Pulsating Jet Impingement Heat Transfer Enhancement

This article presents results from a numerical study of pulsating jet impingement heat transfer. The motivation is to seek conditions offering a significant enhancement compared to steady flow impingement drying. The CFD software package FLUENT was used for simulating slot-type pulsating jet impingement flows with confinement. The parameter study included velocity amplitude ratio, mean jet velocity, and pulsation frequency. The distance from nozzle exit to surface was three times the hydraulic diameter of the nozzle. The Reynolds number based on the nozzle hydraulic diameter and jet temperature was 2,460 with a mean jet velocity of 30 m/s, which is the base case of the numerical experiments. Results showed that time-averaged surface heat transfer increased with increasing velocity amplitude for the same mean jet velocity. Large velocity amplitudes helped enhance heat transfer by two mechanisms: high jet velocity during the positive cycle and strong recirculating flows during the negative cycle. For the cases with different mean jet velocities but the same maximum velocity, time-averaged surface heat flux decreased with decreasing mean jet velocity. As for the effects of pulsation frequency, with high-velocity amplitude ratio, time-averaged surface heat fluxes were at the same level regardless of frequency. However, at low-velocity amplitude ratio, high frequency caused stronger recirculating flows resulting in greater heat transfer compared to the cases with a lower frequency.     

二高炉4号热风炉烘炉实践

介绍了二高炉4号热风炉烘炉的特点、前期准备工作、具体操作过程中的注意事项及烘炉后的相关作业。此次生产实践对今后类似情况的热风炉烘炉具有参考价值。     

Convective cooling of supercritical carbon dioxide inside tubes: heat transfer analysis through neural networks

In a previous work, convective heating of carbon dioxide was studied with neural networks (NN), obtaining a totally heuristical heat transfer equation from the direct regression of experimental data. In the present work, the analysis focuses on the cooling process, which has a technical relevance in various applications, as for example in transcritical refrigeration cycles. Heat transfer around the critical zone presents a marked enhancement, that follows the peaks in thermophysical properties like thermal conductivity and heat capacity. Similarly, other properties like density and enthalpy, present a strong variation in narrow temperature intervals around the critical point.This constitutes then a highly non-linear phenomenon, for which it is advisable to use a very flexible function approximator like the NNs. NN models were applied both in terms of dimensionless numbers and of physical quantities, obtaining the two corresponding NN architectures. The choice of the optimal number of neurons in the NN hidden layer is discussed. The NN models are then compared with a recent correlation from literature, for which the validation results present an AAD of 27% and a bias of −26% with an evident prediction shifting. On the other hand the NN models in terms of dimensionless numbers and of physical quantities have AAD and bias of 14% and −4%, and of 7% and −2%, respectively, showing a largely better performance.     

纯棉热转移印花色光稳定性的研究

以分散蓝291热转移印花的纯棉织物为例，考察环境诸因素对其色光稳定性的影响，并结合色度参数和XPS谱图分析环境各因素对色光稳定性的影响机制。     

本钢烧结矿冷却及其余热回收的试验研究

从烧结矿冷却并回收其余热的角度出发，介绍了利用烧结机尾落矿空间，采用喷吹空气装置对烧结矿进行冷却的小型模拟试验，从测出的结果来看，有可能成为一种新的烧结矿冷却方式。     

凝析油资源现状及利用

随着燕山石化、金山石化、扬子石化乙烯改造工程相继完成，石脑油的需求将不断提高，通过利用凝析油可以增加化工轻油的来源，起到稳定石脑油市场的作用。现对全球，特别是亚太地区凝析油的资源、生产、销售及未来的发展进行初步分析，并提出相应建议。     

改造加热炉系统 提高加热炉热效率

分析了重整装置加热炉热效率低的原因，介绍了提高加热炉热效率采取的几项措施。     

Kinetics of TSCD zinc oxide nano-layer growth by modified diffuse-interface model

Deposition of zinc oxide films from aqueous solutions containing complex Zn²⁺ ions on soda-lime substrates were studied by two-stage chemical deposition (TSCD) process. It was shown that the film thickness can be controlled by the number of dipping stages. Nano-layers were produced with less than nine times dipping stages. Greater dipping numbers resulted in film thickness exceeding 100 nm. The growth rate obeyed double-stage zeroth order with respect to the concentration and first order with respect to the temperature. This rate was proportional to the difference between the temperature of the hot water and the substrate. Overall activation energy of 17.20 ± 0.42 kJ mol⁻¹ and frequency factor of 2.81 ± 0.07 μm s⁻¹ was determined for ZnO deposition. These values were attributed to two resistances. One resistance corresponded with film heat transfer mechanism. The other was attributed to species attachment to the solid substrate. A modification to the diffuse-interface kinetic model was devised for explanation of the latter. EDAX (electron dispersive elemental analysis), XRD (X-ray diffraction) and SEM (scanning electron microscopy) were used to characterize the layer formed. These methods showed that the product consisted solely of pure elliptical ZnO grains.     

马钢热电总厂高炉煤气综合利用问题研究与思考

介绍马钢热电总厂高炉煤气综合利用的情况及所产生的经济和社会效益，剖析综合利用过程中的问题，提出进一步高效、安全、优化高炉煤气综合利用的建议和思路。     

攀枝花矿产资源特征及循环经济发展策略探讨

文章着重描述了攀枝花矿产资源特征、资源矿物流向和资源产品定位，分析了资源矿物使用行业的不同特点，明确了针对攀枝花矿产资源利用的循环经济目标，根据资源循环利用技术水平和资源循环开发现状，提出了攀枝花矿的循环经济发展策略.