航站楼分层空调负荷计算的经验系数取值研究

结合2010年冬季双流机场T1航站楼空调参数的测试数据,对利用经验系数法计算分层空调负荷的经验系数取值进行研究,研究中CFD技术所需的边界条件按实测值或通过间接计算确定,尽可能接近实际,保证计算结果的可靠性。研究表明,T1航站楼冬季室内仍处于制冷工况,类似于T1航站楼指廊部位的分层空调,经验系数取0．67较为合适,该经验系数适用于冷负荷的计算。同时得出类似高大空间CFD计算的边界条件设置方法。     

上海浦东国际机场T2航站楼自然通风研究

介绍了上海浦东国际机场T2航站楼的建筑概况、地理位置、气候特点及自然通风的研究目的;重点阐述自然通风研究的方法、设计方案的可行性和设计标准;通过外部环境风研究和内部自然通风研究,比较了主楼设置屋面天窗排风口与设置东、西侧墙高位排风口的自然通风效果;结合实际应用的可操作性,确定了合理的通风方案.     

揭阳潮汕机场航站楼通风空调设计

主要从冷热源、空调系统、通风系统、防排烟系统等方面介绍了揭阳潮汕机场航站楼通风空调设计,对同类型建筑工程的通风空调设计有一定的参考意义.     

高大厂房通风降温系统的探讨

针对高大厂房,以地处宝鸡的空压机房为例,采用计算流体力学(CFD)软件FLUENT对通风降温系统进行模拟,模拟内容包括室内温度场、流场,通过对模拟结果与实测值的分析和判断,为高大厂房通风降温系统的优化设计提供参考。介绍了边界条件、湍流模型的选择,求解器的设置等,旨在为他人提供参考。     

边界条件设置及输入地震波特性对边坡动力响应影响分析

对有限计算域边界处理是边坡动力有限元计算的重要问题之一,本文利用有限元弹塑性动力分析方法,把边坡动力响应分析中边界条件设置概括为5种情况,输入3条实测地震波,研究边界条件设置和地震波特性对边坡位移响应、加速度响应以及频谱的影响。研究表明设置不同的边界条件及输入不同地震波,边坡动力响应结果有显著差异。研究结果有助于进一步揭示边坡在地震作用下的响应特性,为边坡的动力破坏机理研究和提高边坡稳定性分析评价的可靠性奠定基础。     

截止阀的有限元模态分析

通过截止阀的三维建模型并进行模态分析,研究不同边界条件设置对模态分析结果的影响,并通过截止阀自由模态试验、工作模态试验对理论分析结果进行验证。结果显示阀杆和阀盘系统的固有频率较低,低噪声截止阀设计时不宜采用刚性壁假设;阀杆的边界条件设置将会极大的影响截止阀的计算结果。     

地铁隧道壁龛式射流通风数值模拟

对地铁隧道壁龛式射流通风的特点进行了分析,建立了重庆某地铁区间隧道的单元通风段模型,设置压力、速度两种不同的进口边界条件,采用PHOENICS软件对隧道内部的速度场、压力场进行了模拟分析,发现隧道内断面气流速度分布存在一个波峰,峰值位于渐缩段末端断面,隧道内气流压力在风机吸入端达到最低值,在射流发展段呈现出渐变的非均匀的逆压运动,在射流发展段末端压力达到最大值,此后由于壁面摩阻损失的影响,在压力通风段压力逐渐降低;分析比较两种进口条件下隧道内部气流运动的不同点,主要体现在回流强度、射流发展段长度以及诱导通风量.     

地下通道火灾排烟的通风系统模拟分析

本文阐述了地下通道火灾排烟的通风系统模拟分析,烟气流过着屏蔽门时的局部阻力系数,再利用网络模型模拟地下隧道、各通风井的通风排烟量,以确定其能否满足通风排烟要求,对地下事故工况风机的设置、地下事故工况的处理预案,不同形式区间隧道通风系统对隧道内通风速度场、温度场及新风量的影响规律。研究同时对通风系统方案进行了初步的技术经济比较。本研究为分析地下通风系统的空气流动与传热提供了参考,为通风系统方案的选择。     

杭州萧山国际机场航站楼空调通风设计

介绍了杭州萧山国际机场航站楼工程的空调、通风及排烟设计.该工程结合大空间场所的特点,采用了地面送风亭射流送风方式、地面排风方式及红外线对射探测器控制的排烟天窗.经冬季、夏季运行表明,达到设计要求.     

华蓥山电厂2x300MW工程汽机房通风方案介绍

本文简要介绍了华蓥山电厂2x300MW工程的汽机房通风系统设计,推荐采用自然进风、自然排风 辅助机械排风的通风方案.汽机房屋面设置屋顶自然通风器排风,除氧器间屋面设置屋顶风机排风.对火力发电厂汽机房的通风方式进行了一些描述,对目前常用的主要通风方式进行了简单的比较.提出了汽机房通风设计中应注意的问题.     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Assessment of intakes of mixtures of radionuclides

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

卧式金属罐容量的测量结果不确定度

本文根据多年的实践检定经验 ,参照JJF1 0 59- 1 999《测量不确定度评定与表示》以及《测量不确定度表达 1 0讲》 ,对卧式金属罐容量的测量结果不确定度进行了评定。     

盐酸浓度不确定度的评估

通过对盐酸浓度标定的过程分析，找出影响结果的各个分量，进行不确定度的评定，按照计量技术规范给出标准的表示法。     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。