建筑幕墙风荷载的数值模拟研究

对幕墙结构中风荷载的脉动特性进行了分析，采用沿高度变化的E．Simiu风速谱，用改进的谐波叠加法模拟了不同高度处脉动风速和风压的时程曲线，给出了风荷载的计算公式，结果表明该方法简单有效，且能够反映脉动风的随机特性，解决了玻璃幕墙风荷载的动力计算问题。     

混凝土对流换热系数的风洞实验研究

提出混凝土表面对流换热系数的实验方案,试件的形式为圆管,从内部加热,安装在TJ-1风洞内,圆管的轴线与风向一致,风速调节范围为1m/s至25m/s,利用专门开发的实验控制系统全自动监控加热过程并自动记录数据。3个试件的实验结果有很好的一致性。实验结果表明,混凝土表面对流换热系数与风速、混凝土表面热辐射系数与温差之间均有很好的线性相关性。由实验结果回归分析得到混凝土表面受迫对流换热系数、混凝土表面热辐射系数、混凝土表面总热交换系数的计算公式,为混凝土结构温度效应分析中热工参数取值提供了依据。     

The adaptive simulation of convective heat transfer at internal building surfaces

A flow responsive algorithm was devised and implemented within the ESP-r simulation program to advance the modelling of convective heat transfer at internal building surfaces. Empirical methods were extracted from the literature and a new method for characterizing mixed flow was created to provide the algorithm with a basis of 28 convection coefficient correlations. Collectively these methods can calculate convection coefficients for most flows of practical interest in building modelling. Working with this suite of correlations, the algorithm dynamically controls the modelling of convection by assigning appropriate equations to each internal surface each time-step of the simulation.     

传热系数现场检测中的数值模拟

研究了利用防护热箱现场检测围护结构传热系数的方法,并且利用MATLAB软件对检测过程中墙体内的温度场分布进行模拟.结果证明,将数值模拟应用到现场检测中,可以准确地分析围护结构的温度场及其达到稳定所需的时间,而且模拟过程不受外界温度、风速等外在因素的影响.     

室内空气自然对流换热的数值模拟研究

应用PHOENICS软件对自然对流换热条件下室内空气温度场和速度场进行了数值模拟，并对温度场的模拟结果进行了实验验证。结果表明，模拟计算值与实验值吻合得较好。     

Numerical analysis of convective heat transfer in fenestration with between-the-glass louvered shades

A two-dimensional steady laminar natural convection model of a window cavity with between-panes louvers (i.e., slats) was developed by approximating the system as a vertical cavity with isothermal walls at different temperatures, and with rotatable baffles located midway between the walls. The baffles were set to a third temperature so that night-time and day-time conditions could be considered. The effects of wall spacing, baffle angle and temperature, and the wall-to-wall temperature difference were examined. It was found that the system is suited to a traditional one-dimensional analysis, and that the convective heat transfer is largely independent of the Rayleigh number for the conditions of practical interest.     

密集型桩埋换热器管群周围土壤换热特性的数值模拟

以一实际地源热泵系统为例,在全年逐时负荷计算的基础上,对大面积密集型桩埋换热器管群周围土壤的换热特性进行了数值模拟。提出了土壤换热中热屏障的概念,并分析了热屏障的形成原因及其特性,即形状不规则、动态变化和危害性。长期运行中,热屏障带的温度增长速率要高于土壤平均温度的增长,建议从负荷平衡和热屏障两个角度进行分析,以保证地源热泵系统稳定可靠的运行。     

混凝土内部T型弯管流动换热数值模拟

采用有限元方法计算了三通弯管的流场分布和换热效率.获得了T型弯管横截面的平均速度和Nu换热系数沿管程的分布曲线.数值结果表明,弯曲位置附近流场分布复杂,弯曲位置后水流量得到二次分配;分支管壁出现分离区和回流区,横截面出现二次流.Nu数在主管和分支管沿管长方向均出现衰减,且分支管衰减比率大于横向管.在数值分析混凝土结构温度场中,应注意弯管节点附近施加不同的换热系数.     

Sensitivity of the predicted convective heat transfer in a cooled room to the computational fluid dynamics simulation approach

Computational fluid dynamics (CFD) plays an increasingly important role in the design, analysis and optimization of engineering systems. However, CFD does not necessarily provide reliable results. The most crucial numerical solution error is caused by inadequate grid resolution, and the key modelling error sources in CFD in ventilated indoor environments are turbulence modelling and diffuser modelling. Many researchers already proposed guidelines, but they based their analyses on local variables. In response, underlying study intended to verify the impact of the CFD simulation approach on the convective heat flux, an integral quantity. The authors tested several grids, Reynolds averaged Navier–Stokes turbulence models and diffuser models for three convection regimes in a cooled room. The diffuser modelling had a much larger impact than the grid and the turbulence modelling, as long as the jet dominated the airflow. So, CFD users, who want to model forced/mixed convection airflow indoors, certainly need to pay attention to the diffuser modelling.     

肋片管换热器管外三维流动与传热的数值模拟

对肋片管换热器管外三维流动与传热情况进行了数值模拟,计算结果表明所建立的简化模型是可行的,拟合得到的换热公式达到了一定的准确度。     

数值模拟技术在多孔砖墙传热性能研究中应用

本文总结了多孔砖的数值设计优化步骤。通过例子介绍了多孔砖墙传热数值模拟过程,以及砖孔可视表面辐射的模拟和墙体表面温度、热流密度的计算方法,并给出了有关结果。     

Determination of the convective heat transfer coefficient in three-dimensional inverse heat conduction problems

A thin steel plate probe (24 mm wide×24 mm long×3 mm thick) surrounded by insulation except for the exposed surface was constructed. Using the temperature measurements of the steel plate and the heat flux measured by a Gardon gauge and with the assistance of numerical calculations, two methods based on three-dimensional inverse conduction problems are developed to determine the convective heat transfer coefficient in fire experiments. The first one is based on optimisation of the predictions of the temperature of the steel plate using different heat transfer coefficients, while the second adopts a “predictor–corrector” method to determine the instantaneous heat transfer coefficient. Validation of both methods is accomplished by performing experiments in the cone calorimeter at a known constant heat flux. Subsequently, the two methods are applied to experiments in enclosures to examine the sensitivities of the two methods.     

Numerical simulation of ground heat and water transfer for groundwater heat pump system based on real-scale experiment

The groundwater heat pump (GWHP) system is an open-loop system that draws water from a well or surface water, passes it through a heat exchanger and discharges the water into an injection well or nearby river. By utilizing the relatively stable temperature of groundwater, GWHP system can achieve a higher coefficient of performance and can save more energy than conventional air-source heat pump (ASHP) system. The performance of the system depends on the condition of groundwater, especially temperature and depth, which affect performance of the heat pump and system. For the optimization of design and operation of GWHP systems, it is necessary to develop a simulation tool which can predict groundwater and heat flow and evaluate system performance comprehensively. In this research, 3D numerical heat-water transfer simulation and experiments utilizing real-scale equipment has been conducted in order to develop the optimization method for GWHP systems. Simulation results were compared with the experimental results, and the validity of the simulation model was confirmed. Furthermore, several case studies for the optimal operation method have been conducted by calculating the coefficient of performance on various groundwater and well conditions.     

载人航天空间站舱内通风对流换热数值研究进展

CFD模拟是研究载人航天器舱内环境控制和地面模型试验验证的有效方法,介绍了国内外载人航天器舱内通风对流换热数值模拟的研究进展,目前的相关研究涉及舱内不同通风方式的数值模拟、通风参数的优化设计仿真、人体散热对通风环境的影响分析、舱内壁面温度分布和结露控制、微重力下通风换热问题的地面模型试验及其数值模拟验证、传热传质等诸多方面。指出数值模拟模型、舱内通风空调环境评定、通风空调系统整体优化、舱内环境数字仿真演示系统等是载人航天器舱内环境数值模拟领域值得进一步研究的问题。     

混凝土火灾高温中传热传质的数值模拟分析

将混凝土模型化为非饱和变形多孔多相介质。基于控制干空气、湿份及基质溶解物的质量守恒、混凝土介质混合体的动量守恒和焓(能量)守恒的耦合偏微分方程组,建立了一个混凝土化学-热-湿-力全耦合数学模型,其中基本未知变量为固相位移、混合气体压力、毛细压力、温度和基质溶解物质量。通过数值预测结果与试验测量结果的定量比较,显示出所发展的数学模型在重现高温条件下混凝土中化学-热-湿-力耦合现象的能力。     

基于FLUENT的下击暴流风场的数值模拟

基于冲击射流理论,利用CFD（Computational FluidDynamics）通用商业软件FLUENT对下击暴流风场建立三维数值模型,分析了下击暴流风场径向速度的竖向剖面分布,并将此结果与三种经验风速剖面和一种实测风速剖面进行对比,认为此模拟方法所得到的下击暴流风场可信,这对进一步研究实际工程的抗风设计有一定的借鉴意义。     

Numerical model of natural convective heat transfer within a solar dryer using an indirect double pass collector

The double pass collector is one of the most efficient means of drying crops because heating of air takes place from both sides of the absorber plate. To investigate the performance, a double pass natural convection solar dryer was fabricated for experimentation; the results were collected and used to develop a validated numerical model using MATLAB. The experiments were undertaken during February–March 2016 in Salem Tamil Nadu, India over 10 sunshine days. The simulation was carried using the developed model under the measured ambient conditions. The results showed that the mathematical model could predict the performance of the double pass collector for a particular ambient condition to an uncertainty of ±5%. This model could be used to optimise the performance of the collector so that we can predict and investigate the actual performance of the collector with the various optimised designs before fabricating the dryer.     

开洞门式刚架房屋风荷载的数值模拟

结合风洞模型试验对门式刚架房屋在不同风向来流风作用下的屋面风压进行了数值模拟分析．通过分析比较数值模拟结果和风洞试验结果发现,开洞位置和风向角对轻钢门式刚架的风压具有显著影响,当开洞的大小一定时,越接近屋面的位置,对建筑风荷载减小的程度越大,风向角在0°到90°的范围内,随角度的增大,屋面的减压效果越来越明显等相关结论。     

中空玻璃传热系数的传热过程及检测方法

论述了中空玻璃的传热过程,对标定热箱法、防护热板法、热流计法三种中空玻璃传热系数的检测方法进行详细分析,阐明了各方法的适用范围、检测原理、检测设备及对样品的要求,为深入了解中空玻璃的传热过程奠定了基础。