流阻

The simulation results show that the rod baffles placed vertically and horizontally in the unit duct continuously shear and comminute the streamlines of the flow when the fluid crosses over the rod-baffles, change the fluid flow directions, and result in the disruption of the continuity and stability of the fluid. The disturbing flow can promote the fluid turbulent intensity and effectively enhance the heat transfer.

结果表明，纵横交错布置的折流杆在单元流道中不断分割和剪切流道内流体，其扰流作用促进了流体湍流，减薄了液体边界层，减小了对流换热热阻，因而有效地提高了流体的对流换热强度。

The forward section of the blocker door is attached to the sleeve with two bolts, the blocker door drag link attaches the blocker door to the inner duct.

当外壳移动后部，阻流门转到阻流位，由于外壳转动，并且门连接在内部管道。

Numerous impermeable underground structures exist in urban seepage field. Since the corner of the structure is singular point and the dimension of the structure is negligibly small compared with the whole urban seepage field, it is difficult to model seepage field in urban area with existing methods.

城区渗流场中地下阻水结构物众多，由于结构物角点为奇异点，而且结构物的尺寸跟整个渗流场的尺寸相比起来非常小，这导致现有的计算方法难以对城区渗流场进行模拟分析。

By analyzing phases velocity profiles and resistance lawv resulted from gas slug in the pipe center,the condition that the secondary flow occurs,phases velocity profiles,formula of drag reduction and a curve of drag reduction have been obtained.

以流体力学基本方程为基础，通过对气体在管道中心形成段塞流的相速度分布和阻力规律分析，得到了二次流发生的条件、各相流体速度分布、减阻率关系式以及减阻率曲线。

The change of condenser steam flow field causes the changes of its heat transfer coefficient and the vapor lock,with the analysis on the change of the tube bundle arrangement with the alteration of the steam flow field,proposed the change scope of the correction factor of the arrangement of condenser tube bundle with the alteration of the condenser steam flow field.

凝汽器蒸汽流场的变化使其传热系数和汽阻发生变化，传热系数和汽阻的改变使凝汽器管束布置修正系数随着负荷变化，分析了管束布置修正系数随蒸汽流场的变化而变化，提出了管束布置修正系数随蒸汽流场变化的范围。

In order to do research on pipe flow and pump characteristics of polymer flooding and water flooding rod-pumped well in especially high water-cut stage, rheometric test aimed at production stream from polymer flooding and water flooding rod-pumped well in especially high water-cut stage has been made, and the characteristic of production stream in especially high water-cut stage is confirmed as Newtonian fluid. Experiments using different mediums about pipe flow and pump characteristics is made. Frictional resistance and coefficient of friction resistance of annulus fluid between sucker rod and the pipe flow is calculated under different working conditions. Frictional resistance between plunger and pump barrel under different parameters is calculated based on related theory of pump characteristic and the strained analytical model of oil-well pump. Besides, using the theory of slit flow and hydraulic -clamping pressure, the frictional resistance is calculated, and the error between the result and measured value is no more than 13%.

为研究特高含水期水驱及聚驱抽油机井管流特性与泵特性，本文针对特高含水期水驱及聚驱井采出液进行了流变性试验，确定了特高含水期油井采出液的性质属牛顿流体；利用不同介质，进行管流特性与泵特性试验，得到了不同工况下杆、管环空流的摩擦阻力和摩阻系数；根据泵特性相关理论和抽油泵受力分析模型，计算了不同参数下柱塞与泵筒间的摩擦阻力，并利用缝隙流与液压卡紧力理论对柱塞与泵筒间的摩擦阻力进行了计算，计算结果与实测值误差在13%以内。

As a preliminary theoretical exploration, a limited series of stream function was employed to study the characteristics of the reattachment boundary layer. The tentative analysis showed that the reattachment boundary layer of the circular cylinder, so long as it began at the effective reattachment region discussed above, would be developing to its reseparated point downstream the cross section of the cylinder, which essentially gave the new idea RCDR a theoretical cycle.

本文提出的&再附—减阻&机制可表述为：柱面上扰流元件后向锐缘处诱发的流动分离，既改变了柱面压强分布格局，又破坏了柱面附近的流动状态；若扰流元件锐缘后方流动在圆柱壁面上再附，形成再附边界层，再附边界层将沿流向发展，直至越过柱面最大迎流截面之后，才从圆柱面上分离，致使分离流的尾涡区变窄，绕流阻力降低。

The results of pressure drop characteristics experiments indicate that the new type cyclone tube's pressure drop reduction extent is directly related to the sticks'number, length and the radial position of the straight stick pressure drop reduction frame; is directly related to the length, width and number of grid pressure drop reduction frame installed under the split flow core tube.

安装在排气芯管内的直杆减阻框、栅格减阻框使旋风管的压降有不同程度的降低，减阻幅度与直杆减阻框杆数和长度成正比；与直杆的径向位置大小成反比；与安装位置、绕流截面形状有一定的关系；并与栅格减阻框的长度、宽度和片数成反比。

Using conformal mapping, the longitudinal protrusion height and the lateral protrusion height on the V-grooved surfaces are given, on this basis, some drag reducing features in parallel-flow, cross-flow and enlarge- flow are presented and analyzed; In addition, drag reducing features with blade-shaped grooves and U-shaped grooves are discussed, consequently, the riblets designing criterions are suggested which will reduce the drag and noise most effectively underwater.

3利用保角变换方法求出V—型条纹的纵向和横向突出高度，在此基础上得出纵向流、横向流和带角度流动时的降阻特性，并分析结果；而且分析了叶片型条纹和U—型条纹表面上的降阻情况，提出水下具有最佳降阻效果的条纹表面设计准则。

Experimental results also showed that the size and shape of the stick cross-section made a prominent effect on the strength and shape of flow wake.

对比实验的结果表明不同结构型式的减阻杆后绕流尾涡区的流动分布不同，其中减阻杆的迎风宽度及形状对减阻杆后绕流尾涡区的流动分布有明显影响。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐