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195 results on '"Zhou, L.X."'

16. 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 model

Author

Yu, Y., Zhou, L.X., Zheng, C.G., and Liu, Z.H.

Subjects
Fluid dynamics -- Models, Eddies -- Models, Engineering and manufacturing industries, Science and technology
Abstract

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.

Published
2003

17. Nonlinear k-[epsilon]-[k.sub.p] two-phase turbulence model

Author

Zhou, L.X. and Gu, H.X.

Subjects
Fluid mechanics -- Analysis, Turbulence -- Models, Nonlinear functional analysis -- Models, Reynolds number -- Measurement, Engineering and manufacturing industries, Science and technology
Abstract

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-[epsilon]-[k.sub.p] 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-[epsilon]-[k.sub.p] 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. [DOI: 10.1115/1.1522414]

Published
2003

45. Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2) from in situ and air archive observations

Author

Simmonds, P.G., Rigby, M., Manning, A. J., Lunt, M.F., O'Doherty, S., McCulloch, A., Fraser, P.J., Henne, S., Vollmer, M.K., Mühle, J., Young, D, Reimann, S., Wenger, A., Arnold, T., Harth, C.M., Krummel, P.B., Steele, L.P., Dunse, B.L., Miller, B.R., Lunder, Chris Rene, Hermansen, Ove, Schmidbauer, Josef Norbert, Saito, T., Yokouchi, Y., Park, S., Li, S., Yao, B., Zhou, L.X., Arduini, J., Maione, M., Wang, R.H.J., Ivy, D., and Prinn, R.G.

Subjects
Zeppelinobservatoriet
Published
2016

48. Research on Sheet Hydroforming with a Movable Die Component

Author

Zhang, Shi-Hong, Palumbo, G., Xu, Y.C., Zhou, L.X., Lang, L.H., Danckert, Joachim, Nielsen, Karl Brian, Kang, D.C., Tricarico, L., and Stören, Sigurd

Subjects
Forminglimit, FLexibleforming, Sheethydro-forming, Movabledie
Published
2004

50. Nested atmospheric inversion for the terrestrial carbon sources and sinks in China

Author

Jiang, F., Wang, H.W., Chen, J.M., Zhou, L.X., Ju, W.M., Peters, W., Jiang, F., Wang, H.W., Chen, J.M., Zhou, L.X., Ju, W.M., and Peters, W.

Abstract

In this study, we establish a~nested atmospheric inversion system with a focus on China using the Bayes theory. The global surface is separated into 43 regions based on the 22 TransCom large regions, with 13 small regions in China. Monthly CO2 concentrations from 130 GlobalView sites and a Hong Kong site are used in this system. The core component of this system is atmospheric transport matrix, which is created using the TM5 model with a horizontal resolution of 3° × 2°. The net carbon fluxes over the 43 global land and ocean regions are inverted for the period from 2002 to 2009. The inverted global terrestrial carbon sinks mainly occur in Boreal Asia, South and Southeast Asia, eastern US and southern South America (SA). Most China areas appear to be carbon sinks, with strongest carbon sinks located in Northeast China. From 2002 to 2009, the global terrestrial carbon sink has an increasing trend, with the lowest carbon sink in 2002. The inter-annual variation (IAV) of the land sinks shows remarkable correlation with the El Niño Southern Oscillation (ENSO). However, no obvious trend is found for the terrestrial carbon sinks in China. The IAVs of carbon sinks in China show strong relationship with drought and temperature. The mean global and China terrestrial carbon sinks over the period 2002–2009 are -3.15 ± 1.48 and -0.21 ± 0.23 Pg C yr-1, respectively. The uncertainties in the posterior carbon flux of China are still very large, mostly due to the lack of CO2 measurement data in China.

Published
2013

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