The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Curtis M. Oldenburg - One of the best experts on this subject based on the ideXlab platform.
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Joule thomson cooling due to co2 injection into natural gas reservoirs
Energy Conversion and Management, 2007Co-Authors: Curtis M. OldenburgAbstract:Depleted natural gas reservoirs are a promising target for Carbon Sequestration with Enhanced Gas Recovery (CSEGR). The focus of this study is on evaluating the importance of Joule-Thomson cooling during CO2 injection into depleted natural gas reservoirs. Joule-Thomson cooling is the adiabatic cooling that accompanies the expansion of a real gas. If Joule-Thomson cooling were extreme, injectivity and formation permeability could be altered by the freezing of residual water, formation of hydrates, and fracturing due to thermal stresses. The TOUGH2/EOS7C module for CO2-CH4-H2O mixtures is used as the simulation analysis tool. For verification of EOS7C, the classic Joule-Thomson expansion experiment is modeled for pure CO2 resulting
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Joule thomson cooling due to co2 injection into natural gas reservoirs
Lawrence Berkeley National Laboratory, 2006Co-Authors: Curtis M. OldenburgAbstract:Depleted natural gas reservoirs are a promising target for Carbon Sequestration with Enhanced Gas Recovery (CSEGR). The focus of this study is on evaluating the importance of Joule-Thomson cooling during CO2 injection into depleted natural gas reservoirs. Joule-Thomson cooling is the adiabatic cooling that accompanies the expansion of a real gas. If Joule-Thomson cooling were extreme, injectivity and formation permeability could be altered by the freezing of residual water, formation of hydrates, and fracturing due to thermal stresses. The TOUGH2/EOS7C module for CO2-CH4-H2O mixtures is used as the simulation analysis tool. For verification of EOS7C, the classic Joule-Thomson expansion experiment is modeled for pure CO2 resulting in Joule-Thomson coefficients in agreement with standard references to within 5-7 percent. For demonstration purposes, CO2 injection at constant pressure and with a large pressure drop (~;50 bars) is presented in order to show that cooling by more than 20oC can occur by this effect. Two more-realistic constant-rate injection cases show that for typical systems in the Sacramento Valley, California, the Joule-Thomson cooling effect is minimal. This simulation study shows that for constant-rate injections into high-permeability reservoirs, the Joule-Thomson cooling effect is not expected to create significant problems for CSEGR.
H Q Gong - One of the best experts on this subject based on the ideXlab platform.
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Joule heating and its effects on electrokinetic transport of solutes in rectangular microchannels
Sensors and Actuators A-physical, 2007Co-Authors: Gongyue Tang, H Q Gong, Chun Yang, Cheekiong ChaiAbstract:Abstract In this paper, the studies of the Joule heating and its effects on electrokinetic transport (i.e., electroosmotic flow and electrophoretic transport) of solutes in rectangular microchannels are reported. 3D mathematical models describing the Joule heating induced temperature field and its effects on the EOF and electrophoretic transport of solutes in microchannels are developed, and the coupled governing equations are solved numerically using the finite volume based CFD technique. In addition, experiments are carried out to investigate the Joule heating associated phenomena and to verify the numerical models. A Rhodamine B based thermometry technique was employed to measure the solution temperature distributions in PDMS microfluidic channels. The micro particle image velocimetry (micro-PIV) technique was used to measure the velocity profiles of the EOF under the influence of Joule heating. The numerical solutions were compared with experimental results, and reasonable agreement was found. Both the numerical simulations and the experimental results show that the presence of the Joule heating causes the EOF velocity to deviate from its normal “plug-like” profile; moreover, the numerical simulations show that Joule heating not only accelerates the sample transport but also distorts the shape of the sample band. The simulation results also reveal that the Joule heating and its effects in a PDMS/PDMS channel is more significant than those in a glass/PDMS channel.
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Assessment of Joule heating and its effects on electroosmotic flow and electrophoretic transport of solutes in microfluidic channels
Electrophoresis, 2006Co-Authors: Gongyue Tang, H Q Gong, Chun Yang, J C ChaiAbstract:Joule heating is inevitable when an electric field is applied across a conducting medium. It would impose limitations on the performance of electrokinetic microfluidic devices. This article presents a 3-D mathematical model for Joule heating and its effects on the EOF and electrophoretic transport of solutes in microfluidic channels. The governing equations were numerically solved using the finite-volume method. Experiments were carried out to investigate the Joule heating associated phenomena and to verify the numerical models. A rhodamine B-based thermometry technique was employed to measure the solution temperature distributions in microfluidic channels. The microparticle image velocimetry technique was used to measure the velocity profiles of EOF under the influence of Joule heating. The numerical solutions were compared with experimental results, and reasonable agreement was found. It is found that with the presence of Joule heating, the EOF velocity deviates from its normal “pluglike” profile. The numerical simulations show that Joule heating not only accelerates the sample transport but also distorts the shape of the sample band.
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numerical analysis of the thermal effect on electroosmotic flow and electrokinetic mass transport in microchannels
Analytica Chimica Acta, 2004Co-Authors: Gongyue Tang, Cheekiong Chai, Chun Yang, H Q GongAbstract:Abstract Joule heating is present in electrokinetically driven flow and mass transport in microfluidic systems. Nowadays, there is a trend of replacing costly glass-based microfluidic systems by the disposable, cheap polymer-based microfluidic systems. Due to poor thermal conductivity of polymer materials, the thermal management of the polymer-based microfluidic systems may become a problem. In this study, numerical analysis is presented for transient temperature development due to Joule heating and its effect on the electroosmotic flow (EOF) and mass species transport in microchannels. The proposed model includes the coupling Poisson–Boltzmann (P–B) equation, the modified Navier–Stokes (N–S) equations, the conjugate energy equation, and the mass species transport equation. The results show that the time development for both the electroosmotic flow field and the Joule heating induced temperature field are less than 1 s. The Joule heating induced temperature field is strongly dependent on channel size, electrolyte concentration, and applied electric field strength. The simulations reveal that the presence of the Joule heating can result in significantly different characteristics of the electroosmotic flow and electrokinetic mass transport in microchannels.
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Joule heating effect on electroosmotic flow and mass species transport in a microcapillary
International Journal of Heat and Mass Transfer, 2004Co-Authors: Gongyue Tang, J C Chai, Chun Yang, H Q GongAbstract:This study presents a numerical analysis of Joule heating effect on the electroosmotic flow and mass species transport, which has a direct application in the capillary electrophoresis based BioChip technology. A rigorous mathematic model for describing the Joule heating in an electroosmotic flow including the Poisson–Boltzmann equation, the modified Navier–Stokes equations and the energy equation is developed. All these equations are coupled through the temperature-dependent liquid dielectric constant, viscosity, and thermal conductivity. By numerically solving the aforementioned equations simultaneously, the double layer potential profile, the electroosmotic flow field, and the temperature distribution in a cylindrical microcapillary are computed. A systematic study is carried out to evaluate the Joule heating and its effects under the influences of the capillary radius, the buffer solution concentration, the applied electric field strength, and the heat transfer coefficient. In addition, the Joule heating effect on sample species transport in a microcapillary is also investigated by numerically solving the mass transfer equation with consideration of temperature-dependent diffusion coefficient and electrophoresis mobility. The simulations reveal that the presence of the Joule heating could have a great impact on the electroosmotic flow and mass species transport.
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modeling of electroosmotic flow and capillary electrophoresis with the Joule heating effect the nernst planck equation versus the boltzmann distribution
Langmuir, 2003Co-Authors: G Y Tang, C J Chai, Chun Yang, H Q GongAbstract:Joule heating is present in electrokinetic transport phenomena, which are widely used in microfluidic systems. In this paper, a rigorous mathematical model is developed to describe the Joule heating and its effects on electroosmotic flow and mass species transport in microchannels. The proposed model includes the Poisson equation, the modified Navier−Stokes equation, and the conjugate energy equation (for the liquid solution and the capillary wall). Specifically, the ionic concentration distributions are modeled using (i) the general Nernst−Planck equation and (ii) the simple Boltzmann distribution. The relevant governing equations are coupled through the temperature-dependent solution dielectric constant, viscosity, and thermal conductivity, and, hence, they are numerically solved using a finite-volume-based CFD technique. The applicability of the Nernst−Planck equation and the Boltzmann distribution in the electroosmotic flow with Joule heating has been discussed. The results of the time and spatial dev...
Chun Yang - One of the best experts on this subject based on the ideXlab platform.
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towards high concentration enhancement of microfluidic temperature gradient focusing of sample solutes using combined ac and dc field induced Joule heating
Lab on a Chip, 2011Co-Authors: Wei Wang, Chun YangAbstract:It is challenging to continuously concentrate sample solutes in microfluidic channels. We present an improved electrokinetic technique for enhancing microfluidic temperature gradient focusing (TGF) of sample solutes using combined AC and DC field induced Joule heating effects. The introduction of an AC electric field component services dual functions: one is to produce Joule heat for generating temperature gradient; the other is to suppress electroosmotic flow. Consequently the required DC voltages for achieving sample concentration by Joule heating induced TGF are reduced, thereby leading to smaller electroosmotic flow (EOF) and thus backpressure effects. As a demonstration, the proposed technique can lead to concentration enhancement of sample solutes of more than 2500-fold, which is much higher than the existing literature reported microfluidic concentration enhancement by utilizing the Joule heating induced TGF technique.
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Joule heating and its effects on electrokinetic transport of solutes in rectangular microchannels
Sensors and Actuators A-physical, 2007Co-Authors: Gongyue Tang, H Q Gong, Chun Yang, Cheekiong ChaiAbstract:Abstract In this paper, the studies of the Joule heating and its effects on electrokinetic transport (i.e., electroosmotic flow and electrophoretic transport) of solutes in rectangular microchannels are reported. 3D mathematical models describing the Joule heating induced temperature field and its effects on the EOF and electrophoretic transport of solutes in microchannels are developed, and the coupled governing equations are solved numerically using the finite volume based CFD technique. In addition, experiments are carried out to investigate the Joule heating associated phenomena and to verify the numerical models. A Rhodamine B based thermometry technique was employed to measure the solution temperature distributions in PDMS microfluidic channels. The micro particle image velocimetry (micro-PIV) technique was used to measure the velocity profiles of the EOF under the influence of Joule heating. The numerical solutions were compared with experimental results, and reasonable agreement was found. Both the numerical simulations and the experimental results show that the presence of the Joule heating causes the EOF velocity to deviate from its normal “plug-like” profile; moreover, the numerical simulations show that Joule heating not only accelerates the sample transport but also distorts the shape of the sample band. The simulation results also reveal that the Joule heating and its effects in a PDMS/PDMS channel is more significant than those in a glass/PDMS channel.
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Assessment of Joule heating and its effects on electroosmotic flow and electrophoretic transport of solutes in microfluidic channels
Electrophoresis, 2006Co-Authors: Gongyue Tang, H Q Gong, Chun Yang, J C ChaiAbstract:Joule heating is inevitable when an electric field is applied across a conducting medium. It would impose limitations on the performance of electrokinetic microfluidic devices. This article presents a 3-D mathematical model for Joule heating and its effects on the EOF and electrophoretic transport of solutes in microfluidic channels. The governing equations were numerically solved using the finite-volume method. Experiments were carried out to investigate the Joule heating associated phenomena and to verify the numerical models. A rhodamine B-based thermometry technique was employed to measure the solution temperature distributions in microfluidic channels. The microparticle image velocimetry technique was used to measure the velocity profiles of EOF under the influence of Joule heating. The numerical solutions were compared with experimental results, and reasonable agreement was found. It is found that with the presence of Joule heating, the EOF velocity deviates from its normal “pluglike” profile. The numerical simulations show that Joule heating not only accelerates the sample transport but also distorts the shape of the sample band.
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numerical analysis of the thermal effect on electroosmotic flow and electrokinetic mass transport in microchannels
Analytica Chimica Acta, 2004Co-Authors: Gongyue Tang, Cheekiong Chai, Chun Yang, H Q GongAbstract:Abstract Joule heating is present in electrokinetically driven flow and mass transport in microfluidic systems. Nowadays, there is a trend of replacing costly glass-based microfluidic systems by the disposable, cheap polymer-based microfluidic systems. Due to poor thermal conductivity of polymer materials, the thermal management of the polymer-based microfluidic systems may become a problem. In this study, numerical analysis is presented for transient temperature development due to Joule heating and its effect on the electroosmotic flow (EOF) and mass species transport in microchannels. The proposed model includes the coupling Poisson–Boltzmann (P–B) equation, the modified Navier–Stokes (N–S) equations, the conjugate energy equation, and the mass species transport equation. The results show that the time development for both the electroosmotic flow field and the Joule heating induced temperature field are less than 1 s. The Joule heating induced temperature field is strongly dependent on channel size, electrolyte concentration, and applied electric field strength. The simulations reveal that the presence of the Joule heating can result in significantly different characteristics of the electroosmotic flow and electrokinetic mass transport in microchannels.
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Joule heating effect on electroosmotic flow and mass species transport in a microcapillary
International Journal of Heat and Mass Transfer, 2004Co-Authors: Gongyue Tang, J C Chai, Chun Yang, H Q GongAbstract:This study presents a numerical analysis of Joule heating effect on the electroosmotic flow and mass species transport, which has a direct application in the capillary electrophoresis based BioChip technology. A rigorous mathematic model for describing the Joule heating in an electroosmotic flow including the Poisson–Boltzmann equation, the modified Navier–Stokes equations and the energy equation is developed. All these equations are coupled through the temperature-dependent liquid dielectric constant, viscosity, and thermal conductivity. By numerically solving the aforementioned equations simultaneously, the double layer potential profile, the electroosmotic flow field, and the temperature distribution in a cylindrical microcapillary are computed. A systematic study is carried out to evaluate the Joule heating and its effects under the influences of the capillary radius, the buffer solution concentration, the applied electric field strength, and the heat transfer coefficient. In addition, the Joule heating effect on sample species transport in a microcapillary is also investigated by numerically solving the mass transfer equation with consideration of temperature-dependent diffusion coefficient and electrophoresis mobility. The simulations reveal that the presence of the Joule heating could have a great impact on the electroosmotic flow and mass species transport.
A P Roskilly - One of the best experts on this subject based on the ideXlab platform.
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the characteristics of a linear Joule engine generator operating on a dry friction principle
Applied Energy, 2019Co-Authors: Ugochukwu Ngwaka, Christopher Lawrence, Dawei Wu, Andrew Smallbone, A P RoskillyAbstract:Abstract In this paper, the friction characteristics of a novel Linear Joule Engine Generator operating on dry friction mechanism is presented. A numerical model of the friction forces is represented through the development of a dry friction force model integrated into a mass-spring-damper system with viscous damping and spring constant to emulate compressor and expander operating pressures. Experimental results from a Linear Joule Engine Generator prototype are compared with the numerical simulation results predicted by the proposed friction model and other reported friction models identified from the wider engineering literature. Finally, the relationship between electric generator load and friction power of Linear Joule Engine Generator is established.
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design modelling and validation of a linear Joule engine generator designed for renewable energy sources
Energy Conversion and Management, 2018Co-Authors: Boru Jia, Christopher Lawrence, Andrew Smallbone, A P RoskillyAbstract:Abstract The Linear Joule Engine Generator (LJEG) incorporates the Joule Engine technology and the permanent magnet linear alternator design, which is a promising power generation device for the applications of range extenders for electric vehicles, Combined Heat and Power (CHP) systems, or as a stand-alone power unit. It combines the advantages from both a Joule Engine and a linear alternator, i.e. high efficiency, compact in size, and flexible to renewable energy integration, etc. In this paper, the background and recent developments of the LJEGs are summarised. A detailed 0-dimentional numerical model is described for the evaluation of the system dynamics and thermodynamic characteristics. Model validation is conducted using the test data obtained from both a reciprocating Joule Engine and a LJEG prototype, which proved to be in good agreement with the simulation results. The fundamental operational characteristics of the system were then explained using the validated numerical model. It was found that the piston displacement profile has certain similarity with a sinusoidal wave function with an amplitude of 51.0 mm and a frequency of 13 Hz. The electric power output from the linear alternator can reach 4.4 kW e . The engine thermal efficiency can reach above 34%, with an electric generating efficiency of 30%.
Gongyue Tang - One of the best experts on this subject based on the ideXlab platform.
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Joule heating and its effects on electrokinetic transport of solutes in rectangular microchannels
Sensors and Actuators A-physical, 2007Co-Authors: Gongyue Tang, H Q Gong, Chun Yang, Cheekiong ChaiAbstract:Abstract In this paper, the studies of the Joule heating and its effects on electrokinetic transport (i.e., electroosmotic flow and electrophoretic transport) of solutes in rectangular microchannels are reported. 3D mathematical models describing the Joule heating induced temperature field and its effects on the EOF and electrophoretic transport of solutes in microchannels are developed, and the coupled governing equations are solved numerically using the finite volume based CFD technique. In addition, experiments are carried out to investigate the Joule heating associated phenomena and to verify the numerical models. A Rhodamine B based thermometry technique was employed to measure the solution temperature distributions in PDMS microfluidic channels. The micro particle image velocimetry (micro-PIV) technique was used to measure the velocity profiles of the EOF under the influence of Joule heating. The numerical solutions were compared with experimental results, and reasonable agreement was found. Both the numerical simulations and the experimental results show that the presence of the Joule heating causes the EOF velocity to deviate from its normal “plug-like” profile; moreover, the numerical simulations show that Joule heating not only accelerates the sample transport but also distorts the shape of the sample band. The simulation results also reveal that the Joule heating and its effects in a PDMS/PDMS channel is more significant than those in a glass/PDMS channel.
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Assessment of Joule heating and its effects on electroosmotic flow and electrophoretic transport of solutes in microfluidic channels
Electrophoresis, 2006Co-Authors: Gongyue Tang, H Q Gong, Chun Yang, J C ChaiAbstract:Joule heating is inevitable when an electric field is applied across a conducting medium. It would impose limitations on the performance of electrokinetic microfluidic devices. This article presents a 3-D mathematical model for Joule heating and its effects on the EOF and electrophoretic transport of solutes in microfluidic channels. The governing equations were numerically solved using the finite-volume method. Experiments were carried out to investigate the Joule heating associated phenomena and to verify the numerical models. A rhodamine B-based thermometry technique was employed to measure the solution temperature distributions in microfluidic channels. The microparticle image velocimetry technique was used to measure the velocity profiles of EOF under the influence of Joule heating. The numerical solutions were compared with experimental results, and reasonable agreement was found. It is found that with the presence of Joule heating, the EOF velocity deviates from its normal “pluglike” profile. The numerical simulations show that Joule heating not only accelerates the sample transport but also distorts the shape of the sample band.
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numerical analysis of the thermal effect on electroosmotic flow and electrokinetic mass transport in microchannels
Analytica Chimica Acta, 2004Co-Authors: Gongyue Tang, Cheekiong Chai, Chun Yang, H Q GongAbstract:Abstract Joule heating is present in electrokinetically driven flow and mass transport in microfluidic systems. Nowadays, there is a trend of replacing costly glass-based microfluidic systems by the disposable, cheap polymer-based microfluidic systems. Due to poor thermal conductivity of polymer materials, the thermal management of the polymer-based microfluidic systems may become a problem. In this study, numerical analysis is presented for transient temperature development due to Joule heating and its effect on the electroosmotic flow (EOF) and mass species transport in microchannels. The proposed model includes the coupling Poisson–Boltzmann (P–B) equation, the modified Navier–Stokes (N–S) equations, the conjugate energy equation, and the mass species transport equation. The results show that the time development for both the electroosmotic flow field and the Joule heating induced temperature field are less than 1 s. The Joule heating induced temperature field is strongly dependent on channel size, electrolyte concentration, and applied electric field strength. The simulations reveal that the presence of the Joule heating can result in significantly different characteristics of the electroosmotic flow and electrokinetic mass transport in microchannels.
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Joule heating effect on electroosmotic flow and mass species transport in a microcapillary
International Journal of Heat and Mass Transfer, 2004Co-Authors: Gongyue Tang, J C Chai, Chun Yang, H Q GongAbstract:This study presents a numerical analysis of Joule heating effect on the electroosmotic flow and mass species transport, which has a direct application in the capillary electrophoresis based BioChip technology. A rigorous mathematic model for describing the Joule heating in an electroosmotic flow including the Poisson–Boltzmann equation, the modified Navier–Stokes equations and the energy equation is developed. All these equations are coupled through the temperature-dependent liquid dielectric constant, viscosity, and thermal conductivity. By numerically solving the aforementioned equations simultaneously, the double layer potential profile, the electroosmotic flow field, and the temperature distribution in a cylindrical microcapillary are computed. A systematic study is carried out to evaluate the Joule heating and its effects under the influences of the capillary radius, the buffer solution concentration, the applied electric field strength, and the heat transfer coefficient. In addition, the Joule heating effect on sample species transport in a microcapillary is also investigated by numerically solving the mass transfer equation with consideration of temperature-dependent diffusion coefficient and electrophoresis mobility. The simulations reveal that the presence of the Joule heating could have a great impact on the electroosmotic flow and mass species transport.
