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  • Numerical and Experimental Study of a Tornado Mixer
  • Abstract A new design of a selective catalytic reduction (SCR) mixer called tornado was developed for a heavy-duty diesel engine to solve the urea deposition problem. A combination of CFD simulation and experimental studies was used to comprehensively evaluate the performance of the tornado mixer. According to the numerical simulations, this mixer can improve the front surface flow uniformity of the SCR carrier by 6.67% and the NH3 distribution uniformity by 3.19% compared to a traditional mixer. Similarly, steady state SCR conversion efficiency test results have shown that the tornado mixer can increase the average SCR conversion efficiency by 1.73% compared…
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  • Using Image Processing Technology and General Fluid Mechanics Principles to Model Smoke Diffusion in Forest Fires
  • Abstract In the present study, the laws of smoke diffusion during forest fires are determined using the general principles of fluid mechanics and dedicated data obtained experimentally using an “ad hoc” imaging technology. Experimental images mimicking smoke in a real scenario are used to extract some “statistics”. These in turn are used to obtain the “divergence” of the flow (this fluid-dynamic parameter describing the amount of air that converges to a certain place from the surroundings or vice versa). The results show that the divergence of the smoke depends on the outside airflow and finally tends to zero as time passes.…
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  • Development and Application of a Heating Remote Monitoring System Based on KingSCADA
  • Abstract A remote monitoring system for a secondary heating pipe network is designed on the basis of the KingSCADA software. Remote data communication is implemented through the IP mapping technology. Remote data are sorted through IOServer, and the remote monitoring of the pipe network unit port return is implemented accordingly. Using data such as water temperature and pressure of the water supply and return pipes, valve opening can be remotely adjusted to optimize the performances of the network to meet user needs in real time. The research results show that this remote monitoring system displays a reasonable degree of stability and…
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  • Experimental Study on the Axial Compression Behavior of Short Columns of Steel-Fiber-Reinforced Recycled Aggregate Concrete
  • Abstract In order to study the axial compression performances of short columns made of recycled aggregate concrete, four samples were designed with different recycled aggregate replacement rates and carbon fibre reinforced plastics (CFRP) sheets. Then, monotonic loading was implemented to assess the variation trends of their axial compression properties. The ABAQUS finite element software was also used to determined the compression performances. Good agreement between experimental and numerical results has been found for the different parameters being considered. As shown by the results, recycled coarse aggregates result in improved ductility and better deformation performance of the specimens. The failure of specimens…
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  • On the Stability of Carbon Shale Slope under Rainfall Infiltration
  • Abstract Carbonaceous shale is a sedimentary rock containing a large amount of dispersed carbonaceous organic material. It is easy to crack and soften when exposed to water. In the present work, the stability of such a rock and its sensitivity to the formation of infiltrations due to rainfall are analyzed numerically using the GeoStudio software. The slope stability coefficient is calculated and verified using the landslide thrust calculation method. The results show that under the action of heavy rainfall, water infiltrates into the slope layer by layer, and, accordingly, the soil volume water content is different with respect to that typical…
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  • A Study on the Pyrolytic Characteristics of Xanthoceras Sorbifolia Husk and Its Crude Cellulose Extract
  • Abstract Huge amounts of Xanthoceras sorbifolia husks (XSH) are typically discarded after oil extraction. Since pyrolysis represents a promising solution to harness the bio-energy of XSH, in the present work the pyrolytic and kinetic characteristics of XSH and related crude cellulose extract (CCE) were studied considering different rates of heating (10, 30 and 50°C min−1). The pyrolysis activation energy, pre-exponential factors and mechanism function were computed using different models namely Popescu, FWO (Flynn-Wall-Ozawa) and KAS (Kissinger-Akahira-Sunose). The pyrolysis process was articulated into three stages: dehydration (Stage I), primary devolatilization (Stage II), residual decomposition (Stage III). Marked variations in the average activation…
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  • A Study on the Unsteady Flow Characteristics and Energy Conversion in the Volute of a Pump-as-Turbine Device
  • Abstract To study the unsteady flow and related energy conversion process in the volute of a pump-as-turbine (PAT) device, six different working conditions have been considered. Through numerical calculation, the spatio-temporal variation of static pressure, dynamic pressure, total pressure and turbulent energy dissipation have been determined in each section of the volute. It is concluded that the reduction of the total power of two adjacent sections of the PAT volute is equal to the sum of the power lost by the fluid while moving from one section to the other and the power output from the two adjacent sections. For a…
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  • Assessment of the Application of Subcooled Fluid Boiling to Diesel Engines for Heat Transfer Enhancement
  • Abstract The increasing demand of cooling in internal combustion engines (ICE) due to engine downsizing may require a shift in the heat removal method from the traditional single phase liquid convection to the application of new technologies based on subcooled fluid boiling. Accordingly, in the present study, experiments based on subcooled flow boiling of 50/50 by volume mixture of ethylene glycol and water coolant (EG/W) in a rectangular channel heated by a cast iron block are presented. Different degrees of subcooling, velocity and pressure conditions are examined. Comparison of three empirical reference models shows that noticeable deviations occur especially when low…
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  • On the Development of an Effective Pressure Driving System for Ultra-Low Permeability Reservoirs
  • Abstract Given its relevance to the exploitation of ultra-low permeability reservoirs, which account for a substantial proportion of the world’s exploited and still unexploited reserves, in the present study the development of an adequate water injection system is considered. Due to the poor properties and weak seepage capacity of these reservoirs, the water injection pressure typically increases continuously during water flooding. In this research, the impact on such a process of factors as permeability, row spacing, and pressure gradient is evaluated experimentally using a high-pressure large-scale outcrop model. On this basis, a comprehensive evaluation coefficient is introduced able to account for…
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  • Experimental and Numerical Analysis of the Relationship between Pressure and Drip Rate in a Vertical Polypropylene Infusion Bag
  • Abstract Vertical infusion (self-emptying) bags used for Intravenous infusion are typically obtained by moulding a soft envelope of polypropylene. In normal conditions a continuous flow of liquid can be obtained with no need to use a pump. In the present study, the relationship between air pressure effects and the drug drip rate have been investigated experimentally and numerically. After determining relevant experimental data about the descending height of liquid level, the dropping speed and pressure, the ordinary least square method and MATLAB have been used to reconstruct the related variation and interrelation laws. Numerical simulations have been performed to determine the…
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