钛合金在炮口制退器上的应用

为减小炮口制退器重量,提高射击精度和密集度,对钛合金在炮口制退器上的应用进行研究。以计算流体动力学以及有限元理论为基础,综合应用计算流体力学数值仿真技术和有限元分析方法,完成了从炮口制退器炮口流场三维数值模拟到有限元分析的全过程,得出了TC4钛合金和炮钢材料下的炮口制退器应力分布和变形结果。结果表明,在满足使用条件的情况下,TC4材料的使用能够减轻炮口制退器的重量,从而可以减小其它部件的设计难度。     

CFD技术在求解电子系统风道特性上的应用研究

电子系统的风道特性是合理选择冷却风扇的关键,快速准确地得到风道特性是电子系统热设计的重要内容之一.文中采用CFD数值仿真技术,利用大型工程软件I-DEAS求解某电子系统的风道特性,并给出了求解过程.     

A Study on the Estimation of Aeroheating upon the Warhead Nose at Supersonic Speed

An expression for estimating the aeroheating on a warhead nose at different supersonic speeds is proposed by incorporating CFD （computational fluid dynamics） and the least-square method. Compared with the traditional estimation formula, the expression is more accurate, convenient and can be used in the optimized design of warheads. The error from the result obtained in the test of a ball cartridge flight is less than 3 %. It satisfies the engineering requirements.     

小型轴流CPU风扇设计与数值模拟

根据空气强迫对流冷却系统一体化设计理念,对小型轴流CPU风扇进行空气动力设计,由Fortran输出三维空间曲线文件,导入Pro/E实现实体造型.通过标准风洞对CNC铣床雕刻出的样品进行风扇性能测试.为了减少费用和缩短设计周期,利用CFD对风扇性能预测,风扇出口流向角结论为曲线型散热器设计提供依据;数值模拟结果与实验特性曲线比较吻合,为一体化数值模拟积累了经验.     

Compressively sampled light field reconstruction using orthogonal frequency selection and refinement

This paper considers the compressive sensing framework as a way of overcoming the spatio-angular trade-off inherent to light field acquisition devices. We present a novel method to reconstruct a full 4D light field from a sparse set of data samples or measurements. The approach relies on the assumption that sparse models in the 4D Fourier domain can efficiently represent light fields. The proposed algorithm reconstructs light fields by selecting the frequencies of the Fourier basis functions that best approximate the available samples in 4D hyper-blocks. The performance of the reconstruction algorithm is further improved by enforcing orthogonality of the approximation residue at each iteration, i.e. for each selected basis function. Since sparsity is better preserved in the continuous Fourier domain, we propose to refine the selected frequencies by searching for neighboring non-integer frequency values. Experiments show that the proposed algorithm yields performance improvements of more than 1 dB compared to state-of-the-art compressive light field reconstruction methods. The frequency refinement step also significantly enhances the visual quality of reconstruction results of our method by a 1.8 dB average.     

Development of a hybrid refrigerator combining thermoelectric and vapor compression technologies

A domestic refrigerator with three compartments has been developed: refrigerator compartment, at 4 °C (vapor compression cooling system); freezer compartment, at −22 °C (vapor compression cooling system); and a new super-conservation compartment, at 0 °C (thermoelectric cooling system). The thermoelectric system designed for the super-conservation compartment eliminates the oscillation of its temperature due to the start and stop compressor cycles, obtaining a constant temperature and thus, a better preservation of the food.For the design and optimization of this application, a computational model, based in the numerical method of finite differences, has been developed. This model allows to simulate the complete hybrid refrigerator (vapor compression–thermoelectricity). The accuracy of the model has been experimentally checked, with a maximum error of 1.2 °C for temperature values, and 8% for electric power consumption.By simulations with the computational model, the design of the refrigerator has been optimized, obtaining a final prototype highly competitive, by the features on food preservation and power consumption: 1.15 kW h per day (48.1 W) for an ambient temperature of 25 °C. According to European rules, this power consumption value means that this new refrigerator could be included on energy efficiency class B.     

计算流体力学应用于子通道分析的初步方法研究

多尺度耦合分析是目前开展反应堆安全分析的一种趋势，常规的多尺度耦合是将不同程序通过一公共耦合平台实现数据间的传递和交换。本文提出一种新的多尺度耦合思路，认为基于相对小尺度的分析手段可扩展应用至大尺度，并用计算流体力学（CFD）应用于子通道尺度的数值模拟方法进行验证。验证结果表明，该方法具有一定的合理性，但这种方法对湍流交混能力的考虑仍存在欠缺，还需进一步改进。     

CFD and artificial neural network modeling of two-phase flow pressure drop

A large number of experiments in a 2 cm diameter and 6 m length tube were carried out in order to study the two-phase flow regimes and pressure drops in it. The two-phase flow in the experimental tube was modeled using commercial CFD code, Fluent 6.2. An Artificial Neural Network (ANN) with three inputs including gas and liquid velocities and tube slope was designed and trained to predict average pressure drop across the tube. The comparison between CFD and ANN predictions of pressure drops with experimental measurements shows that the CFD results are more accurate than the ANN evaluations for new conditions.     

Composites structural modelling with uncertain data

The aim of this paper is to propose a methodology to take into account the influence of uncertain data in structural calculations. A specific method, based on the approximation of the responses as a function of the uncertain data, is proposed. Classical methods from the literature are also considered. The different methods are compared on a simple example in terms of response (average value and standard deviation) and in terms of computational cost. The method proposed in the present work permits to estimate correctly the whole response and is very simple to use (pre and post processing). This method is applied to a structural calculation on a “hat-shapes” part called, manufactured in the quasi-isotropic IM7/977-2 composite.     

Experimental and CFD study on the effect of jet position on reactant dispersion performance

This paper reports the effect of jet position on the acid dispersion in a neutralization process. Experiments were carried out in a continuous stirred reactor and the effect of jet nozzle position on non-reactive dye dispersion at seven layouts was studied. Consequently, the neutralization reaction mixing was carried out at the best and worst positions. The results reveal that the ways that flow pushes the acid inside the tank are quite different and the neutralization performance can significantly be affected by the jet position. The Computational Fluid Dynamics (CFD) modeling was carried out in order to analyze the experimental observations.