弹性管束换热器传热与阻力特性的实验研究     

程菲  田茂诚 《实验室研究与探索》2007,26(11):23-25,41

对弹性管束水-水换热器的传热与阻力特性进行了研究。主要分析了换热器在不同工况下的传热系数的变化规律;研究了弹性管束在管外流体和管内流体的共同诱导作用下,管外和管内对流换热的情况;并对管程和壳程的流动阻力损失进行了实验测量,得出了管程和壳程的阻力损失变化的规律,以及换热器管程阻力损失的计算方法。  相似文献   

相平衡与CO2在水中的扩散速率--CO2排水集气法   总被引：1，自引：0，他引：1  

郑萍  陈明元 《贵州教育学院学报》2004,15(2):69-70

根据相平衡等的有关计算可知，常压下CO2溶于水的过程为物理吸收，CO2的饱和水溶液为稀溶液，而且溶液里碳酸的生成和电离可以忽略不计。CO2在水中的扩散系数非常小，其数量级为10^-5cm^2／s，在CO2排水集气法操作中，CO2气体不被水吸收。  相似文献   

常系数齐线性微分方程组的一种解法     

罗俊丽 《商洛学院学报》2004,18(2):12-14

从广义特征向量的定义出发,给出了常系数齐线性微分方程组的一基本解组的形式,运用此基本解组形式解常系数齐线性微分方程组比较简单.  相似文献   

微孔膜内大分子有效扩散系数的计算     

何志敏 《天津大学学报(英文版)》1995,(1)

报道一种计算分子尺寸与构型对微孔内大分子有效扩散系数影响的理论方法。基于刚性圆球分子在圆柱型孔内的扩散理论，定义分子平均投影半径和水力学球半径，分别用于估算孔内外浓度分配系数和孔内水力学拖曳力。对不同构型的大分子，使用该法计算的有效扩散系数与已发表的实验数据吻合良好。  相似文献   

关于不等式2x/π＜sinx＜x,x∈(0,π/2)的四种证法     

汪义瑞  高小燕 《安康学院学报》2006,18(3):71-72,90

运用微分方法给出该不等式的四种证法：①中值定理证法；②单调性证法；③极值证法；④凸凹性证法。  相似文献   

Flow Field of Circulating Fluidized Bed Reactor with Venturi Inlet Configuration     

胡金榜李艳平  陈安新 《天津大学学报(英文版)》2005,11(2):106-109

Different two-equation k-ε models were used to simulate the gas flow field generated by a new type of circulating fluidized bed reactor with venturi gas distributor. The numerical results were compared with the experimental data. It has been shown that the simulation results from the standard k-ε model have the best match with the experimental data. Based on this model, the gas flow field in the venturi diffuser and riser was analyzed by the concept of velocity nonuniformity and dead zone percentage. Both the nonuniformity of gas velocity and the dead zone percentage reach the maximum at the venturi outlet due to the effect of the vortex. At the same time, it provides a good platform for the further optimization of the inlet configuration of circulating fluidized bed reactor.  相似文献   

仿古唐三彩碎纹釉的研制     

钱跃进  廖桂华 《洛阳工业高等专科学校学报》2002,12(1):5-7

介绍了在ＳｉＯ２－ＰｂＯ－Ｆｅ２Ｏ３红色彩绘料基础上，根据 α坯＜α釉且差值 α＞４．０×１０－６１／ｋ的原则，通过添加热膨胀系数大的熔剂原料来增大坯釉不适应性，使釉面产生均匀分布的网状裂纹制成了一种视觉效果良好的唐三彩碎纹釉，同时对其碎纹机理作了初步探讨。  相似文献   

二阶电路衰减系数α的修正     

刘湘秋 《三明学院学报》2006,23(2):160-161

欠阻尼情况的RLC串联电路,用同频率的正弦波替代电感、电容两端的振荡波,测出电路的附加损耗,对衰减系数的理论值进行修正,可使衰减系数的实验值与理论值趋于一致。  相似文献   

三种样本相关系数之内在联系     

孙贺琦 《三明学院学报》2001,18(2):1-4

论证了积差相关系数、点二列相关系数和等级相关系数等三种样本相关系数,都是同一概念和公式的不同应用和表现.所述的三种相关系数的使用条件要从它们的原始来源中来理解和要求.  相似文献   

Experimental Study of Structure Shock Vibration in Soil Caused by Explosion of Conventional Weapons     

FENG Jinji  XIE Qingliang  ZHAO Dayong 《天津大学学报(英文版)》2006,12(Z1)

When hitting underground structures directly or exploding in rock-soil media near underground structures, the conventional weapons with large charge weight will make underground structures be subjected to strong shock vibration and cause personal casualty and damage of precision electronic equipments. The shock vibration has become one of the cardinal killing means of weapons. However, the existing methods of predicting structure shock vibration are limited evidently. In this paper the coupling coefficient of acceleration in clayey soil is obtained firstly. Subsequently based on repeated experiments of chemical explosion, after dimension analysis and by using method of multivariate stepwise regression, the calculation formulae of shock vibration acceleration for the underground structure are obtained finally. The formulae consider top and side explosion respectively, taking into account the effects of penetration depth, charge weight, distance to explosion center, rock-soil media, size of structure and buried depth. They are easy to use with high practicability and degree of confidence, and can provide credible evidence for prediction of shock vibration and vibration isolating design of underground structure.  相似文献