Papers by Keyword: Air-Cooling

Abstract: Li-ion batteries generate significant heat during operation, which leads to an increase in temperature and, consequently, a reduction in the battery's efficiency and lifespan. In this study, different cooling methods are simulated for the thermal management of the battery. The cooling using air and liquids is investigated with laminar flow at varying velocities. Results indicated that the use of water/glycol is more effective than air and mineral oil.

Abstract: Using the industrial limestone, fly ash and pure chemical reagents as raw materials, the blast furnace slag was prepared by the fast air-cooled method. Using orthogonal experiment method, the influence of process conditions such as heating rate, heat preservation time of the blast furnace slag in hearth, discharge temperature of slag and cooling speed on the glass content and hydraulic activity of blast furnace slag were studied, the main influence factors and the optimal process conditions of blast furnace slag were determined. The results showed that the discharge temperature of slag was the key factor influencing on the glass content of granulated blast furnace slag. The impact degree of all process conditions on the glass content of granulated blast furnace slag accord with the following sequence: discharge temperature of slag > heat preservation time > heating rate > cooling rate. And heat preservation time and cooling rate were the key factors influencing 28 days activity index of blast furnace slag, the impact sequence of all process conditions on the 28 days activity index of granulated blast furnace slag was as follows: heat preservation time > cooling rate > discharge temperature of slag > heating rate. This study also optimized the process conditions of granulated blast furnace slag for different indicators.

Abstract: The new type dynamic phase diagrams and the non-equilibrium lever principle of carbon steel have been established and discussed, the corresponding structures and chemical compositions are analyzed. The computer calculation programming of phase diagram and main computer program have been setted.

Abstract: According to the structural characteristics of the controller and micro-groove heat sink technique, a new cooling system was designed for high power control unit of electric vehicles. And an experimental comparison on the radiating effect of forced air cooling, micro capillary groove radiator and their combination was then carried out. The experimental results showed that when compared with air-cooling method, the higher the power is, the more significant the heat dissipation effect is. The air cooling unit alone cannot meet cooling requirements when the heating power reaches 30 watts, with temperature exceeding the allowable ceiling for power devices. The strong heat removal ability of micro capillary groove radiator has a better effect for diminishing local overheating of IGBT, and it’s more applicable to cooling conditions of large heat flux.

Abstract: Electrical wiring is the main fireorigin on electrical fire, and aluminum wire laying lines used more fire hazard. The melting mark formed in process of fire is the important material evidence to analysis the cause, but the aluminum wire melting mark organization feature is also different in different solidification conditions, therefore, to identify the mark characteristics formaed in different environment conditions has become a important task of fire evidence identification. Prepared fire sample melting by the means of simulation test, and observed to analysis the experimental sample, then summarizes the influence of solidification environment on microstructure characteristics of aluminum wire trace sample. Through the analysis found that, because of the influence of subcooled temperature, make the most of the organization of melt mark cooled in the air have oversize equiaxial crystal organization, almost no holes; and the dip in water cooling of melting mark is formed in larger subcooling, so the organization have more than a small columnar crystal and cellular crystal, and have more small holes exist. These features of aluminum conductor mark can provide strong technical support for fire investigation.

Abstract: Local environment control system (LECS) has been widely used in many areas as the necessary guarantee for most precision instruments. A sealed air cooling constant temperature box with dual-chamber structure that can provide constant working condition for precision instruments in-vehicle was developed. According to the heat transfer analysis of the double plate-fins heatsink, the heat radiation area and dimensions were determined based on electrical analogy. The air flow rate and temperature distribution of the system in heat steady-state was simulated by CFD software, and the results are consistent with that of experimental test. In different conditions, the thermal test results indicate that when the heat flow rate in the inner chamber is about 170 W, the temperature difference between inner chamber and environment is no more than 6.5 °C. The thermal design and test methods can be as the reference for the design of other precision instruments in-vehicle.

Abstract: The paper presents the methodology of determination of emissivity coefficient of steel in the direct cooling temperature range, which allow self-definition of this parameter in automated temperature control system used for direct cooling of drop-forged parts. Based on the actual temperature of the surface of the workpiece, the system automatically adjusts the velocity of fan-forced air to produce desired cooling rate and course of cooling curves. To enable automatic correction of cooling rate, the system must rely on exact remote temperature measurements. This is conditioned by correct definition of emissivity in pyrometer gauge system. Traditionally, pyrometers use presets of a constant value, selected as to get optimum consistency for the temperature range concerned. As the emissivity is time-dependent, the idea of the approach presented in the paper is to use time dependent characteristics, to attain the minimum discrepancy between actual and measured values during the whole cooling cycle.

Abstract: The latent heat’s releasing has effect on temperature dropping.. For example of 40Cr bar, using ANSYS finite element establish transient temperature field model in air cooling condition, and using Thermal compensation calculate latent heat can simulate cross-sectional temperature field in air cooling, obtain the temperature variation with time, this founds base for the quantitative description of the microstructure and properties of rolled steel.

Abstract: Lotus-type porous metal with many straight pores is attractive as a heat sink because larger heat transfer capacity is obtained due to the small diameter of the pores. The heat transfer capacity of the lotus-type porous copper heat sink was calculated using the model with the pores of uniform diameters. However, actual lotus-type porous metals have a distribution of pore diameter. In the present work, we investigated the lotus-type porous copper fin model by considering size distribution of the lotus-type porous copper fin. Prediction of the heat transfer characteristics for the lotus-type porous copper heat sink shows a good agreement with the experimental data.

Abstract: Air cooling is a near dry machining method, which cools cutting area and evacuates chips using low temperature cold wind instead of cutting liquid. It can decrease tool wear, increase tool life, reduce machining cost and bring no chemical pollution. In this paper, air cooling test was carried on, in which vortex tube was used for cooling and high hardness bear steel GCr15 was machined by PCBN tool. Experiment results indicated that cold air from vortex tube has a significant effect on cutting force, cutting temperature and chip formation process. This paper’s conclusions will have a great reference value for the practical application of air cooling technology.