ABSTRACT Forward army bases at high ambient temperature off-grid locations require both power and... more ABSTRACT Forward army bases at high ambient temperature off-grid locations require both power and cooling capacity to function properly. Due to the inefficient existing configuration to meet these demands, there are safety and stability issues as each liter of fuel consumed for electrical power must first pass through a complex, hostile network. In place of the conventional configuration composed of a Genset (electrical generator set) and an electrically powered VCS (vapor compression system), utilizing a smaller Genset with a waste heat driven LiBr/H2O (lithium bromide/water) AS (absorption system) provides a more efficient CHP (combined heat and power) configuration. With design criteria of ambient temperatures up to 51.7 °C, providing up to 3 kW of non-cooling electricity, and 5.3 kW of cooling, these two configurations were simulated in both steady-state and transient conditions. Additionally, the proposed AS's avoid crystallization and have air-cooled heat exchangers unlike conventional AS's which crystallize at high ambient temperatures and have bulky cooling towers. In the transient simulation for the hottest week, results showed a fuel savings of 34–37% with the CHP configuration.
A method for improving the efficiency of a central (100) generating combined cycle power and desa... more A method for improving the efficiency of a central (100) generating combined cycle power and desalination unit, the method comprising: supplying exhaust gas from a group (104) of the gas turbine is used to generate power a power generator (108) steam heat recovery (HRSG); supplying water (160) into a salt unit (103) thermal desalination; use steam in HRSG from thermal desalination unit to produce a vapor distillate and brine from desalination unit by heat exchange; and introducing thermal energy from an additional heat source from the power generation plant in combined cycle thermal desalination unit to increase the mass flow of product water from the desalination unit; wherein the additional heat source comprises an exchanger (140) fed heat by a condensate from the unit (103) thermal desalination, in which water heated by the heat exchanger to a tank (184) is provided flash evaporation reduced atmosphere, and wherein the water vapor is flash evaporated in the flash tank is provided...
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, 2019
Four different control methods for ramping down the power output from a Supercritical Carbon Diox... more Four different control methods for ramping down the power output from a Supercritical Carbon Dioxide (sCO2) simple cycle were studied to support the development of 10 MWe Pilot Plant Test Facility, funded by the US Department of Energy. These detailed transient models are written using NPSS (Numerical Propulsion System Simulation). The main components of the NPSS models include a compressor, turbine, High-Temperature Recuperative heat exchanger (HTR), cooler, heater, pipes, and valves. In the transient models, the thermal mass and CO2 fluid volume for each main component are based on representative data or proven design practices for the corresponding component. The steady-state performance of each main component has been validated with representative data while the transient performance of the HTR has been validated with published experimental data. The models have been used to study the methods to ramp down the power output. The methods include extracting the CO2 from the inventor...
Volume 4: Cycle Innovations; Fans and Blowers; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine; Oil and Gas Applications, 2011
This work is part of a larger program aimed at understanding and modeling the unsteady combustion... more This work is part of a larger program aimed at understanding and modeling the unsteady combustion of propellants. The steady state work is required for development of comprehensive numerical models which can be extended to the unsteady case. The steady state chemical and thermal structures of several solid propellants during pyrolysis and combustion were investigated primarily by experimental methods. Combustion response to oscillatory heat flux was also studied. The propellants studied were pure HMX, cured GAP, HMX/GAP (80% HMX and 20% GAP by weight). A COsb2 laser was used as an external energy source. A microprobe/triple quadrupole mass spectrometer system was used to measure all the stable species evolved from the propellant surface and also used for laser-driven combustion response measurements. Fine-wire thermocouples were used to measure temperature from the subsurface to the final flame. A high-magnification video camera was used to record flame structure. A micro-force transducer was used to measure thrust. Laser-induced pyrolysis, laser-assisted combustion, and self-sustained combustion were experimentally investigated for HMX. At a heat flux of 30 W/cmsp2, the oscillations of species and temperature were observed at a frequency of 4 Hz. At a heat flux of 100 W/cmsp2, a nonluminous primary flame zone produced by the reaction of Hsb2CO and NOsb2 was followed by a luminous secondary reaction zone mainly formed by the reaction of HCN and NO. Temperature remained approximately constant until the CN flame. During self-sustained combustion, the species structure was very similar to that at a heat flux of 100 W/cmsp2. The surface temperature and species were insensitive to the heat flux level for GAP. The surface temperature was around 1050 K and several species were measured. The HMX/GAP flame displayed a narrow primary reaction zone and a relatively long preparation zone between the primary and secondary reactions. The temperature profile was in good agreement with the species profiles. The flame height measurements for combustion response showed a similar resonant frequency as the burning rate measurement. The species; measurement for combustion response showed that NO always oscillated in phase with HCN, but 180sp° out of phase with Nsb2.
ABSTRACT Forward army bases at high ambient temperature off-grid locations require both power and... more ABSTRACT Forward army bases at high ambient temperature off-grid locations require both power and cooling capacity to function properly. Due to the inefficient existing configuration to meet these demands, there are safety and stability issues as each liter of fuel consumed for electrical power must first pass through a complex, hostile network. In place of the conventional configuration composed of a Genset (electrical generator set) and an electrically powered VCS (vapor compression system), utilizing a smaller Genset with a waste heat driven LiBr/H2O (lithium bromide/water) AS (absorption system) provides a more efficient CHP (combined heat and power) configuration. With design criteria of ambient temperatures up to 51.7 °C, providing up to 3 kW of non-cooling electricity, and 5.3 kW of cooling, these two configurations were simulated in both steady-state and transient conditions. Additionally, the proposed AS's avoid crystallization and have air-cooled heat exchangers unlike conventional AS's which crystallize at high ambient temperatures and have bulky cooling towers. In the transient simulation for the hottest week, results showed a fuel savings of 34–37% with the CHP configuration.
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, Jun 17, 2019
Four different control methods for ramping down the power output from a Supercritical Carbon Diox... more Four different control methods for ramping down the power output from a Supercritical Carbon Dioxide (sCO2) simple cycle were studied to support the development of 10 MWe Pilot Plant Test Facility, funded by the US Department of Energy. These detailed transient models are written using NPSS (Numerical Propulsion System Simulation). The main components of the NPSS models include a compressor, turbine, High-Temperature Recuperative heat exchanger (HTR), cooler, heater, pipes, and valves. In the transient models, the thermal mass and CO2 fluid volume for each main component are based on representative data or proven design practices for the corresponding component. The steady-state performance of each main component has been validated with representative data while the transient performance of the HTR has been validated with published experimental data. The models have been used to study the methods to ramp down the power output. The methods include extracting the CO2 from the inventory, reducing the opening of turbine inlet throttle valve, and increasing the temperature of the cooling water entering the cooler. These methods, along with a hybrid method of combining the first two methods, were evaluated for the rate of turndown in the power output, operability of the compressor, and cycle efficiency. The preliminary results suggest that inventory extraction is the most efficient but has a slow turndown rate while turbine throttle control is less efficient but results in a faster turndown rate. In addition, the inventory extraction reduces the margin of the compressor choke line but the turbine throttle control increases the margin of the choke line.
This work is part of a larger program aimed at understanding and modeling the unsteady combustion... more This work is part of a larger program aimed at understanding and modeling the unsteady combustion of propellants. The steady state work is required for development of comprehensive numerical models which can be extended to the unsteady case. The steady state chemical and thermal structures of several solid propellants during pyrolysis and combustion were investigated primarily by experimental methods. Combustion response to oscillatory heat flux was also studied. The propellants studied were pure HMX, cured GAP, HMX/GAP (80% HMX and 20% GAP by weight). A COsb2 laser was used as an external energy source. A microprobe/triple quadrupole mass spectrometer system was used to measure all the stable species evolved from the propellant surface and also used for laser-driven combustion response measurements. Fine-wire thermocouples were used to measure temperature from the subsurface to the final flame. A high-magnification video camera was used to record flame structure. A micro-force transducer was used to measure thrust. Laser-induced pyrolysis, laser-assisted combustion, and self-sustained combustion were experimentally investigated for HMX. At a heat flux of 30 W/cmsp2, the oscillations of species and temperature were observed at a frequency of 4 Hz. At a heat flux of 100 W/cmsp2, a nonluminous primary flame zone produced by the reaction of Hsb2CO and NOsb2 was followed by a luminous secondary reaction zone mainly formed by the reaction of HCN and NO. Temperature remained approximately constant until the CN flame. During self-sustained combustion, the species structure was very similar to that at a heat flux of 100 W/cmsp2. The surface temperature and species were insensitive to the heat flux level for GAP. The surface temperature was around 1050 K and several species were measured. The HMX/GAP flame displayed a narrow primary reaction zone and a relatively long preparation zone between the primary and secondary reactions. The temperature profile was in good agreement with the species profiles. The flame height measurements for combustion response showed a similar resonant frequency as the burning rate measurement. The species; measurement for combustion response showed that NO always oscillated in phase with HCN, but 180sp° out of phase with Nsb2.
ABSTRACT A triple quadrupole mass spectrometer (TQMS) system utilizing the collision-induced diss... more ABSTRACT A triple quadrupole mass spectrometer (TQMS) system utilizing the collision-induced dissociation process has been constructed for studies of gas-phase combustion chemistry of energetic materials under various conditions of pressure and incident laser heat flux. A unique feature of the TQMS system is its capability to differentiate species at the same mass-to-charge value and to identify chemical structures of the gaseous species evolved from the energetic materials, through the recognition of the fragmentation characteristics of chemical functional groups in species. Two different settings for high and low collision energy modes were developed for the daughter mode of operation. A calibration method at the two settings in the daughter mode was also developed for the quantification of the measured species. The TQMS system developed also includes integrated vacuum system, quartz microprobes for gas species sampling, customized software for data acquisition and data reduction. Typical results are presented to illustrate the methods used to differentiate the measured species and to identify their chemical structures.
ABSTRACT Forward army bases at high ambient temperature off-grid locations require both power and... more ABSTRACT Forward army bases at high ambient temperature off-grid locations require both power and cooling capacity to function properly. Due to the inefficient existing configuration to meet these demands, there are safety and stability issues as each liter of fuel consumed for electrical power must first pass through a complex, hostile network. In place of the conventional configuration composed of a Genset (electrical generator set) and an electrically powered VCS (vapor compression system), utilizing a smaller Genset with a waste heat driven LiBr/H2O (lithium bromide/water) AS (absorption system) provides a more efficient CHP (combined heat and power) configuration. With design criteria of ambient temperatures up to 51.7 °C, providing up to 3 kW of non-cooling electricity, and 5.3 kW of cooling, these two configurations were simulated in both steady-state and transient conditions. Additionally, the proposed AS's avoid crystallization and have air-cooled heat exchangers unlike conventional AS's which crystallize at high ambient temperatures and have bulky cooling towers. In the transient simulation for the hottest week, results showed a fuel savings of 34–37% with the CHP configuration.
A method for improving the efficiency of a central (100) generating combined cycle power and desa... more A method for improving the efficiency of a central (100) generating combined cycle power and desalination unit, the method comprising: supplying exhaust gas from a group (104) of the gas turbine is used to generate power a power generator (108) steam heat recovery (HRSG); supplying water (160) into a salt unit (103) thermal desalination; use steam in HRSG from thermal desalination unit to produce a vapor distillate and brine from desalination unit by heat exchange; and introducing thermal energy from an additional heat source from the power generation plant in combined cycle thermal desalination unit to increase the mass flow of product water from the desalination unit; wherein the additional heat source comprises an exchanger (140) fed heat by a condensate from the unit (103) thermal desalination, in which water heated by the heat exchanger to a tank (184) is provided flash evaporation reduced atmosphere, and wherein the water vapor is flash evaporated in the flash tank is provided...
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, 2019
Four different control methods for ramping down the power output from a Supercritical Carbon Diox... more Four different control methods for ramping down the power output from a Supercritical Carbon Dioxide (sCO2) simple cycle were studied to support the development of 10 MWe Pilot Plant Test Facility, funded by the US Department of Energy. These detailed transient models are written using NPSS (Numerical Propulsion System Simulation). The main components of the NPSS models include a compressor, turbine, High-Temperature Recuperative heat exchanger (HTR), cooler, heater, pipes, and valves. In the transient models, the thermal mass and CO2 fluid volume for each main component are based on representative data or proven design practices for the corresponding component. The steady-state performance of each main component has been validated with representative data while the transient performance of the HTR has been validated with published experimental data. The models have been used to study the methods to ramp down the power output. The methods include extracting the CO2 from the inventor...
Volume 4: Cycle Innovations; Fans and Blowers; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine; Oil and Gas Applications, 2011
This work is part of a larger program aimed at understanding and modeling the unsteady combustion... more This work is part of a larger program aimed at understanding and modeling the unsteady combustion of propellants. The steady state work is required for development of comprehensive numerical models which can be extended to the unsteady case. The steady state chemical and thermal structures of several solid propellants during pyrolysis and combustion were investigated primarily by experimental methods. Combustion response to oscillatory heat flux was also studied. The propellants studied were pure HMX, cured GAP, HMX/GAP (80% HMX and 20% GAP by weight). A COsb2 laser was used as an external energy source. A microprobe/triple quadrupole mass spectrometer system was used to measure all the stable species evolved from the propellant surface and also used for laser-driven combustion response measurements. Fine-wire thermocouples were used to measure temperature from the subsurface to the final flame. A high-magnification video camera was used to record flame structure. A micro-force transducer was used to measure thrust. Laser-induced pyrolysis, laser-assisted combustion, and self-sustained combustion were experimentally investigated for HMX. At a heat flux of 30 W/cmsp2, the oscillations of species and temperature were observed at a frequency of 4 Hz. At a heat flux of 100 W/cmsp2, a nonluminous primary flame zone produced by the reaction of Hsb2CO and NOsb2 was followed by a luminous secondary reaction zone mainly formed by the reaction of HCN and NO. Temperature remained approximately constant until the CN flame. During self-sustained combustion, the species structure was very similar to that at a heat flux of 100 W/cmsp2. The surface temperature and species were insensitive to the heat flux level for GAP. The surface temperature was around 1050 K and several species were measured. The HMX/GAP flame displayed a narrow primary reaction zone and a relatively long preparation zone between the primary and secondary reactions. The temperature profile was in good agreement with the species profiles. The flame height measurements for combustion response showed a similar resonant frequency as the burning rate measurement. The species; measurement for combustion response showed that NO always oscillated in phase with HCN, but 180sp° out of phase with Nsb2.
ABSTRACT Forward army bases at high ambient temperature off-grid locations require both power and... more ABSTRACT Forward army bases at high ambient temperature off-grid locations require both power and cooling capacity to function properly. Due to the inefficient existing configuration to meet these demands, there are safety and stability issues as each liter of fuel consumed for electrical power must first pass through a complex, hostile network. In place of the conventional configuration composed of a Genset (electrical generator set) and an electrically powered VCS (vapor compression system), utilizing a smaller Genset with a waste heat driven LiBr/H2O (lithium bromide/water) AS (absorption system) provides a more efficient CHP (combined heat and power) configuration. With design criteria of ambient temperatures up to 51.7 °C, providing up to 3 kW of non-cooling electricity, and 5.3 kW of cooling, these two configurations were simulated in both steady-state and transient conditions. Additionally, the proposed AS's avoid crystallization and have air-cooled heat exchangers unlike conventional AS's which crystallize at high ambient temperatures and have bulky cooling towers. In the transient simulation for the hottest week, results showed a fuel savings of 34–37% with the CHP configuration.
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, Jun 17, 2019
Four different control methods for ramping down the power output from a Supercritical Carbon Diox... more Four different control methods for ramping down the power output from a Supercritical Carbon Dioxide (sCO2) simple cycle were studied to support the development of 10 MWe Pilot Plant Test Facility, funded by the US Department of Energy. These detailed transient models are written using NPSS (Numerical Propulsion System Simulation). The main components of the NPSS models include a compressor, turbine, High-Temperature Recuperative heat exchanger (HTR), cooler, heater, pipes, and valves. In the transient models, the thermal mass and CO2 fluid volume for each main component are based on representative data or proven design practices for the corresponding component. The steady-state performance of each main component has been validated with representative data while the transient performance of the HTR has been validated with published experimental data. The models have been used to study the methods to ramp down the power output. The methods include extracting the CO2 from the inventory, reducing the opening of turbine inlet throttle valve, and increasing the temperature of the cooling water entering the cooler. These methods, along with a hybrid method of combining the first two methods, were evaluated for the rate of turndown in the power output, operability of the compressor, and cycle efficiency. The preliminary results suggest that inventory extraction is the most efficient but has a slow turndown rate while turbine throttle control is less efficient but results in a faster turndown rate. In addition, the inventory extraction reduces the margin of the compressor choke line but the turbine throttle control increases the margin of the choke line.
This work is part of a larger program aimed at understanding and modeling the unsteady combustion... more This work is part of a larger program aimed at understanding and modeling the unsteady combustion of propellants. The steady state work is required for development of comprehensive numerical models which can be extended to the unsteady case. The steady state chemical and thermal structures of several solid propellants during pyrolysis and combustion were investigated primarily by experimental methods. Combustion response to oscillatory heat flux was also studied. The propellants studied were pure HMX, cured GAP, HMX/GAP (80% HMX and 20% GAP by weight). A COsb2 laser was used as an external energy source. A microprobe/triple quadrupole mass spectrometer system was used to measure all the stable species evolved from the propellant surface and also used for laser-driven combustion response measurements. Fine-wire thermocouples were used to measure temperature from the subsurface to the final flame. A high-magnification video camera was used to record flame structure. A micro-force transducer was used to measure thrust. Laser-induced pyrolysis, laser-assisted combustion, and self-sustained combustion were experimentally investigated for HMX. At a heat flux of 30 W/cmsp2, the oscillations of species and temperature were observed at a frequency of 4 Hz. At a heat flux of 100 W/cmsp2, a nonluminous primary flame zone produced by the reaction of Hsb2CO and NOsb2 was followed by a luminous secondary reaction zone mainly formed by the reaction of HCN and NO. Temperature remained approximately constant until the CN flame. During self-sustained combustion, the species structure was very similar to that at a heat flux of 100 W/cmsp2. The surface temperature and species were insensitive to the heat flux level for GAP. The surface temperature was around 1050 K and several species were measured. The HMX/GAP flame displayed a narrow primary reaction zone and a relatively long preparation zone between the primary and secondary reactions. The temperature profile was in good agreement with the species profiles. The flame height measurements for combustion response showed a similar resonant frequency as the burning rate measurement. The species; measurement for combustion response showed that NO always oscillated in phase with HCN, but 180sp° out of phase with Nsb2.
ABSTRACT A triple quadrupole mass spectrometer (TQMS) system utilizing the collision-induced diss... more ABSTRACT A triple quadrupole mass spectrometer (TQMS) system utilizing the collision-induced dissociation process has been constructed for studies of gas-phase combustion chemistry of energetic materials under various conditions of pressure and incident laser heat flux. A unique feature of the TQMS system is its capability to differentiate species at the same mass-to-charge value and to identify chemical structures of the gaseous species evolved from the energetic materials, through the recognition of the fragmentation characteristics of chemical functional groups in species. Two different settings for high and low collision energy modes were developed for the daughter mode of operation. A calibration method at the two settings in the daughter mode was also developed for the quantification of the measured species. The TQMS system developed also includes integrated vacuum system, quartz microprobes for gas species sampling, customized software for data acquisition and data reduction. Typical results are presented to illustrate the methods used to differentiate the measured species and to identify their chemical structures.
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