深层高温高压气井临界产量计算模型

基于热膨胀效应和环空体积变化效应这两种环空带压机理,结合气井生产过程中井筒温度-压力分布计算方法,考虑油层套管和油管的许可压力值,建立一个深层高温高压气井临界产量计算模型.运用迭代法求解模型,编制相关程序.结果表明:环空压力与主要受温度的影响,气井产量越高,井口温度越高,环空压力越大,油套管安全系数越低,因此需要考虑管柱安全性确定临界流量.利用新疆某深层高温高压气井的实际数据进行实例计算,结果可为深层高温高压气井的合理配产提供依据.     

强流相对论环形电子束自调制振荡研究

 主要研究了强流相对论环形电子束在等位谐振腔内的非线性自调制振荡，用小信号理论分析了电子起振的条件，得出了电子起振的扰动频率。基于该理论分析，又提出了一种不外加磁场的新型高功率微波器件，该器件主要由一个圆柱谐振腔和一个同轴波导输出腔构成。用2.5维MAGIC粒子模拟软件对该非线性过程进行数值模拟，分析了输入电压、电流对输出微波功率的影响。模拟结果表明这种结构中确实存在非线性不稳定性，自调制的扰动频率则由电子束的初始能量、电荷密度和电子束的半径以及谐振腔的空间结构给定。利用谐振腔长为4.7 cm、二极管电压为2.8 MV、电流为20 kA的电子束，可以得到频率为4.29 GHz、功率为6 GW的微波输出，束-波转换效率约为11%。     

Biofilms as bio-indicator for polluted waters?

The aim of this work was to investigate the heavy metal accumulation by natural biofilms living in the catchment area of the Tisza river in Hungary, as well as in biofilms cultivated in vitro. Laboratory tests have demonstrated that metals can be adsorbed on biofilms, depending on their concentration and on the availability of free sorptive places. Biofilms were cultivated in vitro in natural freshwater from the Saale river, Germany. After reaching the plateau phase, Cu was added to reach a concentration of 100 µg/L. An increase of its mass fraction in the biofilm was observed, which caused the decrease of the concentration in the water phase. Unfortunately, the reactor wall was also found to act as adsorbent for Cu. More detailed results of our in vitro experiments will be published in a forthcoming paper. Naturally grown biofilm samples from exposed as well as background places at the Hungarian rivers Szamos and Tisza were collected in 2000 and 2002 after the cyanide spill, and analysed using total reflection X-ray fluorescence analysis (TXRF). Metal mass fraction differences as high as two orders of magnitude were found between polluted and unpolluted (background) sampling points. Extremely high concentration values, e.g. 5600 µg/g Zn in biofilm, were found at highly polluted sampling points. This means an enrichment factor of ca. 10,000 compared to the water phase.     

Entrance flow in eccentric annular ducts

A control-volume-based solution of the complete set of Navier-Stokes equations for the laminar, three-dimensional developing flow in straight, eccentric, cylindrical annular ducts is described. Numerical results for velocity and pressure development, pressure defect and entrance lengths are presented for a wide range of duct parameters, i.e. relative eccentricity ? and radius ratio γ. The present results match very well with earlier numerical solutions for the limiting cases of developing flow in concentric ducts and fully developed flow in eccentric ducts. Comparison with earlier approximate results for developing flow in eccentric ducts indicates that the approximate model predicts the velocity and pressure development with an error of about 10%. However, the development length predicted by the approximate model is grossly in error. The pressure defect and development length in eccentric ducts are very high compared with their counterparts in concentric ducts. The pressure defect, development length and maximum velocity increase with the radius ratio for eccentric ducts, while the reverse is true for concentric ducts. Also, the apparent friction factor decreases as the eccentricity increases.     

在大径高比环形透平叶栅中叶片弯曲对二次流影响的实验研究

1实验装置与模型叶片倾斜和弯曲的概念是针对小径高比环形叶栅提出来的。在短叶片环形叶栅中采用弯曲叶片的效果如何，本文作者对此进行了研究。同时也讨论了边界条件对静叶出口流场的影响。本实验是在哈尔滨工业大学的环形叶栅风洞上进行的。实验用的三套叶栅为：（1）常规径向叶片；（2）两端倾斜角为15”的弯曲叶片；（3）两端倾斜角为22“的弯曲叶片。其特性参数为：径高比为10．553，弦长b—31．Zmm，叶型安装角风一45．3“，进气角。0—90”，几何平均出气角。1—15”。出口马赫数M＝0．26左右。（1）（）（3）均为等截面叶栅，（2）…     

Hopf bifurcation in annular liquid jets with mass transfer

A numerical study of Hopf bifuractions in annular liquid jets with mass transfer is presented. The study is based on the asymptotic equations which govern the dynamics of inviscid, incompressible, thin, annular liquid jets and on equilibrium conditions for mass transfer at the jet's inner and outer interfaces. It is shown that the amplitude of the time-periodic motion that results from the Hopf bifurcation increases whereas its frequency decreases as the solubility ratio is increased.     

有机环形光纤中二次谐波产生的研究

本文从经典电磁理论出发，分析了有机环形光纤中二次谐波产生（ＳＨＧ）的转换效率，着重讨论利用环形光纤中模式的色散特性实现相位匹配等问题。报道了采用ＬＢ膜方法，制成半花菁环形光纤，由高灵敏度光检测计测出在强泵光（１．０６μｍ，ＹＡＧ激光）作用下该光纤中的二次谐波产生的实验结果。     

环型孔成像系统在部份相干光照明下对两个点物之分辨

在部份相干光照明下的环型孔成像系统，对两个点物之分辨，按照Ｓｐａｒｒｏｗ判据作了分析和研究，将两点之分辨作为两个参数的函数进行讨论－其一为照明光的空间相干条件，其二为环型孔的中心阻挡，在与圆型孔和完全相干照明的情况比较之后指出，环型孔和部份相干照明情况具有更高的两个点物的分辨本领。     

重力水平对热毛细-浮力对流耗散结构的影响

为了了解重力水平对环形液池内热毛细-浮力对流耗散结构的影响,利用有限容积法进行了非稳态三维数值模拟,环形液池外壁被加热,内壁被冷却,流体为0．65cSt硅油,其Pr数为6．7。结果表明,在微重力条件下,流动为三维振荡流动;当重力水平增加到0．1go时,流动结构转化为沿周向运动的一组滚胞,其轴线与温度梯度方向一致;当重力...     

热声交变流动中浮力效应理论分析

热声交变流动是热声热机的工作基础,研究交变流动机理有助于人们认识热声热机的工作过程。鉴于前人的理论分析一般没有考虑浮力效应的影响,本文从流体热动力学的角度研究了浮力对流与热声交变流动的耦合规律。基于线性理论方法,给出了考虑浮力项和热对流Rayleigh数的热声线性理论模型,分析了浮力效应对平行交变流动的影响,发现热对流...