 185-102. The use of combined cycle for large scale power generation has recently become more widespread. In these plants, the main spallation issue will be that of combustor can alloys. Units using reheat will add a new dimension to this problem. However, spallation of highly cooled turbine blading should not be neglected. Combined cycle will he linked in the longer term to coal gasification processes. Where the gasifiers are of the entrained or fluidized bed type, HCI induced spallation of downstream heat exchangers is a neglected aspect of much experimental work. In the UK and Northern Europe CHP (Combined Heat and Power), using natural gas as a fuel, will take an increasing share of the market. The most advanced concepts will use recuperative gas turbines, as these have many advantages at low to medium outputs. Again, scale spallation will be an important design consideration. The paper calls for more efforts on alloys other than chromia farmers; alumina formers offer much better high temperature hehaviour, apart from their spallation behaviour. There is also a strong economic case for work on alloys reliant on silica. A review is given of spallation and related phenomena on alumina forming ODS alloys intended for advanced indirect fired gas turbine cycles. Emphasis is given to the statistically variable nature of spallation, and to the fact that. in practice. spallntion failures involve more than one mechanism.
Smith, A. R. ef al. J. Eng. Gas Turbinrs Power. 1997, I IY, (2). 2YX-30-1. The commercialization of integrated gasification combined cycle (IGCC) power has been aided hy concepts involving the integration of a cryogenic air separation unit (ASU) with the gas turbine combined-cycle module. Other processes, such as coal-based iron-making and combined power, industrial gas production facilities, can also benefit from the Integration. Continuing advancements in both air separation and gas turhinc technologies offer new integration opportunities to improve performance and reduce costs. This paper reviews basic integration principles and describe\ next-generation concepts based on advanced high pressure ratio ~a\ turbines. humid air turbine (HAT) cycles and integration of comprersycm heat and refrigeration sources from the ASU. Operability issues associated with integration are reviewed and control measures are described for the safe, efficient, and reliable operation of these facilities.
Exergetic evaluation of gas turbine 97/03095 systems for district heating and cooling
97lO3101 generator
cogeneration
Pak, P. S. and Suzuki, Y. Inf. J. Energy Ret., 1997, 21, (3). 209-220. In order to cope efficiently with the heat demand change in district heating and cooling, a cogeneration system (CGS) generating both power and heat is necessary. In this paper, two types of gas turbine CGSs were investigated: (1) a CGS using a dual fluid cycle; and (2) a CGS using a combined cycle. Exergy flows at various points of each CGS have been evaluated when its heat demand is changed. A simple criterion has been derived for determining which type of CGS has higher average exergetic efficiency for a specific district when its heat demand characteristics are known.
254
Fuel and Energy Abstracts
July 1997
97/03100 separation
Next-generation integration units and gas turbines
concepts
for
air
On the comparison between a detailed turbineEMTP simulation and corresponding field test results
Khodabakhchian, B. et al. Elecrricul Power d; Eneyp S~v~mm. 1997. IY. (4). 263-268. In some cases, the machines of the LGI generating station may bc isolated from the Hydro-Quebec system but remain connected to an unloaded transmission line. After the risk of harmonic overvoltagea was highlighted by a preliminary study. a more thorough EMTP investigation wa\ performed in which the models and data were adjusted to reproduce recordings from a field test. The results pointed out the need to u\e detailed modelling for similar studies. Furthermore, recommendations :Irc given
Engines (power generation
and propulsion,
electrical vehicles)
Development of cumulative and availability rate 97103091 balances in a multi-cylinder turbocharged indirect injection diesel engine
97103096 Exergetic evaluation of methods for improving power generation efficiency of a gas turbine cogeneration system
EnrrXy Cor1vers. M~r?ll. lY97. 38, Rakopoulos, C. D. and Giakoumis, E.G. (4). 347-369. A single-zone thermodynamic model was used to analyse a multi-cylinder turbocharged Diesel engine from a second law analysis point of view. For this purpose, a comprehensive digital computer program is developed that incorporates sub-routines to simulate, among other things, combustion. heat transfer, indirect fuel injection. mass flow through valves, turbocharger and aftercooler behaviour. and real multi-cylinder engine action. This is tested favourably against relevant data from an experimental investigation conducted at the authors’ laboratory. A second law analysis was performed in all parts of the engine. The analysis provides the proper evaluation of every component’s irreversibilities. The model is applied to a six-cylinder, turbocharged and aftercooled, indirect injection, four-stroke, medium-high speed diesel engine, installed at the authors’ laboratory. The results demonstrate that the second law analysis offers a more spherical and comprehensive insight into the processes occurring in a diesel engine than its traditional first law counterpart.
Pak. P.S. and Suzuki, Y. Int. J. Energy Res., 1097, 21. (X), 737-747. The paper describes a cogeneration system generating both heat and power for district heating and cooling is required to be more efficient to improve its economy. Three typical methods for improving the power generation efficiency of a gas turbine cogeneration system are evaluated hy examining exergy flow at various points of the system. These are: (a) to raise turbine inlet temperature, (b) to incorporate a regenerative cycle. and (c) to introduce a dual-fluid cycle. Exergy flows at various point\ ot each cogeneration system have heen evaluated. It has hecn shown through quantitative analyses of exergy flows (I) what kind of exergy loss of the system can be reduced by introducing each efficiency-improving method. (2) that the method of incorporating a regenerative cycle is highly useful in improving exergy efficiency of the cogeneration system.
97103092 bio-fuel oil
Development
of gas turbine
combustor
fed with
Proc.-Biomass Conf Am.: Energy, EI1l?ron., Ape. lad., Ardy, P.L.et ul. 2nd 1995, 429-438. ENELiCRT carried out some experimental investigations on the feasibility of biofuels utilization in the electricity production systems. The paper considers the experimental activity for the development and the design optimization of a gas turbine combustor suitable to he fed with biofuel oil. It is based on the pressurized combustion performance obtained in a small gas turbine combustor fed with biofuel oil and ethanol-biofuel oil mixtures. Combustion tests were performed using the combustion chamber of a 40 kW gas turbine. A small pressurized rig has been constructed including a nozzle for pressurization and a heat recovering combustion air preheating system, together with a proper injection system consisting of two dual fuel atomizers. A parametric investigation on the combustion performance has been performed in order to evaluate the effect of fuel properties, operating conditions and injection system geometry, especially as regards CO and NO, emissions and smoke index.
97103093
Effect of temoerature
on the droolet size in a diesel
spray
Rev. Gen. Therm., 1997, 36. (I), 51-58. (In French) Amara, S. ef al. By experimental conditions close to those of a diesel engine, the fuel spray from a one-hole injector was characterized. Droplet sizes and velocity histories were measured using a phase-Doppler analyzer in a transparent constant-volume combustion chamber. The combined effects of temperature, coalescence, and aerodynamic drag lead to an increase of the Sauter mean diameter with increasing penetration of the spray. At room temperature, droplet coalescence predominates and at higher temperatures, this growth is mainly due to the smallest drops evaporating.
97103094 spallation
Emerging
power
technologies
and
oxide
scale
97103097 performance
A generalised
model of a real heat engine
and its
Chen L. ef nl. J. Imr. Energy, December IYYh, (4X1). 214-222. The loss of heat resistance between the engine and its surrounding heat reservoirs is the sole irreversibility considered in an cndo-revrraihle Carnot heat engine model. Several internal irreversihilities of the heat engine are taken into account to present a new steady-state-now irrever\ihle Carnot heat engine model. A constant parameter and a constant coefficient, together with the loss of heat resistance is used to achieve this. The model was analysed to investigate the effect of the various irrcversibllitics on the performance of the model. Numerical examples arc given to shon the model’s effectiveness.
97103098 Improved energy storage
load-frequency
control
with
capacitive
Tripathy, S. C. Ener&y Cmwrs. M~II, IY97, 38, (6). 551-562. Fast acting energy storage devices can effectively damp electromechanical oscillations in a power system. This is because additional energy storage capacity is provided as a supplement to the kinetic energy storage in the moving mass of the generator rotor. The energy storage devices share the sudden changes in power requirement in the load A new scheme using a small rating capacitive energy storage unit is proposed in this paper to improve the dynamic performance of a power system having load-frequcncl control. A comprehensive digital computer model of a two-arca interconnected power system. which includes the governor dead-band nonlinearity, steam reheat turbine, boiler dynamics and the generator rate constraint. is developed for the analysis.
97103099 system
The
momentum
turbine:
a gravitational
energy
Sen, A. K. Energy Convers. Mgmt. 1997. 38, (7). 665-677. A complete review of the author’s work during the past decade on a new scheme for generating electricity using gravitational energy is reported. The system is called a ‘momentum turhine’, and it uses a set of massi\,e underground spinning wheels. Each wheel is fitted with a mechanism to receive and transmit gravitational torque pulses from a passing vehicle to keep the wheels in motion. In combination with an appropriate gear system. each wheel then acts as the prime mover of an alternator which produces the electricity. It is shown that as much as 9.4 Megawatts of mechanical power can be easily generated with a reasonable design of the momentum turbine.
Starr, F. Mater. High Temp., 1995 (Pub. 1996). 13, (4), 185-102. The use of combined cycle for large scale power generation has recently become more widespread. In these plants, the main spallation issue will be that of combustor can alloys. Units using reheat will add a new dimension to this problem. However, spallation of highly cooled turbine blading should not be neglected. Combined cycle will he linked in the longer term to coal gasification processes. Where the gasifiers are of the entrained or fluidized bed type, HCI induced spallation of downstream heat exchangers is a neglected aspect of much experimental work. In the UK and Northern Europe CHP (Combined Heat and Power), using natural gas as a fuel, will take an increasing share of the market. The most advanced concepts will use recuperative gas turbines, as these have many advantages at low to medium outputs. Again, scale spallation will be an important design consideration. The paper calls for more efforts on alloys other than chromia farmers; alumina formers offer much better high temperature hehaviour, apart from their spallation behaviour. There is also a strong economic case for work on alloys reliant on silica. A review is given of spallation and related phenomena on alumina forming ODS alloys intended for advanced indirect fired gas turbine cycles. Emphasis is given to the statistically variable nature of spallation, and to the fact that. in practice. spallntion failures involve more than one mechanism.
Smith, A. R. ef al. J. Eng. Gas Turbinrs Power. 1997, I IY, (2). 2YX-30-1. The commercialization of integrated gasification combined cycle (IGCC) power has been aided hy concepts involving the integration of a cryogenic air separation unit (ASU) with the gas turbine combined-cycle module. Other processes, such as coal-based iron-making and combined power, industrial gas production facilities, can also benefit from the Integration. Continuing advancements in both air separation and gas turhinc technologies offer new integration opportunities to improve performance and reduce costs. This paper reviews basic integration principles and describe\ next-generation concepts based on advanced high pressure ratio ~a\ turbines. humid air turbine (HAT) cycles and integration of comprersycm heat and refrigeration sources from the ASU. Operability issues associated with integration are reviewed and control measures are described for the safe, efficient, and reliable operation of these facilities.
Exergetic evaluation of gas turbine 97/03095 systems for district heating and cooling
97lO3101 generator
cogeneration
Pak, P. S. and Suzuki, Y. Inf. J. Energy Ret., 1997, 21, (3). 209-220. In order to cope efficiently with the heat demand change in district heating and cooling, a cogeneration system (CGS) generating both power and heat is necessary. In this paper, two types of gas turbine CGSs were investigated: (1) a CGS using a dual fluid cycle; and (2) a CGS using a combined cycle. Exergy flows at various points of each CGS have been evaluated when its heat demand is changed. A simple criterion has been derived for determining which type of CGS has higher average exergetic efficiency for a specific district when its heat demand characteristics are known.
254
Fuel and Energy Abstracts
July 1997
97/03100 separation
Next-generation integration units and gas turbines
concepts
for
air
On the comparison between a detailed turbineEMTP simulation and corresponding field test results
Khodabakhchian, B. et al. Elecrricul Power d; Eneyp S~v~mm. 1997. IY. (4). 263-268. In some cases, the machines of the LGI generating station may bc isolated from the Hydro-Quebec system but remain connected to an unloaded transmission line. After the risk of harmonic overvoltagea was highlighted by a preliminary study. a more thorough EMTP investigation wa\ performed in which the models and data were adjusted to reproduce recordings from a field test. The results pointed out the need to u\e detailed modelling for similar studies. Furthermore, recommendations :Irc given