The paper presents three power-type correlations of a simple form, which are valid for Reynolds numbers range from 3.10^3 ≤ Re ≤ 10^6, and for three different ranges of Prandtl number： 0.1 ≤ Pr ≤ 1.0, 1.0≤ Pr ≤...The paper presents three power-type correlations of a simple form, which are valid for Reynolds numbers range from 3.10^3 ≤ Re ≤ 10^6, and for three different ranges of Prandtl number： 0.1 ≤ Pr ≤ 1.0, 1.0≤ Pr ≤ 3.0, and 3.0 ≤Pr ≤ 10^3. Heat transfer correlations developed in the paper were compared with experimental results available in the literature. The comparisons performed in the paper confLrm the good accuracy of the proposed correlations. They are also much simpler compared with the relationship of Gnielinski, which is also widely used in the heat transfer calculations.展开更多
Flooding phenomenon limits the stability and the flow of a liquid film falling along the walls of a channel in which a gas is flowing upwards. As known, the entrainment effect can completely prevent the liquid to fall...Flooding phenomenon limits the stability and the flow of a liquid film falling along the walls of a channel in which a gas is flowing upwards. As known, the entrainment effect can completely prevent the liquid to fall from its natural flow. The present work proposes a new mechanistic model for the prediction of the onset of flooding in vertical and inclined pipes in the presence of obstructions, as well as taking into account the viscosity effect. The good performance of the model in the different geometrical conditions and for variable viscosities of the liquid component assesses the validity of the hypothesis that the instability of a wavelike disturbance limits the countercurrent flow in a channel.展开更多
文摘The paper presents three power-type correlations of a simple form, which are valid for Reynolds numbers range from 3.10^3 ≤ Re ≤ 10^6, and for three different ranges of Prandtl number： 0.1 ≤ Pr ≤ 1.0, 1.0≤ Pr ≤ 3.0, and 3.0 ≤Pr ≤ 10^3. Heat transfer correlations developed in the paper were compared with experimental results available in the literature. The comparisons performed in the paper confLrm the good accuracy of the proposed correlations. They are also much simpler compared with the relationship of Gnielinski, which is also widely used in the heat transfer calculations.
文摘Flooding phenomenon limits the stability and the flow of a liquid film falling along the walls of a channel in which a gas is flowing upwards. As known, the entrainment effect can completely prevent the liquid to fall from its natural flow. The present work proposes a new mechanistic model for the prediction of the onset of flooding in vertical and inclined pipes in the presence of obstructions, as well as taking into account the viscosity effect. The good performance of the model in the different geometrical conditions and for variable viscosities of the liquid component assesses the validity of the hypothesis that the instability of a wavelike disturbance limits the countercurrent flow in a channel.
