The Experts below are selected from a list of 1215 Experts worldwide ranked by ideXlab platform

Ashwin W Patwardhan - One of the best experts on this subject based on the ideXlab platform.

  • cfd and experimental studies of solids hold up distribution and circulation patterns in gas solid fluidized beds
    Chemical Engineering Journal, 2008
    Co-Authors: G N Ahuja, Ashwin W Patwardhan
    Abstract:

    Abstract The hydrodynamics of a gas–solid fluidized bed was studied using a combination of experiments and CFD simulations. Experiments were conducted with polypropylene particles (710–1000 μm in diameter) as solid phase and air as gas phase. A multifluid Eulerian model incorporating the kinetic theory for solid particles is used to simulate the gas–solid flow. Momentum Exchange Coefficient was calculated using the Gidaspow drag model. Effects of gas velocity, type of sparger, presence of draft tube on solid hold-up distribution and solid circulation pattern have been investigated. The presented experimental data and comparison with CFD predictions provide useful basis for further work on understanding bubbling fluidized beds.

Wang Enlu - One of the best experts on this subject based on the ideXlab platform.

G N Ahuja - One of the best experts on this subject based on the ideXlab platform.

  • cfd and experimental studies of solids hold up distribution and circulation patterns in gas solid fluidized beds
    Chemical Engineering Journal, 2008
    Co-Authors: G N Ahuja, Ashwin W Patwardhan
    Abstract:

    Abstract The hydrodynamics of a gas–solid fluidized bed was studied using a combination of experiments and CFD simulations. Experiments were conducted with polypropylene particles (710–1000 μm in diameter) as solid phase and air as gas phase. A multifluid Eulerian model incorporating the kinetic theory for solid particles is used to simulate the gas–solid flow. Momentum Exchange Coefficient was calculated using the Gidaspow drag model. Effects of gas velocity, type of sparger, presence of draft tube on solid hold-up distribution and solid circulation pattern have been investigated. The presented experimental data and comparison with CFD predictions provide useful basis for further work on understanding bubbling fluidized beds.

Ian A. Renfrew - One of the best experts on this subject based on the ideXlab platform.

  • aircraft based observations of air sea fluxes over denmark strait and the irminger sea during high wind speed conditions
    Quarterly Journal of the Royal Meteorological Society, 2009
    Co-Authors: Guðrún Nína Petersen, Ian A. Renfrew
    Abstract:

    During the Greenland Flow Distortion experiment (GFDex), aircraft-based observations of air–sea fluxes were obtained over Denmark Strait and the Irminger Sea. High-frequency observations of velocity, temperature and water vapour have been used to calculate turbulent fluxes of Momentum, heat and moisture using the eddy covariance method. These are the first direct air–sea flux observations in this region, and add to the relatively small collection of direct air–sea flux observations made in high wind speed conditions. The aircraft-based turbulence legs were flown at remarkably low levels, only 30–50 m above the sea-surface and so within the atmospheric surface layer. Results are presented for 145 flux runs, each of 2 min (approximately 12 km), 131 over open water and 14 over sea ice and the marginal ice zone. The flux data were obtained in 10 m neutral wind speeds of up to 25 m s−1, with 80% of the flux data in the range 15–19 m s−1. Over open water, the wind stress varied from 0.2 to 1.9 N m−2 and the surface sensible and latent heat fluxes from 50 to 300 W m−2, resulting in total surface heat fluxes of up to 600 W m−2. The Exchange Coefficients are at the upper end of those previously observed. Mean values for the 15–19 m s−1 range are CDN = 2.04 × 10−3, CHN = 1.63 × 10−3 and CEN = 1.57 × 10−3 for Momentum, heat and moisture, respectively. The value of the Momentum Exchange Coefficient is in line with previous studies; however, both the heat and moisture Exchange Coefficients are higher than in previous studies. Values of CDN over sea ice and the marginal ice zone were in the range 1.67–6.29 × 10−3 and were, for these conditions, generally higher than CDN over adjacent open water areas. No significant spatial patterns in the Exchange Coefficients over open water have been detected, although there is some suggestion of higher Exchange Coefficients immediately downwind of the sea ice. Copyright © 2009 Royal Meteorological Society

Kui Chen - One of the best experts on this subject based on the ideXlab platform.

  • Momentum Exchange Coefficient for two jet flows mixing in a tee junction
    Frontiers of Chemical Engineering in China, 2009
    Co-Authors: Lijun Ji, Bin Wu, Kui Chen
    Abstract:

    Momentum Exchange Coefficient (K) is a crucial parameter for the mixing process of two jet flows. In this paper, the Momentum Exchange Coefficient for two jet flows mixing in a tee junction was investigated with air-air, water-water and water-air system in a wide region of mass flow ratio. The pressure drop of two jets mixing in a tee junction was analyzed according to the flow characteristics. It was considered that the total pressure drop mainly included the pressure drop of Momentum Exchange and the pressure drop of friction. Based on the pressure drop data measured in this study, the pressure drops due to Momentum Exchange were obtained by the extrapolation method, and then the Momentum Exchange Coefficient was calculated. The results show that, the Momentum Exchange Coefficient was mainly dependent on the Momentum flux ratio (M) of the two jets and almost independent with the physical properties of jet flows. The relationship between K and M is correlated with the following equation: $$ K = 1 + 0.236M^{0.25} $$ .