有旋流

The stream function equations are derived, based on the fluid equations of motion on a revolving S 1 stream surface in centrifugal pump impeller, for indirect boundary element method. The equations are suitable ideal and incompressible fluid flow with rotation or non rotation in absolute coordinate system.

根据离心泵叶轮S1流面的流体运动方程，推导了间接边界元法所需的流函数方程，它适用于不可压理想流体的绝对流动有旋或无旋流动。

First, the typhoon flow field is decomposed into two parts: the maximum asymmetric vortex and irrotational environmental flow field. Then the maximum asymmetric vortex is also decomposed into two parts: the maximum symmetric vortex and β-gyres. Finally, typhoon Pearl(2006) is simulated by WRF model(weather research and forcasting model), and flow fields at various times at 500hPa...

首先，将台风的流场分解成最大的、不对称的涡旋流场和无旋流场；然后将不对称的涡旋流场分解成最大的对称涡旋和不对称的β涡旋对；最后，利用WRF(weather research and forcasting)模式(V2.1.2)模拟了200601号珍珠台风，并对各时次的500hPa风场用该方法进行分解，结果表明：该方法对台风的运动机理研究和实际的台风路径预测提供了有价值的信息。

At the same time, recirculation bubbles aggrandized. This paper advanced the measure of combustion of underbred coal that based on the characte ristic of the low volatile ma...

在此基础上针对低挥发分煤挥发分少，着火点高，燃烬时间长的特点，提出应同时提高旋流风速度和减小旋流角的低挥发分煤燃烧技术，对于工业上合理选择燃烧器的工作参数及燃用低挥发分煤有重要的指导意义。

Studied the solid particles cyclone separation under structural parameters and operating parameters of different hydrocyclone, the results showed that major factor influence split ratio is in the ratio of entrance to exit pressure of hydrocyclone. Exit pressure has a certain influence on the split ratio, the various of the diameter and cone angle of hydrocyclone (in the ratio of entrance to exit pressure is constant) have no influence on split ratio; With diameter and cone angle increase, the separation granularity gradually increasing and recovery ratio decreasing; With entrance pressure increase, the separation granularity of hydrocyclone decrease, the split ratio of underset will increase slowly; With the diameter of overflow pipe increase, the separation granularity of hydrocyclone increasing and recovery ratio decreasing; With the diameter of underset pipe increasing, the separation granularity of hydrocyclone decreasing and recovery ratio increasing.

在不同的水力旋流器结构参数和操作参数下，对固体颗粒的旋流分离进行了分析研究，结果表明：旋流器的排出口比是影响分流比的主要因素，进口压力对分流比有一定影响，水力旋流器的直径变化和锥段角度变化对分流比基本上没有影响；随着直径、锥段角度的增大，分离粒度逐渐增大，回收率降低；随着入口压力增大，水力旋流器的分离粒度变小，底流的分流比会缓慢增加；随着溢流管管径的增加，分离粒度增大，分流比明显减小，回收率降低；随着底流管直径的增加，分离粒度减小，分级效果明显下降，回收率会增加。

A modified homogeneous flow model was introduced to calculate the flow field in RH degasser,thus getting rid of some earlier methods that are unavailable to be generalized,such as reducing the computation region or presetting the distribution of gas volume fraction.

分别对有、无旋转磁场作用时的RH系统进行了模拟计算。模拟结果表明：流场和脱碳过程与现有文献中实验结果相符合；当旋转磁场作用后，磁感应强度为0.04 T时，初期脱碳速度比无旋流作用时增加了约15%，这是由于旋流增加了系统的搅拌能，提高了脱碳反应速率。

Based on an analysis of distribution pattern of hydrocyclone"s axial velocity, by changing the inlet flow rate Qi and split ratio Fand making an investigation in the effect of Qi and F on axial velocity field, the factors causing the forming of short-cut circuit and circulating flow are found. It is considered that the short-cut circuit and circulating flow are produced by the structure of the hydrocyclone, and can"t be eliminated completely, though they interfere the flow field inside a hydrocyclone and affect the separation accuracy. Test results show that, by increasing Qi and F and controlling them in a certain range, the separation efficiency of the hydrocyclone can be improved.

在研究旋流器轴向速度分布规律的基础上，分析了短路流与循环流的形成原因，试验研究了改变操作参数，即改变入口流量Qi与分流比F对轴向速度场的影响认为短路流与循环流是由旋流器结构决定的，很难完全消除，它们干扰了旋流腔和大锥段的流场，在一定程度上也影响了分离精度试验结果表明，加大入口流量Qi与分流比F，并将其控制在一定范围内，便可提高分离效率这项研究对水力旋流器分离机理的认识与实际应用均有重要意义

Results show this new-inlet hydrocyclone has original sides on liquid spin-making and stabilize its flow field. Moreover this gradual contraction inlet may translate some pressure energy of liquid into kinetic energy and increase circumrotate speed. These play active actions on improving separation efficiency. Moreover, the uniflow hydrocyclone has the traits of big capacity, low pressure drop and a little low separation efficiency in contrast to the returned flow hydrocyclone. This hydrocyclone system has the higher separation property in contrast to the single-level hydrocyclone.

实验结果表明：这种新型入口结构水力旋流器在流体的导旋方面具有独到之处，能很好的形成稳定的流场；同时这种渐缩式入口方式，可将来液的一部分压能逐渐转化为动能，提高了旋流速度，对提高分离效率起到积极作用；采用新型入口的直流式水力旋流器比返流式水力旋流器压降低，处理量大且分离效率略低；组成返流式水力旋流器串联系统相对于单级水力旋流器具有更高的分离性能。

Experimental studies of turbulent combustion were conducted in a test facility for swirl combustor with staged air injection.

特 别是当旋流与其它燃烧方式，如分级燃烧等方式结合时，需要探讨在分级进风或有多股射流相互作用的条件下，旋流对NO二排放的控制作用。

What's more,the three-dimensional velocity,density and pressure distribution of the flow field in the gravity-fed 3-product H.M.cyclone were studied as well,some conclusions were summarized.

通过对无压给料三产品重介质旋流器流场的三维速度、压强、密度和空气柱的数值模拟研究，对无压给料三产品重介质旋流器内的流场有了更深入和细致的了解，得到了几点有意义的结论。

In this paper,mathematical expressions of some swirl characteristic s of typical level hollow swirling flow in inner dissipation discharge tunnel with inlet shaft have been put forward under velocity distribution supposition.

试验观测结果表明，相对于起始断面的各种旋流特性具有明显的分段性质和沿程衰减的特性；下游水位对空腔环流的旋流特性有显著的影响。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。