Hydrodynamic predictions of dense gas–particle flows using a second-order-moment frictional stress model

2011 ◽  
Vol 22 (4) ◽  
pp. 504-511 ◽  
Author(s):  
Yang Liu ◽  
Xue Liu ◽  
Sirpa Kallio ◽  
Lixing Zhou
Keyword(s):  
Second Order ◽  
Order Moment ◽  
Frictional Stress ◽  
Stress Model ◽  
Dense Gas ◽  
Particle Flows

A second-order moment method of dense gas–solid flow for bubbling fluidization

2009 ◽  
Vol 64 (23) ◽  
pp. 5013-5027 ◽  
Author(s):  
Sun Dan ◽  
Wang Shuyan ◽  
Lu Huilin ◽  
Shen Zhiheng ◽  
Li Xiang ◽  
...  
Keyword(s):  
Moment Method ◽  
Second Order ◽  
Order Moment ◽  
Dense Gas ◽  
Solid Flow

Simulation of Swirling Gas-Particle Flows Using Different Time Scales for the Closure of Two-Phase Velocity Correlation in the Second-Order Moment Two-Phase Turbulence Model1

2003 ◽  
Vol 125 (2) ◽  
pp. 247-250 ◽  
Author(s):  
Y. Yu ◽  
L. X. Zhou ◽  
C. G. Zheng ◽  
Z. H. Liu
Keyword(s):  
Phase Velocity ◽  
Time Scale ◽  
Second Order ◽  
Order Moment ◽  
Velocity Correlation ◽  
Two Phase ◽  
Fluctuation Velocity ◽  
Particle Flows ◽  
Measured Particle ◽  
Different Time Scales

Three different time scales—the gas turbulence integral time scale, the particle relaxation time, and the eddy interaction time—are used for closing the dissipation term in the transport equation of two-phase velocity correlation of the second-order moment two-phase turbulence model. The mass-weighted averaged second-order moment (MSM) model is used to simulate swirling turbulent gas-particle flows with a swirl number of 0.47. The prediction results are compared with the PDPA measurement results taking from references. Good agreement is obtained between the predicted and measured particle axial and tangential time-averaged velocities. There is some discrepancy between the predicted and measured particle axial and tangential fluctuation velocities. The results indicate that the time scale has an important effect. It is found that the predictions using the eddy interaction time scale give the right tendency—for example, the particle tangential fluctuation velocity is smaller than the gas tangential fluctuation velocity, as that given by the PDPA measurements.

scholarly journals Hydrodynamic Modeling of Swirling Binary Mixture Gas–Particle Flows Using a Second-Order-Moment Turbulence Model

ACS Omega ◽  
2020 ◽  
Vol 5 (49) ◽  
pp. 31490-31501
Author(s):  
Yang Liu ◽  
Ziyun Chen ◽  
Yongju Zhang ◽  
Lixing Zhou
Keyword(s):  
Binary Mixture ◽  
Turbulence Model ◽  
Hydrodynamic Modeling ◽  
Second Order ◽  
Order Moment ◽  
Particle Flows

A Nonlinear k-ε-kp Two-Phase Turbulence Model

2003 ◽  
Vol 125 (1) ◽  
pp. 191-194 ◽  
Author(s):  
L. X. Zhou ◽  
H. X. Gu
Keyword(s):  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Turbulence Model ◽  
Computation Time ◽  
Second Order ◽  
Phase Correlation ◽  
Order Moment ◽  
Reynolds Stresses ◽  
Two Phase ◽  
Particle Flows

Nonlinear relationships of two-phase Reynolds stresses with the strain rates together with the transport equations of gas and particle turbulent kinetic energy and the two-phase correlation turbulent kinetic energy are proposed as the nonlinear k-ε-kp turbulence model. The proposed model is applied to simulate swirling gas-particle flows. The predicted two-phase time-averaged velocities and Reynolds stresses are compared with the PDPA measurements and those predicted using the second-order moment model. The results indicate that the nonlinear k-ε-kp model has the modeling capability near to that of the second-order moment model, but the former can save much computation time than the latter.

scholarly journals Method for Measuring the Second-Order Moment of Atmospheric Turbulence

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 564
Author(s):  
Hong Shen ◽  
Longkun Yu ◽  
Xu Jing ◽  
Fengfu Tan
Keyword(s):  
Atmospheric Turbulence ◽  
Weighting Function ◽  
Structure Constant ◽  
Turbulence Models ◽  
Second Order ◽  
Index Structure ◽  
Order Moment ◽  
Site Testing ◽  
Optical Effects ◽  
Novel Method

The turbulence moment of order m (μm) is defined as the refractive index structure constant Cn2 integrated over the whole path z with path-weighting function zm. Optical effects of atmospheric turbulence are directly related to turbulence moments. To evaluate the optical effects of atmospheric turbulence, it is necessary to measure the turbulence moment. It is well known that zero-order moments of turbulence (μ0) and five-thirds-order moments of turbulence (μ5/3), which correspond to the seeing and the isoplanatic angles, respectively, have been monitored as routine parameters in astronomical site testing. However, the direct measurement of second-order moments of turbulence (μ2) of the whole layer atmosphere has not been reported. Using a star as the light source, it has been found that μ2 can be measured through the covariance of the irradiance in two receiver apertures with suitable aperture size and aperture separation. Numerical results show that the theoretical error of this novel method is negligible in all the typical turbulence models. This method enabled us to monitor μ2 as a routine parameter in astronomical site testing, which is helpful to understand the characteristics of atmospheric turbulence better combined with μ0 and μ5/3.

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