The Experts below are selected from a list of 10377 Experts worldwide ranked by ideXlab platform
Ping Cheng - One of the best experts on this subject based on the ideXlab platform.
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a new lattice boltzmann model for solid liquid phase change
International Journal of Heat and Mass Transfer, 2013Co-Authors: Rongzong Huang, Ping ChengAbstract:Abstract The solid–liquid phase change problems were solved by the lattice Boltzmann method in this paper. By modifying the equilibrium distribution function for the temperature, a new approach was developed to treat the latent-Heat Source Term. As compared with the previous work, the approach developed in this paper could avoid iteration steps or solving a group of linear equations, which guaranteed this approach’s high efficiency. The phase interface was traced by updating the total enthalpy, and the moving interface was treated by the immersed moving boundary scheme proposed by Noble and Torczynski for simulation of particulate suspensions. The approach was firstly validated by the problem of conduction-induced melting in a semi-infinite space, and good agreement with the analytical result was obtained. Then it was used to simulate melting problems coupled with natural convection, which demonstrated that the approach could produce consistent results as compared with other numerical method.
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A new lattice Boltzmann model for solid–liquid phase change
International Journal of Heat and Mass Transfer, 2013Co-Authors: Rongzong Huang, Ping ChengAbstract:Abstract The solid–liquid phase change problems were solved by the lattice Boltzmann method in this paper. By modifying the equilibrium distribution function for the temperature, a new approach was developed to treat the latent-Heat Source Term. As compared with the previous work, the approach developed in this paper could avoid iteration steps or solving a group of linear equations, which guaranteed this approach’s high efficiency. The phase interface was traced by updating the total enthalpy, and the moving interface was treated by the immersed moving boundary scheme proposed by Noble and Torczynski for simulation of particulate suspensions. The approach was firstly validated by the problem of conduction-induced melting in a semi-infinite space, and good agreement with the analytical result was obtained. Then it was used to simulate melting problems coupled with natural convection, which demonstrated that the approach could produce consistent results as compared with other numerical method.
Rongzong Huang - One of the best experts on this subject based on the ideXlab platform.
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a new lattice boltzmann model for solid liquid phase change
International Journal of Heat and Mass Transfer, 2013Co-Authors: Rongzong Huang, Ping ChengAbstract:Abstract The solid–liquid phase change problems were solved by the lattice Boltzmann method in this paper. By modifying the equilibrium distribution function for the temperature, a new approach was developed to treat the latent-Heat Source Term. As compared with the previous work, the approach developed in this paper could avoid iteration steps or solving a group of linear equations, which guaranteed this approach’s high efficiency. The phase interface was traced by updating the total enthalpy, and the moving interface was treated by the immersed moving boundary scheme proposed by Noble and Torczynski for simulation of particulate suspensions. The approach was firstly validated by the problem of conduction-induced melting in a semi-infinite space, and good agreement with the analytical result was obtained. Then it was used to simulate melting problems coupled with natural convection, which demonstrated that the approach could produce consistent results as compared with other numerical method.
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A new lattice Boltzmann model for solid–liquid phase change
International Journal of Heat and Mass Transfer, 2013Co-Authors: Rongzong Huang, Ping ChengAbstract:Abstract The solid–liquid phase change problems were solved by the lattice Boltzmann method in this paper. By modifying the equilibrium distribution function for the temperature, a new approach was developed to treat the latent-Heat Source Term. As compared with the previous work, the approach developed in this paper could avoid iteration steps or solving a group of linear equations, which guaranteed this approach’s high efficiency. The phase interface was traced by updating the total enthalpy, and the moving interface was treated by the immersed moving boundary scheme proposed by Noble and Torczynski for simulation of particulate suspensions. The approach was firstly validated by the problem of conduction-induced melting in a semi-infinite space, and good agreement with the analytical result was obtained. Then it was used to simulate melting problems coupled with natural convection, which demonstrated that the approach could produce consistent results as compared with other numerical method.
Qing Liu - One of the best experts on this subject based on the ideXlab platform.
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Double multiple-relaxation-time lattice Boltzmann model for solid-liquid phase change with natural convection in porous media
arXiv: Fluid Dynamics, 2015Co-Authors: Qing LiuAbstract:In this paper, a double multiple-relaxation-time lattice Boltzmann model is developed for simulating transient solid-liquid phase change problems in porous media at the representative elementary volume scale. The model uses two different multiple-relaxation-time lattice Boltzmann equations, one for the flow field and the other for the temperature field with nonlinear latent Heat Source Term. The model is based on the generalized non-Darcy formulation, and the solid-liquid phase change interface is traced through the liquid fraction which is deTermined by the enthalpy method. The model is validated by numerical simulations of conduction melting in a semi-infinite space, solidification in a semi-infinite corner, and convection melting in a square cavity filled with porous media. The numerical results demonstrate the efficiency and accuracy of the present model for simulating transient solid-liquid phase change problems in porous media.
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Double multiple-relaxation-time lattice Boltzmann model for solid–liquid phase change with natural convection in porous media
Physica A: Statistical Mechanics and its Applications, 2015Co-Authors: Qing LiuAbstract:In this paper, a double multiple-relaxation-time lattice Boltzmann model is developed for simulating transient solid–liquid phase change problems in porous media at the representative elementary volume scale. The model uses two different multiple-relaxation-time lattice Boltzmann equations, one for the flow field and the other for the temperature field with nonlinear latent Heat Source Term. The model is based on the generalized non-Darcy formulation, and the solid–liquid interface is traced through the liquid fraction which is deTermined by the enthalpy-based method. The present model is validated by numerical simulations of conduction melting in a semi-infinite space, solidification in a semi-infinite corner, and convection melting in a square cavity filled with porous media. The numerical results demonstrate the efficiency and accuracy of the present model for simulating transient solid–liquid phase change problems in porous media.
H.p. Tan - One of the best experts on this subject based on the ideXlab platform.
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Transient coupled Heat transfer in a multi-layer composite with opaque specular surfaces and semitransparent specular interfaces
International Journal of Thermal Sciences, 2003Co-Authors: H.p. Tan, Jian-feng Luo, Li-ming RuanAbstract:Abstract In this paper, one-dimensional transient coupled radiative and conductive Heat transfer in a multi-layer absorbing and isotropic scattering composite is investigated. The composite is considered to be of opaque specular boundaries and semitransparent specular interfaces. In combination with ray tracing method, spectral band model and the Hottel and Sarofim's zonal method, the radiative transfer coefficients (RTCs) of the multi-layer composite are deduced. The RTCs are used to calculate the radiative Heat Source Term in the transient energy control equation, which is solved by the fully implicit discrete control-volume method. The effects of refractive index and vacuum space on transient coupled Heat transfer are analyzed. Except for refractive index, all the other parameters of each layer have been kept the same, and the total thickness also has been kept unchanged, then along the thickness of the composite when the decrement or the increment of refractive index decreases as layer number increases, the temperature profile becomes smoother and the steady Heat flux increases.
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Transient Coupled Radiation and Conduction in a Three-Layer Composite With Semitransparent Specular Interfaces and Surfaces
Journal of Heat Transfer, 2002Co-Authors: H.p. Tan, Jian-feng Luo, Xin-lin XiaAbstract:Transient coupled radiative and conductive Heat transfer in a three-layer absorbing and isotropically scattering composite with semitransparent specular interfaces and surfaces is investigated. The transient energy equation is solved by the full implicit control-volume method in combination with spectral band model. The radiative Heat Source Term is calculated by the radiative transfer coefficients (RTCs), which are deduced by the ray tracing method in combination with Hottel and Sarofim's zonal method. The effects of extinction coefficient, refractive index, and scattering albedo etc., on coupled Heat transfer are studied under radiative and convective boundary conditions. The effect of isolating space on coupled Heat transfer and the appearance of temperature peaks within the composite are investigated
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Transient Coupled Radiation -Conduction in Semitransparent Spherical Particle
Journal of Thermophysics and Heat Transfer, 2002Co-Authors: L.h. Liu, H.p. Tan, Timothy W. TongAbstract:Amethod toanalyzetransientcoupled radiation ‐conductionina semitransparentsphericalparticlesurrounded by isothermal black walls was developed. The radiative transfer coefe cients were deduced using the ray tracing method in combination with Hottel and Saroe m’ s zonal method. The radiative Heat Source Term was calculated by the radiative transfer coefe cients, and the transient energy equation was solved by an implicit e nite difference method. The effects of the related parameters on the transient radiative Heat Source and temperature distribution wereanalyzed.TheresultsshowthatthepeakofdimensionlessradialradiativeHeatSourcecanlocateintheinterior shell of the particleordropletwith small optical thickness when Heated by surrounding radiation. Treating volume radiation as surface radiation results in large transient temperature distribution errors for the particle with small optical thickness.
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Transient Coupled Heat Transfer in Three-Layer Composite with Opaque Specular Surfaces
Journal of Thermophysics and Heat Transfer, 2002Co-Authors: Jian-feng Luo, H.p. Tan, Xin-lin Xia, Timothy W. TongAbstract:A ray tracing/node analyzing method is applied to investigate one-dimensional transient coupled radiative and conductive Heat transfer in a three-layer absorbing and isotropically scattering composite with opaque specular surfaces and semitransparent specular interfaces. The reflectivities of the semitransparent interfaces are angularly dependent and deTermined by Fresnel's reflective law and Snell's refractive law. The radiative transfer coefficients for calculating the radiative Heat Source Term are deduced by the ray tracing method in combination with the zonal method. The transient energy equation is solved by the fully implicit control-volume method in combination with the spectral band model. The effects of surface emissivity, scattering albedo, refractive index and extinction coefficient on transient coupled Heat transfer are investigated in detail under radiative and convective boundary conditions
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Transient thermal analysis of semitransparent composite layer with an opaque boundary
International Journal of Heat and Mass Transfer, 2002Co-Authors: Ping-yang Wang, Hui-er Cheng, H.p. TanAbstract:Abstract Transient coupled radiative and conductive Heat transfer in a two-layer, absorbing, emitting, and isotropically scattering non-gray slab is investigated by the ray tracing method in combination with Hottel's zonal method. One outer boundary is opaque, and another is semitransparent. The radiative energy transfer process in a semitransparent composite is divided into two sub-processes, one of which considers scattering, the other does not. The radiative transfer coefficients of the composite are deduced under specular and diffuse reflection and combined specular and diffuse reflection, respectively. The radiative Heat Source Term is calculated by the radiative transfer coefficients. Temperature and Heat flux are obtained by using the full implicit control-volume method in combination with the spectral band model. The method presented here needs only to disperse the space position, instead of the solid angle. A comparison with previous results shows that the results are more accurate.
G. Cortela - One of the best experts on this subject based on the ideXlab platform.
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Effect of the ultrasound wave propagation regime in the Heat Source Term of Penne’s bio-Heat transfer equation
2016Co-Authors: G. Cortela, Carlos Negreira, Wagner Coelho De Albuquerque PereiraAbstract:This work analyses the influence of the ultrasound wave propagation regime on the temperature increase on biological media. Simulated and experimental temperature values from bovine ex-vivo tissue in two different depths, 5 and 40 mm, respectively smaller and bigger than the mean free propagation path (lS = 8.52 mm), are obtained. Temperature curves measured during US therapeutic application (High Intensity Therapeutic Ultrasound, HITU, 1 MHz, 1.5 – 2.0 Wcm−2) for 10 min, are compared to simulated ones using the Penne’s bio-Heat transfer equation (BHTE) at the same frequency and intensities and using the standard Source Term (ultrasonic absorption coefficient). At 5 mm, estimated and measured temperature diverge no more than 1%, while at 40 mm, when the scattering starts being not negligible, the simulated temperature is 20% smaller than the measured one. The results indicate that absorption increases when the wave propagation regime changes for depths greater than the lS value. This work analyses the influence of the ultrasound wave propagation regime on the temperature increase on biological media. Simulated and experimental temperature values from bovine ex-vivo tissue in two different depths, 5 and 40 mm, respectively smaller and bigger than the mean free propagation path (lS = 8.52 mm), are obtained. Temperature curves measured during US therapeutic application (High Intensity Therapeutic Ultrasound, HITU, 1 MHz, 1.5 – 2.0 Wcm−2) for 10 min, are compared to simulated ones using the Penne’s bio-Heat transfer equation (BHTE) at the same frequency and intensities and using the standard Source Term (ultrasonic absorption coefficient). At 5 mm, estimated and measured temperature diverge no more than 1%, while at 40 mm, when the scattering starts being not negligible, the simulated temperature is 20% smaller than the measured one. The r...
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effect of the ultrasound wave propagation regime in the Heat Source Term of penne s bio Heat transfer equation
Fourth International Conference on the Effects of Noise on Aquatic Life, 2016Co-Authors: G. Cortela, Carlos Negreira, W C A PereiraAbstract:This work analyses the influence of the ultrasound wave propagation regime on the temperature increase on biological media. Simulated and experimental temperature values from bovine ex-vivo tissue in two different depths, 5 and 40 mm, respectively smaller and bigger than the mean free propagation path (lS = 8.52 mm), are obtained. Temperature curves measured during US therapeutic application (High Intensity Therapeutic Ultrasound, HITU, 1 MHz, 1.5 – 2.0 Wcm−2) for 10 min, are compared to simulated ones using the Penne’s bio-Heat transfer equation (BHTE) at the same frequency and intensities and using the standard Source Term (ultrasonic absorption coefficient). At 5 mm, estimated and measured temperature diverge no more than 1%, while at 40 mm, when the scattering starts being not negligible, the simulated temperature is 20% smaller than the measured one. The results indicate that absorption increases when the wave propagation regime changes for depths greater than the lS value. This work analyses the influence of the ultrasound wave propagation regime on the temperature increase on biological media. Simulated and experimental temperature values from bovine ex-vivo tissue in two different depths, 5 and 40 mm, respectively smaller and bigger than the mean free propagation path (lS = 8.52 mm), are obtained. Temperature curves measured during US therapeutic application (High Intensity Therapeutic Ultrasound, HITU, 1 MHz, 1.5 – 2.0 Wcm−2) for 10 min, are compared to simulated ones using the Penne’s bio-Heat transfer equation (BHTE) at the same frequency and intensities and using the standard Source Term (ultrasonic absorption coefficient). At 5 mm, estimated and measured temperature diverge no more than 1%, while at 40 mm, when the scattering starts being not negligible, the simulated temperature is 20% smaller than the measured one. The r...