Numerical Simulation on Heat Transfer Characteristic of Steam Generator of ACME Facility

Taking the steam generator (SG) of the ACME facility as the study object, two-fluid model was chosen for the secondary side of the SG and a direct simulation was made on the whole SG of the ACME facility with the CFD software CFX. The stable test conditions were calculated. The primary side and secondary side temperature distribution of SG, the secondary side void fraction distribution and the wall temperature of heat transfer tube were obtained. The secondary side detailed flow and heat transfer characteristics were arrived. The results show that bubbles begin to accumulate from the second baffle and bubble amount increases as the tube is higher. Near the bend area and above, they all become steam. The calculated results are all in accordance with the experimental results.     

垂直同心环形管内上升气液两相环状流含气率与压降预测

对垂直同心环形管内上升气液环状流的截面含气率及压降预测进行了研究.根据Kelessidis有关团状流向环状流转换的思路以及Wallis有关圆管内环状流积分分析的方法，考虑环形管的结构特征及环状流的流型特征，通过两相动力学理论建立了新的预测截面含气率及总压降的模型.将新模型及现有模型与实验数据的分析比较表明新模型对于总压降的预测效果较好.     

高温高压下用光纤探针测量截面含汽率的实验研究

引　言在研究两相流的流型转换、摩擦压降等性能时 ,两相流截面含汽率是一个极其重要的参数 ,一旦知道了两相流的截面含汽率便可求得两相混合物的平均密度、计算压力梯度、分析管内流动状况等 .它的测量是否准确直接关系到计算结果的正确性和设备运行的可靠性 .光纤传感器是纤维光学领域中的新技术 ,利用其对汽水折射率不同的特点可进行截面含汽率的测量 .光纤探针有很好的响应和性能 ,在高性能的数据采集板和计算机帮助下 ,对信号的处理也很方便 .本文应用法国ＲＢＩ公司耐高温高压的光纤探针测量圆管含汽率的变化规律 .应用光纤探针测得管…     

一种测量气--液两相流的线列阵传感器设计

针对气—液两相流研究对含气率测量的需求，基于线列阵测量技术原理，设计了一种可移动式线列阵两相流测量传感器，该传感器具有较高的空间分辨率（3 mm）和极高的时间分辨率（2500 Hz），设计了线列阵传感器标定和含气率算法，实现了瞬时二维局部含气率的测量。经过射流冲击试验验证表明：该线列阵传感器结构稳定，基于原始测量数据，采用标定和含气率求解算法，可计算气泡夹带现象在水平截面的平均含气率分布情况。     

空泡份额模型在矩形通道沸腾压降计算中的适用性评价

分析了各空泡份额模型随质量流量、系统压力及质量含气率的变化关系,并对各空泡份额计算模型在窄矩形通道内的应用进行了评价。研究结果表明:尽管空泡份额模型选取对重位压降及加速压降计算影响极大,但由于窄矩形通道内的饱和沸腾流动以环状流为主,重位压降及加速压降在两相总压降中的份额极小,因此在两相摩擦压降计算过程中,空泡份额模型的影响非常轻微。采用Zivi模型计算得到的沸腾摩擦压降与其他关系式计算值相对偏差在±5%范围内,因此建议采用Zivi模型计算窄矩形通道内空泡份额。     

基于高速图像采集的管束间气液两相绕流旋涡特性研究

采用高速图像采集方法,研究了不同节距比时以旋转正方形排列的错列管束间气液两相流旋涡的演化特性,通过动态图像重建了旋涡生成、卷吸及聚合过程,分析了旋涡演化机理,并运用时间序列图像相关性对比分析了旋涡脱落的周期特征.结果表明:随着节距比的增大,斯特罗哈数增大;随着含气率的增大,斯特罗哈数减小;当含气率大于0.14时,不存在周期性旋涡脱落现象;随着雷诺数的增大,旋涡脱落频率增加.     

基于截面含气率的气／液两相流相关速度测量

基于双截面电阻层析成像技术进行气／液两相流的相关速度测试研究，分析了相关速度测量原理，提出了基于截面含气率的相关测速方法。通过插值增加上游、下游双截面含气率的采样数据，利用独立开发的软件系统具有的数据存储与回放功能对基于截面含气率的相关测速方法进行评定实验。实验结果表明：该方法测速精度较高，且稳定可靠。     

Optimization of material and process parameters of fibrous quilt for comfortable heat loss from human body

Various quilt samples are prepared by carding (web formation) of three kinds of fibers viz. cotton, normal polyester and hollow polyester and stitching the webs with a covering fabric. Effects of various parameters such as fiber type, fiber fineness, mass per square meter of the quilt (g m^?2), applied compression and temperature difference on thermal conductivity of the quilts are investigated. Comfortable heat loss from the human body is theoretically estimated (123.66–159.14?W m^?2), and these parameters are optimized by employing 3³ Box-Behnken response surface design and analysis of variance (ANOVA) to maintain the comfortable heat loss from human body by the quilts. One empirical model has been derived to predict heat loss through the quilts with the given quilt parameters. The empirical model helps to understand and design a quilt suitable for the use in a designated cold climate.     

Void fraction measurement by a computerized double-point resistivity probe

A technique for void fraction and gas velocity measurements in two-phase gas-liquid bubbly flow is described. The double-point resistivity probe, appropriate signal-conditioning units and a personal computer have been integrated to form a data acquisition and analysis package enabling the determination of local flow properties. The system has been tested in an adiabatic air-water vertical up-flow situation and typical results are presented here.     

圆管中气液两相流动空隙率数学模型

由于气液两相流动的复杂性 ,很难应用流体运动的基本方程确定空隙率的变化规律 .故采用实验研究途径 ,开发了美国NorthCarolina州大学研制的应用软件SAS ,并对多次气液两相流动实验的 6× 10 4 多组实验数据进行了多元非线性回归 ,建立了圆管中不同流动型态下气液两相流动空隙率数学模型 .在多相混输管路实际应用中表明 ,本方法适用于不同管径、不同倾角下的上升或下降管路中各种流动型态两相流动的水力计算 ,并具有计算简便、精度高的特点