恒幅载荷下复合材料剩余刚度退化模型

在分析现有纤维增强复合材料层合板疲劳累积损伤模型的基础上,根据复合材料层合板疲劳损伤演变过程和剩余刚度退化规律,提出一种用于描述恒幅疲劳载荷作用下复合材料层合板刚度退化规律的模型.该模型适用于描述复合材料层合板的三阶段非线性刚度退化轨迹.通过T300/HT3复合材料层合板、玻璃纤维/环氧复合材料层合板以及T300/QY...     

陶瓷纤维炉衬的研究

通过对全纤维棉式，隔板式，空气隔层式等三种形式的陶瓷纤维炉衬在加热地过程中温度场的测量，并据此计算上述三种形式炉衬的热损失，结果表明：在纤维绵的内层加一薄隔热板可使该处在加热过程中的温度下降达１５０℃，热量损失减少２０％以上；采用空气隔层式炉衬，可将基厚度从全纤维棉炉衬的１５０ｍｍ厚降至１１０ｍｍ，且热损失减少３０％。     

非均匀高热流密度对热电器件热应力的影响分析

太阳能热电发电系统的热端热流密度过高会导致热端与冷端温度梯度过大,从而导致热应力过高,引起翘曲,危及热电器件的使用寿命。同样,加热均匀度过低也是引起热电器件热应力增大的原因。基于此,建立高热流密度下热电发电器件的热-结构耦合数学模型,分析加热均匀度等因素对多对热电器件温度分布以及热应力分布的影响。数值模拟结果表明:加热均匀度与最高温度以及最大热应力呈负相关性,加热均匀度越低,热电器件模型的最大热应力就越大,并且随着加热均匀度的降低,热电器件的热应力的增加越来越剧烈,高热应力的分布也越来越集中。在加热均匀度大于70%的情况下,热电器件的最大热应力相比均匀加热增加量在5%以下。因此,在太阳能热发电系统中,虽然我们应尽量使聚焦的太阳能均匀地照射在热电器件的热聚层上,以有效减小整个器件的热应力,提高热电器件的效率。但是追求过高的加热均匀度没有必要。     

活塞热冲击平壁模型的计算与分析

建立了与热冲击试验台加热环境相适应的矩形热冲击模型和平壁热传导模型，并求得相应的解析解。利用上述模型对6150柴油机活塞受矩形热冲击时的温度响应和热应力进行了计算，结果表明，该模型可较好地预测试验台加热环境下活塞温度和应力变化规律，为活塞热疲劳的研究打下良好的基础。     

高强化内燃机活塞瞬态温度场分布规律研究

应用ANSYS有限元分析软件,建立了某高强化150内燃机活塞的三维有限元分析模型,计算了瞬态过程和快速冷起动过程中活塞温度场的变化历程及热应力状况。计算结果表明：瞬态活塞顶面的温度波动最大达到22℃,由此产生的瞬态热应力幅值与稳态热应力幅值处于相同的数量级。而冷起动过程活塞温度近似按指数规律上升。这些快速变化的温度引起的附加热应力是活塞顶面热损伤不可忽视的因素。     

基于能量法的复合材料层合板性能等效算法研究与应用

为简化风力机叶片的建模和计算、提高效率,提出基于能量法的复合材料层合板性能参数等效方法。以材料的代表性体积单元RVE为研究对象,在能量法二维理论的基础上,根据RVE和均质等效体应力场与应变场在一定条件下相同的特点,利用变形能守恒理论,通过对不同形式变形能公式的变换,推导出层合板三维情况的性能等效刚度矩阵系数与RVE变形能的关系及等效矩阵的能量表达式。将该算法应用于[0°,±45°]三向层合板,计算结果与实测数据吻合。分别对1.5 MW叶片根部层合单元模型和等效模型进行结构分析和对比,结果表明二者数值吻合良好,验证了算法的可行性和有效性。     

基于瞬态非线性分析的中厚板坯加热过程应力场仿真研究

为提高中厚板坯加热效率和防止出现热应力裂纹,需要精确研究中厚板坯加热升温热应力规律。本文在热弹塑性分析理论基础上,采用有限元方法,研究了中厚板坯加热过程中全时域内热应力场变化规律。本文针对实际生产加热工艺,建立了3500板坯加热过程分析模型,考虑了导热系数、比热变化对加热的影响,仿真了中厚板坯的加热过程,得出加热炉温度与加热速度对板坯加热过程热应力的影响规律,具有重要工程应用意义。     

采用床内强制对流进行传热传质的固体吸附式循环分析

采用一维两温度模型，以活性炭纤维－氨为工质对，模拟计算了对流热波循环的吸附床加热过程和冷却过程中床内的温度分布和变化趋势，并分析计算了对流热波循环的性能参数。系统的回热率达０．４，热泵效率达１．７８，热泵系统的能量密度为１６１６Ｗ／ｋｇ。对系统加以优化，可获得更高的回热率和ＣＯＰ。     

风电叶片复合材料在高温环境下的拉压力学性能研究

为了探究高温环境对风电叶片玻纤/环氧树脂复合材料拉压力学性能的影响，采用真空辅助RTM工艺制备叶片用单向玻纤/环氧树脂复合材料层合板，研究复合材料从常温到65℃高温下的拉伸、压缩力学性能，并利用扫描电子显微镜（SEM）对压缩试样断口的微观结构进行表征分析。结果显示：复合材料的纵向拉伸强度和压缩强度随温度升高均有不同程度的下降，纵向压缩强度在高温下的降幅更大，当环境温度高于50℃，纵向压缩强度将低于材料设计值；纵向拉伸模量和压缩模量随温度升高变化较小，横向拉伸强度和模量随温度升高均有明显下降。高温环境引起复合材料拉压力学性能下降主要是由于复合材料在高温下玻纤与树脂基体的界面黏结减弱以及树脂性能降低所致。     

退火过程对硅锭热应力与位错影响的数值分析

利用CGSim软件对定向凝固多晶硅从长晶过程开始到退火过程结束进行瞬态数值模拟,研究不同退火温度和退火时间对多晶硅锭内热应力及位错密度的影响。通过软件中热弹性应力非稳态模型（Haasen-Alexander-Sumino模型）计算出位错和Von-Mises应力。结果表明：随着退火温度的升高和退火时间的增加,热应力及位错增殖速率的逐渐减小,在退火1 h后热应力和位错增殖速率大幅减小,退火3 h后减小效果减弱。高温退火时热应力和位错密度低于低温退火,在1250℃下退火3 h是比较合适的方案。     

螺旋隔板光滑管单管换热器的数值模拟

采用FLUENT6.0软件对整个螺旋隔板光滑管单管换热器的流场、温度场和压力场进行数值模拟,并与实验测量和计算结果进行了对比,验证了数值模拟的准确性。流场模拟结果显示,流体在壳程呈螺旋状流动,没有死区,而且流速比较均匀,变化比较小,从而进一步验证了许多学者经过实验研究分析得出的螺旋隔板换热器具有的优良性能。     

Assessment of different bio-inspired flow fields for direct methanol fuel cells through 3D modeling and experimental studies

The performance impact of using bio-inspired interdigitated and non-interdigitated flow fields (I-FF and NI-FF, respectively) within a DMFC is investigated. These two flow fields, as well as a conventional serpentine flow field (S-FF, used as a reference), were examined as possible anode and cathode flow field candidates. To examine the performance of each of these candidates, each flow field was manufactured and experimentally tested under different anode and cathode flow rate combinations (1.3 mL/min [methanol] and 400 mL/min [oxygen], as well as 2 and 3 times these flow rates), and different methanol concentrations (0.50 M, 0.75 M, and 1.00 M). To help understand the experimental results and the underlying physics, a three dimensional numerical model was developed. Of the examined flow fields, the S-FF and the I-FF yielded the best performance on the anode and cathode, respectively. This finding was mainly due to the enhanced under-rib convection of both of these flow fields. Although the I-FF provided a higher mean methanol concentration on the anode catalyst layer surface, its distribution was less uniform than that of the S-FF. This caused the rate of methanol permeation to the cathode to increase (for the anode I-FF configuration), along with the anode and cathode activation polarizations, deteriorating the fuel cell performance. The NI-FF provided the lowest pressure drops of the examined configurations. However, the hydrodynamics within the flow field made the reactants susceptible to traveling directly from inlet to outlet, leading to several low concentration pockets. This significantly decreased the reactant uniformity across its respective catalyst layer, and caused this FFs performance to be the lowest of the examined configurations.     

柴油机活塞温度场和耦合应力计算

采用AVL BOOST软件对活塞的工作过程进行计算,得到了活塞的换热边界条件和最高燃烧压力;在此基础上,采用ANSYS有限元软件对组合式活塞有无冷却时的温度场和耦合应力及变形进行了分析计算;另外对活塞的连接螺栓进行了应力强度考核。     

A numerical and experimental study of chevron,corrugated-plate heat exchangers

In this work, the widely used chevron corrugated-plate heat exchanger was simulated, and the three-dimensional temperature, pressure, and velocity fields were obtained. From the temperature field we can see that in the first zone, the temperature gradient increases gradually and get the maximum; in the central of the flow, the temperature gradient becomes smaller again. The highest temperature appears around the upper port, while the lowest temperature appears in the cold fluid inflow around the lower port. From the pressure field, we can see that the fluid pressure is gradually reduced along the flow direction. From the flow field, no matter the fluid inflows or outflows the port, there is a marked “dead zone” departed from the corrugated side of the port, where the fluid flow rate is very low. The fluid flows along the side of the port and appears a minor's “bias” (uneven-distributed) phenomenon. Meanwhile, it can be seen that a large number of contact points are distributed in the chevron corrugated-plate heat exchanger. In addition, the simulated results are compared with the experimental values and found that trends of the outside temperature are consistent with those of pressure drop, and experimental values were similar to those of simulated values.     

330MW对冲燃烧锅炉燃烧和污染物排放的数值模拟

分别对330MW对冲锅炉在额定负荷、55％额定负荷工况下的流场、温度场、煤粉颗粒场和NOx场进行了模拟研究,模拟结果与实际运行经验吻合较好。通过研究得出了一些有参考价值的数据,对大型对冲燃烧锅炉的设计优化和安全运行具有较为重要的参考价值。     

瞬态电场测量系统的研制与试验

针对瞬态电场的测量,研制了一款以基于MSP430系列微处理器为核心,应用高速模数转化芯片与高速存储器的测量系统,所用球形探头具有体积小、功耗低、可编程和测量范围可调的特点。通过试验验证和改进,该测量系统能够满足电力系统中的电场测量要求。     

Numerical simulation of the effect of electrode insertion depth on melting process of self-supporting lining electric furnace

This research is on the melting process of slag in non-inner lining furnaces. In this electric furnace, slag is solidified into the lining of the inner wall during the melting process by means of water cooling of the outer wall. It is a self-supporting lining electric furnace. In this study, the slag melting process was simulated using ANSYS software, and the electromagnetic field, temperature field, and furnace lining thickness of the self-supporting lining were analyzed at different electrode insertion depths. The results show that the self-supporting lining can be formed under the three insertion depth of the electrodes, and the thickness of the lining increases with the insertion depth of the electrode.     

利用火焰图像同时重建温度场和浓度场的试验研究

煤粉火焰图像是火焰辐射经过发射、衰减和散射等过程后到达摄像机靶面的投影。火焰发射出的辐射强度与火焰自身的温度密切相关，而辐射强度的衰减则取决于弥散介质的特性和浓度。该文首先研究了辐射衰减系数与粒子浓度场的关系，提出了对温度场和浓度场进行同时重建的控制方程。最后，在小型燥粉炉上进行断面温度场和浓度场的重建试验。图ll参l2     

消声器内部流场及温度场的数值分析

对一典型结构消声器的内部流场及温度场进行了数值模拟研究，并就消声器内部气流速度、温度变化对消声性能的影响进行了分析。消声器设计应遵循以下原则：穿孔管小孔总的流通面积应大于排气管口的面积；应充分利用气流与声波流的逆向作用来提高消声效果；消声器入口段应尽量采用均匀过渡结构；出口直径不宜过小。     

Design optimization of a solar tower power plant heliostat field by considering different heliostat shapes

The present study focuses on the optimization of solar tower power plant heliostat field by considering different heliostat shapes including rectangular, square, pentagon, hexagon, heptagon, octagon, and circular heliostat shapes. The optimization is carried out using an in-house developed code-based MATLAB program. The developed in-house code is validated first on a well-known PS10 Solar Thermal Power plant having rectangular heliostats shape and the resulting yearly unweighted heliostat field efficiency of about 64.43% could be obtained. The optimized PS10 heliostat field using different heliostat shapes showed that the circular and octagon heliostat shapes provide better efficiency with minimum land area. The yearly efficiency is increased from 69.65% for the rectangular heliostat shape to 70.96% and 71% for the octagon and circular shapes, respectively. In addition, the calculated field area (land area) is reduced for the case of circular and octagon heliostat shapes with a gain of about 11.10% and 10.93% (about 42.0436 × 10³ and 41.4036 × 10³ m²), respectively, in comparison with the PS10 field area.