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  • Analysis of the Thermal Behavior of a Lithium Cell Undergoing Thermal Runaway
  • Abstract This study examines the thermal runaway of a lithium ion battery caused by poor heat dissipation performances. The heat transfer process is analyzed on the basis of standard theoretical concepts. Water mist additives are considered as a tool to suppress the thermal runaway process. The ensuing behaviour of the battery in terms of surface temperature and heat generation is analyzed for different charge and discharge rates. It is found that when the remaining charge is 100%, the heat generation rate of the battery is the lowest, and the surface temperature with a 2C charge rate is higher than that obtained…
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  • Models for Predicting the Jet Trajectory and Intensity Drop Point of Fire Monitors
  • Abstract Two models are defined for predicting the trajectory of a foam jet originating from a fire monitor (hydrant) and the related intensity drop point. An experimental framework is also defined and used accordingly to compare real-time data with the predictions of such models. This mixed theoretical-experimental approach is proven to be effective for the determination of otherwise unknown coefficients which take into account several important factors such as the operation pressure, the elevation angle and the nozzle diameter. It is shown that the mean absolute error is smaller than 20%.
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  • A study on the Gas-based Lubrication of Elastic Foil Bearings Using an Over Relaxation Iteration Method
  • Abstract A new type of foil bearings with a specific surface microstructure is studied. First, relevant boundary conditions based on the assumption of rarefied gas flow are proposed, then, the static bearing capacity and friction torque are analyzed in the framework of a numerical technique based on the discretization of the governing equation for rarefied gas-dynamics. It is shown that under the same static load, the difference between the minimum film thickness calculated in this exploration and the results provided by dedicated tests is not obvious; with an increase in the load, the simulation results are closer to the test values;…
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  • Visualization of Water Plugging Displacement with Foam/Gel Flooding in Internally Heterogeneous Reservoirs
  • Abstract During the displacement of water plugging with binary flooding in internally heterogeneous reservoirs, it is essential to understand the distributions of remaining oil as well as the oil displacement mechanisms at different stages. In this study, two types of internally heterogeneous systems, i.e., vertical and horizontal wells are investigated experimentally through a microscopic approach. The results show that plugging agent types have a greater impact on oil recovery than well types, and foam injection can enhance oil recovery more effectively than gel injection. Additionally, the injection sequence of plugging agents significantly affects oil displacement efficiency. Injecting gel after foam is…
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  • Effects of Particle Concentration on the Dynamics of a Single-Channel Sewage Pump under Low-Flow-Rate Conditions
  • Abstract Single-channel sewage pumps are generally used to transport solid-liquid two-phase media consisting of a fluid and solid particles due to the good non-clogging property of such devices. However, the non-axisymmetric structure of the impeller of this type of pumps generally induces flow asymmetry, oscillatory outflow during operations, and hydraulic imbalance. In severe cases, these effects can jeopardize the safety and stability of the overall pump. In the present study, such a problem is investigated in the framework of a Mixture multiphase flow method coupled with a RNG turbulence model used to determine the structure of the flow field and the…
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  • On Aircraft Lift and Drag Reduction Using V Shaped Riblets
  • Abstract Reducing drag during take-off and nominal (cruise) conditions is a problem of fundamental importance in aeronautical engineering. Existing studies have demonstrated that v-shaped symmetrical riblets can effectively be used for turbulence control, with those with dimensionless depth h+ = 15 and dimensionless width s+ = 15 having the best drag reduction effect. In the present study, experimental tests have been conducted considering two models of the same size, one with smooth surface, the other with v-shaped riblets of the h+ = 15 and s+ = 15 type. The results show that for an angle of attack in the 8°~20° range…
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  • Coupled Effects of Heat and Moisture of Early-Age Concrete
  • Abstract In order to analyze the coupled influence of temperature and humidity on early-age concrete (including cement and copper tailings), a mathematical model is introduced on the basis of the Krstulovic-Dabic hydration reaction kinetic equations. In such a framework, the influence of hydration-released heat and water consumption are also taken into account. The results provided by such a model are verified by means of experiments and related sensor measurements. The research results show that this model can adequately predict the internal temperature and the humidity temporal evolution laws.
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  • Mixed Convection in a Two-Sided Lid-Driven Square Cavity Filled with Different Types of Nanoparticles: A Comparative Study Assuming Nanoparticles with Different Shapes
  • Abstract Steady, laminar mixed convection inside a lid-driven square cavity filled with nanofluid is investigated numerically. We consider the case where the right and left walls are moving downwards and upwards respectively and maintained at different temperatures while the other two horizontal ones are kept adiabatic and impermeable. The set of nonlinear coupled governing mass, momentum, and energy equations are solved using an extensively validated and a highly accurate finite difference method of fourth-order. Comparisons with previously conducted investigations on special configurations are performed and show an excellent agreement. Meanwhile, attention is focused on the heat transfer enhancement when different nano-particles:…
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  • Haemodynamic Analysis of the Relationship between the Morphological Alterations of the Ascending Aorta and the Type A Aortic-Dissection Disease
  • Abstract Type A aortic dissection (AD) is one of the most serious cardiovascular diseases, whose risk predictors are controversial. The purpose of this research was to investigate how elongation accompanied by dilation of the ascending aorta (AAo) affects the relevant haemodynamic characteristics using image-based computational models. Five elongated AAos with different levels of dilation have been reconstructed based on the centerlines data of an elderly and an AD patient. Numerical simulations have been performed assuming an inflow waveform and a Windkessel model with three elements for all outflow boundaries. The numerical results have revealed that the elongation of AAo can disturb…
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  • A Research on the Flow Characteristics of a Splitter-Based Water Cooling System for Computer Boards
  • Abstract The splitter is an important component of water-based cooling systems used to extract heat from computer boards. In the present study, the flow characteristics of a 16-splitter structure were numerically simulated and compared with experimental results to verify the reliability of the numerical simulation method. Accordingly, the concept of splitter structural coefficients was proposed. Based on the results of this study, we recommend a selection range of 5 ≤ k ≤ 6 for the structure factor k of the splitter; after optimization, the maximum deviation of the splitter outlet flow was reduced from the original value of 100% to 8.3%.
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