The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Peng Liu - One of the best experts on this subject based on the ideXlab platform.
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Experimental research on the effects of fluid and heater on thermal Stratification of liquefied gas
Experimental Thermal and Fluid Science, 2013Co-Authors: Jianyun Shi, Jingjie Ren, Peng LiuAbstract:Abstract The thermal Stratification of liquefied gas influences the equipment safety. To find the factors and principles governing the thermal Stratification, a device was set up to simulate the thermal response of a liquefied gas tank. A small steel vessel was used to simulate the tank, and two working fluids were used: water and R22. The heating region and liquid level were precisely adjusted in the tests to simulate different accident conditions. The experimental results showed saturation pressure of the working fluid affected the thermal Stratification when the liquid wall was heated solely. For the case the liquid and vapor wall were heated together, evident thermal Stratifications formed both in R22 and water tests. The degree and duration of thermal Stratification are affected by the intensity of heat loading on the surface liquid. It is concluded that nucleate boiling in the lower liquid has great power to eliminate the thermal Stratification. When the nucleate boiling is suppressed by hydrostatic pressure or saturation pressure of the warm surface liquid, the thermal Stratification can form and maintain by natural convection. The stratifying process can be explained by a natural convection model.
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Simulation on thermal Stratification and de-Stratification in liquefied gas tanks
International Journal of Hydrogen Energy, 2013Co-Authors: Jingjie Ren, Jianyun Shi, Peng Liu, Kai JiaAbstract:Abstract The phenomena of thermal Stratification and de-Stratification in liquefied gas tanks with heat leak through the side wall were researched numerically. The calculating model developed on ANSYS FLUENT 12.0 was verified through the experimental results from literature. The flow behaviors of the liquid and the temperature distributions at Stratification and de-Stratification stages were illustrated and the interaction between them was analyzed. When the liquid is stratified, the flow field presents a semi-circulation near the liquid surface with a plume-like flow under it and there exists a cold core under the surface which resisting the warmer circulating flow. The de-Stratification of the stratified liquid begins when the circulating loops close with the resistance reduced because of the disappearance of the cold core, and once the circulation forms, it extends down to make the thermal Stratifications disappear layer by layer from up to down.
Jianyun Shi - One of the best experts on this subject based on the ideXlab platform.
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Experimental research on the effects of fluid and heater on thermal Stratification of liquefied gas
Experimental Thermal and Fluid Science, 2013Co-Authors: Jianyun Shi, Jingjie Ren, Peng LiuAbstract:Abstract The thermal Stratification of liquefied gas influences the equipment safety. To find the factors and principles governing the thermal Stratification, a device was set up to simulate the thermal response of a liquefied gas tank. A small steel vessel was used to simulate the tank, and two working fluids were used: water and R22. The heating region and liquid level were precisely adjusted in the tests to simulate different accident conditions. The experimental results showed saturation pressure of the working fluid affected the thermal Stratification when the liquid wall was heated solely. For the case the liquid and vapor wall were heated together, evident thermal Stratifications formed both in R22 and water tests. The degree and duration of thermal Stratification are affected by the intensity of heat loading on the surface liquid. It is concluded that nucleate boiling in the lower liquid has great power to eliminate the thermal Stratification. When the nucleate boiling is suppressed by hydrostatic pressure or saturation pressure of the warm surface liquid, the thermal Stratification can form and maintain by natural convection. The stratifying process can be explained by a natural convection model.
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Simulation on thermal Stratification and de-Stratification in liquefied gas tanks
International Journal of Hydrogen Energy, 2013Co-Authors: Jingjie Ren, Jianyun Shi, Peng Liu, Kai JiaAbstract:Abstract The phenomena of thermal Stratification and de-Stratification in liquefied gas tanks with heat leak through the side wall were researched numerically. The calculating model developed on ANSYS FLUENT 12.0 was verified through the experimental results from literature. The flow behaviors of the liquid and the temperature distributions at Stratification and de-Stratification stages were illustrated and the interaction between them was analyzed. When the liquid is stratified, the flow field presents a semi-circulation near the liquid surface with a plume-like flow under it and there exists a cold core under the surface which resisting the warmer circulating flow. The de-Stratification of the stratified liquid begins when the circulating loops close with the resistance reduced because of the disappearance of the cold core, and once the circulation forms, it extends down to make the thermal Stratifications disappear layer by layer from up to down.
Jingjie Ren - One of the best experts on this subject based on the ideXlab platform.
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Experimental research on the effects of fluid and heater on thermal Stratification of liquefied gas
Experimental Thermal and Fluid Science, 2013Co-Authors: Jianyun Shi, Jingjie Ren, Peng LiuAbstract:Abstract The thermal Stratification of liquefied gas influences the equipment safety. To find the factors and principles governing the thermal Stratification, a device was set up to simulate the thermal response of a liquefied gas tank. A small steel vessel was used to simulate the tank, and two working fluids were used: water and R22. The heating region and liquid level were precisely adjusted in the tests to simulate different accident conditions. The experimental results showed saturation pressure of the working fluid affected the thermal Stratification when the liquid wall was heated solely. For the case the liquid and vapor wall were heated together, evident thermal Stratifications formed both in R22 and water tests. The degree and duration of thermal Stratification are affected by the intensity of heat loading on the surface liquid. It is concluded that nucleate boiling in the lower liquid has great power to eliminate the thermal Stratification. When the nucleate boiling is suppressed by hydrostatic pressure or saturation pressure of the warm surface liquid, the thermal Stratification can form and maintain by natural convection. The stratifying process can be explained by a natural convection model.
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Simulation on thermal Stratification and de-Stratification in liquefied gas tanks
International Journal of Hydrogen Energy, 2013Co-Authors: Jingjie Ren, Jianyun Shi, Peng Liu, Kai JiaAbstract:Abstract The phenomena of thermal Stratification and de-Stratification in liquefied gas tanks with heat leak through the side wall were researched numerically. The calculating model developed on ANSYS FLUENT 12.0 was verified through the experimental results from literature. The flow behaviors of the liquid and the temperature distributions at Stratification and de-Stratification stages were illustrated and the interaction between them was analyzed. When the liquid is stratified, the flow field presents a semi-circulation near the liquid surface with a plume-like flow under it and there exists a cold core under the surface which resisting the warmer circulating flow. The de-Stratification of the stratified liquid begins when the circulating loops close with the resistance reduced because of the disappearance of the cold core, and once the circulation forms, it extends down to make the thermal Stratifications disappear layer by layer from up to down.
M J Stift - One of the best experts on this subject based on the ideXlab platform.
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modelling apbp star atmospheres with stratified abundances consistent with atomic diffusion
Monthly Notices of the Royal Astronomical Society, 2012Co-Authors: M J Stift, G AlecianAbstract:Elemental abundances have been found – both empirically and theoretically – to be stratified in the magnetic atmospheres of many chemically peculiar (CP) stars, but these findings are rarely if ever taken into account for example in (Zeeman) Doppler mapping, resulting in a disturbing problem of self-consistency. Such a lack of self-consistency is also present in many studies of atomic diffusion which have usually been based on vertically homogeneous atmospheric models. In this paper we go one step further in our modelling of diffusion in magnetic CP star atmospheres and discuss self-consistent equilibrium Stratifications of elements, in particular of Fe. In an iterative approach, the atmospheric structure is adjusted to the latest Stratification profiles of the various elements until zero particle flux throughout the atmosphere is achieved. It can be shown that the resulting Stratifications are different from those calculated with vertically homogeneous atmospheres – mainly on account of the change in temperature structure – and that the unphysical behaviour resulting from the latter atmospheres may be avoided. An important finding concerns the mutual interaction between the various elements, leading to Stratification profiles that differ substantially depending on whether e.g. Fe alone is allowed to diffuse or whether other elements may diffuse too. This presentation ends with a discussion of these interactions in the context of time-dependent diffusion calculations.
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time dependent diffusion in stellar atmospheres
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: G Alecian, M J Stift, E A DorfiAbstract:The chemical peculiarities of Ap stars are due to abundance Stratifications produced by atomic diffusion in their outer layers. Theoretical models can predict such Stratifications, but so far only provide equilibrium solutions which correspond to the maximum depth-dependent abundances for each element that can be supported by the radiation field. However, these Stratifications are actually built up through a non-linear, time-dependent process which has never been modelled for realistic stellar atmospheres. Here, we present the first numerical simulations of time-dependent diffusion. We solve the continuity equation after having computed, as accurately as possible, atomic diffusion velocities (with and without a magnetic field) for a simplified fictitious – but still realistic – chemical element: cloudium. The direct comparison with existing observations is not the immediate aim of this work but rather a general understanding of how the Stratification build-up proceeds in time and space. Our results raise serious questions as to the relevance of equilibrium solutions and reinforce the suspicion that certain accumulations of chemical elements might prove unstable.
Janet C Cole - One of the best experts on this subject based on the ideXlab platform.
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Stratification improves seed germination of five native wildflower species
Hortscience, 1993Co-Authors: Carlma B Bratcher, John M Dole, Janet C ColeAbstract:Additional index words. Baptisia australis, Echinacea purpurea, Helianthus maximiliani, seed dormancy, Solidago petiolaris, Vernonia missurica Abstract. The germination responses of wild blue indigo (Baptisia australis (L.) R. Br.), purple coneflower (Echinacea purpurea (L.) Moench.), Maximilian sunflower (Helianthus maximiliani Schrad.), spike goldenrod (Solidago petiolaris Ait.), and Missouri ironweed (Vernonia missurica Raf.) seeds after 0, 2, 4, 6, 8, or 10 weeks of Stratification at 5C were investigated. Seed viability was determined using triphenyl tetrazolium chloride staining and germination based on the percentage of viable seeds. Germination percentage (GP) increased in all five species as weeks of Stratification increased. Days to first germination and germination range (days from first to last germinating seed) decreased with increasing weeks of stratificatio n, but the effect beyond 4 to 6 weeks was minimal. The number of weeks of Stratification for maximum GP was 4 for purple coneflower, 6 for Maximilian sunflower, 8 for Missouri ironweed, and 10 for wild blue indigo and spike goldenrod.
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Stratification improves seed germination of five native wildflower species
Hortscience, 1993Co-Authors: Carlma B Bratcher, John M Dole, Janet C ColeAbstract:Additional index words. Baptisia australis, Echinacea purpurea, Helianthus maximiliani, seed dormancy, Solidago petiolaris, Vernonia missurica Abstract. The germination responses of wild blue indigo (Baptisia australis (L.) R. Br.), purple coneflower (Echinacea purpurea (L.) Moench.), Maximilian sunflower (Helianthus maximiliani Schrad.), spike goldenrod (Solidago petiolaris Ait.), and Missouri ironweed (Vernonia missurica Raf.) seeds after 0, 2, 4, 6, 8, or 10 weeks of Stratification at 5C were investigated. Seed viability was determined using triphenyl tetrazolium chloride staining and germination based on the percentage of viable seeds. Germination percentage (GP) increased in all five species as weeks of Stratification increased. Days to first germination and germination range (days from first to last germinating seed) decreased with increasing weeks of stratificatio n, but the effect beyond 4 to 6 weeks was minimal. The number of weeks of Stratification for maximum GP was 4 for purple coneflower, 6 for Maximilian sunflower, 8 for Missouri ironweed, and 10 for wild blue indigo and spike goldenrod.
