A combined approach of inverse method and direct flow analysis is presented for the hydrodynamic design of gas-liquid two-phase flow rotodynamic pump impeller. The geometry of impeller blades is designed for a specified velocity torque distribution by treating the two-phase mixture as a homogeneous fluid under the design condition. The three-dimensional flow in the designed impeller is verified by direct turbulent flow analysis, and the design specification is further modified to optimize the flow distribution. A helical axial pump of high specific speed has been developed. To obtain a favorable pressure distribution the impeller blade was back-loaded at the hub side compared to the tip side. Experimental results demonstrate that the designed pump works in a wide flow rate range until the gas volume fraction increases to over 50% and its optimum hydraulic efficiency reaches to 44.0% when the gas volume fraction of two-phase flow is about 15.6%. The validity of design computation has been proved.
Hepatitis E virus (HEV) infection causes subclinical diseases, leading to high mortality (>25%) in pregnant women. HEV replication is aggressively escalated in pregnant women, especially in the third trimester of pregnancy. Oestrogen plays an important role in pregnancy. However, the pathogenesis of HEV in pregnant women or immunosuppressive pregnant women (such as HIV-infected or organ-transplanted pregnant women) remains unclear. We investigated the role of oestradiol in HEV infection in a cell culture system. HEV-infected pregnant women had significantly higher oestradiol levels compared with uninfected individuals. HEV infection was significantly increased in cells treated with analogues of oestradiol, diethylstilbestrol (DES) or 17β-oestradiol in a dose-dependent way. However, tamoxifen, an antagonist oestrogen, inhibited HEV replication. HEV infection inhibits oestrogen receptor (ER-α) expression. Immunofluorescence and co-immunoprecipitation assays indicated that ER-α interacted with the helicase of HEV ORF1 indirectly. More importantly, HEV infection was exacerbated in immunosuppressive cells treated with an inhibitor of PI3K-AKT-mTOR signal pathway (LY296004) and supplemented with pregnant women serum with high oestradiol simultaneously. These results strongly suggest that pregnant women with high oestradiol and/or immunosuppression will be vulnerable to HEV infection.
We study the cyclic dynamics of a single polymer tethered to a hard wall in shear flow using Brownian dynamics, the lattice Boltzmann method, and a recent stochastic event-driven molecular dynamics algorithm. We focus on the dynamics of the free end (last bead) of the tethered chain and we examine the cross-correlation function and power spectral density of the chain extensions in the flow and gradient directions as a function of chain length N and dimensionless shear rate Wi. Extensive simulation results suggest a classical fluctuation-dissipation stochastic process and question the existence of periodicity of the cyclic dynamics, as previously claimed. We support our numerical findings with a simple analytical calculation for a harmonic dimer in shear flow.
(2015),"Comparative study of SGS models for simulating the flow in a centrifugal-pump impeller using single passage", Engineering Computations, Vol. 32 Iss 7 pp. 2120-2135 https://doi.org/10.1108/EC-09-2014-0193 Access to this document was granted through an Emerald subscription provided by All users group
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