By the use of modelling software, this paper set up the three-dimensional physical model of single-stage turbine and guided it into the pre-process software. After meshing the turbine flow channel, simulating the mud ...
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By the use of modelling software, this paper set up the three-dimensional physical model of single-stage turbine and guided it into the pre-process software. After meshing the turbine flow channel, simulating the mud flow characteristics in Turbine with CFD, and calculating the pressure drawdown at the inlet/outlet and the pressure distributions in single-stage turbine. Such results indicate that the pressure drawdown of single-stage turbine is influenced by the mud discharge capacity, drilling fluid density and viscosity. The pressure drop increases with the augment of mud discharge, which is approximately linear. There are significantly positive correlations between the pressure drawdown and the increase of mud density. The research in the paper provides reliable guidance in turbine flow channel design and the drilling technological parameters optimizing.
Background Understanding the interaction between the mitral valve(MV)and the left ventricle(LV)is very important in assessing cardiac pump function,especially when the MV is *** dysfunction is a major medical problem ...
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Background Understanding the interaction between the mitral valve(MV)and the left ventricle(LV)is very important in assessing cardiac pump function,especially when the MV is *** dysfunction is a major medical problem owing to the essential role of the MV in cardiac pump *** modelling can provide new approaches to gain insight into the functions of the MV and *** In this study,a previously developed LV-MV model was used to study cardiac dynamics of MV leaflets under normal and pathological conditions,including hypertrophic cardiomyopathy(HOCM)and calcification of the *** coupled LV-MV model was implemented using a hybrid immersed boundary/finite element method to enable assessment of MV haemodynamic *** parameters of the HOCM and calcified valves were inversely determined from published experimental *** LV compensation mechanism was further studied in the case of the calcified *** Our results showed that MV dynamics and LV pump function could be greatly affected by MV *** example,the HOCM case showed bulged MV leaflets at the systole owing to low stiffness,and the calcified MV was associated with impaired diastolic filling and much-reduced stroke *** further demonstrated that either increasing the LV filling pressure or increasing myocardial contractility could enable a calcified valve to achieve near-normal pump *** The modelling approach developed in this study may deepen our understanding of the interactions between the MV and the LV and help in risk stratification of heart valve disease and in silico treatment planning by exploring intrinsic compensation mechanisms.
Waste biomass is always generated during the production process in industries. The ordinary way to get rid of the waste biomass is to send them to landfill or burn it in the open field. The waste may potentially be us...
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Waste biomass is always generated during the production process in industries. The ordinary way to get rid of the waste biomass is to send them to landfill or burn it in the open field. The waste may potentially be used for co-firing with coal to save fossil fuel consumption and also reduce net carbon emissions. In this case study, the bio-waste from a Nicotiana Tahacum (NT) pre-treatment plant is used as the biomass to co-fire with coal. The samples of NT wastes were analysed. It was found that the wastes were of the relatively high energy content which were suitable for co-firing with coal. To investigate the potential and benefits for adding NT wastes to a Fluidised Bed Combustion (FBC) boiler in the plant, detailed modelling and simulation are carried out using the European Coal Liquefaction Process simulation and Evaluation (ECLIPSE) process simulation package. The feedstock blending ratios of NT waste to coal studied in this work are varied from 0% to 30%. The results show that the addition of NT wastes may decrease the emissions of CO2 and SOx without reducing the boiler performance.
Laser powder bed fusion(LPBF)is a popular metal additive manufacturing ***,the materials employed for LPBF are discrete and particulate metal ***,the discontinuous behaviors exhibited by the powder materials cannot be...
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Laser powder bed fusion(LPBF)is a popular metal additive manufacturing ***,the materials employed for LPBF are discrete and particulate metal ***,the discontinuous behaviors exhibited by the powder materials cannot be simulated solely using conventional continuum-based computational approaches,such as finite-element or finite-difference *** discrete element method(DEM)is a proven numerical method to model discrete matter,such as powder particles,by tracking the motion and temperature of individual ***,DEM simulation has gained popularity in LPBF ***,it has not been widely *** study reviews the existing applications of DEM in LPBF processing,such as powder spreading and fusion.A review of the existing literature indicates that DEM is a promising approach in the study of the kinetic and thermal fluid behaviors of powder particles in LPBF additive manufacturing.
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