Papers by Keyword: Hot Spot

Abstract: The foundry casting process is complex and takes various stages to produce the desired component; as a result, simulation is necessary before manufacturing. Hot spots are areas that become thermally isolated and take the longest to cool, resulting in cavities during the solidification of the casting. So it is important to know about the hot spot location and size so that any casting designer can identify the hot spot behaviours before the casting. To predict the initiation of the hot spot, a 3D aluminium permanent mould casting model has been developed by Ansys Fluent. The suitable boundary and initial conditions such as temperature, pressure, convectional heat transfer coefficient, etc. are reasonably established in the simulation of Ansys Fluent. The simulation has been performed for varied pouring parameters i.e. pouring velocity and pouring temperature, to examine the beginning of hot spots. This study can predict the position and approximate size of the hot spots for various pouring conditions and it is found that a hot spot is commonly located below the riser.

Abstract: Compatibility and safetysystems research and production equipment and technology of explosives betweenitself, the establishment and development of the explosion mechanism ofexplosive accidents and prevent the occurrence of accidental explosion ofexplosives to achieve disaster prevention and reduction, to ensure the safetyof personnel and minimize property damage. Explosives production of metals andalloys commonly used in the device in an aqueous system, the compatibility ofthe ammonium nitrate, especially at higher temperatures and a variety ofelements from the synergy of explosives, etc. to accelerate the reactionconditions, to select a material with good compatibility, the nature of theexplosive increase in production safety, to solve the production of explosivesexplosion problem

Abstract: The main background was the "3.11" accident in this paper. The starting point was based on the experts’ conclusions of investigation and analysis in the accident. Combining the decomposition mechanism of ammonium nitrate in the emulsion explosives and the lessons from the production of emulsion explosives explosion, the conditions of the emulsion explosives (matrix) thermal decomposition in the emulsifier are given that are the formation of hot spot and the accumulation of heat. Then the factors of hot spots generated in the production of emulsion explosives and the occurred conditions of the heat accumulation are analyzed and summarized.

Abstract: We carried out an atomic-scale study of the behavior of nanoscale void defect in shock loading condition by the means of non-equilibrium molecular dynamic simulation. Atom trajectory and local temperature were investigated in different stages in the non-equilibrium process in the conditions with specific shock speed. The results show that the local temperature is significantly affected by the nanoscale void defect of bcc iron and a hot spot is formed in the initiation stage of the shock loading compression and consequently the hot spot induces the melting of the sample.

Abstract: With the increase of performance demands, the nonuniformity of on-chip power dissipation becomes greater, causing localized high heat flux hot spots that can degrade the processor performance and reliability. In this paper, a three-dimensional model of the copper microchannel heat sink, with hot spot heating and background heating on the back, was developed and used for numerical simulation to predict the hot spot cooling performance. The hot spot is cooled by localized cross channels. The pressure drop, thermal resistance and effects of hot spot heat flux and fluid flow velocity on the cooling of on-chip hot spots, are investigated in detail.

Abstract: Computer room cooling performance directly affect the operation of the engine room, the air conditioning out of the wind through the method to build a three-dimensional simulation of the engine room to explore the room hotspot locations, and to optimize the configuration of the cabinet task according to the engine room heat distribution. Using the Fluent Fluid Dynamics processing software provides simple algorithm to simulate the flow and temperature fields of the simulation engine room, the idea of sampling point using the model output parameters, use the function fitting, build a function of the wind speed of the air speed sampling point obtained reasonable outlet velocity.

Abstract: The bucket is a metal entity, linked to a machine called DRAGLINE, used for loading the different sizes of granular materials in large quantities. Each bucket is provided with six teeth which in contact with materials to be discharged, in order to extract the mineral. These teeth are connected to the bucket via a semi-rigid connection. In operation, except for the wear phenomenon "normal", some teeth break after a few hours of operation at the fixed portion in the singularity region (radius of curvature equal to zero). We observed via elastic numerical simulation in quasi-static regime, performed using PATRAN and NASTRAN software, that hot spots are located at the singularity region. We also used this numerical calculation for analyzing the effect of the variation radius of curvature on the stress concentration factor by plotting the variation of this factor vs of said radius. To deepen, we repeated the same study but this time considering the material of the tooth as elastic perfectly plastic for seeking the limit load. For each value of the radius of curvature, was plotted the variation of the elasto-plastic external force according to the displacement of the front end of the tooth, knowing that the other end is fixed.

Abstract: The theory of building skin is a topic of great concern in domestic architectural theory community in recent years. In this paper, through to retrieve the keywords from the Chinese journal full-text database, China Ph.D. Thesis full text data, China's excellent master's degree thesis full-text database and WANFANG DATA(ten thousand party database), analysis and deduced that architecture ontology, architecture techniques, architecture arts and culture are the top three themes that the architect concerned about in the domestic, and the skin space, ecological skin and skin culture are the hot spots in these three themes, and they can supply scientific data.for further in-depth study of building skin theory.

Abstract: This paper provides proof of concept for a technique that uses high resolution thermal infrared imager to detect faults for outdoor operation photovoltaic array. An experimental study focused on two situations was tested: abnormal emitting heat of monocrystalline silicon solar cells (hot spot); open circuit fault of photovoltaic array. Experimental results show that the infrared image could clearly give prominence to the faulty solar cell or PV array. The back surface temperature of solar cell with hot spot is higher than normal ones with 13.2°C in mean value，and the back surface temperature of open circuit PV array is higher than normal ones with 2.8°C in mean value.

Abstract: Hot judder characteristics of a ventilated disc brake system are discussed. Three dimensional finite element models of the ventilated disc, pads and pistons are created, and a fully coupled thermo-mechanical analysis of the hot judder phenomenon of the disc brake system is performed using SAMCEF. The brake dynamo test is carried out according to the high speed judder test mode. The evolution of the temperature distribution on the disc surface is described, and the hot spot generation process is investigated. The simulation results such as the maximum disc temperature, BTV are compared to the data from the dynamo test, and the reliabilities of the analysis technique and simulation model presented in this paper are verified.